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Influence of swimming activity on sodium and water balance in the rainbow trout (Salmo gairdneri). Wood, Christopher Michael 1971

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THE  INFLUENCE OF SWIMMING A C T I V I T Y ON AND WATER  BALANCE IN THE RAINBOW  SODIUM  TROUT  (SALMO GAIRDNERI)  by CHRIS M. WOOD B.Sc,  University  of British  Columbia,  1968  A T H E S I S SUBMITTED IN PARTIAL FULFILMENT OF THE  REQUIREMENTS MASTER  in  FOR THE DEGREE OF  OF SCIENCE  t h e Department of Zoology  We a c c e p t t h i s required  THE  thesis  as conforming  to the  standard  UNIVERSITY OF B R I T I S H January,  19 71  COLUMBIA  In  presenting  this  an a d v a n c e d  degree  the L i b r a r y  shall  I  f u r t h e r agree  for  scholarly  by h i s of  this  written  thesis at  the U n i v e r s i t y  make  it  tt  financial gain  of  Zoology  The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, C a n a d a  January  Columbia  27th, 1971  the  requirements  B r i t i s h Columbia, for  I agree  r e f e r e n c e and copying of  this  shall  that  not  copying  or  for  that  study. thesis  by t h e Head o f my D e p a r t m e n t  is understood  permission.  Department  of  for extensive  p u r p o s e s may be g r a n t e d  for  fulfiIment of  freely available  that permission  representatives, thesis  in p a r t i a l  or  publication  be a l l o w e d w i t h o u t my  ABSTRACT The  permeability  o f the t e l e o s t b r a n c h i a l exchanger to oxygen  carbon d i o x i d e i s apparently p e r f u s i o n of t h i n walled ary lamellae. may  enhanced d u r i n g  e x e r c i s e by i n c r e a s e d  h i g h s u r f a c e a r e a pathways i n the g i l l s ,  However t h i s augmented p e r m e a b i l i t y  and  blood the  second-  t o r e s p i r a t o r y gases  w e l l be accompanied by u n f a v o u r a b l e e l e v a t i o n s o f water and e l e c t r o l y t e  f l u x e s between i n t e r n a l and s t u d y was  e x t e r n a l environments.  The  o b j e c t o f the  present  t o i n v e s t i g a t e the e f f e c t o f imposed swimming a c t i v i t y on sodium  and  water r e g u l a t i o n i n the f r e s h water adapted rainbow t r o u t , Salmo g a i r d n e r i . Radiotracer  methods were used to measure u n i d i r e c t i o n a l components  o f b r a n c h i a l sodium exchange i n f i s h a t r e s t , d u r i n g one d u r i n g one during  hour o f r e c o v e r y  extended e x e r c i s e  from t h i s e x e r c i s e c o n d i t i o n .  and  Sodium f l u x e s  (up to 8 h o u r s ) were q u a n t i f i e d by s i m i l a r t e c h n i q u e s  i n a second s e r i e s o f experiments. f l u x r a t e data.at  hour o f swimming,  These l o n g term swimming t r i a l s  a wide range o f e x t e r n a l sodium c o n c e n t r a t i o n s ;  provided  a n a l y s i s of  t h e s e r e s u l t s h e l p e d t o e l u c i d a t e the r e l a t i v e importance o f d i f f e r e n t mechanisms o f b r a n c h i a l sodium t r a n s f e r i n the rainbow t r o u t . m i n a t i o n s o f u r i n e f l o w s and  permitted  an a n a l y s i s o f water r e g u l -  d i r e c t measurement o f r e n a l e l e c t r o l y t e l o s s e s d u r i n g The  deter-  body weight changes under c o n t r o l l e d e x e r c i s e  c o n d i t i o n s i n a swimming r e s p i r o m e t e r a t i o n and  Finally,  activity.  sodium uptake system o f Salmo g a i r d n e r i i n the p r e s e n t  study  an e x t r e m e l y h i g h a f f i n i t y f o r the i o n ( h a l f s a t u r a t i o n c o n c e n t r a t i o n . 0 1 4 mEq  Na /L).  had  =  Both u n i d i r e c t i o n a l f l u x r a t e s a t the g i l l s o f rainbow  +  t r o u t were g r e a t e r  than those r e p o r t e d  f o r any  other  f r e s h water t e l e o s t o f  comparable s i z e , d e s p i t e e x t e r n a l sodium l e v e l s much lower t h a n those used other workers.  The  t h e t r o u t g i l l was  p r e s e n c e o f an exchange d i f f u s i o n mechanism f o r sodium i n  s t r o n g l y i n d i c a t e d but  p o r t o f the e l e c t r o l y t e was  r  by  not  confirmed..  Branchial  trans-  t e n t a t i v e l y d i v i d e d i n t o a l a r g e exchange d i f f -  u s i o n component, and  s m a l l e r a c t i v e i n f l u x and  simple  diffusional  efflux  elements. I n r e s t i n g animals, equal.  b r a n c h i a l sodium i n f l u x and  However s h o r t term a c t i v i t y  ( 1 hour) was  i n c r e a s e i n e f f l u x o f sodium a c r o s s the g i l l s , T h i s e f f e c t was swimming.  As  quickly reversed  70%  associated with a  c r e a t i n g a net sodium  deficit.  ( w i t h i n 5 minutes) upon the t e r m i n a t i o n  i n f l u x d i d not v a r y ,  changes i n t h e s i m p l e  e f f l u x r a t e s were  these phenomena p r o b a b l y  d i f f u s i o n a l e f f l u x component without  c a r r i e r m e d i a t e d sodium t r a n s p o r t mechanisms.  represented  disturbance  B r a n c h i a l water e n t r y  a l s o g r e a t l y e l e v a t e d a t the s t a r t o f e x e r c i s e .  of  of was  These r e s u l t s were i n t e r -  p r e t e d i n terms o f augmented p a s s i v e movements o f sodium and water caused by i n c r e a s e d b l o o d p e r f u s i o n o f t h e h i g h p e r m e a b i l i t y r e s p i r a t o r y pathways o f the g i l l s The  d u r i n g swimming. extended e x e r c i s e experiments r e v e a l e d t h a t the h i g h sodium  e f f l u x r a t e o f the f i r s t and had r e t u r n e d  hour o f a c t i v i t y d i m i n i s h e d , d u r i n g the second hour,  to r e s t i n g l e v e l s by the t h i r d and  swimming; i n f l u x a g a i n remained unchanged. water e n t r y was (15 -  60  a l s o apparently  m i n u t e s a f t e r the onset  p e r m e a b i l i t y t o water and  The  subsequent hours o f  i n i t i a l high branchial  c u r t a i l e d , but o v e r a s h o r t e r time i n t e r v a l of a c t i v i t y ) .  These r e d u c t i o n s i n b r a n c h i a l  sodium were i n t e r p r e t e d as compensations to  de-  c r e a s e the o s m o t i c p e n a l t y o f e x e r c i s e . As water e n t r y t h r o u g h the g i l l s  d e c l i n e d , u r i n a r y output  mented; an e l e v a t e d r e n a l sodium l o s s accompanied the d i u r e s i s .  was  However  sodium e f f l u x t h r o u g h the k i d n e y remained s m a l l r e l a t i v e to t h e e f f l u x t h i s e l e c t r o l y t e through the g i l l s . e n t r y and r e n a l e x c r e t i o n o f water was r a t e than d u r i n g r e s t . had  Before  aug-  of  A f i n a l e q u i l i b r i u m between b r a n c h i a l a t t a i n e d , but a t a h i g h e r  t h i s balance,  turnover  however, u r i n a r y e l i m i n a t i o n  over-compensated f o r the i n i t i a l water g a i n .  The  r e s u l t i n g net water  iii  d e f i c i t r e d u c e d the b l o o d space below r e s t i n g volume, c a u s i n g a s l i g h t i n crease  i n plasma sodium l e v e l s d e s p i t e enhanced b r a n c h i a l and  o f the i o n .  An i s c h e m i a  o f " w h i t e " muscle may  renal losses  a l s o have accompanied  the  haemoconcentration. I n summary, the r e s u l t s i n d i c a t e d t h a t an i n i t i a l d i s t u r b a n c e was the g i l l s and  a s s o c i a t e d with a r e d i s t r i b u t i o n o f blood flow  d u r i n g swimming, but t h a t b o t h b r a n c h i a l h y d r o m i n e r a l  the f u n c t i o n i n g o f o t h e r systems c o u l d be m o d i f i e d by  necessary  osmoregulatory  to maintain  sodium and water b a l a n c e  through permeability  compensations  d u r i n g extended e x e r c i s e .  iv  T A B L E OF CONTENTS Page ABSTRACT  •  i  TABLE OF CONTENTS  iv  L I S T OF TABLES  '  v i  L I S T OF FIGURES  viii  ACKNOWLEDGEMENTS GENERAL  x i 1  INTRODUCTION  SECTION I  - THE E F F E C T OF E X E R C I S E SODIUM BALANCE.  INTRODUCTION  (ONE HOUR) ON 14  I  18  METHODS I  — -  1. E x p e r i m e n t a l /inimals 2. O p e r a t i n g P r o c e d u r e s a n d C a n n u l a t i o n s 3. E x p e r i m e n t a l S y s t e m 4. A n a l y t i c a l P r o c e d u r e s 5. C a l c u l a t i o n s 6. P r e s e n t a t i o n o f D a t a -  43  RESULTS AND DISCUSSION I A.  The E f f e c t o f C h a s i n g on V e n t i l a t o r y and C a r d i o v a s c u l a r Parameters B. T h e E f f e c t o f E x e r c i s e o n B r a n c h i a l Sodium f l u x e s C. T h e E f f e c t o f E x e r c i s e o n S o d i u m a n d Water D i s t r i b u t i o n SUMMARY  SECTION I I - THE E F F E C T OF EXTENDED E X E R C I S E ON BALANCE.  54 74  SODIUM 97  II  101  METHODS I I 1. E x p e r i m e n t a l Animals 2. O p e r a t i n g P r o c e d u r e s a n d C a n n u l a t i o n s 3. E x p e r i m e n t a l S y s t e m 4. A n a l y t i c a l P r o c e d u r e s 5. C a l c u l a t i o n s  Sodium F l u x R a t e s Exercise  101 101 101 106 106 110  RESULTS AND DISCUSSION I I A.  43  95  I  INTRODUCTION  18 19 -2"4 ~ 33 36 40  during  Extended 110  V Page B. T h e C o n c e n t r a t i o n D e p e n d e n c e o f B r a n c h i a l Sodium F l u x e s SUMMARY SECTION  I I  129 143  I I I - THE E F F E C T OF E X E R C I S E ON WATER BALANCE INTRODUCTION I I I  146  METHODS I I I  149  I . U r i n e Flow v e r s u s Experiments  II.  Oxygen C o n s u m p t i o n 149  1. O p e r a t i n g P r o c e d u r e a n d C a n n u l a t i o n s 2. E x p e r i m e n t a l S y s t e m 3. A n a l y t i c a l P r o c e d u r e s W e i g h t C h a n g e v e r s u s Swimming D u r a t i o n  Experiments RESULTS  157  AND DISCUSSION  III  159  SUMMARY I I I GENERAL DISCUSSION LITERATURE  CITED  149 150 154  186 —  —  '  -  —188 203  VI  LIST I.  II.  III.  IV.  V.  VI.  VII.  OF  TABLES  Page  V e n t i l a t o r y and c a r d i o v a s c u l a r responses o f trout during r e s t i n g , a c t i v e , and r e c o v e r y experiments, e x p r e s s e d i n t e r m s o f mean "% r o u t i n e " v a l u e s .  44  Physical dimensions o f trout mental groups o f Section I.  56  i n the three  experi-  Average b r a n c h i a l sodium f l u x r a t e s over t h e experimental periods o f Section I i n resting, active, and r e c o v e r y g r o u p s o f t r o u t .  58  Summary o f b r a n c h i a l u n i d i r e c t i o n a l fresh water t e l e o s t s .  71  flux  rates  i n  E f f e c t i v e b l o o d p o o l s c a l c u l a t e d from h e m a t o c r i t changes i n r e s t i n g , a c t i v e , and r e c o v e r y groups of. trout.  77  T e r m i n a l c o n c e n t r a t i o n s o f sodium and water i n plasma and t i s s u e s o f r e s t i n g , a c t i v e , and recovery groups o f trout.  82  Measures o f i n t e r n a l d i s t r i b u t i o n o f i n f l u x e d sodium i n r e s t i n g , a c t i v e , and r e c o v e r y groups trout.  of 92  VIII.  B a l a n c e s h e e t o f f a t e o f i n f l u x e c ^ s o d i u m a t 60 m i n u t e s a f t e r i n t r o d u c t i o n o f Na i n resting,active and r e c o v e r y g r o u p s o f t r o u t . 92  IX.  Physical dimensions o f trout ment g r o u p s o f S e c t i o n I I .  X.  XI.  XII.  XIII.  i n the three  treatI l l  Urinary s o d i u m e f f l u x r a t e s o f shams e s t i m a t e d b y s u b t r a c t i o n o f t h e mean b r a n c h i a l e f f l u x r a t e s o f t h e u r i n a r y b l o c k a g e g r o u p f r o m t h e mean v/hole a n i m a l e f f l u x r a t e s o f t h e shams.  121  Comparison o f c a l c u l a t e d r e n a l sodium e f f l u x r a t e s during swimming i n shams w i t h r e p o r t e d direct m e a s u r e m e n t s o f maximum u r i n a r y s o d i u m d i s c h a r g e i n Salmo g a i r d n e r i .  122  T e r m i n a l measurements o f i n t e r n a l sodium and water l e v e l s , r a d i o s o d i u m spaces, h e m a t o c r i t s , and weight changes over the experimental p e r i o d i n normal, sham, a n d u r i n a r y b l o c k a g e t r e a t m e n t g r o u p s .  124  Summary o f maximum s o d i u m i n f l u x r a t e s (Fi(max)) and h a l f s a t u r a t i o n c o n c e n t r a t i o n s (Ks) f o r sodium uptake systems i n a v a r i e t y o f animals.  133  v i i Page XIV.  XV.  XVI.  XVII.  XVIII.  C a l c u l a t e d c o n t r i b u t i o n o f d i f f e r e n t mechanisms to t o t a l b r a n c h i a l sodium exchange i n u r i n a r y blockage t r o u t assuming a l l i n f l u x - e f f l u x linkage t o be c a u s e d by exchange d i f f u s i o n .  140  Physical III.  164  dimensions of  the  trout  used  i n  Section  Resting state u r i n e f l o w s , oxygen u p t a k e s , and v e n t i l a t i o n rates f o r 5 t r o u t i n metabolism boxes.  164  T a i l b e a t f r e q u e n c i e s , v e n t i l a t i o n r a t e s , and oxygen consumptions during each hour o f the imposed swimming r e g i m e o f S e c t i o n I I I .  166  U r i n e flows and c o n c e n t r a t i o n s of e a c h h o u r o f t h e imposed swimming Section I I I .  180  !  4 cations regime o f  during  viii  L I S T OF  FIGURES Facing  1  2  3 4  5  6 _ 7  8 9  10  11 12 13  14  15  A d r a w i n g o f t h e l o c a t i o n and s i z e o f t h e b u c c a l and d o r s a l a o r t i c c a n n u l a e u s e d i n Section I. Drawings o f the f i x a t i o n o f the A drawing of Section I.  the  20  c o n s t r u c t i o n , p l a c e m e n t , and u r i n a r y c a t h e t e r used i n S e c t i o n experimental  system  used  Page  I.  22  in 26  T y p i c a l p r e s s u r e r e c o r d i n g s from the d o r s a l and b u c c a l c a v i t y o f a r a i n b o w t r o u t d u r i n g c h a s i n g , and r e c o v e r y .  aorta rest,  Changes i n h e a r t r a t e under r e s t i n g , a c t i v e , recovery conditions of Section I.  45 and 46  C h a n g e s i n a r e a mean d o r s a l a o r t i c b l o o d pressure u n d e r r e s t i n g , a c t i v e , and r e c o v e r y c o n d i t i o n s _of S e c t i o n I . - _ _ -  49  Changes i n v e n t i l a t i o n r a t e under r e s t i n g , a c t i v e , and r e c o v e r y c o n d i t i o n s o f S e c t i o n I .  51  Changes i n b u c c a l p r e s s u r e a m p l i t u d e under r e s t i n g , a c t i v e , and r e c o v e r y c o n d i t i o n s o f S e c t i o n I .  52  B r a n c h i a l sodium f l u x r a t e s over c o n s e c u t i v e i n t e r v a l s o f the experimental p e r i o d s i n r e s t i n g , a c t i v e , and r e c o v e r y g r o u p s o f t r o u t .  57  B r a n c h i a l sodium net f l u x r a t e s over i n t e r v a l s o f the experimental p e r i o d recovery treatment group.  61  consecutive f o r the  Mean u r i n e f l o w r a t e s i n r e s t i n g , a c t i v e , recovery groups of t r o u t .  and  Changes i n h e m a t o c r i t i n r e s t i n g , a c t i v e , recovery groups of t r o u t .  and  73  Changes i n plasma sodium c o n c e n t r a t i o n s o v e r e x p e r i m e n t a l p e r i o d s i n r e s t i n g , a c t i v e , and recovery groups o f t r o u t . The e v o l u t i o n o f t h e r a d i o s o d i u m i n r e s t i n g , a c t i v e , and r e c o v e r y  75 the  space with time groups of t r o u t .  The e v o l u t i o n w i t h t i m e o f t h e c o n c e n t r a t i o n i n plasma o f sodium t r a n s p o r t e d from the e x t e r n a l env i r o n m e n t i n r e s t i n g , a c t i v e , and r e c o v e r y g r o u p s of trout.  80  85  86  -  ix Facing 16  17  18  19  20  21  22  23  24  25  26  A drawing long term  o f the r e v o l v i n g chamber u s e d f o r exercise of trout i n Section II.  Results of a illustrating  t y p i c a l experiment the method o f data  29  103  of Section II analysis applied.  112  R e s u l t s o f two e x p e r i m e n t s o f S e c t i o n I I demonstrating: (a) f l u x r a t e d a t a from a t r o u t w h i c h swam c o n t i n u o u s l y f o r 8 h o u r s , ( b ) f l u x r a t e d a t a f r o m a t r o u t w h i c h was i n a c t i v e f o r most o f the experimental period.  114  Sodium f l u x r a t e s , measured at e x t e r n a l concent r a t i o n s g r e a t e r t h a n 0.8 ug/ml, under different e x e r c i s e c o n d i t i o n s i n n o r m a l , sham, and urinary blockage trout.  116  The r e l a t i o n s h i p between r a t e and e x t e r n a l sodium  130  b r a n c h i a l sodium concentration.  influx  Comparison of the c o n c e n t r a t i o n dependence o f b r a n c h i a l sodium i n f l u x i n the rainbow t r o u t w i t h that reported i n four_other f r e s h water f i s h . _ The - r e l a t i o n s h i p between b r a n c h i a l s o d i u m r a t e and e x t e r n a l sodium c o n c e n t r a t i o n . A diagram o f the Section III. The d e c l i n e anaesthesia  swimming  respirometer  efflux  used  138 in  i n u r i n e f l o w w i t h t i m e a f t e r MS and c a t h e t e r i z a t i o n i n 5 t r o u t .  The d e c l i n e i n v e n t i l a t i o n r a t e s u m p t i o n w i t h t i m e a f t e r MS 222 catheterization in 3 trout. Simultaneous changes i n u r i n e uptakes during the continuous regime of Section I I I .  135^  152 222 162  and o x y g e n c o n anaesthesia and 163  f l o w s and oxygen imposed swimming  2 7 The r e l a t i o n s h i p between o x y g e n urine flow i n 3 t r o u t subjected swimming r e g i m e . 28  Page  168 consumption and to a continuous 170  T h r e e examples o f the phenomenon i n w h i c h an extreme d i u r e s i s at the s t a r t of e x e r c i s e was d r a s t i c a l l y reduced during continued swimming.  171  Changes i n body weight o f t r o u t i n response to v a r i o u s e x e r c i s e d u r a t i o n s and i n r e s p o n s e t o the handling necessary f o r the determinations alone.  174  30 A tentative model of water balance i n the rainbow trout during exercise.  177  -  X  F a c i n g Page 31 C o n c e n t r a t i o n changes o f 4 c a t i o n s i n u r i n e from a s i n g l e t r o u t o v e r t h e c o n t i n u o u s swimming regime o f S e c t i o n I I I .  182  32 The not r e n a l e x c r e t i o n o f 4 c a t i o n s d u r i n g t h e c o n t i n u o u s swimming regime o f S e c t i o n I I I .  185  33 Models . . i l l u s t r a t i n g sodium and water b a l a n c e i n the rainbow t r o u t a t r e s t , s h o r t l y a f t e r t h e o n s e t o f a c t i v i t y , and a f t e r p r o l o n g e d e x e r c i s e .  189  xi  ACKNOWLEDGEMENTS  I wish both  t o t h a n k my s u p e r v i s o r , D r . D a v i d  f o rh i s e x c e l l e n t guidance  study  a n d f o r m a k i n g my p a s t  British  Columbia  indebted  a very  few y e a r s  enjoyable  t o Dr. J . E . P h i l l i p s ,  McConnell  f o rtheir  throughout  generous  the course  Dr. A.M.Perks,  I am a l s o a n d Mr. F r e d  o f advice  and equipment.  My s i n c e r e a p p r e c i a t i o n a l s o g o e s t o t h e f o l l o w i n g Miss  Ora Johannsson,  use  o f computing  Mr.  Eric  f o rher invaluable help,  facilities;  my.colleagues,  interest  who c h e e r f u l l y  and a s s i s t a n c e ;  performed  Mr. J o h n  a n d my m o t h e r ,  the laborious task  persons:  especially i n  W a t t s , -Dr. Dan Toews-j-and D r . J i m Cameron  continued  o fthe  at the University o f  experience.  supply  Randall,  Davis,  for their Mrs.0.A.Wood,  o f typing the  manuscript. Personal ships McLean U.B.C.  from  financial  support  was p r o v i d e d  by s c h o l a r -  t h e N a t i o n a l R e s e a r c h C o u n c i l o f Canada and t h e  Fraser  fund,  and a s m a l l  T h e r e s e a r c h was f u n d e d  Research C o u n c i l and t h e B r i t i s h  teaching  assistantship  by g r a n t s  from  Columbia Heart  from  the National Foundation.  GENERAL  In represents and  a l l higher the point  external  area and  ation  of closest  minimal  dioxide  relative  conditions  organisms,  environments.  presents carbon  down  may  equally  appropriate  gradients  be  ment  area  which  detrimental  i s easily  elevation  medium  Under readily media  diffusible  may  exist  substances, able  this  phenomenon.  diffusional  problem  respiratory  medium.  Loss  may  the  purpose  of this  state-  artificial  component  significant  surface.  be  of the  gradients  for  external F o r some  sufficiently  The e v o l u t i o n  c a n be viewed  concomitant  sur-  such  unfavour-  l i m i t a t i o n s o f t h e exchange  system.  o f body  the across  of the internal or  to necessitate  tetrapods  species  monoxide).  fluxes  of the respiratory  air-breathing  o f a common  the respiratory  the resultant  species  across  o f substances  the effect of  constituents  designed f o r  the validity  circumstances,  across  to the.animal  capacity in  normal  optimizes  to i t s respiratory  to the organism;  (e.g. carbon  i t s situ-  molecular  exist  this  oxygen  o f one m o l e c u l a r  The movement  levels  while  fluids  o f another  are.extraneous  t o abnormal  ventilatory  gradients,  f o r the latter  by  of  to the d i f f u s i o n of  transport  demonstrated  the internal  the structure  However a system  the flux  o f the exchanger.  exchange may  serve  surface  between  o f exchanging  f o r gas t r a n s f e r .  well  such,  activity  effective diffusional  face  As  to the flows  the respiratory  proximity  resistance  the  i f  INTRODUCTION  water with  The development  as a g r o s s  i s t h e most  of the  lung  example  of  serious  the use o f a i r as a o f an i n t e r n a l g a s  2 exchanger tated  effectively  assumption  ventilation, because  of the relatively  a limitation  o f the high  coefficients, A  somewhat  and  between  This of  osmotic  t h e mode  with  control  1/2  and water  per unit - 1/7  that  diffusion times  body  greater  (Hildebrandt  deficit  Active  has been  devices ment, lost tated  even  Thus  medium  i n water  concentrations milieux  cause  through  or permeability  of  epithelium.  modification o f an  will  (Hughes,1966)  exchanger  effectively surface  i s only  and Young,1965)  (Newstead,1967)  while  a r e up t o  than  ions  delet-  the respiratory  and blood  the possession been  s i x  i n the lung  Tolerance  e f f e c t e d through with  apparatus  to their  to eliminate  and i n t e s t i n a l  further  gained  absorption  to a hyperosmotic  external  b y t h e u s e o f an a q u e o u s  t o pump  fluxes,  from  medium  o f secondary  demand. ions i n  efficient  a hypo-osmotic  capabilities have  control  o f the osmotic  energetic  on t h e g i l l  small  to fully  the development  net diffusional water  of a relatively  sufficient  movements.  mechanisms  transport  opposition  diffusion  and Young,1965).  and water  compensatory  afford  gaseous  the possession  (Hildebrandt  has not, by i t s e l f ,  electrolyte  mode o f  the respiratory  i n teleosts  between  i n the g i l l  However exchanger  only  fluxes.  i n mammals  distances  across  "size"  weight  could  applies  be prevented  of ventilation;  salt  situation  and e x t e r n a l  cannot  functional  large  differential  exchange  deficit  a small  area  internal  hydrominerai  the organism  tidal  of a i r .  analagous where  but necessi-  inefficient  capacity,  and low d e n s i t y  vertebrates  erious  which  oxygen  breathing water  controlled dehydration  renal environ-  to replace a l l been  r e s p i r a t o r y medium.  water  necessiComparisons  between that 30%  fish  these  in  normal  and  osmoregulatory  isosmotic  environments  requirements  of  the  organism's  Farmer  and  Beamish,1969).  The  tissue  may  thus  partially  osmoregulatory The development by  the  be  at  of  involved  teleost  ion  and  tolerate.  Yet  i t i s known  consumption  ten  times  cardiac  output,  (Randall of  gas  the  transferred  appear  ective ural  limits time,  et The  been  teleost  more  the  indicate  fish  The unit  latter  the  have  the  branchial  repeatedly  which  development  s t r u c t u r a l , and  of  will  must  and  limited can  their  of  the  oxygen  gills  refers be  to  to  units  affected  vary  within  the  that,  osmotic  eff-  at a  any  dynamic  regulation Randall  Randall,1970 be  observations  traced on  the  is  the  g i l l .  two  are  fundamental rows  of  Parallel situated  unit  these rows on  of  branchial  flattened of  both  leaf-like, sides  of  structure  tapers  are  lacunar  each  i t  struct-  Kruysse,1964;  may  by  Thus  the  represent  hypothesis  physiological  medium.  in ventilation,  concept  and  the  animal  Kirschner,1969;  this  teleost  exchanger.  capacity  to  anatomical  is  elevate  entire  demand  al.,1968;  the  factor  and  The  (Steen  of  the  increases  permeability  respiratory  up  an aqueous  that  epithelium  previously.  rate  expression  gradient  for  (Rao,1968;  epithelium  can  through  respiratory  et  breathing  oxygen.transfer  teleosts  Taylor  and  that  revealed  a t t r i b u t a b l e to  exchange  diffusion of  advanced  hemibranch. lamellae  per  between  The filament;  of  this  origin  the  described  al.,1967;  physical,  to  that  "size"  compromise has  and  or  al_.,1967).  resistance  would  one  et  in  metabolic  respiratory  water  account  consumption  low  considerations  the  of  oxygen  least  penalty  above  level  total  may  have  borne  on  a  secondary  filament.  The  to  a)  4 lamellae a  of  adjacent  sieve-like  ventilatory water  ment. is  water  efficient 1962).  any  are  blood  net  described  D  =  i s  AD X  a measured  movement  of  cated.  For  move  be  considered  external nal  particle the  X  may  across  branchial components present tissue.  and  feasible  "size". may  the  of  thus the  respiratory  system the  surface  an  and  internal by  f i l a leaflets  creating  (Hughes  the  or  sieve,  body  thus  Shelton,  and  exter-  the  bulk  diffusion  respiratory  or  osmosis)  epithelium  F  =  net  Ci Co A  = = =  X  =  D  =  a c t i v i t y of p a r t i c l e s inside activity of particles outside surface area across which movement occurs d i s t a n c e t h r o u g h w h i c h movement occurs coefficient  substance this  the  order i t i s the  flux  the  over  by  homeostatic  to  resistance  the  discussion,  determined  mechanisms  In  on  the  variations in  operate,  information  ( i . e . by  quantifying  of  constants  However  a l l be  the  the  exchange  of  relation:  purpose  environment  milieu.  of  flow,  migration  particular  as  in  portion  i n gas , i o n ,  and  between  the  Co)  the  flow  exchange  coefficient  the  pores  that  produce  water.  by  (Ci -  the  water  where F  i n t e r l o c k to  involved  lamellae  of  to  passive  of  is  blood  which  brought and  species  be  of  that  Substances  of  the  counter-current  The  may  to  which  of  spatially  Hughes,1966);  through  direction  milieux  flows  of  walls  opposition  (see  flow  passes  the  The  in  nal  structure  exchange  contacting  filaments  the  for  anatomy  Co  must  nature  of  the  demands  the A,  the  each  necessary and  of  parameters  how  impli-  and  regulating  examine  first  distance Ci  the  to  to  physiology  of  inter-  D,  and  effective these  consider of  branchial  5 Studies demonstrated capillary  that  icular the  et  of  Keys  and  fluid  on  the  limited  to  increase,  flow  through  in vivo their  actions  entire  circulatory  interpret  with  Steen  Kruysse,1964;  and  1969). the on  respect  However,  results excised  seem  at to  g i l l  by  the  filament  demonstrated afferent lacunae  to of  filament. artery the at  the  single  of  and  and  has  and  with  which  resistance  difficult  alone  and  far  effects  Stevens,1967;  adrenaline  decreases,  so  the  therefore area  part-  Data  drugs  output  in  choline  pressure,  qualitatively  these  double  that  at  efferent the  resistance  nature  of  any  excised  Steen  one  time,  filamental  the  latter via  to  (Mott,1951; Kirschner,  noradrenaline, the  the  filament.  filaments  adrenaline,  blood  addition  acetyl  sinus,  moved  a  observations  or  and  Kruysse  blood  can  probably  or  that  restricted  to  the flow  typical  the  the  the  the  body  of  the  excurrent tissue  of  presence  lamellae; entirely  space,  connections  examination the  have  from  vascular  in  a  through  connective  direct  through  flow  through  passage  in  (1964)  either  Microscopic  solely  is  circulation  large  indicated  choline  shifts  arteries  pathway,  either  "lymphatic"  t i p of  the  respiratory lamellae  i s possible  of  agree  for  (Riess,1881).  In  central  blood  branchial  Randall  least  these  cardiac  the  Fange,1962;  preparation.  of  system,  to  and  agents  preparations.  Mediation effected  on  vaso-active  acetyl  have  branchial  Fromra,1969,1970);  the  on  the  Ostlund  while  effects  u l t i m a t e l y dependent the  and  preparations  of  several  Bateman,1932;  Richards  g i l l  resistance  s e n s i t i v e to  al.,1969;  of  collected  are  is  perfused  vascular  catecholamines  rate  been  isolated  the  network  (Krawkow,1913; Randall  on  of  conversely to  the  6 filamental  routes.  Fromm,1969, that  the  graded  rather  patterns  are  observations  absolute  and  (Richards but  revealed  filamental  response.  adjustments  These  flow  minor  was  a  workers  in branchial  adrenergically with  and  perfusion  tonic  cholin-  control. factors operating  a  collagen  bearing  matter  respiratory innate  similar Hughes  pillar  lamellae  and to  apparent  the  efferent  of  and  cells  of  has  in  through  However  this  theory  is  only  rheostat  in  the  i t must  be  capable  routes,  then  resistance  to  distribution  the  account among  the  for  skeleton  of  possessing through  these  lent  cells  considerable  combination  with  elements  afferent  some w o r k e r s  in  to  affect  the  Richards  the  pillar  Datta  that,  of  of an  observed In  expansion  Munshi  Fromm  i f the  of  of  resistance  and  an  propose  e x c l u s i v e l y by  or  the  ( R h o d i n , 1 9 6.4 ;  has  in  The  c r o s s - s e c t i o n a l area  circuit  shunts.  in  Newstead,1967;  grounds  the  of  discovery,  muscle  contraction  reject the  led  the  presumably  on  the  contractile  i s regulated  Changes  shunt•pathways.  present.  filaments  finding,  constitute,  at  Newstead,1967)  walls,  would  The  smooth  This  shunts  suspected  cytoplasmic  Grimstone,1965;  lacunae  form  been  structural  distribution  respiratory skeletal  of  arterial  (Hughes  dispute  which  long  vascular  (Plehn,1901).  belief.  Singh,1968).  three  have  Grimstone,1965;  absence  blood  cells  myofilaments  this  these  considerable  microscopy, to  support  cells  of  contractility  electron  and  these  lamellar  significant  however,  that  an  mediated  The  or  between  than  that  sophisticated studies  supported  division  concluded  ergic  1970)  More  the  the  of a l l  (1969)  lamellar  volume  three  parallel  flow  almost  infinite  range  variations in  addition  they  of  blood  have  demon-  7 strated of  muscular  lamellar  control of  and c e n t r a l  of g i l l  afferent  vessels. g i l l  elements  blood  tissues  on  but  opened  be  a  Circumstantial blood  may  idual  lamellae  has  been  filament by  lamellae  volume  for"the  i n other  between  the high  filamental  measured  that  this  may  channels  resistance  changes  personal  with  such  of  adrenaline.  effects,  indiv-  Muir  (1970) fila™  or direct  flow  structures  Whatever  respiratory  of  blood  lamellae  a possible the  have  the operant  regulation  across  blood  of afferent  occlude  provides  live  to the  pressures.  dynamic  volume  on  sinus  distribution of  pressure  lamellae;  that  the  -  distal  administration  teleosts.  remains  walls  combination  filled  on branches  which  of respiratory  the fact  located  to blood  flaps  some  and Randall  specific•opening  valve-like  that  observations  are not normally  i n part  having  observed  distribution  and argue  (Davis  indicates  i n the  a r t e r i o l e s and e f f e r e n t  intravascular  related  groups  mechanisms,  low  that  a r t e r i e s i n the tuna  whole  not  lamellar  laboratory  evidence  discovered  mental to  be  vessels,  distribution involves  reveal  hemibranch  thickenings  infrared photographic  i n this  communication)  may  sinus  and e f f e r e n t Recent  or similar  and  explanation  branchial  netv/ork. Histological tissue of  have  determined  the lamellae  iratory  lamella  bodies  enclose  narrow  an  differences  by  flattened  the aforementioned  the vascular erythrocyte  epithelium,  between  of the filaments.  i s a delicate  supported  which  gross  and t h a t  thick,  with  and c y t o l o g i c a l i n v e s t i g a t i o n s  a basal  area.  makes  the  pillar  about  cells;  The b l o o d / w a t e r contact,  g i l l  structure  typical  structure,  intimate  lamina,  The  of  resp10  these  u cell  barrier,  comprises  and t h e cytoplasmic  a  flanges  8 of  the p i l l a r  (Hughes  total  f o r about  cylindrical  epithelium  (Conte,1969).  A  covered  endothelial  sing  connective  ness  o f this  cells  this  blood/water  and  t h e e x t e r n a l medium.  4,  i t can.be  distribution onents  seen  through  of the relationship, to gases,  distance,  will  in  however  Hughes data  flow  the total  of filamental  length  by Hughes  (Hughes,1966,  (1966).  by  on  blood some  compg i l l  diffusion increases  differences i n  exist  no  reports  and l a m e l l a r s u r f a c e s ;  assuming  o f the lamellae  lamellae  effective  reduced  than  presented  T h e mean  There  thick-  greater  change  modifying  a mean  (from  and Grimstone,(1965)) t o c a l c u l a t e  given  trutta  will  lined  anastomo-  The  equation  o f t h e above  barrier.  possible,  of  30 t i m e s  and water.  because  areas  i t has been  t h e average  thereby  ions,  o f the blood/water  relating  shunting  layers  sinus,  i n branchial  o b v i o u s l y be g r e a t l y  lamellar blood  width  \  X,  a network  long,  filamental  cell  of the respiratory  variations  vascular  permeability  with  to the diffusion how  of 2 - 8  i s the central  i s 10 -  the lacunae  now  space  (Hughes  an i n t e r l a m e l l a e  and Kruysse,1964).  barrier  d i s t a n c e between  Returning  layer  (Steen  the  page  by  and f i l l e d  tissue  5 u  The b l o o d  l a m e l l a r volume  secretory epithelium")  Beneath  with  Newstead,1967).  i s 1 -  b r a n c h i a l f i l a m e n t , however, i s a  process  ("salt  o f the boundary  70% o f t h e t o t a l  Grimstone,1965).  more  width  and Grimstone,1965;  accounts and  cells;  depth  the micrographs  these  F o r a 175 g  p.180), t h e e n t i r e  filament  values  specimen  from  of the  o f Salmo  lamellar area i s 2  approximately  6  times  the total  filamental  surface  (59,222  mm  2 vs.  1 0 , 5 75 mm  therefore  ).  extremely  The area  parameter  labile  to relative  A  o f the equation i s blood  flows  through  the  9 two  regions.  thickness  equal  accessible and  the  former  Making  further  to  diameter  blood  the  space  of  filaments,: then is  1.7  x  that  of  70%  suppositions of  an  total  maximal  the  filament  a  lamellar  erythrocyte  volume  the  of  in  vascular bodies  and  both  the  volume (290  an lamellae  of  mnr  the  vs.  3 173  mm  ).  ratio the is  of  More the  importantly,  lamellar  shunts  filamental routes especially by  the  as  by  that  well  and  as  (203  important  restricted  the is  mm  for  gas  diffusion through  -1  surface  3.3  times  vs.  61  flow  cell  ).  the  effects  volume  than  This  which  membrane  as  to  through  the  various  routes  coefficient,  can  only  hypothetical  this  parameter  teleost  for  of  resistance  than  packed  cells  the  of  impermeability and  to  rate  a  of  these  efficients water  efficients plasma cell  wall  densely  the  interlamellae  the  is  that  of  difference  significantly  and  cytoplasm  (Krogh,1941;  Steen  permit  membrane,  water,  i s  junctions,  pores,  than or  diffusion  osmotic  no  so  and  directly through  that  their  v e s i c l e s which  simple  epithelium. insoluble  that  the  by  the  diffusion relatively high  through the  the  made  mitochondria  solely  are  been  of  diffusional  lipid  severe  However  as  have  less  to  or  measurements  likely  i s determined  migration  blood  interest  membrane  (Krogh,1941)  rather  as  differential  filamental  r e s p i r a t o r y gases  tissue  the  reticulated  plasma  extent  of  of  provides  the  the  D.,  i t seems  Woodbury,1965 ).  for  and  However  substances  (Davson,1964;  on  substances  lamellar  of  lesser  be  the  tissue.  epithelium  in  - 1  i n plasma  the  blood  Kruysse,1964). Conclusions  in  to  greater  mm  exchange  distance  area  ions  movement membrane cosimilar  partition  the  The  co-  phospholipid  restrictive  leaks,  are  postulated  usually  10 for  electrolyte  Woodbury  water  movement  these  pathway  considerations  will  be  effective  most  in  least  the  c e n t r a l f i l a m e n t a l shunts  preventing  fluxes  of  Evidence blood  salts that  sumption  of  and  during  transfer  effect  and  diversion of lamellar  elevation  of  and  always  the  more  found  that  by  and  known  ical  the  secondary  functional  metabolic  rate  resting rates  area  and  lamellae,  on  during  the  Randall  f o r gas  for  must  signifi-  in  the  this increase  activity the  trout, Steen  could  Steen  and  signi-  diffusion  and  and  (1970a)has  be  does  infusions.  values  in  con-  lamellae.  estimated  exchange  isolated  diffusion  rise  gills;  FO^'s  yield  the  significant  distances,  (Saunders,1962;  Conversely,  lamellar  the  medium.  i n oxygen  respiratory  eel, unlike  aortic  in  reflects  permeability  based  gradients  as  gradient  al.,1967)  leaving  passive  adjust  accompanying  the  conversely,  without  intravascular adrenaline  coefficients  Hughes,1966).  The  dorsal  of  of  salmonids  r e l a t e d to  blood  Calculations  exceeding  be  to  exchange  external  increases  catecholamines  saturate  increased  area  g i l l  Tomlinson,1967). fully  et  blood  flov; can  circulatory  (1964)  ficantly  The  (Randall  indicates that  in  and  pathways  pressure  b).  gas  non-functional  dynamically  large  exercise  partial  factor  Increased  Kruysse  the  plasma  lamellar  exchange;  virtually  branchial the  the  in preventing  in vivo,  by  Randall,1967  oxygen  (Nakano  between  different  variations in  through  water  i s provided  be  efficient  t e l e o s t s can,  observed  (Stevens  not  highly  and  perfusion  preparations  cant  but  that  i n promoting  osmotic  will  f  respiration  indicate  effective  and  in  ( P a p p e n h e i m e r , 1 9 5 3;  1965). A l l  blood  and  the  greatly Kruysse,1964;  computed  trout  anatom-  from  the known  11 resting  state  is  20%  only  reported only or  a  of  by  the  a  There osmotic  found  plasma  between  water,  plasma  the  trend  protein  reversed  study  exchange have  evidence  now  the  walls  sinus  of  developed  the by  al.,1966;  active  from  any  up  a  .  l i t t l e  efflux  at  blood  active  and  his  Motais,1967;  transport  and  the  those  of  these  the in  branchial  the  electrolyte  co-workers Maetz,1969)  exchange  and  which and  Radiotracer (e.g. have  diffusion  of  Activity of  did  not latter  exchange/  which  previous  cytological function overlies not  to  only the  the  techniques  Maetz,1956; revealed ions  i n -  water  ion  transport  Conte,1969)  severe  This  surface  Histological  (see  fresh  occurred.  considering  fish;  a)  release  experiments  sodium  sea  plasma  fluxes.  trout  of  in  (1968  water  of  Beamish  unexercised  and  the  be  nilotica;  Stevens  increased  for  osmolarity  increased  respiratory lamellae. Maetz  in  filamental epithelium pathway  blood,  and  during  in  considered.  assigns  Farmer  blood  of  the  with  trout  gills  complexity  compromise not  with  perfuse  should  i n haemoglobin  rainbow  the  must  evidence  arguments,  exceeded  However,  net  interlamellae  central  very  fresh water.  of  rest  surface  fish  resting Tilapia  changes  at  lamella.  exchange.  administration  al.. 1969)  points  in  associated  whether  workers  each  above  gas  and  observed  radiosodium  reveal  et  exercised  that  et  of  the  increased  lamellar  quiescent  however,  by  implicated  respiratory lamellae  concentrations  were  (Randall  to  which,  catecholamine  jected  gas  yet,  as  concentrations  activity and  i s  area  non-significant differences  was  postulated  their  portion  with  (1969)  Thus  small  deficit  concomitant  of  the  anatomical  (1966).  number  only  consumption;  entire  Hughes  small  else  oxygen  that  occur  in  Motais both the  12 g i l l s .  Observed  ortion  of the total  directional seems  simple the  mediated  sites, could  for  that  while  decrease  lation  effects. could  (1971)  purpose  which  but l i t t l e  trout,  s i x years  cardiovascular mental  could  as w e l l  blood  or activate  of carrier  have  sites  of uniIt  affect  as e x e r t i n g  flow more  through transport  pathway  i n operation.  recently provided  experimental  some  support  was  Salmo  gairdneri,  has produced  experimental  animal  performed.  The was  on  i n this  factors,  size  examined  and a wealth  combined  with  ;  the majority with  a slightly  i n the sea water  have  been  adapted  reported  the and  of experi-  the  fish's  i t an e x c e l l e n t  o f the study  was  different  adapted  euryhaline  somewhat  }  results  exchange.  of respiratory  flounder, Paralichthys lethostigma in these  specu-  l a b o r a t o r y over  a n d c o n d i t i o n made  problem,  water  that  i n the  considerable  an u n d e r s t a n d i n g  on v/hich  same  compromise  the fresh  function i n the species These  t o examine  a t t e n t i o n , i o n and water  of research  i n uniform  emphasis,  study  has p r e v i o u s l y r e c e i v e d  availability  detail;  Increased  of the present  techniques.  southern  shunting  prop-  deficit.  perfusion of the respiratory  i n t e n s i v e programme  past  an i o n i c  processes  unmask  a small  measurements  of the respiratory/osmoregulatory  g i l l  rainbow  only  hypothesis.  component teleost  detect  transport  t h e number  and R a n d a l l this  cannot  while  branchial blood  ionic  greater  represent  exchange,  alone  filament  The  An  salt  permeability  central  Wood  fluxes  reasonable  carrier  n e t f l u x e s may  elsewhere  lesser  (Wood  and  Randall,1971). The present  study  general was  investigational  to treat  approach  gas exchange  utilized  as t h e  i n the  independent  13 variable  and  variable.  Thus  therefore and  the  g i l l  was  and  Smith  available the  was  to  sodium as  and a  "size";  to  change  extensive  uptake,  on  the  gas  exchange  on  the  cardio-  Randall,1967  a,  b;  al.,1967;  Stevens,1968  b;  Davis,1968)  circumstances.  evaluate  the  effects  branchial  i n rainbow  mechanisms  swimming  for redistribution  are  The of  adjustment  trout,  and  invoked to  to  i n salmonids Randall  in activity  of blood  overall  changing on  the  aim  were  are  flow of  et a l . ,  the  gills  study  respiratory/  sodium  the  probably  i n the  and  water  determine whether  alter  animal  the  data  Variations  and  quantified.  and  et  of  oxygen  imposed  fluxes  dependent  Stevens  natural  compromise.  water  tool  f o r comparison.  regulation  to modify  the  effects  osmoregulatory  satory  known  b a l a n c e as  respiratory  primary cause  under  water  d i s t r i b u t i o n , were  utilized  (Brett,1964; 1967;  blood  i n branchial  vascular  and  conditions  associated  Exercise factor  electrolyte  dynamics  of  compenthis  14  SECTION  THE  EFFECT  OF  I  EXERCISE  SODIUM  (ONE  component  present  of  compromise  the  to  attacking  the  have  been  long  during  available  in  the  relation  conditions, from  or  to  dilution  in  fish  However  to  the  the the  both  (see  size  water  of of  or  external  i n the  changes  i n osmoregulatory  these  internal (1968)  medium.  environment.  and  Farmer  and  uninformative  because  concentration  of  Chatterton,1970)  by  of  the  the  an  mass  electrolyte  of  ions  i n sampling has  (1969)^ b u t large  of been  natural  to  for  to  the  of  water  under by  the  fish  massive same  swimming  animal's  taken  by  Rao  relatively  variability  in  (Wedemeyer  stress  such  detecting  with the  and  have i n -  the  has- p r o v e n  constitutents  lability  of  exchange  Klontz  animal;  associated  approach  gas  volumes  only possibility  plasma  their  large  i s undetectable due  lies  Beamish  of  techniques  procedures  experimental of  largely  Brett,1964;  swimming  functions  This  teleost and  the  i s  satisfactory  relatively  The  circumstances  osmoregulatory  inherent i n  investigation  release  and  of  Fry,1957;  medium  species  under  difficulties  variety  a l l such  uptake  by  during exercise  f o r the  recirculation  the  respiratory/hydroelectrolyte  g i l l  A  I  i n f o r m a t i o n on  experimental  subject.  Smith,1968). volved  teleost  the  activity  of  postulated  i n the  attributable  lack  ON  BALANCE  INTRODUCTION  The  HOUR)  and  involved  in  1 5  sampling when  such  ences the  procedures methods  (e.g.  to  without  have  greatly  Worthwhile therefore  detecting  and  Radiotracer  quantifying  Maetz  efflux,  between  the  methods  necessitate  greater  than  At  the  failed ature  due  of  favour  the  flux  urine  measured was  very  more  the  rates on  in  the  and  through  and tank  3  techniques processes for  study,  times  which  of  laminar  in  during  a  were  flow  in  quantity than  a  made  and  determin-  exchange  that  in  measuring was  small  external  but  became  aquarium^  with  values  Collection  contribution  of  to  temper-  i t  compared  these  times  respirometers  animals.  renal  transfer  fluxes.  Exercise  activity  prevented  the  few  quantify  directly  chasing  post-exercise  greater  reveal  only  sodium  of  purpose  simultaneous  trout.  manual  during capable  Consequently  of  an  rate  However,  attempts  branchial  for  electrolyte  swimming  for  on  involved.  this  volumes  objective  The  balance  accurately  plans  swimming  exchange.  approximately  to  obtaining  important  resting  water  volume  uptake  light  turnover  environment.  apparatus.  ascertained  outside ionic  fish  small  during  of  components  of  original  fish  use  developed  present  the  oxygen  latter  determined  the  modify  the  on  the  problems  both  use  differ-  concentrations.  ionic  dynamic  been  l i t t l e  i t s salt  internal  i t s external  of  in  the  flux  the  of  in  to  to  of  imposed  of  that  depress  the  significant  shed  Garcia-Romeu,1964)  net  and  regulation  ation  and  fish  fish  necessary  only  and  inception  exercise  have and  influx,  can  Even  theoretically possible  state  demanded  communication).  detect  i n v e s t i g a t i o n of  methods  (Maetz,1956;  or  steady  to  results  i t is  elevate in  personal  able  the  involved;  variation  exercise  been  Toews,1969),  mechanisms  animal  (Houston,  to  water  desirable  for  used  16 optimal mum  precision  volume  fish  yet  which  s t i l l  in  flux  would  yield  rate  measurements,  support  swimming  reasonably  but  was  activity  in  accurate  the  mini-  chased  radiotracer  determin-  ations .  ation  of  swimming  The  use  the  exercise level  speed  cannulation branchial measure  to  swimming et  or  of  such  the  dorsal  respirometry  a l . ,1967;  physiological  the  comparison under  workers. the  in  more  A  further  provision  disturbance samples  of  to  the  l i t t l e  has  been  ation  i n the  order  to  water  interpret with  compromise  in  about  both  the  of  the  swimming of  assay  the  adopted  these  an  chasing  tech-  evaluation procedure  changes  c o n d i t i o n s by  blood  of of  .  a , fo;  ob-  other  vascular catheterization sampling  was  without  plasma  aliquots  from  these  internal  sodium  levels  and  experiment. of  rainbow about  this  have  Salmo  processes  form  changes of  type  trout,  the  adapted  possible  g i l l ,  permitted  for  subjected  Randall,1967 of  of  and  been  salmonids  cardio-respiratory  readjustment  the  Bell,1964)  recently  in  and  study  techniques  reported  have  for serial  intact  fresh  associated  possible  to  and  Application  determination  throughout  applied  (Smith  changes  advantage  animal;  Radiotracer been  procedures  significance  a means  permitted  distribution  ly  However  (Stevens  controlled  evalu-  rate.  aorta  the  direct  measurement  present  with  permit  through  D a v i s , 1968)..  of  served  trout  d i d not  imposed  cardio-respiratory  to  through  system  (Saunders,1962)  niques the  a  metabolic  chambers  to  Smith  of  of  in  sodium  previous-  gairdneri,  of  this  not  sodium  and  regul-  species.  In  balance  the r e s p i r a t o r y / o s m o r e g u l a t o r y  i t was  necessary  to  steady  state  dynamic  and  learn  as  much  as  distribution  of  the  ion within  related flux  to  this  topic  to  object  describe  of  sodium  adapted  rainbow  trout  (ii)  examine  the  to  exercise this  organism. were  Thus  measured  a number  of  factors  i n addition  to  branchial  rates. The  (i)  the  on  the  teleost.  this  section  "metabolism"  effect  processes  of  was  i n the  exercise  involved  therefore  and  fresh  twofold: water  recovery  i n sodium  from  regulation  i n  18  METHODS  1.  Experimental All  bow  trout  Sun  Valley  between of  British  steel  Animals  fish  (Salmo Trout  180  and  the  from  Prior o f two  14.5-1.5°C. glass  tanks the  s e x u a l l y mature  gairdneri) obtained  from  a commercial  Farm,  Port  g.  The  animals  time,  pellets. May  coil  utilized  gallon  weeks.  and  two  250  lights  as  each  tank  an  activated  replaced sodium yielded  was  at weekly  values  sewn  from  1.0  with into  MS  -  the trout  water  Each  tank  watt  aquarium  situated  The  and  the dorsal  at  seasonal  f e d weekly  were  during  was  and h e l d  at  supplied with heaters.  sources  to  of the maintain  and r e c i r c u l a t e d and  water through  partially  determinations  of  water  ug/ml. most  labelled caudal  trout with fins  were  lightly  coloured to  a  During  dechlorinated fresh  Periodic  and  with  transferred  i n the covers  heat  aerated  of transfer, 222  University  performed  tanks  Fiberglas filter,  4.0  weighed  galvanized  i n the acclimation f a c i l i t y  the time  anaesthetized  and  or  were  were  concrete  intervals.  concentration  At  threads  continually  charcoal  concrete  supplier,  trout  at the  rain-  1969.  supplemental  a c c l i m a t i o n temperature.  in  The  held  the f i s h  to experimentation,  for 1 - 4  were  Experiments  t o December,  160  B.C.  dechlorinated fresh  this  and December,  were  Coquitlam,  i n large outdoor  indoor  cooling  November  were  During  trout  one  i n this  supplied with  commercial  to  study  350  temperatures.  period  used  Columbia  tanks  I  cotton  separate  19  different held  acclimation batches.  i n each  period,  Operating  planted  up  table  were  Procedures  containing on  an  operating  so  constructed  (1/20,000  MS  222)  the  o r backwards  entire  operation  was  range  o f 11°C. to 17°C.  were  acclimation  to avoid  faecal experiments.  MS  Trout  222  and  cannulae were  then  were  placed  ventral  (Smith  and B e l l , 1 9 6 4 ) .  that  either  an  could  anaesthetic be  the g i l l s . 30  perfused The  minutes.  solution through  this  not c o n t r o l l e d , but remained The  The  duration  During  im-  anaesthetized  table  about  temperature  the  fish  i n subsequent  fish.  over  water  20  Cannulations  f r e s h water  was  During  water  1/15,000  or  than  b u c c a l , and u r i n a r y  was  mouth  time.  and  aortic,  more  not fed i n order  i n a l lexperimental  water  side  one  of the external  Dorsal  in  a t any  the animals  contamination  2.  tank  No  of the time,  i n the  following cannulations  were  performed: (a) A portion  Buccal  small  Cavity  hole  o f the snout  scalpel.  Care  was  naris  aortic  cannulation  tubing  (Clay-Adams),  passed  the  level  punched  slightly taken  ternal  was  was  Cannulation  left  valves  technique. with  out through  through  this  damage i n both  Eighty  a heat hole  the c a r t i l a g i n o u s  o f the midline  to avoid  or the buccal  (Fig.l)  cm  flared and  using  to either this o f PE  on  iris  t h e ex-  and t h e d o r s a l 60  polyethylene  t i p t o a c t as  tied  an  an  the dorsal  anchor, side  of  rostrum. (b)  Dorsal  Aortic  The  dorsal  aorta  of the f i r s t  g i l l  Cannulation was  arch  cannulated (Smith  (Fig.l) i n the midline  and Bell,1964)  with  at the a  #21  20  Figure 1  A drawing o f t h e a n t e r i o r p o r t i o n  o f a rainbow  showing the l o c a t i o n and s i z e o f the b u c c a l dorsal Section  trout  and  a o r t i c c a n n u l a e used i n t h e experiments o f I.  PE 60 tubing  dorsal aortic cannula buccal cannula  PE 200 jacket tied around PE 60 tubing  heat flared tips  Huber  point  catheter punched  was on  lined  with  PE  was  60  two  silk  the  inner  prevent  a  to the  right  short  loosely  tubing  inward  of  hand  the side  length  of  anchored and  at  to  the  of  saline  pin.  Both  dorsal  and  /  of  the  60  through  of  snout;  the  the  PE  200  jacket  of  the  of  emergence  ml  was  of  were  hole was  tightly  from  the  heparinized into  plugged  anchored  the  with  snout  approximately  6  to  I.U./ml) aorta  stainless  single  cm  or  after  (20  a  a  one  around  dorsal  with  The  with  Immediately  infused  cannula  a  tubing.  mouth  tied  The  hole  200  the  cannula.  fish  tubing.  cavity  roof  the  PE  buccal  the  catheters  side  of  to  (Wolf,1963)  clotting  cm  h e a t - f l a r e d PE  i t s point  movement  80  c a t h e t e r i z a t i o n , 0.5  prevent  the  out  stitches,  Cortland  steel  connected  passed  the  successful  to  needle  stitch  posterior  to  snout. (c) A  epoxy  urinary  resin,  length This  Urinary  of  end  PE of  polished. heavily to  a  the  proximal  was  constructed  approximately  1.5  cm  the  smaller  The  distal  flared,  0.5  cm  of  widths,  end  cannula  could  phology  of  a  then  of  the  o f . PE cm  had the  PE was  60  from  PE  with  on  lengths,  hand, and  lightly had  similarly holes  heated by  were  #22  be  fitted  to  the  specific  trout;  length  having  cm  the  latter.  heat been flattened, punched  a a  variety range  in  A  urogenital  diameter  of  the  of  of  t i p lengths.  particular and  80  needle.  representing proximal  with  an  t i p of  jacket  end  facilitated  around  very  small a  gluing,  the  190  proximal  by  190  been  Numerous  catheters  jacket  1.5  tubing  and  cannulation  pre-constructed flare  approximately  l e s s e r degree.  Successful  (Fig.2)  cannula  60  heat  but  Cannulation  mor-  uro-  22  Figure 2  Upper: A drawing o f t h e c o n s t r u c t i o n o f t h e p r o x i m a l end o f the u r i n a r y  catheter.  Lower: A drawing o f the placement the u r i n a r y c a t h e t e r  and f i x a t i o n o f  used i n t h i s s t u d y .  PE 60 tubing  P E 1 9 0  i  a c k e t  h e a t  polished tip  [V.  distal flange  proximal flange  holes punched with * 2 2  n e e d l e  stitch in ventral body wall  genital dual  papillae  are  features which  the  urogenital  ing  the  flange  of  was  proximal ation  the  PE  flange with  stitch  pelvic  fins  distal  flange of  Tension  of  pull  the  on  rather  and  the  further  on  was  the  was  indivi-  trials  view  of  protocol  other  published  Stainer,  1966; (i)  ligatures.  0.5  ml  with of  ventral  body  force  delicate  to  such  on  papilla to  removed  water,  the  anal  was  the  saline. infused  a  pin.  between around  the the  string  ligature.  that  ventro-caudad  a  ventral  from  and  with  The  cannul-  was  wall  itself.  the  the  l e d back  a purse  adjusted  exerted  plug  in  thread  proximal  behind  saline  the  of  insert-  Cortland  into  ends  the  During  filled  and  of  papilla.  jacket  plugged  was  body  Finally  f i n with the  wall  a  cannula  reinserted  the single only  during  when any  procedures.  technique  mental  the  cannula  was  the  inside  the  The  with  just  aperture  forceps,  and  anchored  transfer  fine  around  catheter  returned  of  the  the  loosely  This from  the  opening  was  silk  loose  threads  stitch. fish  the  by  until  insertion,  tied  cannula  than  catheter  of  among  catheter dorsad  c a t h e t e r was  system  then  pair  tightly  following  was  the  two  the  urinary  a  jacket  tied  procedure,  the  silk  200  performed  with  t i p of  then  Immediately into  was  papilla  proximal  papilla  the  widely  fish. Cannulation  A  vary  many  of  urinary  different  demands in this  placed  techniques  procedures.  on  study,  string  the  the  (e.g.  Hammond,1969)  catheterization  for  cannulae  method  The  purse  ligature  the  preparation during  the  by  seemed  Enomoto,1967; several  From  the  the  point  experi-  superior  Holmes  different  ensured  evolved  to  and  reasons:  durability  experimental  of  exercising  24 procedure. (ii)The  presence  collecting ence  of  of  prevented  Following vived  by  ferred  aquarium  3.  a  trout  prepared  other  fish  as  were  contamination  of  recovery.  of The  of  sodium  aortic  tudes,  ventilatory  were  animals.  with  period of  around  fresh  in  the  the  behind  the  incid-  a  flange  outside  the  water  10  to  48  fish and  (14.5^*1.5°C.)  above;  of  15  was  re-  then  trans-  gallon  hours.  The  influx,  blood  a  trout  volume, at  of  and  the  equal  spaces,  rates, two  plasma  tissue  end  hour  of  and  number  of  and/or  into  three active,  simultaneous flux  urine  rates,  production  pressure  hematocrits  period.  In  tissue  water,  radiosodium  the  rainbow  resting,  net  buccal and  a  divided  size:  and  32  failure  consisted of  pressures,  or  were  on  from  cannulae  efflux,  cardiac one  performed  results  of  radiosodium  and  over  taken  were  because  for determination fluid  papilla  procedures,  controlled  experiments  dorsal  group  gills  approximately  rates,  levels  the  samples.  levels,  cellular  urine  above  described  sodium  samples  of  experiments  plasma  treatment  holes  catheter reduced  urogenital  the  rejected  groups  measurements  of  System  Successful  and  of  recovery  Experimental  treatment  the  temperature  for  the  number  catheter.  perfusion of a  large  occlusion.  leakage  completion  to  a  t i p of  mucous  (iii)Ligation  the  of  experiment  and  ampliin  each  addition, extra-  total  f o r each  sodium set  of  rium 5.5  (a)  Experimental  All  experiments  (length o r 6.0  =  L  35  were  width  =  1.70  ug/ml)  plastic  to reduce with  (Fig.3)  performed  =  20  of dechlorinated  tration  equipped  cm;  Chamber  cm;  a glass  depth  f r e s h water  and c o v e r e d  visual  i n a small  on  and  24  cm)  (mean  a l ls i d e s  stimulation.  standpipe  =  The  funnel  glass  aqua-  containing  sodium with  concen-  black  aquarium  was  f o r the addition of  22 Na  solutions or anaesthetic  polythylene the  water  and  mixing  water with  tubing  level,  15  and  airstones  gallon  temperature  temperature  disturbance  f o r the withdrawal  o f the water.  filled  without  to provide  The  chamber  aquarium  relay.  The  o f samples  from  adequate  was  fish,  beneath  aeration  suspended  containing  apparatus  to the  inside  a refrigeration  maintained  o f 14.5io.5°C. i n the experimental  a  a unit  stable  tank.  Ad-  22 sorption  o f Na  by  the glass  walls  o f the aquarium  was  negligible. (b)  Treatment  Groups and E x p e r i m e n t a l  Cannulated  t r o u t were  aquarium  containing  5.5  at  2 hours  least  prior  aortic  and b u c c a l  ducers  immediately  however,  was  transferred to the  o f water  and l e f t  to the start  cannulae after  were  this  beginning  the  3 pieces  o f an of  for Dorsal  to pressure The  only  to avoid  undisturbed  experiment.  transfer.  experiment  small  a  trans-  urinary  catheter,  few m i n u t e s  excessive  before  tangling of  tubing.  Resting  Trout.  water  containing  added  t o the aquarium.  concentrations  o f an  attached  l e d o u t o f t h e chamber  the  (i)  L  Procedure  a known  At  amount The  zero o f Na  changes  of the external  medium  time,  22  Cl  500 (7 -  i n total were  ml  of  fresh  lOuC.) sodium  monitored  were and  over  22  Na the  Figure 3  A drawing o f the e x p e r i m e n t a l system used i n S e c t i o n  dorsal aortic cannula  > blood //^sampling  pressure transducers  buccal cannula  funnel and standpipe for addition of N a " solution or MS 2 2 2  constant temperature bath experimental chamber  refrigeration coil with temperature relay airstone water level in experimental chamber  following by  33  -  50%  periodic fish a  60  of  left  solution  1/10,000  of  the  level.  sampling  from  the  MS  of  followed  by  All  from  data  release  external  of  was  resumed  1  sampling  amount  small  trout  terminated 1 after  of  In  minutes  the  hour,  i t became  the  caudal  other that  of  avoid  periodic  for the  fish  minute  the  was  effect,  the  hour  to  took  keep  the  an  induce  to  reversals  of  the  trout.  blood each  only  the  40  by  tap  sampling of  the  5  direction  three of  was  minout  movement during  the the  and blood  minutes  end  of  fish  i n  With.practice, the  with:  hour.  swimming  continually  of  wall.  manually  occasional  experimental procedure resting  body  discarded.  However  activity.  cannula,  therefore  animal  experiment.  by  approximately 2  f o r about merely  prep-  procedures.  the  experimental  As  active  i n  checked  chased  i t s completion. the  head  was  were  each  excessive tangling  aspects, the used  experiment,  necessary  to  and  of  removed  ventro-posterior  leakage,  during  sufficient  first  the  was  into  before  kept  60.  region  saline  minutes,  chamber.  weighing  of  The  during  was  the  through  rod  and  the  the  catheter  Trout.  glass  trout  to  the  on  60  the  concentration  fish  urinary dyed  catheter, At  to  the  a blow  sampling  exhibiting  Active  r o d was  possible  the  during  added  declined  exception of  aortic  provide a  was  by  p r e s s u r e on  procedures  total  tissue  a  minute  the  the  stunned  the  time.  equilibrium,  of  urine  Chasing  of  and  of  this  to  medium  patency  fire-polished  a  loss  gentle  (ii)  of  sufficient  f o r immediate  injection  utes,  222  generally  With  dorsal  undisturbed during  after  the  radioactivity  time  aquarium  Finally,  a  water  zero  i n the  Immediately  aration  the  blood  were  from  minutes;  i t  was  cannulae  chasing. identical  In to  28 (iii) the  fish  isotope of  was was  water  added  In  chasing  was  ponding  to  the  chased  i n the  minutes.  in  Recovery  Trout.  over  to  a  the  active  no  hour  for 4  At  60  active  period.  at  blood  zero  at  5.5  L  periods  minutes,  500  thus  f o r the  were  necessitated  experiments,  However,  time;  samples  minute  interruptions fish.  f o r the  remained  addition,  the  one  chamber  aquarium  terminated  As  ml  the first  times  blood of  radio-  volume 60  withdrawn,  at  by  no  but  corres-  sampling  water c o n t a i n i n g  22 7  -  lOuC  of  experiment to  those  Na  Cl. were  proceeded  used (c)  Recording  measured in  of  activity  the  rate  and  an  Each  pressure  together  Beckman  Type  rically  balanced  before  each  sampling,  time  Dynograph zero  level  addition  exact  cavity;  however,  movements few  also  be  The  the  identical  signal  on  to  at  negative  pressure  system  end of  solution  amplitude  apparent  the that  the P-23  were  of  dis-  a elect-  i n the  tank  of  each  run.  fish,  prevented  of  B.B.  was  the  pressures  o b t a i n a b l e from  from  changes  the  Heart  Statham  level  movement  Cl  significance  channels  water  treatment  chasing.  a  The  calibrated to 22  by  two  Recorder.  i t became  a l l three  pressure  and  trials,  and  pressures  ascertained  positive  s t i l l  in  connected  due  buccal  fish  Na  total  and  the  the  was  methods  physiological  of  the  medium,  the  against the  i n water  and  on  was  and  of  first  could  experiment  utation  the  quantify  transducer.  at  with  experiment  imposed  a  hour  pressures  the  cannula  with  R.S.  Fluctuations  atory  to  level  external  animals.  blood  breathing rate  (venous) played  aortic  attempt  recordings.  the  Techniques  throughout  groups  to  f o r another  for resting  Dorsal were  added  i n the the  water  compbuccal  respir-  records. both  traces  After  29 became  highly  systematic the  1  pressure  minute  period; ative  an  from  time  with  the  and 1,  water, with  active removed  in  plasma,  the  and  Samples. through  Ten  PE  subsequently  60  frozen  represented  the  start  isotope  treatments. 30,  45,  and  experiments, at  zero  60  Thus taken  blood  during  sampling  therefore,  5,  handling  tissue  ml  of  to  represent-  to  the  were  plastic  For  the  the  recovery  30,  45,  58,  drawn  coincided  the  resting  zero  resting  time,  and  s t u d i e s , water 61,  65,  use.  groups,  but  at  to  vials  a l l  i n only  withdrawn  care-  syringes;  polyethylene  chamber  during  been  prior  experiment  minutes  15,  had  samples  -12°C. the  subsequent  dried  into  were  in  and  water  at  and  samples  water  Samples  while  time,  are,  transferred  and  of  each  tubing  Corporation)  15,  after  glass-distilled  addition  Fig.4).  post-exercise condition,  used  of  (see  generally only  trout  apparatus  active 5,  active  All  were  zero  and  Procedures  aquarium  (Nalgene  were  Sampling  ( i ) ..Water  samples  before  immediately  washed  the  chasing  (d)  processing  from  during  recordings  interval  recordings  of  fully  irregular  75,  was  90,  105,  22 and were  120  minutes.  taken  in  (ii) the zero  dorsal time  minutes  In  a l l  catheter  "spillage"  was  taken  at  65,  75,  90,  105,  including  =  time and  from  of  the  and  and  uL);  ml). 60  5,  Na  From  =  solution  15,  30,  recovery 100  uL);  trout  45,  volume  (both  ml).  withdrawn  active  ( a l l 200  1.60  were  and  (total  minutes  minutes  "spillage"  samples  resting  uL)  200  1.45  120  Blood  100  ( a l l approximately  including  removed  Samples.  (approximately  zero  aliquots  experiments.  Blood  aortic  addition,  and  60  removed fish,  uL)  was  blood  and  (total  Blood  at  at  volume allowed  via  30 to  flow  own  from  the  pressure  rinsed  with  ution  and  adequate enough  or a  catheter under  100  allowed to  to  samples.  As  take  and  blood  to  this  dry;  clotting  significant  i t was water  before  the  designated was  started. were  Thus  compromise  blood  to  three  a  but  1  to  samples  not  of  the  minute  were  on  15  seconds 30  time,  blood  own  red  pressure,  technique  drops  discarded  fluid  was  designed  as  a  effects:  was  slowly  reconnected  disappeared Blood  and  reinjected into  was  the  to  from  the  with  levels  dorsal  forcing  emerging  ("spillage"),  cannula  saline  of  the  allowed  thereby  samples _  Contamination of plasma s t i l l i n s i d e the trout the r e i n t r o d u c t i o n of blood mixed with saline.  was  seconds;  procedure)  3.  blood  to  late.  undesirable  disconnection of  great  following  Reduction o f i n t e r n a l sodium through excessive bleeding.  after  was  plasma  approximately 2  flow  out the  blood  and  aortic  the  up  saline  catheter  the  tubing The  c a t h e t e r were sample  the  pressure  until  the  blood  through  hematocrit  saline.  to  through  from under first  simply  collected. transducer  i n the  tubing  Then and had  trout.  transferred  to  pre-  sol-  experimenter  commenced  lasted  (a  was  i t s  been  water  heparinization  single  water  had  2.  its  just  reduce  of  seconds  sampling  of  under  Contamination of the blood a l i q u o t "smearing" i n the cannula.  manometer,  the  water  syringe  contamination  for  and  syringe  1.  the  3  while  The  simultaneously,  sampling  s y s t e m a t i c a l l y 90 The  Thus  time  plastic  haemolysis  sodium  Aspiration  blood  level  or  samples  used.  ml  heparin/distilled  impossible  was  then  1  suction.  sodium  scheme  only  slight  a  I.U./ml  prevent  cause  into  Clay-Adams  0.6  ml  glass  _  hematocrit ocrits  tubes  were  read  supernatant A  small  was  portion of  (American  at  could  from  plasma  from  content  the  catheter,  production  converted  to  at  although from  patent,  these  e x h i b i t e d symptoms  water  levels)  was  drainage basis,  and  data  on  at  ml)  then  was  In  measured  some  experiments,  occluded;  rejected.  None  distension,  high  urine  of  these  tissue  urinary occlusion  therefore  assumed  that  associated with  the  beginning  a l l other  production  rendered  were  chronic  ionic  of  parameters  Contamination  experimental  through  analysis.  apparently  (urogenital  water  samples  production  were  refractive  of  probably  started  accepted.  (0.35  I t was  Refractometer  plasma  The  vials.  samples  measured  periods.  was  fish  characteristic  II).  recent  Urine  The  terminal  further  experimental  trout  Section  percent  until  hemat-  polyethylene  Goldberg  instrument;  Samples.  hour  data  device  be  Urine 2  a  This  -12°C.  or  with  meter).  and  1  uL)  TS  frozen  the  (20  minutes;  centrifuge tubes.  the  the  over  the  f o r 10  small  supplied with  (iii)  it G  aspirated into  tables  stored  13000  was  f o r water  Optical  which  spun  directly  plasma  analyzed  index  and  the  the  the  urine  from  the  dead  failure  suction of  siphon  experiment.  for these  of  analyses  cannula  space  On  animals  sample  with  of  the  uninformative.  (see  this  were  precannula However,  22 assay that  of  Na  renal  therefore  i n urine excretion of  had  no  effect  from  a  the on  few  experiments  r a d i o i s o t o p e was flux  rate  and  demonstrated negligible  sodium  space  and  deter-  minations. (iv) with  MS  maintain  222 any  Tissue prior  to  Samples. sacrifice  physiological  Anaesthetization of  the  was  attempt  performed  difference  in  in  tissue  an  samples  trout to  32 resulting Extreme could  from  differences  hyper-activity  well  resting  have  state  or  recovery  and  stunning,  water  and  dried  the  1.5  right  visibly  g  the  with  each)  side  of  of  contaminated  with  handling  conditions.  fish  was  trout  After  quickly  towels.  dorsal  with  treatments. in  normal  characteristics distinctive  paper  the  experimental  associated  eliminated  water  imately  in  below  the  lateral  rinsed  Three  epaxial  line  removal with  portions  of  the  fresh (approx-  were  excised  dorsal  f i n .  Any  muscle  the  from  muscle  red  trout  or  from  samples  skin  were  discarded. In  early  immediately to  .1  from  mg an  transferred  accuracy.  vial  and  weighing.  obtained for  72  hours  The  dishes  container  of  surface  and  water  ionic  Physical  the  gills  area  determinations tissue  weighed  of  flux  set body  of  over  within  10  to  a  tissue  samples  in  a  results  were  small  poly-  separation were  dried  calculated  by  thereafter  stored  of  at  weight  the  Fish.  103°C.  difference.  in  a  closed  on  fish.  the  minutes  weight. a  It  weight  Accurate  were  and  therefore  carcass of  per  the  Ionic  flux  proportional  l i m i t e d range,  body  rates  weight  dissection,  weighed  before  identical  was  and  sealed  minutes  Tissues  were  dish  a l l three  t h e o r e t i c a l l y be  proportional  homogeneous  that  tissue  analysis.  should  branchial  30  Measurements  implicated;  express  -  of  aluminum  immediately  contents  later  piece  runs,  methods.  for  to  and  two  each  tared  20  showed  tissue  considered  After  for  dried  be  fairly  the  were  of  (v) rates  left  a  later  fish  Tests  with  to  In  individual  ethylene and  experiments,  g i l l is  to  area  the may  customary  basis  for  a  systematic necessary.  was  carefully redried  end  of  the  experiment.  33 A  correction  added  to give  degree g i l l  factor  o f body  area  records  final  efficient  was  length,  The  the weight  weight.  development  ratio)  of  taken.  1969)  a  (2 x  of  condition,  f o r each  among  length,  measurements  order  of Condition  =  100  x  weight  d e p t h , were of  the  "plumpness"  Body  (Fork Analytical  of  the to  treatment groups,  calculation  expression  was  whether  the body  maximum  permitted an  test  different  and  tissue)  also co-  (Toews,  trout.  Coefficient  4.  to  (and t h e r e f o r e  similar  fork  In  o f removed  Weight  Length)  3  (g)  (cm)  Procedures 22  of P  each  (a)  Na  (i)  Water.  water  emission  equipped  sample  with  samples  for  30  an  triplicate  on  planchets  were  similarly from  the  1.0 and  ml  counted f o r  470  gas  flow  changer  and  decade  analysis  were  aliquots  detector  counted  scaler. 3  times  counts.  Plasma.  sample  resulting  dried  or  a u t o m a t i c sample  minutes/10,000  then  was  were  for radioactivity  (ii)  and  Duplicate  i n a N u c l e a r - C h i c a g o Model  All  plasma  Concentration.  Single  diluted  with  c o u n t e d and small  50  or  1.0  100 ml  dried.  amounts  of  uL  aliquots  of water Self  solid  on  of  each  planchets,  absorption  material  i n the  plasma  insignificant. (iii)  correction necessary  Tissue.  factors to  count  the  planchet.  Dried  to  a  fine  with  of  storage,  the  avoid  for a variety  each  powder  To  same  a mortar had  of  amount  tissue  samples  derivation tissue  were  by  (75  -  was  85  individually  pestle.  rehydrated  self-absorption  weights, i t  of material  samples and  of  During 10  -  15%  the of  mg)  i n  ground period  their  true  dry  were  weighed  12  weight.  hours.  samples were and  The a  85  tared  true  -  dry  were  planchet  in  entire  order  slurry  lamp  to  with  avoid  planchets analysed  to  surface  fine  area;  a  an  the  and as  then  emissions  of  added  drying  the  -  85  mg  the  values  each  of  matter  mixed  under  powder  correction by  for  those 75  to  was  Triplicate A  only  acceptable  paste  slow  above.  103°C.  distribution  of  tissue  appropriately corrected  resultant  flaking  at  range  until  was  even  experiment.  self-absorption of  the  were  After  powdered  redried  within  water  needle.  counted  each  of  of  reweighed;  repeated  obtain  cracking  were for  ml  amounts and  samples  dessication process One  mg  then  weight  Rejected  obtained.  95  planchets  planchets  accepted.  were  for  into  with  the  the  Thus  to  a  over a  heat  surface,  the  a l i q u o t s were  ( x 1.4661)  factor  tissues  was  determined  22 by  assaying  and  dried  known  with  muscle.  In  corrections counter months  to  75  amounts  of  Na  -  of  powdered  85  mg  a d d i t i o n , i t was for  the  after  which  as  those  of  Total  Sodium  tissue  plasma  and  to  incubated  apply  water  were  from  change  counted  a  epaxial  appropriate  efficiency  samples  and  been  unlabelled dorsal  necessary  r a d i o a c t i v e decay results  had  of  the  9-12  particular  experiment. (b)  Water. water  samples  5890 &  was  against  in  volume  vals  L  were  As  caused  extremely  concentration  sodium by  appropriate  (Harleco).  6  The  assayed  standard a  Concentration  range  small, was  flame  emission  dilutions  the  by  concentration  a  actual 200  g  of  impractical.  of  at  commercially in  over  15  sodium  prepared levels  minute  a l l samples Two  external  photometry  changes  trout  dilution  a  of  to  different  intera  common  methods  of  analysis  the  were  applied,  two d i f f e r e n t Samples  were  assayed  Absorption it  trations  photometers from  used  Model  Spectaphotometer.  ( e . g . 1.75 -  state  Sp 900A Over  to calibrate  greater  than  A  o f the instrument i n this  and s i m i l a r l y  Absorption ranges  the 0  exclusive  and  mode  were  ug/ml  with  a  1/2  conwith  o f marked i n -  of operation,  performed  o f a T e c h t r o n Model .  multiple  at less  than  50%  +  over  3.00 u g N a / m l , +  the-highest  Each  120  Atomic  intervals  calibration  o f 0 - 1.00,  withi consequent ranges.  was r e a d  range  were  loss  but the latter  (ii) distilled  Plasma. water)  - 1.00 u g N a / m l +  was  f a r more  Triplicate  o f each  plasma  calibration  twice;  this  stability  at nearly  maximal  those ex-  again diluted  by two.  t o be  efficient.  dilutions sample  range  of  However  f o r by t h e extreme  unknown  Thus  t h e a c c u r a c y o f t h e two t e c h n i q u e s a p p e a r e d  comparable,  analysed  not feasible.  o f d e t e r m i n a t i o n s even  deflections.  Overall,  was  i n the higher concentration  was p a r t i a l l y c o m p e n s a t e d  ceeding  AA  were  Operation o f the instrument  o f 0 ug Na /ml calibrated  reproducibility  scale  0  was  - 2.00, a n d 0 -  fault  Because  h  the concen-  diluted  the recovery experiments  Spectrophotometer  photometer  accuracy  of  from  t h e e m i s s i o n mode  at  read.  unknown  0.50  Na /ml,  deflection. Samples  on  were  +  stability  scale  3.50 u g  few samples  3.50 u g N a / m l  water  on each  0 -  bracketing  +  experiments  Emission/Atomic  the instrument over  distilled  determinations  and a c t i v e  Flame  2.25 u g N a / m l )  of  study.  t h e range  o f experimental samples.  centration  by t h e p r o p e r t i e s  i n this  the resting  on a Unicam  was p o s s i b l e  intervals  as determined  ( 1 u L i n 6.00 m i s  were  on e i t h e r  assayed flame  i nthe  photometer.  Each  dilution  freezing  of  proteins, nor  the  this  The to  significantly  was  not  personal  term  were were  true then  heated  room  temperature.  to  10.0  mis  0  -  that  50  high  200  5.  sodium  K /ml +  of  swamp  the  to  of  by  freezing  the  50  sake  of  con-  throughout  samples.  tared  1.0  of  each  powdered  polyethylene hours  ml  and  vials.  reweighed  of concentrated  i n c u b a t e d f o r 48  hours  uL  diluted  aliquots  were  Techtron  flame  photometer  over  range.  Toews  (1966)  shown  potassium  standards  eliminate  concentrations  i s used  f o r 24  samples  e m i s s i o n by  both  Sodium  Flux  Measurements change  i n sodium  hour  influx, the  small  plasma  sodium  aliquots  Exactly  the  on  mg  of  neither  f o r the  frozen  70°C.  calibration  flame  changed  that  as  i n trout  much  and  this  as  muscle  15%.  unknowns  has  Therefore  contained  a  effect.  Calculations (a)  one  at  concentration  dilutions  ug  into  Triplicate  assayed +  enhances final  and  uEq- N a / L  the  115  dry weights. and  that  concentration  Single  added,  i s strictly  shown  noted  precipitation  communication);  weighed  at  a  have  "plasma"  Tissue.  containers  HNO^  which  are  sample  obtain  sample  I t s h o u l d be  in partial  f o r d e t e r m i n a t i o n s on  (iii) muscle  result  tests  the  thesis  times.  However  (Toews,  venience,  2 - 3  may  producing a  fluid  process  read  plasma  serum.  of  was  the  efflux,  and  net  flux  Multiplication  (ug/ml)  decline  concentration  experimental period  trout.  sodium  of  Rates  and  Na  22  of  in radioactivity  the  external  and  medium  over  allowed calculation  of  across  surface  of  (cpm/ml)  the by  the  external  sodium  concentration  of  the  water  volume  of  the  of  total in  the  chamber  (after  appropriate  correction  f o r sampling  deficits) 22  yielded in  absolute  the external  amounts medium  (At),  the influx  could  be  rate  calculated  radioactivity  of total  sodium  (Na e x t ) a n d Na  a t any one t i m e .  Over  ( F i )o f sodium(ug/min)  from  the specific  (AQ) o f t h e e x t e r n a l  any time  into  activity  the  (Q) period  fish  and l o s s i n  medium:  AQ Fi  =  "  A  (1)  t  Na e x t Similarly interval (ANa  could  be  rate  computed  (Fn) o f sodium from  over  t h e change  t h e same  of total  time  sodium  e x t ) i n t h e v/ater:  Fn  Thus  the net flux  =  - ANa e x t A t  the net flux  diminished.  was  Finally  (2)  p o s i t i v e when the efflux  external  rate  Na  ( F o ) was  concentration  +  c a l c u l a t e d by  difference: Fo Flux It  =  F i -  rates  should  mental  have be  been  noted  periods  Fn  (3) e x p r e s s e d as ug Na /100 +  that  a t no  time  d i d the internal  represent  more  than  rendering  backflux  during  specific  3.5% o f t h e e x t e r n a l o f Na  22  into  g body  weight/min.  t h e one hour activity value,  the water  of  experi-  sodium  thereby  insignificant. 22  (b) This the  Apparent  parameter  distribution  is  defined  in  the organism  tration  Volume  i s a theoretically  of the radioisotope  as t h e volume  as t h a t  o f D i s t r i b u t i o n o f Na  when  (ml/lOOg  within  body  derived  22 o r Na  measure  the organism.  weight)  occupied  uniformly  d i s t r i b u t e d a t t h e same  o f the plasma.  The r a d i o s o d i u m space  by  Space of I t 22 Na  concen(Vint)  38 at  a particular  centration amount  time  o f Na  22  was  calculated  i n the plasma  of radioactivity  from  (Na  22  i n the trout  the measured  con-  /ml p t ) a n d t h e known  (Qo - Q ) .  Qo  represents  22 the  amount  o f Na  (cpm)  added  to the external  medium  at  time  zero . Vint  (c)  =  Fate  Qo - Q 22 Na /ml p t  o f Sodium  Taken  (4)  up  from  the External  Environment  22 The fluxed  factors:  could  a rapid  volume.  sodium  (i) tration medium  within  volume taken  among up  i n plasma  o f sodium  ( N a p t ) was  high  following  tissue  sodium,  or a large i n  dis-  plasma  radio-  the treatment groups, the the external  blood ions  estimated  f o r the  o f the  with  differences  from  At each  a relatively  sodium  ofi n -  causes  one o r more  of the radioisotope  Plasma.  no  the system,  to investigate  ions  b y means  from  o f plasma  "sink"  In order  o f sodium  result  of dispersal  but reveals  F o r example,  exchange  distribution  traced  a measure  i n the organism,  volume  localized  sodium  provides  distribution.  tribution  fate  space  sodium  observed  a  Na  i n both  plasma  sampling time,  transported  from  environment  from  t h e measured  and  was  tissue.  the concenthe  external  concentration  22 of  Na  over the  i n plasma  and t h e average  the experimental total  sodium  Na  period  content  pt  =  up  dorsal water  Tissue.  epaxial during  muscle  to that  o f the water  2 x Na  2 2  /ml  t i m e . Na  a t time  ext  activity Q  represents  zero.  pt  (5)  -Na e x t  Similarly which  specific  Q  Qo Na e x t o (ii)  external  the level  had o r i g i n a t e d  the experimental  period  ( Na  o f sodium from  the  t t ) could  ions i n external be  approxi-  mated  from  the  radioactivity  per  gram  of  the  terminal  tissue  22 sample  (Na  Na  In  /g  t t  this  tt) =  2 2  case,  Q Na  activity merely had  at  60  must  period;  minutes.  influxed the  concentration  from  value  the  necessarily  proportional  its  been  specific  reduced  by  However  the  be  amount  activity)  to  wxth  of  this  the 22  Na  total  i n muscle over  absolute  ions  by the 22 ( Na /Na  ( i n the  the  to  an  up  activity  dilution  way  sodium  taken  proportional  external  specific  emphasized  environment  i s i n no  o f plasma  has  the  I t s h o u l d be  corporation  sodium  represent  ext  estimates the  been  (6)  2 x Na /q t t Qo + Q Na e x t Na e x t o  into  gills  into  total)  incorporated of  the  the  of  nor  the i n -  even external  bloodstream,  drastically 23 Na ions i n plasma  of  in tissue  of  which  be  average  incorporation  t t  minute  Once  will  number  60  measure  tissue,  Na  sodium  the  parameter.  large  ratio  of  that  should  external  sodium  ions  s t i l l  specific  from  the  water. (d)  Extracellular  Extracellular volume  of  the is  are  i o n i n the known  radiosodium  space.  Na  utilized space  volume  f o r the  but  body  be  e s t i m a t e d from  sodium  when  heterogeneous calculated  should not  following  Na  t  x  (H 0)p  Na  p  x  R  2  be  formula,  for computation =  (E.C.F.V.)  may  E.C.F.V.  space, The  Volume  total  organism.  sodium  was  of  applied  as  (1954)  fluid  distribution  corrections  Fluid  of  the  appropriate  distribution in this  manner  confused  with  as  by  given  of  Manery  E.C.F.V.: (7)  40 Where: Na  t  =  (H„0)p Na  p  R  tissue  water  = plasma  Na  =  Gibbs  established =  6.  0.942,  Such  losses  on  i t was  o f an  by  N  =  acceptable  with  the exception would  absence  a  fish  was  has  +  tissue,  so  not y e t been  the  s t u d i e s , was  value  used.  o f cases  hematocrit from  which  some  data  and  dilution a l l data o r two  mult-  be  lost.  (e.g. cannula processing  errors). from  of  should  i n the later  Yet i t  a particular  samples.  group, time  values  were  for a  presented  of observations.  i n i t s own  tissue  simultaneous  trout  Therefore  used.  number  bias  F o r example,  involving  and the c o l l e c t i o n  o f one  treatment  obviously  i n which  however  plasma  plasma  the experiment  failure)  measurement  data  animal  during  to discard  each  a t each  accompanied  question.  for Na  that  (e.g. contamination,  Within  for  both  f o l l o w i n g scheme  sample  nature,  inevitable  or transducer  unreasonable  parameter  teleost  mammalian  of this  occurred  the basis  the  ratio  o f several parameters  samples,  samples  i n mEq/L  wet  Data  a study  iple  seemed  of  i n ml/kg  tissue  f o r Na  Donnan  from  wet  Organization  measurement  of  ratio  f o r f r e s h water  (a) In  concentration  Donnan  obtained  i n mEq/kg  concentration  the Gibbs  Presentation  occlusion  concentration  +  = plasma  Unfortunately  R  Na  right where  included  failure  the inclusion  plasma  sodium  two  water  blood  a  i n the  were was  values  samples  mean  piece  of  average, a  of the value  values  sodium  as  to obtain  concentration  and p l a s m a only  was  Each  particular  used  related i n from  unavailable;  were were  rejected drawn, f o r  an  41  the  normal  serial  ponsible  for  in  trout.  other  mean  the  The  following techniques  of  this  the lines  sets  variance. their  the  is  the  not  by  Kramer  essentially  greatly, cant  there  homogeneous  which  F  a  by  within this  single  i t has  differences.  of  not  been  time  data  by  points  a  one  from  use  of  of  an  equal  the  a  number  analyses  of  numbers  number  ranked  under-scores p o s s i b l e to  Significance  levels  subsets  In of  demonstrate of  Duncan's i s  each  measure-  a condition  of  of  replications, technique  replicates  means  each  extension of  increased probability of  and  test  The  of  of  within  replicates, The  para-  differences  i n which  utilized.  " i f the  subset  some  analysis  Means  study.  been  For  Duncan's  data  been  regression  significant  f o r unequal has  the  of  have  a modification of  of  present  Test  an  sets  by  way  presented. for  error  as  coefficients.  squares.  to  a l l three  parameters  test".(Kramer,1956).  line  res-  expressed  standard  correlation  least  are  the  (Duncan,1955).  in  be  to  compared  (1956),  will  with  applied in  between  obtained  conservative;  difference  figures,  of  Test  Range  factors  been  and  subjected  then  apply  these  partially  £  simple  method  contains  least  ha)» g e n e r a l l y b e e n  fitted  analysis  Multiple  proposed  of  were  were  at  have  number  significance  Range  for  does  New  N  protection level  category  which  the  values  of  Multiple  ment  the  been  data  group  5%  designed  by  of  levels  the  New  have  The  treatment at  Data  calculation  computed  meters,  in  Possible relationships  by  Straight  by  was  Analyses  study.  accompanied  tested  changes  Statistical  mean.  lines  observed  process  (b)  sections a  the  sampling  a  signifi-  classed  legends means  differs  as  for within  significant  difference  between  comp-  arable  means  tained  by  otherwise level.  of different  application stated,  of  treatment the  groups have  "Student's"  significance  has  been  t  been  -test.  assumed  ascerUnless  at the  .05  RESULTS  A.  The  Effect  of  AND  DISCUSSION  Chasing  on  I  Ventilatory  and  Cardiovascular  Parameters Chasing than  the  animal's  satisfactory technique  body  this  exercise, to  did  fact  function changes  cause  between were  swimming,  Two  5,  6,  7,  In  Table  sample The  and I,  Brett's going  in  determinations  in  specific in  a  data  the  that  "%  description recording prior  relative state;  in  far  was  from  the  flux  only  rate  important  of  to  sodium  procedure  the  balance  adopted  cardio-respiratory of  fish,  and  that  resting  of  to  as  data  means  these  state,  are  used  in  a  the  metabolic  in  the  laboratory  to  zero  the  in  i n measured value  for  obscured  apparent.  by  rate  have  this  values. at  selected  Davis,1968).  homologous  of  results  real  (cf.  of  been  fish  under-  considered is  parameters  advantfor  particular  variability  It will  to  situation;  manner  that  for  Figures  summarized  sense  time  utilized  data. of  routine" values  trends  t h e r e f o r e become  been  respiratory  results  c o n s i d e r i n g changes fish  the  groups  hand,  of  Expression  quiescent may  investigation  p r e s e n t a t i o n have  other  taken  but  a  longer  conditions.  "routine" i s here (1962)  be  sodium  representative of  of  terms  continuous  ageous  the  experimental  the  slightly  to  activity,  differences  present  on  "routine".  appeared  c a r d i o v a s c u l a r and 8  times  term  real  methods  only  simultaneous  demonstrate  recovery  of  chamber  therefore, critically  distinctly  and  expression  with  study,  during  a  inducing  I t was,  of  in  initially  for  compatible  part  in  trout  method  measurements. major  of  be  in  noted  a animal the  that  44  Table  I.  resting,  Ventilatory active,  "% r o u t i n e "  Heart  rate:  Dorsal aortic blood pressure:  Ventilation rate:  Buccal pressure amplitude:  and c a r d i o v a s c u l a r  and r e c o v e r y  responses during the  e x p e r i m e n t s i n t e r m s o f mean  values. 5 o r 65 minutes  30 o r 90 minutes  60 o r 120 minutes  rest  104.25  103.00  107.44  active  109.32  120.19  117.16  recovery  108.14  103.00  105.97  98.06  93.86  92.08  106.28  101.12  103.12  recovery  87.92  94.41  88.93  rest  99.86  99.73  99.35  active  110.35  109.38  107.10  recovery  101.85  98.41  96.21  rest  108.40  102.52  92.52  active  141.96  169.28  169.44  recovery  132.26  102.45  104.11  rest active  45  Figure  4  Typical pressure and b u c c a l rest,  I.  from  c a v i t y o f a rainbow  chasing,  Section  recordings  and  recovery  F i s h #U.  the d o r s a l  aorta  trout obtained  i n the p r o t o c o l  235.4 g . R e c o v e r y  of  group.  during  DORSAL 50r AORTIC BLOOD 25k PRESSURE (mm Hg )  BUCCAL PRESSURE (mm Hg )  5i  resume chasing  10 seconds 0 MINUTES-REST  DORSAL AORTIC  ll  YWYYVYYVVVYVw^^  30 MINUTES-EXERCISE  50p  BLOOD PRESSURE  25h  (mm Hg )  0«-  BUCCAL PRESSURE (mm Hg)  cease chasing 60 MINUTES-EXERCISE  120 MINUTES-RECOVERY  46  Figure  5  V a r i a t i o n s i n heart r a t e over in  resting,  First during  active,  hour v a l u e s  and  the  recovery groups of  for recovery  their  initial  + - 1 standard  error.  experimental  chasing  fish  were  treatment.  periods  trout.  obtained Means  REST N=7  80H  40-  15  i  45  30  ACTIVE N=9  ,L  F-' 8 0 -  z. 2  60  J  • = ACTIVE FISH A - RECOVERY FISH - 1 s t HOUR  ^2 6 0 CD UJ  40-  I— < cn  0  15  35T  x  45  __J  60  RECOVERY N =8  or 8 0 < UJ  60H  40-  60  75  90 TIME (MINUTES)  105  120  47 "%routine" points while  in  values Figs.  the  increases blood  5 - 8 ;  latter The  presented  in  of  and,  bradycardia  changing  (Fig.  However  throughout ations  of  rates  after  the  values  pressures  are  was  a  values  probably attained  a  after  time  have  lower  exercised  immediate  dorsal  15  -  highly  actual  intervals  with  than  fish  short-term seconds  erratic determin-  exercise  periods.  recordings  immediately been  aortic  30  systematic  from  from  percentages  noticeable  remained  during  computed  means.  rate,  precluding  somewhat by  and  be  of  associated  extracted  rest  sampling  of  tachycardia traces  cannot means  animals,  pressures  minute  blood  are  i n many to  I  percentages  thereby  and  only  one  each  former  chasing  both  chasing,  Consequently, during  be  Table  v e n t i l a t o r y amplitude  pressure,  4).  the  would  onset  in  taken  before  reported. the  during  and  These  mean  rates  and  the  experimental  periods. Heart increased exercise is ten  a  levels  minutes  speeds  than  the  of  increase  and  (15%)  40  Randall,1967  a).  sockeye  in in  severe  salmon  on  frequency  cardiac  rate  i s probably  pre-  Salmo  to  52  cm/sec.)  in  a  The  increase  is  far  gairdneri  observed  rainbow no  response  related  to  cardioacceleration  Stevens  of  rest,  declined  salmon^ O n c h o r y n c h u s However,  during  in  tachycardia  exercise  cardiac the  recorded (up  80%  and  This  swimming  -  stable  chasing,  recovery.  moderate and  remained  during  Davis,1968).  imposition  difference  2 0%  that  i n mature  al.,1967;  trout  to  of  ( F i g . 5)  during  (Stevens  smaller  an  maximum  comparable  tunnel  rate  to  to the  water  fatigue  nerka ^(Smith  (1968  trout  more  at  during  b)  found  could  than  absence  that  elicit  15%.  swimming  et  The between  in  the  48 former  (Stevens  (Randall Randall during 4.5  and  a,  moderate  fold  in  The  cardiac  can  be  fluid;  during  to  an  and  and  but in  von and  -  trations  have  activity  rhythms  (Boehlke  et  the  partially delivery general  and  in  the  blood  flow  through  stimulation  Starling  in  as  of  curves  return no  have  the  an  at  been  study  of  the  an  per-  increase  increases of  venous  stores  of  unidentified  reported  Fa.nge,1961;  that  g i l l s .  probably  yet  a  different  causes  Ample  as  and  gairdneri  measures  teleosts.  with  present  Salmo  factor  yet  plus  the  concentrations  either  are  in  in  Nakano  and  in  that  cate-  teleost and  tissue,  Tomlinson,  of the  with  concen-  diurnal  to  induced  these  hormones  maintenance  adrenaline the  blood  of  were and  It  at  high  cardiac in  noradrenaline capillary  Increased  seems  least  presented  branchial  flow.  is  }  exercise  Tomlinson,1967).  Arguments  lamellar  catecholamine  catfish^Ictalurus punctatus  and  vasodilation of of  plasma  response  (Nakano  for  of  correspondence  channel  swimming.  introduction for  heart  Stevens  probable  in  Venous  mobilization  responsible  responsible  seems  fish  and  found  trout  during  It  latter  cardioacceleration  chased  elevations  al_.,1967)  that  associated  output.  rest.  the  Burnstock,1969).  been  rainbow  probable  was  of  4")  Euler  Significant  in  rainbows  catecholamine  vivo  ("catechol  Gannon  15%  of  there  in  the  isolated  series  presence  that  noradrenaline  ( O s t l u n d , 1954; 1967;  the  (Bennion,1968).  adrenaline cholamine  of a  pressures  vagal  but  at  of  elevation  swimming,  filling  in  a),  tone  cardiac  occurred  pressures  output  in  augmentation  related  fusion  in  output  of  calculated  activity  changes  f i l l i n g  b,)  increase  resulting  Randall,1967  Stevens,1967)  (1967  similar  in  and  the are  also  network  passage  of  49  Figure 6  Variations  i n dorsal  a o r t i c b l o o d p r e s s u r e over the  e x p e r i m e n t a l p e r i o d s i n r e s t i n g , a c t i v e , and groups o f t r o u t .  F i r s t hour v a l u e s f o r r e c o v e r y  were o b t a i n e d d u r i n g t h e i r i n i t i a l Means - 1 s t a n d a r d  recovery fish  chasing treatment.  error.  A r e a mean b l o o d p r e s s u r e =  2(diastolic) + 1 systolic 3  40 H  30-^ REST N=7 O)  20 H  I  E E UJ  10  o  15  30  ACTIVE N=8  or  Z> UI UI  LU o:  GO  45  30-^  Q.  Q  Q CQ  • = ACTIVE FISH A= RECOVERY FISH - 1 s t HOUR  20-  g  O <  10  O  15  60  75  30  <  L  60 45 RECOVERY N=7  8 30 H z < LU  Z  20H  < LU <  10  90 TIME (MINUTES)  105  120  50 blood  through  ilitate appear  these  oxygen that  culatory  and  respiratory carbon  dioxide  catecholamines  adaptation  to  pathv;ays  are  the  should  exchange.  turn  I t would  instrumental  increased  in  in  factherefore  effecting  metabolic  demands  cir-  of  exercise. Dorsal individual fell  animals  slightly  Expression revealed above  blood  resting by  resting  in  salmon  in  blood  During  to  over the  blood the  the  experimental  data  levels  (Smith  recovery,  follow  of  exercise and  and  the  Both (Fig. Chased  8)  Randall  of  in  Davis,1968);  constant  demonstrated  with  a  in  did  were  of  (70%)  present  been  these  and  resting polypnea  noted  the  drop  response  appropriate  are  applied  study,  during  (Table  observed  withdrawn.  in  When  sampling  in  immediately  decrease  the  to  data,  moderate  conditions  studies,  variations  the  have  volume  fluid.  ( F i g . 7)  blood  reduction  least  I)  slightly  Smith,1967),  controlled in  (Table  in pressure  the  not  the  slight  pressure  and  reported  more  rate  fall  to  blood  those  correlated  i n buccal  and  circulatory  under  breathing  remained  fish  increases  be  a;  to  This  or  6).  pressures removal  between  stable  values  Similar effects  measured  recovery  could  serial  proportioned  effects  similar  Randall,1967  changes  I).  (Fig.  routine  protocol.  chasing  changes  trends  the  "^routine" pressures  termination  pressure  to  maintained  al.,1967;  being  period  progressive  (Table  et  pressure  the  further depletion of  the  trout  varied greatly  g e n e r a l l y remained  in relation  despite  explains  for  mean  experimental  animals  corrections  pressure  but  exercised  the  volume  in  after  of  that  demanded  aortic  pressure  in cardiac  buccal group (10%)  (Stevens  output.  pressure of  trout.  and  I ) ; these  very trends  large were  51  Figure 7  Variations  i n v e n t i l a t i o n r a t e over the  experimental  p e r i o d s i n r e s t i n g , a c t i v e , and r e c o v e r y groups o f trout.  First  hour v a l u e s f o r r e c o v e r y f i s h were  obtained during t h e i r i n i t i a l Means - 1 s t a n d a r d  error.  chasing  treatment.  REST N=10  90-i  8 OH  LU  i—  70-  ZD  O  15  30  45  60  ACTIVE N=11  00 LJ 100H  DC ZD  9 U  90H  X  • --ACTIVE FISH  I-  A= R E C O V E R Y FISH  ZD  O 2  LU  - 1 s t HOUR  80H  CC  o  15  30  45  60  O 100i RECOVERY N = 11  Lu 9 0 H >  80-  70  60  -LL  75  90 T I M E (MINUTES)  105  120  52  Figure 8  Variations  i n buccal pressure  experimental  amplitude  periods i n resting,  active,  groups of t r o u t .  First  fish  during their i n i t i a l  were o b t a i n e d  treatment.  Means -  1  hour v a l u e s  standard  over and  the recovery  for recovery  error.  chasing  REST N=10  •= ACTIVE FISH A = RECOVERY FISH -1st HOUR O  15  30  I  45  I  60  RECOVERY N=10  4-fc 60  75  90  TIME(MINUTES)  105  120  quickly  reversed  of  rest  a t each  in  both  components.  associated and  of  with  mammals  rate  buccal  that  3.0  from  Stevens  e f f e c t e d by  joint-tendon  reflex  stimulatory  on c e n t r a l r e s p i r a t o r y  Stevens  flow  v-7as  cycle  when  study.  A  swimming  against  of  measured  at  (Davis,1968). study  breathing 4  fold  However,  t h e mouth  signi-  of  vent  Saunders,1970)  be enhanced  during  are  Elevations  i n a recent and  indicate  frequencies  t o those  their  (1967 a, b ) .  volume would  and Kendall,1968)  breathing  reported  i n salmon  (Hughes  elevated  chasing  calculated f o r moderately  and Randall  ventilation  actual  group.  presented  than  (1967 a ) , b u t  ventilatory  speeds  i n the present  (10%) a r e lower  values  are similar  trout  fish  here  treatment  the data  chased  fold  ventilatory  by  volumes  increment i n swimming  trout  i t i s likely  "ram"  opening  a constant  ventilation  phase  of the  current  i n a  tunnel. The  ledge  a r e commonly  a) o r a d i r e c t  during  o f mean  swimming  i n the rainbow  suggests  water  be  and Randall  post-exercise  however,  to fatigue  Extrapolation ilation  taken  the exercised  pressure,  reported  by Stevens  of recordings  by  moderate  (Muir  a n d may  catecholamines  underestimations  attained  that  reductions  (Saunders,1962;  to the Harrison  increases  the immediately  -  Davis,1968)  intervals  marked  i n ventilation  and Randall,1967  (30%) observed  ficant  2.5  produced  i n teleosts  similar  the short  (Waitzenegger,1967).  inspection that  a, b;  Even  time  Increases  (Stevens  The those  sampling  of circulatory  centres  recovery.  exercise  a mechanism  action  by  blood  Randall,1967  either  during  data  of teleost  reported  above  physiology  add*  nothing  by themselves,  new  b u t do  t o o u r knowdemonstrate  54 that  the  of  slight  a  desired fall  serial  blood  in  "routine"  the  The  similar  during  a,  unreasonable in  the  B.  E f f e c t of  resting  Before use  of  needs  rate  chased  to  The  the  across  skin  general  urinary  release  Intestinal rainbov;  do  Gordon,19695. contamination gelatinous  Howaver  of  sodium.  may  main  system,  move  the  e l e c t r o l y t e s was  not  of  the  tube  which The  In  of  sodium  drink  in  of  and  external mucoid Gordon  normally  medium,  (1969)  encloses of  was  have  measured  Salmo  a  and  the  system,  g i l l ,  and  the  experiments, by  by  catheterization.  the  fact  (Shehadeh  vented  fed  some from  faecal trials,  the that  fish,  gairdneri  that  and  eliminated  during  in  fluxes  internal  demonstrated  faeces  by  results,  teleost:  these  but  seem  consump-  these  the  a  starvation  material  impermeability  of  x^7ater  not  Fluxes  of  to  negated  fresh  fold  measured.  prevented  was  5  and  characterized  intestinal  surface.  a  oxygen  between  regions  trout  i t does  Sodium  reference  were  (Stevens  in  evaluation  Pre-experimental  Shehadeh  material,  of  body  in  period.  rainbow  level;  parameters  and  remained  chasing  measured  was  Branchial  ions  four  urinary  absorption  trout  the  of  in  increase  Recovery  on  "branchial" for  exercise  to  experimental  speeds  workers  exception  group  correlates  similar  in  Exercise  the  the  this a  levels  epithelium, of  at  the  moderate  the  attributable  documented  latter  presentation  term  media  at  animals.  justification,  external  a  The  With  treatment  throughout  swimming  estimate  return  resting  previously  b).  to  the  cardiovascular  those  controlled  produced.  aortic pressure  condition  in metabolic  tion  dorsal  and  to  Randall,1967 rise  in  sampling,  ventilatory  very  e f f e c t s were  is  skin  anus. this devoid to  55  sodium The  has  been  assumption  observed  was  are  permitting 100  g  of  resting, are  a  Data  over  active,  three the  and  (Table  maintained (17.62 being mean  a  ug/100  state  of  net  uptake  branchial remained an  across  efflux  the  to  body  time  rates  Average  thus  reduction  not  rates.  that  ion.  markedly  0.001)  to  on  small  at  the  only  a  net  causing  animals influx  g/minute) a very  0.01)  slight  while  of  after  influx  there  sodium an  of positive  efflux  the  however,  loss  period,  state  i n the  among  Consequently,  .001)  and  concen-  gills,  ug/100  was  f o r the  factor  (70%, p <  levels.  returned  there-  g/minute  sodium  Resting  (16.88 there  a  During activity,  resting  (p <  and  i n Fig. 9  external  was  efflux  the  of very  differ  surface  groups  significantly  recovery  a  g i l l  used,  treatment groups  the  fish  to  between  equilibrium  so  sets.  d i d not  are presented  (p <  the  two  fish  intervals.  differ  and  Over  range  resting  other  groups  movements  extremely significant gills.  the  weight  weight  i n flux  increased  identical  exercise,  through  of  f o r the  the  and  approximately equal  of  of  e x p r e s s e d i n ug/100  sodium  g/minute)  size  experimental  been  III.  observed differences  i n each  has  flux  groups  trout  rates  III) d i d not  experimental  f o r the  flux  recovery  i n Table  origin  of  short  sodium  Fromm,1968).  sound.  that  common  narrow  comparison  sodium  summarized  tration  of  condition  f o r the  Branchial  was  than  convenience i n discussing  amounts  seem  I I ; t h e mean  larger  of  basis.  branchial  dimensions of  indicating  fore  (Holmes.,1959;  therefore,  i n Table  coefficients  relationship  for  exclusively  slightly  area  per  repeatedly  would,  tabulated  significantly,  a  an  physical  obviously  However  of  fluxes The  group  proven  hour balance  parameter  to  56  T a b l e I I . P h y s i c a l dimensions  o f t r o u t i n the t h r e e  e x p e r i m e n t a l groups o f S e c t i o n I . Resting N = 10 Body weight  (g) 259.66 ± 12.79  Means - s t a n d a r d  Active N = 11  Recovery N = 11  233.95 - 11.19  228.17 - 8.05  P  p^< .05  = n.s.  1  P  Length  (cm)  29.95 ±  0.50  28.81 - 0.45  s= n.s.  = n.s.  1  p  28.63 -  0.47  = n.s.  2  29.65 - 0.49 P  Fork l e n g t h (cm)  2  6.18 -  0.14  27.62 - 0.40  P  p  = n.s.  1  v;eight x 100(fork l e n g t h )  1.101 - 0.022  = n.s,  1  = n.s,  2  5.91 ± 0.14  5.87 t  P  p  1  = n.s.  P  Coefficient of condition  = n.s.  28.01 - 0.51  P  Max.depth (cm)  error.  0.09  = n.s,  x  = n.s.  2  1.062 - 0.028  1.084 i 0.029  p^j^n.s.  p  1  &2  = n.s, =  *'  n  S  p  1  = s i g n i f i c a n c e with respect to corresponding r e s t i n g value.  P  2  = s i g n i f i c a n c e with respect to corresponding active value.  57 Figure  9  B r a n c h i a l sodium f l u x r a t e s o v e r c o n s e c u t i v e i n t e r vals o f the experimental periods i n resting, active, and r e c o v e r y g r o u p s o f t r o u t . B l a c k b a r s = mean branchial s o d i u m i n f l u x r a t e s ; d o t t e d b a r s «= mean branchial s o d i u m e f f l u x r a t e s ; c l e a r b a r s = mean branchial sodium n e t f l u x r a t e s . The v e r t i c a l l i n e s r e p r e s e n t 1 s t a n d a r d e r r o r o f e a c h mean. S t a t i s t i c a l C o m p a r i s o n s : (Numbers r e f e r t o means o f i n t e r v a l s as l a b e l l e d a t t h e head o f t h e graph.) Resting:  Influx 4  5  Efflux 3 Net 4 Active:  5  2  3  Efflux 2 Net 1 Recovery:  3  2  5  Efflux 3 Net 3  3  1  Rate. 4  2  5  F=0.53,n.s. 1  4  2  3  5  F = 1.37, n . s . 1  Rate. 1 5  3  F = 0.48, n . s . 4  Rate. 5  4  2  F = 2.44, n . s . 1  Rate. 5  4  2  F = 1.48, n . s . 1  Rate. 1  F = 1.25, n . s .  4  Rate.  Flux 5  1  Rate.  Flux  Influx 3  2  F = 1.20, n . s .  F l u x R a t e . F = 0.34, n . s .  Influx 4  Rate.  F = 0.80, n.s,  2  A = s i g n i f i c a n t l y d i f f e r e n t from c o r r e s p o n d i n g r e s t i n g v a l u e ( p < .05) B = significantly different a c t i v e v a l u e ( p < .05) —=  from c o r r e s p o n d i n g  not s i g n i f i c a n t l y different p o n d i n g v a l u e s ( p "7 .05)  from o t h e r  corres-  TIME  PERIOD O F D E T E R M I N A T I O N ( M I N U T E S )  1  2  0-5  5-15  60-65 65-75 •30 +20 +10 0 -10 o -20 o -30  4  5  15-30 30-45  45-60  average 0-60  75-90 90-105 105-120 60-120 n=10  n=10  :I  <D  3  n=K)  n=9  n=10  n=9  n=ll  RCCTIMP  ACTIVE FISH :  Pp^  V E R Y  RESTING  •5  -,  C  mm  CD  :  »7  »•  V  3• C  X  I  i.t  1 n=10  n=10  n=11  UJ  n=ll 1  X  z>  ACTIVE  Pi  J  r Q  O to  -30  :  5 A A  I  < X  u z  +30 +20 +-100 -10 -20 h -30  : I  n=ll  _ A A  n=ll  n=ll  n=ll  n=ll RECOVERY  S I __ B  BB  _ B B  _ B B  _ B B  58  Table I I I .  Average b r a n c h i a l sodium  experimental periods.  E x t e r n a l Sodium C o n c e n t r aatt i o n (ug/ml)  f l u x r a t e s over the  Means - 1 s t a n d a r d  error.  Resting  Active  Recovery  N = 10  N = 11  N = 11  1.550 - 0.151  1.612 - 0.151 = n.s.  1.851 - 0.254 p =n.s. P = n.s. 1  2  Sodium I n f l u x Rate (ug/100 g/min)  N = 10 + 17.62 - 1.15  N = 11  N = 11  + 16.41 - 1.49 + 19.24 ± 2.86 P =n.s. 1  p P  Sodium E f f l u x Rate (ug/100 g/min)  N = 10 - 16.88 - 1.57  2  N = 11  F l u x Rate Rate (ug/100 g/min)  - 28.50 ± 3.55 - 14.70 ± 2.36 p  1  N = 10 + 0.74 - 1.43  = n.s,  N = 11  <  .01  p^ = n.s. P  Sodium Net  = n.s,  N = 11 - 12.14 - 2.94 P  1  <.01  2  < .001  N = 11 +4.54 - 1.99 p^ = n.s, P < 2  .001  p^ = s i g n i f i c a n c e w i t h r e s p e c t t o c o r r e s p o n d i n g r e s t i n g value, ^2 = s i g n i f i c a n c e w i t h r e s p e c t t o c o r r e s p o n d i n g a c t i v e  value  resting  values,  parameter. sodium some  It  influx  factor  results  again  without  significant  would  appear,  therefore,  is  or  i n s e n s i t i v e , but  factors  clarify  the  associated  observations  change that  of  the  influx  branchial  e f f l u x extremely  labile,  with  The  of  exercise.  Randall  et  to  present  aJL.(1969)  who 22  noted from  that the  decide  activity  gills  whether  turnover  rate  presented  first  time  high  three This in  flux  minimal  medium,  have  small  number  epithelium  due  to  rates  the  by  was  traced  Na  the  ions  the  interval  disappearance  (Fig.  of  to  sodium  Data  measured  three  15  9).  The  5  minute  standard each  number  of  concentration  over  minute error interval  errors  set  of  causes: of  in  the  on  a l l  fish. the  change  water  were  analytical precision;  and  complete  mixing  of  untrue;  importantly, there 22 o f Na i o n s v;ith the  that would  to  the  latter  specific of  external  most  exchange  This  the  the  unlabelled  adsorbed  of  unable  true. were  in  Na  originally  slight  (Fromm,1968).  short  a  limitations of  probably  occurred a 2 3  to  alone.  be  large  period  were  stimulation  initial  instantaneous  with  to  hour  the  radiosodium to  a  injected but  following  the  this  of  trout  fluxes  the  over  for  equilibrated with  this  and  and  effective until  sodium  group,  experimental  assumed  of  latter  be  solution which  adapted  can  subject  could  the  10,  components  and  labelled  over  the  sodium  release  e f f l u x component  i s manifested  measurements  been  next  inaccuracy  total  the  treatment  exchange  and  water  indicates  of  the  effect represented  of  the  periods  estimating was  or  each  5,  fresh  the  here In  the  of  augmented  mucus  factor  activity free  have  of  sodium  been  radiotracer  of  would  in  the  the  as  animal's  only  adsorbed  detected from  the  have  skin  water, an  but  influx  external  60  compartment. puted  as  As  the  enhancement  difference of  component.  were  influx  There  directional sequent  In  attained  borderline  level, for  final  of  the  attached  to  flux  net  treatment implies flux of  ment,  (Fig.  10)  ments  of  or  9,  and  the  that,  the  these  the  resting  initial  with  no  over  within  lag  of  the  no  than  the  negative  active  influx 5%  protection to  values  importance  in is  in  v a r i a t i o n of sodium  the of  latter  of  net  a  were the  limits influx,  exchange hour.  changeover  rest to  to  the  flux  based  first  uptake  fluxes). to  significance  tests, of  efflux,  within  This  in  from  a  the  each turn  branchial  that c h a r a c t e r i s t i c  typical  recovery  arrange-  short.  during  isotope  unidirectional  sub-  However,  detection  experimental  distinctive  from  the  g i l l  phases  parameter  accurate  during  and  high  biological  uni-  elevations  measurement.  is' e s p e c i a l l y persuasive this  but  accompanying  occurred  examination  which,  a  in  than  this  difference.  there  analyses  from  group,  discussion,  extremely  An  minutes  groups,  artificial  higher  intervals of  pattern  were  5  for  three  the  activity,  first  com-  elevated  respect  group  rate  tendency  significant  components  that  automatically  a  but  flux,  reflected in  indicate  and  the  net  not  this  used,  fact  and  Test,  above  methods  influx  measured,  s i g n i f i c a n c e (Duncan's  Figure therefore  directly  have  a l l three  recovery  although  the  light  in  statistically  trout.  not  between  during  for  the  was  would  was  fluxes  periods  not  efflux  5  rates of  the  in  the  point,  solely  on  minute  period,  determinations  Thfsedata  p o s i t i v e sodium  for  flame  (and  demonstrate* balance  recovery  with  group  measure-  photometric were  far  more  therefore, that the  the  switch  onset  of  61  Figure  10  Branchial  sodium  intervals  o f the experimental period  recovery  treatment  represent ceased  a t 60  intervals  group.  Comparisons:  as l a b e l l e d  = 4.68, p <  1  3  4  over  consecutive f o r the  The v e r t i c a l o f each  mean.  lines Chasing  minutes.  F  2  rates  1 standard error  Statistical  5  net flux  8  (Numbers r e f e r  a t t h e head o f t h e graph.)  .005 10  t o means o f  9  6  7  BRANCHIAL NET SODIUM FLUXES (jjg/lOOg/min.) O ^ h O O c o O - ^ N J  o T  b T"  b  b T  b  b  T  b -r  b  T  o  rO  b T  -U- O  b T  b  CO  b O  Cn i _ Cn Cn CO  rO  CO  o  co O i 4x Cn Cn i Cn CO O O i O Cn  73  -mO  O < m  _3_  Cn  O  O Cn i Cn  ¥ o  00  recovery the  occurred  recovery  trout  minute  period  Figure  10  hour  of  of  also  to  These only  iated  a  compromise indicates these  of  exercise  osmotic  or  surface  area,  festation  of  diffusion  of  external  preted  in  coefficient  a  sodium  efflux  theoretical based see  on  a  i f this  reasonable.  The  28.50  during sodium  5  ug/100  their  initial  were  apparently probably  Figs.  5 - 8  after  earlier  assoc-  with  would  an  plasma  rise  the  of  cation,  during  I  correlates inception 8-10)  the A  an  gas  high  principal  increased  in branchial  g/minute  Table  elevation of  perfusion  be  and  (pp.  respiratory lamellae.  10%  recovery.  9).  minutes  blood  major  15  deficit  cardiovascular  concomitant  deficit the  of  which  to  outlined  increased  such  mani-  simple  from  internal  sodium  exercise  to  efflux is  inter-  terms. e x i s t , as  for  possible  be  minutes  last  of  respiratory/osmoregulatory  by  As  walled  these  the  Reference  thin  There  been  of  sodium,  to  of  fluxes  the  (Fig.  efflux,  net  between  fish,  effects,  sodium  occurred  should  milieux.  16.88  group  rapid  5  The  branchial  v e n t i l a t o r y and  had  because  net  active  recovery.  deficit  first  recovery  a  gills.  the  changes  exchange  the  branchial  the  that  of  suffered  of  the  that  readjustment  at  significantly  and  extremely  implicated with  changed  confirms  that  instantaneously.  chasing  exercise,  similar  from  almost  sodium  to  in  determine  was  measurements  teleost  of  the  unproven  suppositions,  the  tentative  enhanced  suppositions  so  diffusion  i t has increase  diffusion  a  of  the  observed  simple  very  of  tissue  However,  explanation These  g i l l  whether  a t t r i b u t a b l e to  basis. number  y e t , no  was  efflux  included  that  on  not in  a  calculation, undertaken was of  in a  any  to way  branchial  sodium  diffusion coefficient  capillaries  (Pappenheimer,1953)  ities  between  Other  p&ssumptions  Hughes  (1966)  Newstead  etized This  rainbow  calculated  suffered  g/minute;  (1970)  of  concentrations.  efflux of  e t _al.(19 70),  similar diffusional i n the present  e f f l u x b y 12 u g / 1 0 0  within  loss  In light  agreement  an o r d e r  by  study  g/minute.  taken,  of  f o r anaesth-  sodium  Kerstetter  trout  values  area  1967).  the trans-  diffusional  a very  Active  were  Maetz  renal  could  n o t be  encountered  attributed  respiratory  exchange  with  sodium  i n many  of  between  o f magnitude  y e t presumably  endured. studies  associated  with  increases  basis,  which  condition  Maetz,1956;  and has  generally  effects  increases recovery  (see Section  of the branchial  This  (e.g.  or handling that  body  a situation  a n d S a w y e r , 1969)  stress,  concomitant  g/minute)  I I I ) ; on a whole  I t i s probable were  a negligible net  balance,  other  and c a n n u l a t i o n  disturbance  adjustment  (Section  indefinitely  t o shock,  anaesthetization caused  loss  a; L a h l o u  explanation.  only  (0.74 ug/100  i n negative  et, a J L . , 1 9 6 4  further  maintained  o f sodium  greater  trout  been  animals  uptake  obviously  been  (Newstead,  encouraging.  branchial  has  a maximum  i n the assumptions  Resting  the  kisutch,and  external  and observed  similar-  the diffusion distance  a t comparable  estimated  uncertainties  structure  et. a _ l .  3 ug/100  branchial  o f t h e marked  of Kerstetter  g/minute).  increased  trutta,  yielded  unstated,  ug/100  was  trout  o f mammalian  the use o f the lamellar  f o r Onchorhynchus  computation  methods  the  f o r Salmo  to that  because  and c a p i l l a r y  comprised  potential  approximately  (2  lamellar  (1967)  epithelial  identical  III,  without  i n from  Fig.  25) a n d  respiratory/osmoregulatory i n diffusional  sodium  64  efflux.  Houston  disturbances and to  tissue  study For to  i n water  after  t h e same  had been  influx  procedures  for  a particular  of  efflux.  (r  =  efflux  0.915,  p <z  not i n a truly groups  pre-experimental  both  "normal"  have  been  cardiac  output.  stances  o f those  catheter-  no  relationship 0.713,  the state  during  that  trout  of  balance  by t h e magnitude exercise  resting  differences  presented  animals  demonstrated  should  caused  s t i l l  b y t h e common  (less  (1967)  onset  of exercise, but this  least  3 hours  into  than  recovery.  elevation Sodium  ( F i g . 5 ) , and c a r d i a c output  o f these  instantaneous  function.  on rainbow  10 m i n u t e s )  perme-  trout  changes  The work o f  levels  was m a i n t a i n e d  (Stevens  sub-  demonstrated  i n plasma  efflux  of  t o ask whether  levels  t h e almost  and heart  increase  the effective  and f o r t h e e l e v a t i o n  i n plasma  with  efflux  and Tomlinson  increasing  t h e mob-  i s responsiblefor  i ti s of interest  of variation  c a n be c o r r e l a t e d  previously that  exercise  exchanger  rapid  rate  state,  f o r up  experimentation.  (r =  accentuated  the fact  during  Therefore  b r a n c h i a l sodium  Nakano  i n plasma  treatment.  of the respiratory  in  was  cannulated  o f catecholamines  course  correlated  largely  the branchial vasodilation  true  bore  determined  Despite  ability  the  rate  that  independent  Arguments ilization  was  marked  i n the present  to  indicating  of similarly  effects  rainbows  net flux  correlation  .01).  and v a s c u l a r  t o which  fish,  very  concentrations  10 - 48 h o u r s " p r i o r  rate,  trout  This  detected  Salvelinus fontinalis,  r a t e b u t was p o s i t i v e l y  .05) w i t h  represent  have  222 a n a e s t h e s i a  resting  p <  between  trout,  subjected  individual  were  MS  (1969)  and e l e c t r o l y t e  o f the brook  72 h o u r s  ization,  e_t a l . ,  a  at the  f o ra t  (Fig. 9), heart  and Randall,1967  b)  drop  rapidly after  mines  may  well  adaptation factors are  no  to  may  be  reflect  a  of  partial  control  and  as  the  of  adrenaline  relationship  ulate  the  filling a  specific  cardiac in  a  causative  lamellae reduced  despite  plasma.  of  catecholamines  ment  to  Ion  At  thus  in  the  exchange  mechanisms  understood  at  present  and  the  confounded  by  obvious  species  diffusion,  active  transport,  venous  by  at  the  change  the be  the  gills,  stim-  but  dependent  would  the  upon  return, tend  to  fall  respiratory would  be  catecholamine the  action  would  venous  of  an  pressure  permeability)  on  only  permeability  greater  s t i l l  integration of  teleosts is  exert  by  number  research  teleost  Thus  filling  high  they  effects.  pressure  of  as  exercise  in  catecholamines  the  other  circulatory  branchial  recovery,  aortic  further  and  and  cardiac  soon  after  facilitated  would  continuance  Clearly  exercise  and  as  and but  high  favourably  time,  (i.e. branchial  the  in  but to  lamella  of  and  r e s p i r a t o r y shunts  sequence,  perfused  same  ventral  activity,  mechanisms  caused  volume  pressure.  and  branchial  effects  observed be  catechola-  catecholamines  activity  could  the  of  opening  that  the  Thus  noradrenaline  activity.,  particular  output,  for  stroke  At  of  breakdown  myocardium  between  dilation  of  of  the  (Bennion,1968).  of  argue  output  onset on  initial  persistence and  cardiac  potentiators  return  at  also  over  cardiac  the  The  activity  could  increased  swimming.  adrenergic  adrenaline  low  One  in  these  required.  tissue.  of  r e s p i r a t o r y demands  over-ride  longer  act  involved  the  concentrations may  termination  nature  levels  of  action  cardiovascular  adjust-  necessary. of  l i t t l e  the  g i l l  knowledge  dependent active  fish  are  available is  differences;  coupled  poorly  exchange  transport,  back-  transport, cated  drinking,  i n sodium  different  fluxes  radiotracer  Garcia-Romeu,1964; Motais,1966; et  al,1970;  The  only  can  be  influx which  Morris  drawn  M o t a i s , 1966; ent  a one  characteristic  et  when  al.,1966; In  previously very  to  70). study  of  were  adapted  and  i s independ-  Maetz,1964). e t aJL.(1966)  a hypothetical forms  sodium  another  u n i d i r e c t i o n a l sodium by  which  mechanism  Garcia-Romeu  and  Potts  branchial  transport  o f Motais  euryhaline  of this  branchial  basic  measured  Randall  occurs  paucity sodium  (an  fluxes  are  carrier) i s  b u t has not been to fresh  water  i n intact  i n fresh  fluids  medium.  against  both  o f the Ussing  rates,  Salmo Recent  water  and Conte,  internal  of information,  flux  considerations.  potentials  that  Application  e t al,19  and which  (Garcia-Romeu  i n which  and  to the extrusion  e t a_l,19 70)  f o r one b a s i s  light  the external  sodium  transport  Garcia-Romeu  (Motais  Evans,1967).  _al.,1970;  revealed  an a c t i v e  linked  the animals  been  epithelial et  by  and  Maetz,1969;  i s that  i n  Maetz  to the present  and Garcia-Romeu,1964;  o f some  unidirectional  from  be  leakiness"  on  observed  occurs  way  Kerstetter  pertinent  d i f f u s i o n , i n the sense  "organized linked  Evans,1967;  impli-  milieux  House,1963;  and Maetz,1964;  investigations  Kerstetter  +  of chloride  Exchange  these  a l l been  and e x t e r n a l  (Maetz,1956;  and Bull,1970;  Maetz H :  internal  e t al.,1966;  water  i n some  (NH*.:  studies  conclusion  from  i n fresh  between  d i f f u s i o n have  Garcia-Romeu  Motais  general  may  cation  and simple  equation  rainbows  of  proceed trans-  (Kerstetter  communication) positive with  the inward  an e l e c t r i c a l  must  measurements  are slightly  of  have n o t  gairdneri  adapted  personal  Therefore  which  analysis  have respect  movement o f  and a chemical  (Ussing,1949a)to  this  gradient.  situation T.E.P.  =  (  [Na]  +6.0  approximate  mv.) 2244  the  contrary,  not  greatly  Ussing  Fromm  sodium  rate if  ions  and  the  at  would  in  both  of  sodium  or  a  1969).  utilize  completely A  priori,  trout of  simple  latter  the  and  seems  most  water  teleosts;  diffusion  unlikely,  active  efflux  has  clearly  the  transport Richards that  an-A.T.P.  measured  the  mechanism internal  influx  remainder,  the  same  agent  and  never  external  but  would  by  been  the  carrier  be radio-  as  to  could  active  trans-  et, a _ l . , 1 9 6 6 ;  Maetz,  contribution  to  demonstrated  therefore,  sodium  equally  diffusion  (Motais  transport  and  is essentially  contribute  Exchange  the  dependent  sodium  transport;  i t would  should,  and  in_ v i t r o  is  On  unity,  satisfied.  electrolyte),  either  and  involved.  almost  e f f l u x parameters  such,  should  diffusion (negligible)  exchange  of  is  g i l l  the  active  separate  an  is  demonstrated  unidirectional fluxes.  hypothetically  trout  are  active  This  As  mechanisms  of  of  influx  efflux/influx ratio  contribution  perfused  transport  uEq/ml;  recovery;  flux  simply  .067  or  recently  consist  =  exercise  least part  technique.  two  port  the  |Najo  the  resting  a t t r i b u t a b l e to  net  detected  for  inward  diffusion.  (no  tracer  be  could  passive  that  passive  the  have  of  Thus  exchange  for  the  uptake  any,  ratio  uEq/ml;  d i f f e r e n t during  ( 1 9 70)  must  117.97  suggests  the  to  process.  =  i f only  criterion  mechanisms and  i  consist  in  of  efflux fresh  simple  and  exchange  d i f f u s i o n i f present.  The  70%  efflux  during  exercise  was  any  change  influx  rate  and  thus  usion.  Consequently  entirely  of  simple  would the  not  associated  not  seem  to  involve  increment  in  efflux probably  diffusion.  with  exchange  rise  in  in  diffconsisted  68 Effective gases  will  be  branchial  determined  coefficient/distance, both  oxygen  (Stevens  essentially may  be  vice on  taken  as  versa.  the  that  stibstances following  efflux  take  as  A  factor  sodium  efflux  during  exercise  is  than  their  disturbance.  rise  first  part  of ing  of an  and  Thus  approximately (Y)  of  simple  this  5-fold  exchange  70%  seems  calculation At  During  activity  remain fluxes  for  and  effect  i t is  assumed  the  then  two the  with  the  oxygen  to  oxygen  then  a  70%  rise  only  a  70%  increase  to  as  only  presented  of  a  5-fold  uptake  during  in  elevation  of  efflux  must  the  simple  diffusion  in  component be Y 5 Y  turn  implies  (J3 ) to  represent  the  efflux;  the  performed: + £ = +^  =  more  minor  data  indicative oxygen  trout  b)  in  up-  i f a l l branchial  response  was  diffusional  a,  may  rest  in  cardiovascular  statement  diffusion  rise  impossible  in  section  increase  This  If  simple  diffusion,  uptake  this  for  will  same  flow,  Thus  associated  Randall,1967  the  efflux.  simple  by  oxygen  the  proportional  invariant).  Yet  the  similar  V e n t i l a t o r y and  (Stevens  chasing.  a  in  directly  be  gradients  equally  blood  diffusion  diffusion  oxygen.  lamellar  or  permeabilities  have  changes  is  should  x  sodium  simple  should and  or  and  effective  increase  (which  occurs  X  (area  ions  advanced.  imply  rate.  the  be  will  in metabolic  in  augmented  gradient  double  stable  may  of  sodium  particular  sodium  the  both  b)  exercise,  and  either  concentration  Randall,1967  in A  to  f a c t o r AD X As  during  remains  arguments  of  transfer  of  during  (1)  4).  and  Changes  either  the  representative  diffusion  D  by  p.  unchanged  permeability  17  ug/100  g/min.  29  ug/100  g/min.  an  component existence follow-  69  Y  =  3 ug/100 g/min.  £ =  14 ug/100 g/min.  T h i s v e r y elementary a n a l y s i s would i n d i c a t e t h a t , i f t h e above assumptions a r e c o r r e c t , o n l y a s m a l l p o r t i o n o f t h e e f f l u x a t r e s t was caused by simple exchange d i f f u s i o n . exchange d i f f u s i o n min.  diffusion,  t h e m a j o r i t y b e i n g due t o  C o n s e q u e n t l y i n f l u x would a l s o be l a r g e l y (14 ug/100 g/min.) w i t h o n l y about 3 ug/100 g/  o f a c t i v e uptake.  The f a c t t h a t exchange d i f f u s i o n has  not p r e v i o u s l y been demonstrated i n f r e s h water t e l e o s t s must weigh a g a i n s t t h i s  hypothesis.  (2) A g a i n presuming an i n t e r l o c k i n g o f D f o r oxygen and  sodium i n t h e g i l l s ,  i t c o u l d a l t e r n a t e l y be  that the only e f f l u x process an a p p r o x i m a t e l y occur,  present  i s simple  hypothesized  diffusion.  Thus  5 - f o l d e l e v a t i o n o f sodium e f f l u x d i d i n f a c t  but the techniques  most o f t h i s i n c r e a s e .  used were i n c a p a b l e o f d e t e c t i n g Such a s i t u a t i o n can o c c u r  i f a back-  t r a n s p o r t pump i s o p e r a t i v e , as has been p o s t u l a t e d i n t h e ammocoete, Lampetra p l a n e r i ( M o r r i s and B u l l , 1 9 7 0 ) . t h i s system, e s c a p i n g  internal  sodium i o n s d i f f u s i n g  Under through  the b r a n c h i a l t i s s u e a r e b a c k - t r a n s p o r t e d toy t h e u n s a t u r a t e d a c t i v e sodium pump b e f o r e t e r n a l medium.  they can e f f e c t i v e l y e n t e r t h e ex-  ' Adrenaline  s t i m u l a t e s t h e n e t sodium uptake o f  the i s o l a t e d p e r f u s e d  trout g i l l  In t h e p r e s e n t  no i n c r e a s e i n i n f l u x was o b s e r v e d  study,  (Richards  d u r i n g e x e r c i s e when plasma a d r e n a l i n e rise  (Nakano and Tomlinson,1967).  e x p l a i n e d by b a c k - t r a n s p o r t  and Fromm,1970).  levels  a r e known t o  T h i s r e s u l t c o u l d w e l l be  i n t h e f o l l o w i n g manner.  Active  inward t r a n s p o r t o f sodium was i n f a c t augmented by t h e s t i m u l a t o r y a c t i o n o f catecholamines during  a c t i v i t y , but t h i s  70 additional  activity  moving  through  no  out  increase  (70%)  of  in  was  increased  influx  efflux stated  occupied  were  loss  (respiratory lamellae)  teleost  g i l l If  based  are  ative  of  letely  the  either If  then Case  the  in  where  gases  can  could is  that  ation  of  used  move  about this  gairdneri,  so  measurements  of  ug/100  of  Consequently  small  this  elevation  argument,  maximum  active  are  however,  diffusional  transport  spatially  (inter-  separated  fresh  and  some  be  in  few  the  than  uEq/100  of  the  two  compmost  is  that  of  coefficients, In  a  on  system  membrane  but  i t is possible during  other. the  fluxes  the  gills  present teleost  data  to  activity  Until  gills,  of of  more  consider-  sodium  (Table  have  intact  with  species  worthwhile  g/hr.,  of  supposition.  across  rates  The  area  the  are  represent-  some  plasma  "pores",  properties  seems  flux  the  exchange  more  other  then  evidence.  through  the  be  combination  diffusional  remain  of  should  considerations  relevant  new  arguments  involved.  unidirectional  water  convenience, g/min.  will  above  invalid,  restrictive  comparison the  or  are  directly  of  the  situation  these  no  determined'"  for  which  sodium  physical  subject  been  sake  of  2,  coefficient  the  previously  in  sites  could  in  be  through  one  on  real  and  to  Simultaneous  examined  and  Case  recruitment  change  known  1,  oxygen  appears  pass  the  mechanism  there  imagine  the  assumptions  which  must  relatively Against  epithelium)  supposition  co-variation  ions  that  assumptions  different  tenuous  fact  diffusion.  ions  (Conte,1969).  valid,  schemes.  a  observed.  be  filamental  simple  only  must  lamellae  the  and  in back-transporting  not  Salmo  reported  which  have  IV).  been  For  have  been  expressed  in  the  unit  popularized  the  both by  Maetz  Table IV.  Summary o f b r a n c h i a l  Species  Weight  Salmo gairdneri  180-350  46.0  Salvelinus fontinalis  0.91-7.72  59.5  unidirectional  (g) I n f l u x r a t e uEq/lOOg/hr  Efflux rate UEq/lOOg/hr 44.1  sodium  flux rates  Influx rate ug/lOOg/min 17.6  i n fresh  Efflux rate ug/lOOg/min 16.9  22.8  26.0  water Ext.Na mEq/L  teleosts. +  Reference  0.07  present study  0.10  Packer & Dunson(1970)  0.20  Potts et a l . (1970)  Salmo salar(smolts)  20-45  68.0  Fundulus heteroclitus  2.0-5.0  58.0  22.2  1.00  Potts & Evans(1967)  Fundulus heteroclitus  9-20  23.0  8.8  1.00  Maetz e t a l . (1967b)  Platichthys flesus  85-115  12.4  4.7  0.43  Motais & Maetz(1964)  Platichthys flesus  60-220  14.0  5.4  0.45  Motais et a l . (1966T  Anguilla anguilla  107-378  21.3  8.2  0.55  Garcia-Romeu, Motais(1966)  Anguilla anguilla  60-120  4.0  1.5  0.12  M a e t z et. a l . (1967a)  Carassius auratus  300-670  21.4  12.3  8.2  4.7  0.70  Maetz(1956)  Carassius auratus  80-330  20.2  19.4  7.7  7.4  0.90  Garcia-Romeu & Maetz(1964)  66.0  25.3  -  T a b l e IV  (Continued)  Species  Weight  Carassius auratus  80-330  34.1  20.6  13.1  7.9  0.90  Maetz & G a r c i a Romeu (1964)  Carassius auratus  80-225  10.8  14.6  4.1  5.6  0.65  Maetz e t a l .  Carassius auratus  15-80  16.0  Carassius auratus  40-120  16.8  Influx rate ug/lOOg/min  Efflux rate Ext.Na ug/lOOg/min mEq/L  +  Reference  (1964aT~  * Efflux rates branchial  (g) I n f l u x r a t e E f f l u x r a t e uEq/lOOg/hr uEq/lOOg/hr  are not tabulated  6.1 25.0  f o r many r e p o r t s  and whole organism e f f l u x e s .  6.4  9.6  0.12  Lahlou e t a l . (1969)  0.50  Lahlou & Sawyer(1969)  as workers f a i l e d t o d i s t i n g u i s h between  72 and h i s co-workers. magnitude, but be  A l l values f a l l  w i t h i n the same o r d e r  t h e r e i s wide v a r i a b i l i t y , much o f which  a s c r i b e d to a s i z e e f f e c t .  Gill  of  may  area per u n i t body weight,  and presumably the f l u x e s f o r which the s u r f a c e i s r e s p o n s i b l e , decrease per 100  with' i n c r e a s i n g body weight  (Muir,1968).  g b a s i s , v e r y s m a l l f i s h w i l l have a p p a r e n t l y g r e a t e r  t u r n o v e r s than those o f l a r g e r a n i m a l s . f l u x e s o f 260 relatively fish  Thus on a  g Salmo g a i r d n e r i  l a r g e and  B r a n c h i a l sodium  from the p r e s e n t  study were  comparable to r a t e s o b s e r v e d  i n other i n v e s t i g a t i o n s .  i n very  small  Even more s u r p r i s i n g i s the  f a c t t h a t these h i g h r a t e s f o r rainbow t r o u t were a s c e r t a i n e d at  e x t e r n a l sodium l e v e l s 1/2  — 1/20  o f those used by  workers; over the c o n c e n t r a t i o n range n o r m a l l y  other  encountered  in  f r e s h water, t h e r e i s a d e f i n i t e p o s i t i v e r e l a t i o n s h i p between i n f l u x r a t e and  e x t e r n a l sodium l e v e l s  Jones e_t a_l.,1969).  The  (Maetz,1956;  magnitude o f both  Chester  unidirectional  f l u x e s i n the rainbow t r o u t r e l a t i v e to o t h e r e u r y h a l i n e forms ( e . g . A n g u i l l a a n g u i l l a , P l a t i c h t h y s f l e s u s ) l e n d s support hypothesis  (1) s t a t e d p r e v i o u s l y ( i . e . presence  diffusion).  are  o f exchange  F u r t h e r c o n s i d e r a t i o n o f the mechanisms o f sodium  exchange i n Salmo g a i r d n e r i w i l l be data r e l a t i n g  to  a p p l i e d i n S e c t i o n I I when  to the c o n c e n t r a t i o n dependence o f the f l u x e s  presented. Augmentation o f b r a n c h i a l p e r m e a b i l i t y to gases  sodium s h o u l d a l s o enhance the net osmotic U r i n e p r o d u c t i o n may  and  e n t r y o f water.  be c o n s i d e r e d e q u i v a l e n t to the  total  i n f l u x o f water as l o n g as the f i s h does not d r i n k (Hickman Trump,1969).  The  this a relatively  work o f Shehadeh and Gordon ( 1 9 6 9 ) s a f e assumption f o r rainbow t r o u t .  and  renders Urine  73  Figure  11  Mean u r i n e in  flow  resting,  First  r a t e s over  active,  hour v a l u e s  during  their  vertical  and r e c o v e r y  f o r recovery  initial  lines  the experimental  chasing  represent  -  groups o f  fish  were  treatment.  1 standard  periods trout.  obtained The  error  o f each  mean.  Statistical labelled  Comparisons:  on t h e graph.)  F ss 1.01, n . s . 1 4  2  3  (Numbers r e f e r ' t o means a s  10.0n=7  ^acH "E  g  n=7  n=7  6.0-  z  n=8 4.0-  2.0-  RESTING  1  ACTIVE  RECOVERY (isthOJR) RECOVERY te^HOUR)  3  4  74 flow  ( F i g . 11)  tended  during  recovery,  cluded  significance.  trout be  during  to rise  although  their  during  large  sampling  throughout  group.  The e f f e c t  fluxes  has been  examined  the topic will  C.  The E f f e c t  n o t be pursued  through  the  v i a the dorsal  these  values  blood  removal  blood  pressure  (Table  over  f o r i t was  erythrocytes time  volume  simply  there  period  concentration. declined  data  sampling  (Stevens  have On  as a  occurred  over  (Fig. 12); the fish  ensatory  changes  difference  to help  i n urine  function no  flows  maintain between  slight  i n  o f t h e amount i n red  obviously  the recovery  experiblood  removed, cell  volumes  i n a l l effected  the circulatory  blood  mobilize  t h e short,  period  i n  i n this  could  red cell  fall  fish  I f the animal's  n e t change  have  from  repetitive  decrease  over  packed  were  samples  informative  the sampling must  blood  The  the trout  1968 b ) .  section  i n resting  some  losses  the contrary,  progressively  hour  (Fig.l2)were that  Distribution  of the  them.  resulted  improbable  and water  Interpretation of  by the e f f e c t  there  decreased  would  catheter.  to ascertain  to replace  mental  groups  that  i n the  i n Section I I I  i n this  o f small  the experimental  Hematocrit  respect  presented  aortic  necessary  and Water  removal  i s complicated  I) i m p l i e s  volume.  then  the serial  may  serial  flow  detail  recovery  fish  i n  period  pre-  present.  Sodium  of the results  obtained fish  on  at  by  active  on u r i n e  greater  decrease  rates  of fluid  of exercise  i n much  of Exercise  Many  removal  by  the experimental  latter  so  than  and  i n the data  production  of exercise  attributed to the continual  blood  variability  The h i g h e r  hour  exercise  three comp-  volume.  group  during  The  75  Figure  12  Changes in  i n hematocrit  resting,  Means  -  1  active,  standard  over  and  the  experimental  recovery  error.  groups  of  periods trout.  Resting  2CH  15H  10-  ^  0  15  30  45  2CH  Active  20H  Recovery  _j  60  ii  10-1  L.  60  75  90  TIME (MINUTES)  105  120  76 their the  hour  active  this  of  exercise  group  Thus to  partially  least  shifts  from  the  could  intracellular also  have  groups,  have  undergone  some p r o g r e s s i v e  However,  s t i l l  be  as  then  the  were  effective  removed  pool  a  the  be  (Hi Y  similar  respect.  expected the  experi-  in a l l  observed  should  also  volume  or  assumption to  provided mixing  was  the  Y  blood  Hx  ZV)  =  Y  H  * Hx  = =  i  =  Hf r  Hf 2Tv  calculated  that  then  for  from  If,  taken  sampling,  basis  pool  interval.  100  the  a  which  samples  the  purposes  for  volume  size  of  estimation  did  the  not  blood  calculated:  -  100  Because  phases  this  during  differences  particular  i n response  could  100  changes  blood  over  comparison,  decline  in  c o n s t i t u e n t s were  were  that  retention.  extracellular  important  regimes  relative  indicated  water  dilution  and  valid. Hematocrit  the  plasma  sampling  to  been  a l l three  experiments,  of  through  in  ment.  of  m l / b l o o d / f i s h removed)  m l / b l o o d / f i s h removed)  at  ( H o u s t o n , 1 9 64)  0.16  (1.20  occurred  Fluid  (only  assumption may  was  represent  allow  legitimate  erent  treatment  not  i  t  i  a  and  of  g  hematocrit  l  average hematocrit samples between H i (including Hi)  of and  =  final  =  t o t a l volume o f b l o o d removed/100 g between and Hf ( i n c l u d i n g t h e sample)  entirely  blood  true,  pool  experimental  Hf  hematocrit  over-estimations.  comparisons groups  n  pool/100  the  compartments  Nevertheless, sizes  intervals  Hi Hi  between on  a  they diff-  relative  basis. The over (or  0 - 3 0 75  -  120  blood  pools  minutes  (or  minutes)  calculated 60  are  -  90  from  the  hematocrit  minutes)  and  over  15  V.  These  presented  i n Table  -  decline 60  minutes  values,  77  T a b l e V.  E f f e c t i v e blood pools  changes over  the f i r s t  calculated  30 a n d f i n a l  from  hematocrit  45 m i n u t e p e r i o d s o f t h e  experiments. Effective First o r  Resting  measurement  0 - 30 . 60 - 9 o m  1.98  blood pools  n  u  t  e  s  + 0.19 -  1.81 -  0.22  7  15-60 _ 0 5  m  i  . n  1 2  2.78 -  0.38  2.01 -  0.34  p = n.s.  1.82 -  0.35  (N = 11)  p  or  measurement  p < 0.10  (N = 9)  Recovery  Second  . i  (N = 9)  Active  (ml/100 g)  = significance  2.83 - 0.39 p < 0.10  with  respect to f i r s t  measurement.  u  t  ^ e  s  despite are  the  probable  inferior  measurement Houston  and  to  total  in  salmonids  volume"of  blood  due  to  measured  than  with  labelled  explanation  may  demonstrated  His  dye  lower  (Smith It  that  allowed  blood  found the  and  i s lower  than  the  for mixing  work  obtained  of  label  dilution  curves  e x h i b i t e d one,  changes  in  before  stabilization  tion  the  of  of  pools  slope  marker.  with  These  different  turnover  circulation,  a  at  one  slov; m i x i n g  The  present  least  fast  shifts  mixing  pool  rates in  compartment  hours  the  cells  likely who on  compartment.  probably  in  blood  occasionally  larger  in  dependent  two ,  after  injec-  reflective  comprising  the  whole  (1963)  (1966)  was  2 - 3  were  distrib-  more  i n the  and  direct  the  red a  Smith  volume the  of  labelled  of  the  Conte  However,  by  Smith,1966;  that  beds;  with  computation,  obtained  Bell,1964;  proteins.  blood  the  i s possible that  volumes  in  in  figures  in capillary  plasma  be  inherent  volume  erythrocytes  "skimming"  fact  time  blood  Dewilde,1969).  ution  the  exaggeration  the  total  vessels,  and  peripheral  capill-  aries.  30  and  dealt  45  largely  arteries between short  minute  and the  would Thus  measured  (Table  V)  were The  (Table  the  period  there  was  that  the  greater  to  this  indicative  of  be  on  this  of  time (p <  the  time did  major  division over  allowed 0.1)  only  probably  distinct  in resting  volume  over  determined  the  increase a  pool  no  volumes  taken  therefore  volumes  minutes)  attributable fact  and  could  dependent  (45  were  equilibrating  pools, be  V)  intervals,  fast As  component  second  fish  the  veins.  interchange.  active  "mixing"  with  interval  effect.  values  for  a  for the  and  active  dependent  mixing  not  occur  reduction of  in the  trout  the pool.  Stevens iated a  (1968  with  of  in  fact  exercise  decrease  data  a)  in  the  Section  during  swimming  influx  and  in  by  Toews  14°  -  16°C.  there  was  caused  resting of  serial  for  (Table  III)  to  systematic  which fact  occur,  were an  and  not  itfithdrawal  a  Analyses  of  tissue  during  significant  exercise,  activity  may  in  volume  blood  concept  i s  significant rainbow was  be  so  supported increase  trout.  r e l a t e d to  Rao the  by  into  plasma  no the  sodium a  work  i n plasma postulated  increased  of  release  this  in  there  during  the  to  but  the  dilution  branchial addition trout, was  in  exercise  post-exercise for  vascular  compartment  net  Rao  of  associated computed water  (1969)  this  the  hour.  evidence  rise  after  in  diminution  recovery  hour,  osmolarity that  loss  In  reduction,  inequality of  reported  increased  sodium  over  experi-  concentration  e f f e c t e d by  levels  provide  the  sodium  first  decline  the  influx.  significance,  blood.  the  water  acclimation  of  a t t r i b u t e d to through  term  existence III)  reduction  net  those  however,  of  sodium  the  long  to  activity,  sodium  samples  intracellular  identical  probably  during  i n plasma  by  of  the  over  The  Pre-experimental  precluded  (Section  sampled  13.  i n plasma  volume  branchial  levels  to  fluids.  between  exceeding  after  was  blood  imbalance  assoc-  he, a t t r i b u t e d  vascular  this  Fig.  were  During  renal  increase  in  fall  trend  the  sodium  variability  despite  followed  ment  plasma  time)  sampling.  to  an  output  rainbows  this  failed  the  in  progressive  trout;  by  presented  Data  a  of  was  (zero  (1969)  content  urinary  haemoconcentration  g a i r d n e r i which  indicates that  are  concentrations  a  III  efflux,  period  Salmo  water  Variations mental  observed  move-  with  previously,  fluxes. who  found  exercise  This a in  osmoconcentration  metabolites  during  80  Figure  13  Changes  i n plasma  experimental recovery  times  periods  groups  Statistical  sodium  Active:  of trout.  Comparisons:  F =  0.52, n . s .  60  15  F =  0.15, n . s .  15  45  Recovery:F  =  120  45  5  2.31, 105  over the  i n r e s t i n g , a c t i v e , and  of the respective  Resting:  concentration  (Numbers  -  5  0  0  30  p<.05 90  75  0  65  1  refer  means.)  30  60  Means  60  standard.error.  to the  sample  81 activity, levels; plasma a  d i d measure  his results water.  adapted  greater  and/or  loss  lesser  tissue  of  parameters water  ments  i n salmonids  sufficient  of  and  accuracy  the  of  the  and  60  increased in was  the  samples  of  from  means  (96.48  sufficient  to  both  levels  recovery  g  a;  f o r the  the  measureand  dilution  of  with  96.30  pre-  concentration plasma  well an  below  the  attempt  exercise  to  without  zero  analyzed  time  i n  encouraging, but  i n one.  vs.  of  plasma  sampling, the were  no  Miles  terminal  In  plasma  statements.  decreased i n four  plasma  i n  associated  during  were  stable  loads.  i n any  the  fallen  fish  results  remained  account  have  be  epithelium  lower  i n water  higher  may  previous  to  catabolism  repetitive  The  ml/100  than  fresh  occurred  Stevens,1968 due  there  preceding  refractometer.  concentration and  groups  higher  would  water  experiments.  i n two,  three  of  i n  water  There  the  slightly  fish  and  VI.  Differences  i n plasma  water  by  exercise  handle water  sodium  of  observed  branchial  prediction  were  protein  the  confounding effects  conclusive:  the  probably  i n active  minute  of  chloride  a reduction  species,  the  kidney to  (Houston,1959;  explain  changes  across  trout  values  by  after  i n this  the  o f plasma  (1969), however,  i n Table  starvation.  levels  of  the  between  the  number  osmolarity  Toews,1969)  to  analytical detect  i n  concentrations  water  sampling  explained  Beamish  summarized  plasma  be  elevation  and  i n exercised  experimental  sodium  well  measured, d e s p i t e  Smith,1968; serial  slight  electrolytes  difference  levels  However  a  nilotica;  ability  are  significant  drop  Tilapia  Terminal and  can  Farmer  non-significant  water a  but  a not  trout,  The ml/100  observed elevation  difference g of  plasma) plasma  82  Table  VI.  plasma  Terminal  and t i s s u e .  c o n c e n t r a t i o n s o f sodium Means - 1 s t a n d a r d Resting  N =  Terminal plasma sodium conc'n. (mEq/L)  115.05  error.  N  2.71  N 8.13  -  0.51  N = 10 96.90  ±  1  3.97  n.s,  ss  -  = n.s.  97.15  p^  -  n.s.  ss  ? ° w ? n n  r  iml/lUOg  a  ^ °  n  N = 10 \  tissue)  81.420  ±  81.569  ±  -  p^  =s  n.s.  p_  = n.s.  96.85  ss  Sodium  N = 9  space  fg^ater/kg/wet  72.38  weight)  ±  n.s.  76.5 7  4.80  s  n.s.  11  ss  P 2  = n.s.  71.14  n.s.  11 ±  3.71  = n.s, 2  p ^ s= s i g n i f i c a n c e  with  respect to corresponding  resting  P  with  respect to corresponding  active  = significance  0.20  p^  P  2  ±  •= n . s .  N =  ±  11  8 2 . 1 0 7 ± 0 . 3 9 9  N = 11 3.99  0.50  p^ = n.s.  N =  0.452  11  ss  8.03  N = 11 0.329  P.P.  = n.s,  P 2  T i s s u e water  2.87  P 2  N =  0.14  ±  ss  N = 11  0.29  9  P ,  N  0.51  ss  115.19  11  8.93 P  Plasma water c co on nc ce en nt tr ra at ti io on n (ml/lOOg plasma)  -  N  9  ss  N  7  ss  120.64  p^  T i s s u e sodium concentration (mEq/kg wet tissue)  Recovery  Active  10 -  and water i n  = n.s.  value, value.  sodium ation  levels.  Stevens  i n plasma  culminating  water  in a  (1968  levels  final  a)  at  gradual  witnessed a  the  onset of  decrease  triphasic exercise  as  swimming  2%  higher  fluctu-  in  trout,  time  was  prolonged. Tissue  water  commonly  quoted  values  al.,1968;  Toews, 1969) ; a g a i n  consequence apparently the  of  higher  well  water  of  with  the  acclimated  cellular  sodium  reflective recovery ations  at  14°  0.754,  plasma  p  and  animals.  levels  i n the  fast-mixing  muscle  during  swimming  space  not  n.s.)  the  tissues  all  three  that  by  presently.  show  of  the  from  pool.  (Stevens,1968  b)  additional  i n  for  buffering  electrolyte  ischemia  would  indivi-  exist  a possible  An  and  correl-  i n  d i d not  changes  largely  respectively)  electrolyte  however,  for  intra-  resting  positive  p <. .05  indicating  plasma  of  Na  be  of  "white"  a probable  evidence for t h i s  distribution As  the  significant  water  fluid  variation,  teleosts,  data  parameters  extracellular  treatment groups.  i n fresh  In both  be  i n  however,  i s l i t t l e should  the  phenom-  22  estimate  did  =  levels  phenomenon;  provided  discussed  r  .033,  • was  sodium  i n plasma.  relationship,  exercise  enon  muscle  levels,  (Toews,1969)  there  0.678,  during  for the  As  .01;  trout  cause  16°C.  a reduction  sodium  figures  et  a probable  to  significant  active  of  due  Muscle  Houston  communication),  occurred  tissue  This (r =  <  being  reported -  was  personal  tissues.  than  (Houston,1959;  hydration  contents  concentrations there  about  (Brett,  (Manery,1954),  groups,  (r =  between dual  of  the  previously  rainbows  were  for salmonids  starvation  f a t content  agreed  levels  Toews unlike  which  from  volume  which were  E.C.F.V's (1969)  has  mammals,  will  were  the  be sodium  calculated similar  demonstrated sodium  space  in  provides  a  more  a c c u r a t e measure  chloride-potassium content  of  the  space  because  intracellular  of  E.C.F.V.  of  the  than  chloride  significant  or  chloride  phase. 22  The activity, temporal  evolution  and  of  recovery  sequence  of  the  Na  space  i s illustrated  the  time  i n F i g . 14,  accumulation  p o r t e d from the e x t e r n a l i s p r e s e n t e d i n F i g . 15.  with  i n plasma  during while  of  rest,  the  sodium  trans  water ("plasma sodium i n c o r p o r a t i o n " ) Plasma sodium i n c o r p o r a t i o n i s a 22  factor  which  permits  between  individual  of  activity  just  i f i c  the  activity  ratio  specific are  the  prior  external  together  with  to of  As  and  actual  resident  i n the  analogous  valid  through  in external  the  this  factor  average  time.  values  sodium  and  sodium  60  minutes  f o r each  at  the  tissue  i n Table  plasma  values  medium  for  i s  external  Thus  internal  use  spec-  summarised  space  120)  levels  concentration of  radiosodium (or  Na  such,  measurement  i n c o r p o r a t i o n " ) are  at  be  differences  the  The  plasma  not  levels  the  time.  the  values  would  to  Na  medium  sample  sodium  due  of  experiments. 22  i n terms  ("tissue  which  plasma  activity  particular  oration  values  between  comparison  fish,  between  expressed  from  the  VII  incorp-  experimental  group.  teleosts  The  time  course  has  been  followed i n only  Nibelle,1969) sodium  into  plasma  approach.from  similar  of  the  the and  level.  i n the  component  the  tissue  The  three  radiosodium  relative  Interpretation  a basic  is  while  of  of form  other  represents  a  the  between  the  in  and  external  therefore  evolution  although  of  (Mayer  completely  t h f s e d a t a must of  expansion  study  incorporation  treatments  points differ  one  space  curve  new proceed (Fig.  magnitudes  experimental  groups.  14)  85  Figure  14  The in  evolution resting,  o f the  active,  Means - 1 s t a n d a r d A  s= s i g n i f i c a n t l y resting  value  radiosodium and  space  with  recovery groups o f  time trout.  error. different (p <  .05)  from  corresponding  Resting  TIME (MINUTES)  86  Figure  15  The  e v o l u t i o n with  plasma o f  sodium  environment resting, Means A  =  time o f  the  transported  ("plasma sodium  a c t i v e , and 1 standard  from the  in  external  incorporation")  recovery  groups of  in  trout.  error.  significantly  different  resting  (p <  value  concentration  .05)  from  corresponding  The  general  dealt  configuration  with  amount  definition,  the per  amount ml  distribution related  to  adsorbed tend p.  to  the  observed  changes  will  be  first.  By between  of  of  The  over  initial  the  skin  e l e v a t e the  radiosodium  space  r a d i o i s o t o p e i n the  plasma.  volume  the  to  of  the  the  exchange  of  the  value  of  Na  22  38)disproportionately to  the the  term  (Qo  with  Na  apparent -  Q)  of  the  was 23  probably  . ions  influx  (see  radioactivity  and  . 2 2 m Na  interval  ions  This  ratio  animal  increase  5 minute  animal.  of  whole  precipitous  first  i s the  would  Methods  the  plasma  22 (Na  /ml  p t ) , thereby  space. least  is  a  exaggerating  Arrival  of  the  plateau,  45  minutes  however,  expansion  more  difficult  distribution  at  equilibrium  considerably  greater  Reference  the  provides enon.  to the  The  the  upward  probably  of  i s about  sodium  curve  plasma  deflection of  explain,  this  the  of 2?  Na at  a  a  34  incorporation  same  large  point  space  g  of  Na  (Section 17  -  21  II),  mls/100  (Fig.  f o r the  sodium  at  radiotracer, 22  data  15)  phenom-  incorporation  "* c o n c e n t r a t i o n ) the  or  volume  at  explanation  plasma  of  ml/100 peak  distribution  zenith,  f o r the  apparent  radiosodium  occurred  at  introduction  mathematical  evolution  levelling  there  plasma  obvious  (representative abrupt  than  calculated  curve  after  to  the  underwent  an  minutes)  as  (45  curve.  Consequently,  increase i n the  parameter  22 Na  /ml  lower  pt  terminal  biological Up  to  curves  relative  45  tributed  minutes,  over  the  estimate  reason  tended  to  of  for this the  rise 22  in  Na  distribution  event,  slopes  to  slowly  an  increasing  of  decline  (Qo  -  Q),  however,  the as  volume,  plasma  resulting volume.  remains  in The  unclear.  incorporation  radiosodium presumably  a  became through  disthe  g.  natural mixing  enlargement pool  and  greater  tissue  minutes  could  influx or  a  of  unlikely sodium  constant  due  into  the  that  mixing  over  of  to  the  stable  curve  took  place  incidence constant speculate  of  only  entry of that  attributable  to  the a  sodium  E.C.F.V.  a  the  the  one  hour  differed  and  single  the  plateau of similar  those of  gills,  the  plus  the  a the such  intra-  of found  excretion"  dye  dilution  injection".  Although  reported here  in  marker  than  rather  i t i s tempting  radiosodium  stabilization  for  diffusion  dilution  the  second  constancy  i n salmonids  slope of  injection  i t across  the  of  the  has  remained  the  by  seems  influxed  i s that  perhaps  "mixing  after  from  pool  limited  volumes  "excretion"  It  rate so  pool,  It  reason  attained  became  initial  plasma  pool.  influx  mixing  or  of  backflux of  probable  spaces  blood  the  a 45  compartment).  (1966),in using  of  "about  experiments  of  rate  the  in question,  most  approached  measure  intersection  with  out  influxed  Smith  dye  The  movement  of  branchial  interval  apply.  compartment  slope  Smith's  the  that  out  into  the  phase.  the  gills  into  tissues  extravascular  Blue  the  to  after  i n the  significant  rate  dispersal  increase  curve  any  of  Evan's  across  the  be  decreased  that  an  of  vascular  dispersal  there would  must  of  diffusional  movement  interpretation  cellular  either  sodium  effective  of  ( F i g . 9)  this  to  the  acclivity  shown,however,  size  of  rate  the  been  The  i n the  that  time  concomitant  mass.  external  from  already  the  be  decrease  with  space  the  to  curve  was  mixing  comp-  radiosodium  space  artment. The evolution the  only  previous  in teleosts  eel, Anguilla  examination  i s that  anguilla.  of  Mayer  These  of and  workers  Nibelle  (1969)  demonstrated  in that  89 the  rate  of  completion  equilibrium the  value,  label.  They  of  the  depended argued  radiosodium  upon  that  the  space,  site  capillary  of  but  not  i t s  introduction  barriers  were  of  negligible  22 in  the  evolution  "filling likened The  up" to  of  the  presence  some  doubt  (1969)  took  unable  to  light  of  Na  a  electrolytes  effect  an  spaced  i n the  use  of  in  an  Mayer  of  radiosodium  could  data  thus  levelling  space  calculation  of  rates  exchangeable  sodium  pools  Maetz,1956;  more  detailed  space  evolution  Mayer  and  atic  Nibelle  attempt  parameter  to  in a  application twelve  are  the  years.  flounder  (Motais  the  majority of  brium  may  there  even  study  For  that  1969),  (1969),  the  particular  to  of  commonly et  be  the  used  exchange  of  Until  data  of  significant  of  regulation Wood  and  space  M o t a i s , 1967) , on has  been  as  the  flux Motais,  no  of system-  this  i t s ubiquitous  radiosodium  work  In  work  been  values  ionic  been  radiosodium the  apparently  equilibrium  teleost  al_. ,1966;  a  had  branchial  kinetics  species, despite  example,  ion  well  the  urgently required.  find  indicate  the  s t u d i e s on  have  values  i n the  1967),  Nibelle  curve.  compartment"  (e.g.  be  solution.  and  would  the  the  casts  "internal and  that  ionized  present  and  and  space)  However,  samples  intermediate  widespread  volume,  (radiosodium  interpretation.  widely  detect  of  plateau  this  distribution  compartment  diffusion  only  the  the  the  of  on  of  over  Randall value  which  performed  underestimation  for  of  of  ( 1 9 71) the  perhaps (Maetz, the  equili-  volume. 22 Differences  volume  between  curves  ( F i g . 14)  similar  course;  i n the  treatment for  groups  active  however  evolution  the  and  may  of  now  recovery  radiosodium  the be  Na  distribution  examined.  trout space  followed expansion  The a lagged  90 n o t i c e a b l y behind  t h i s p a t t e r n d u r i n g r e s t , the d i f f e r e n c e  becoming s i g n i f i c a n t by the t e r m i n a l sample.  I t i s not  i b l e , however, t o say whether the e q u i l i b r i u m v a l u e s a l s o have d i f f e r e d ; thetical and  i n any  case,  poss-  would  the p o i n t i s somewhat hypo-  as an a c t i v e f i s h would s t o p swimming at some time,  a recovery  f i s h would e v e n t u a l l y r e t u r n to the r e s t i n g 2?  condition.  The  hxgher Na  " d i s t r i b u t i o n volumes d u r i n g  e x e r c i s e and  p o s t ~ e x e r c i s e cannot be  r e l a t e d d i r e c t l y to  plasma volume changes d i s c u s s e d e a r l i e r reasons.  f o r at l e a s t  the  two  F i r s t l y the l a r g e r spaces were c h a r a c t e r i s t i c  b o t h a c t i v e and  recovery  s t a t e s , while  volume through d e h y d r a t i o n (Table V).  Secondly,,  the r e d u c t i o n o f  occurred only during  of blood  exercise  a d e c r e a s e i n the s i z e o f the  plasma  22  volume alone would i n c r e a s e the c o n c e n t r a t i o n o f Na on a simple d i l u t i o n b a s i s , and, i n a d d i t i o n , would tend to depress the d i f f u s i o n o f the i s o t o p e out o f the v a s c u l a r p o o l i n t o the tissues.  The  net e f f e c t o f h e m o c o n c e n t r a t i o n would be  i n h i b i t i o n , r a t h e r than a s t i m u l a t i o n , o f the space e v o l u t i o n .  radiosodium  Plasma sodium i n c o r p o r a t i o n v a l u e s  i n d i c a t e t h a t the r e v e r s e was experiment, plasma "Na  22  i n f a c t t r u e ; by  c o n c e n t r a t i o n s " were  lower than the r e s t i n g v a l u e  an  ( F i g . 15) -  the end  of  the  significantly  i n both a c t i v e and  recovery  trout,  22  thereby  generating  the h i g h e r Na  must be noted t h a t t h i s e f f e c t  d i s t r i b u t i o n volume.  It  cannot be r e l a t e d to slower  e n t r y r a t e s o f sodium, f o r i n f l u x e s were i d e n t i c a l  i n a l l three  groups  a greater  (Table I V ) .  emigration  Thus t h e r e must have o c c u r r e d  r a t e o f p r e v i o u s l y i n f l u x e d sodium out o f  sampled plasma p o o l d u r i n g d e s p i t e the p r o b a b l e  activity  and r e c o v e r y  decrease i n s i z e of t h i s  the  than at r e s t ,  compartment  during  exercise.  The t e r m i n a l  epaxial  muscle  samples  were  22 analyzed sodium; on  f o r Na  as a p o s s i b l e  the r e s u l t s , expressed  a wet w e i g h t  muscle  basis,  obviously  oration  being  resting  animal,  ("White"  reception as t i s s u e  are presented  d i dnot receive  somewhat  lower  has found  17%  f i b r e s by volume).  data  i s thus  However,  reflective  correction  hypothetical the  that  this  o f plasma  of tissue  enclosed  plasma  the extravascular  umulated  less  influxed  rest.  radiosodium influxed of  I t must spaces  sodium,  t h e body  sodium  with  therefore  resulted  and thus  may  from  i nt h e  up t o  values.  d i d n o t change  o f "white"  exercise  be c o n c l u d e d  decrease  (personal  incorporation  o f 1 - 4%  a greater  fish.  measurements f o r  muscle  acc-  and r e c o v e r y that  the  accumulation  the radioisotope,  an accompanying  than  contain  incorporation  during  the incorp-  a s Webb  The t i s s u e  region  "White"  i n the recovery  tissue  volumes  that  VII.  trout  incorporation  fact  during  smaller  lost  incorporation  sodium,  i n salmonids,  communication) r e d muscle  extra  i n the active  i s a misnomer  f o rthis  sodium  i n Table  this  and s i g n i f i c a n t l y  muscle  site  i n other  i n "white"  than  higher of  regions muscle  incorporation. Due tissues, minutes of  t o t h e time  the majority probably  greatest. ures  over  tion  may  been  hour  the animal  t h e whole therefore of this common  hour have  from  found during  when e x t e r n a l  Use o f t h e average  estimation have  o f radiosodium  entered  the experimental  l a g i n moving  been  parameter.  to a l l three  However,  to the after  the earlier  specific  tissue  responsible  groups,  i n muscle  specific  external  to calculate  the g i l l s  portion  activities activity  sodium  an e r r o r  and would  were fig-  incorpora-  f o r a systematic such  60  i n fact  over-  would tend to  92 Table at  VII.  Measures  60 m i n u t e s  after  of internal  introduction  distribution of influxed o f Na  Resting Na space (ml/100 g) (60 m i n u t e s )  i  Active  N = 8 1 5 . 7 3 - 1.05  2 2  . Means  1 standard  N = 9 18.45 - 0.70 p < 0.05  N = 9 6 4 . 8 6 - 3.83  N = 10 1 9 . 5 6 - 0.90 p <C 0 . 0 5 x  . N = 9 5 1 . 9 9 - 3.81 P <0.05  p N 2.579 p  = =  n  2  = n.s.  N = 10 4 9 . 1 7 - 4.09 p , < 0.02  t  Tissue sodium N = 10 incorporation 3.077--0.243 (ug/kg/wet t i s s u e ) (60 m i n u t e s )  2  = n.s.  10 N = 10 0.351 2.218 - 0.203 . p, <0.02 s  #  P  2  = n.s.  p^  = significance  with  respect  to corresponding  resting  P  = significance  with  respect  to corresponding  active  2  Table utes  VIII. after  Balance  sheet  introduction  o f fate  o f Na  22  of influxed  sodium  value. value.  a t 60 m i n -  .  Resting Sodium i n f l u x e d / l O O g o v e r 60 m i n u t e s  error,  Recovery  P Plasma sodium incorporation (ug/ml) (60 m i n u t e s )  sodium  Active  1 0 5 7.2 u g  Recovery  984.6  ug  1154.4  ug  Sodium plasma  incorporated i n (3 ml/100 g)  194.6  ug  156.0  ug  147.5  ug  Sodium tissue  incorporated i n (97 g/100 g)  298.5  ug  250.2  ug  215.2  ug  493.1  ug  406.2  ug  362.7 u g  Total i n tissues plasma % o f t o t a l sodium represented  It  has been  sodium oration  and influx  assumed  incorporation and that  41.25%  46.64%  i n t h e above was  plasma  equal volume  calculation  t o "white"  that  muscle  i n t h e major  31.42%  a l l tissue sodium  vessels  was  incorp3 ml/100  g.  enforce  the  substance  If plasma  in  a  generous  the  major  incorporation remainder of  Table  at  60  such  of  the  VIII  be  after  scheme  sodium;  exercise  condition.  some  tissues  muscle,  and  recovery muscle  that  by  and  a  for  the  figure It  is  exchange this  then the  the of  apparent  the  to  that  sodium  the  sheets  in  group  each Even 47%  31.5%  in  under  a l l  the  rest,  the post-  conditions  "white" activity  turnover of  at  of  the  during  rates  for  balance  than  than  for  tissue  isotope. less  turnover  weight  muscle  trout  faster  of  of  the  accenttiated  reduction in  of  fate  is  body  epaxial  decreases  effect  increase  of  for  sodium  g  assumption  taken,  introduction  further  an  that  are  argument.  3 ml/100  the  constructed  this  must  of  and to  mass  accounts  influxed  following  estimate  equal  body  may  the  vessels  values  minutes a  of  and  in  "white"  other  unknown  tissues. The well  be  then  the  unit  weight  muscle The  sodium  proportional discrete  to  red  basis,  blood  therefore  muscle  account  of  and  a  particular  supply. cardiac  2~i t i m e s  a ) , may flow  rate  i t s blood  contain  (Stevens,1968  increased  could  turnover  as  If  this  muscle,  much  tissue is  true,  which,  blood  as  these  for  the  tissues  lower  during  on  a  "white"  p r e f e r e n t i a l l y accumulate  to  might  sodium.  exercise  concentrations  of  in-  2 2 fluxed  sodium  volumes  measured  augmented by  the  lack  how  by  an  reduced  of  sodium  in  the  plasma,  during ischemia  sodium  this  of  the  could  "white"  plasma  also  Na  This  incorporation  previously.  explanation  higher  exercise.  c o r r e l a t i o n between discussed  and  It  of and  is  apply  distribution  effect muscle,  this  be  further  indicated  levels  difficult, the  as  tissue,  tissue  to  could  and of  however,  similar  the total to  sodium  see  space  e l e v a t i o n and decreased  incorporation patterns  determined  should  return  plasma  during  and  "white"  recovery,  t o a more  resting  when  muscle  blood  sodium  flow  configuration.  Thus  22 blood  flow  variation  differences, A  property  the  (Nakano  of high  vitro  the active (Richards  hormones  may  specific  sinks  elevation be  those  liver,  to both  also  circulating  o f radiosodium  spleen,  levels  the uptake  containing high  Na  space  involved.  conditions i s  catecholamines  which  a r e known  across  trout  to  gills  I t i s possible that or turnover  thereby  space.  r e d muscle,  of  o f sodium  and Fromm,1970). promote  factor  and r e c o v e r y  substances  transport  i n the system,  tissues  to the observed  not the major  active  and Tomlinson,1967),  stimulate in  contribute  but i s probably  common  presence  may  o f sodium  by  contributing to the  Again, blood  these  such  sites  volumes,  and c a r d i a c muscle  such  could  well  as t h e  (Stevens,1968 a ) .  95  SUMMARY I 1. The  ventilatory  and  c a r d i o v a s c u l a r responses  of trout  c h a s i n g i n the p r e s e n t study were s i m i l a r to those to  o c c u r d u r i n g normal swimming a c t i v i t y  to  reported  i n other s t u d i e s .  2. U n i d i r e c t i o n a l b r a n c h i a l sodium f l u x e s o f Salmo g a i r d n e r i v/ere h i g h e r than those r e c o r d e d of  comparable s i z e d e s p i t e the extremely  c o n c e n t r a t i o n s used i n t h i s 3.  The  4.  the g i l l s .  and  6.  was  a p p a r e n t l y an  During one  hour o f e x e r c i s e t h e r e o c c u r r e d a net reversed during  recovery.  a l t e r a t i o n s i n net f l u x r a t e at the onset o f e x e r c i s e  the o n s e t o f r e c o v e r y o c c u r r e d extremely  rapidly  Branchial, sodium i n f l u x r a t e remained c o n s t a n t d u r i n g and  activity,  causing a negative balance  situation.  d i r e c t i o n a l outward movement d e c r e a s e d l e v e l s d u r i n g one The  rest,  recovery.  7. B r a n c h i a l sodium e f f l u x r a t e i n c r e a s e d 10% w i t h  8.  (within  minutes).  exercise,  ing  active  a s t a t e o f sodium e q u i l i b r i u m at  b r a n c h i a l sodium l o s s which was The  e x t e r n a l sodium  process.  Resting t r o u t maintained  5.  low  teleosts  study.  uptake o f sodium by the g i l l s  transport  5  f o r o t h e r f r e s h water  hour  swimming This uni-  to s l i g h t l y below r e s t -  recovery.  e l e v a t i o n o f e f f l u x a p p a r e n t l y o c c u r r e d through i n -  creased simple d i f f u s i o n r e s u l t i n g  from an augmented b r a n c h i a l  permeability. 9.  C a l c u l a t i o n s based on h e m a t o c r i t  b l o o d volume d e c r e a s e d  changes suggested  during exercise.  that  10. Plasma  sodium  l e v e l s tended to i n c r e a s e i n e x e r c i s e d  even though t h e r e was  a net l o s s o f sodium.  fish  This effect  was  a p p a r e n t l y caused by the b l o o d volume d e c r e a s e . 1 1 . T e r m i n a l t i s s u e sodium ( E . C . F . V . ) , were s i m i l a r  and water l e v e l s ,  in resting,  and sodium  active,  space  and r e c o v e r y  animals. 12. In a l l groups, the e v o l u t i o n o f the Na"  distribution  volume r e a c h e d a temporary p l a t e a u 45 - 60 minutes d u c t i o n o f the r a d i o i s o t o p e . ponded t o an a c c l i v i t y  after  This l e v e l l i n g effect  i n the plasma sodium  intro-  corres-  incorporation  curve. 13. Sodium g a i n e d from t h e e x t e r n a l environment over the e x p e r i mental p e r i o d was  preferentially  accumulated  (on a per u n i t  weight b a s i s ) i n t i s s u e s o t h e r than "white" muscle  in a l l treat  ments. 14. Radiosodium  space e x p a n s i o n d u r i n g r e s t  lagged behind that  o c c u r r i n g under a c t i v e and r e c o v e r y c o n d i t i o n s , the d i f f e r e n c e becoming  significant  at 60 minutes a f t e r  The o p p o s i t e c o u r s e was values, t h i s icantly  seen i n plasma sodium  factor i n active  inferior  taken up by  incorporation  and r e c o v e r y f i s h becoming  t o r e s t i n g v a l u e s by 60 m i n u t e s .  t r e n d o c c u r r e d i n t i s s u e sodium three groups.  a d d i t i o n o f the t r a c e r  A  signif  parallel  i n c o r p o r a t i o n v a l u e s f o r the  Thus g r e a t e r amounts o f i n f l u x e d sodium were  " s i t e s " o t h e r than"white"muscle d u r i n g a c t i v i t y  r e c o v e r y than d u r i n g  rest.  and  97  SECTION  THE  EFFECT  OF  II  EXTENDED EXERCISE  SODIUM  BALANCE  INTRODUCTION  The rence  of  results  a  experiments of  net  branchial  strongly  by  an  increased  of  effective  simple  g i l l  metabolic  demands  branchial  sodium  31.68  uEq/100  content  (600  apparently reduction ation  g  uEq/100  efflux  the  would  trout  After  only  would  be  fish.  In  compounded pected 1969;  at  a  by the  III.  an  and  a  total  The  the  effect  of  thereby  suffer  of  obviously  swimming urinary  the  sodium  and  to  loss  slight  deficit,  a  augment-  i f such  a  net  swimming,  embarassment. plasma  animal's problems loss,  sodium  by  the  the  would  which  performed  confirmed  was  through  disadvantageous to  sodium  only  sodium  prolonged  total  e x p e r i m e n t s were  Trump,1969) the  1/3  a  caused  the  amounted  However,  osmoregulatory  about  period  volume  during  was  increased  small  producing  maintained  the  plasma  this  The  a readjustment  hour  of  were  these  by  one  concentration.  the  to  l/20th  increased  Thus  due  necessitated Over  balance  g/min.)  situation  time  efflux  decrease i n plasma  hours,  addition,  Hickman  Section  soon  negative  ug/100  content,  rate  6 - 7  lost,  a  sodium  branchial  this  occur-  exercise.  (12.14  g).  n e g a t e d by o f water  during  activity.  about  I demonstrated the  loss  diffusional  deficit or  o f plasma  that  permeability of  II  Section  sodium  indicated  ON  was  be sus-  (Hammond, data  i f unchecked,  of  would  98 clearly Yet  limit  there  fresh  to  exists  water  fatigue  the  the  a  of  small  of  water  again  by  methods  volume  activity.  extended  length  low  speeds,  for  hours.  Collection an  of  implanted  accurate  the  urine  whole  system  Therefore  Sodium  rates  both  as  normal  was  a  were  p a p i l l a e had  release  urine  into  the  mechanism  to  the  been  swim  use  of  of  was  the  relatively  in  supporting  indirect during  problems small  occluded,  in  were  revolv-  albeit  and  at  renal  necessary.  chamber have use  through  been of  a  was  term  compartment.  most  i t s  taken.  exercise  animals  thereby  the  constantly  changed  approach long  the  branchial  repeatedly  employ-  by  a  also  I would by  para-  a  continuously,  experimental  external  both  The  These  development  fish  or  could  the u n i d i r e c t i o n a l  periods.  prevented the  balance  precluded  i n d i v i d u a l s and  the  sub-  designed  difficulties  was  Section  more  unencumbered  that  therefore  techniques.  efflux  measured  urogenital of  body  in  i n which  position. flux  efflux  separate  chasing  outside  s o l u t i o n , but  revolving  were  d i s t i n g u i s h i n g between  catheter  at  was  sodium  demanded  would  trout  to  to  exercise  i n which  contribution  influx,  the  for  section  hours.  Brett,1964)  exercise  i t s attendant  chamber  means  of  more  ing  A  (see  of  compensatory  negative  through  many  matter  indefinitely  some  this  the  Manual  overcome  a  assumption.  once  the  of  radiotracer  with  of  almost  desirable  ion  swimming  eventually  this  of  to  evidence  extended  modification  the  these  during  correction of a  of  induction  loss  of  exercise  swim  experiments  i t was  movements  of  deal  can  The  validity  through  meters,  great  salmonids  As  ment  a  sodium  indicated;  occur  duration  speeds.  reduce  test  the  in  i n which  eliminating The  the  the  difference  99 in  mean  efflux rates  represent  the renal  condition. eliminate  between component  Urinary renal  discharge  Randall  e_t a _ l . , 1 9 6 9 )  unidirectional of  these  of  this  normal were of  this  over  alone  vention  disruptions  sodium  flux  Because n e t sodium  large  from  with  observations cerning  I.  whether and/or  effects  disturb (shams)  the  Weight  influence changes  on t h e u r i n a r y for  determination  and t i s s u e  the experimental  none  water  trout.  These  the urinary  inter-  the occlusion likely  con-  itself,  to disturb  rates. duration  of the trout  dependence  i n many  sodium  cases  flux  rates  The i n f o r m a t i o n  considerable  pertinence  of branchial  In a d d i t i o n ,  o f the experiments, brought  concentrations;  of branchial  changes.  t h e mechanisms  Section  samples  o f i n t e r n a l homeostasis  fluxes  held  determined  ligation,  could  of trout  exchanges.  to test  However  to evaluate  and plasma  o f the extended  r e s u l t o f these  group  recommended  traumatic  e f f e c t s which  were  alterations of external  concentration  to  f o rp a r t i t i o n i n g  the possible  and t e r m i n a l  designed  associated  produced normal  were  a particular  recently  regulators.  intervention  sodium,  taken  thus  (Holmes,1959;  technique  on sodium  fish,  under  previously  trout  a third  period  plasma  were  measurements  in  Thus  to urinary  a n d sham  centrations  a  on t h e animal,  the experimental  hematocrit,  the  considered  balance.  used  has been  i n hypertonic  have  procedure  blockage of  and i n f a c t  fluxes  treatment  subjected  i n rainbow  as an a c c e p t a b l e  workers  ionic  has been  loss  would  of electrolytes i n several  o f osmoregulation  70)  and l i g a t e d f i s h  o f sodium  blockage  studies  (Kirschner,19  normal  sodium  the data  was  a  marked  noted  provided  by  t o arguments exchange  about  as  these  con-  presented  *aa»e n o t c o m p l e t e l y  conson-  100 ant  with  tration  the  results  dependence  of  of  a  sodium  thetized  perfused  Salmo  In  light  of  facts,  in  some  Results  these  detail; and  the  examination  fluxes  gairdneri  topic  Discussion  recent  the  across  i n this  been  the  (Kerstetter  results  has  of  seemed  dealt  Section.  the gills  et  of  anaes-  ail.,1970).  worthy  with  concen-  of  i n Part  .  analysis B  of  101  METHODS I I  1.  Experimental  Animals  Animals sexually between  used  i n this  mature rainbow 160  trout  a n d 280 g .  condition.  Some  The t r o u t  were  described  i n Section I.  fish  maintained  were  sustain ments  the desired  were  February,  2.  Two  ization, to  the  anal  anal  groups  i n this while  section a third  f i n .  constant  immature and  weighing i n breeding  and a c c l i m a t e d as  the acclimation  period,  illumination  (14.5il.5°C.).  December,  the to  Experi-  1969, and J a n u a r y  and  to recover  hourly  and C a n n u l a t i o n s  were group  blockage  silk  and  subjected t o xirinary (normals)  were were  cut o f f approximately stump  was  then  stitches.  f o r 24 t o 72  shams)  catheter-  not handled implanted  2 cm  as i n  posterior  firmly  Operated  prior  tied  fish  to  to the  were  hours.  System influx,  efflux,  and n e t f l u x  f o r the 3 treatment  individually  i n a revolving  Simultaneous  records  blood  (urinary  Urinary cannulae  several  Sodium  terminal  were  held,  temperature  The cannula  Experimental  ermined  of the fish  almost  of trout  I , b u t were  f i nwith  allowed  3.  Procedures  the experiment.  Section  gairdneri)  obtained,  during  both  19 7 0 .  Operating  studied  water  included  (Salmo  During  under  performed  study  swimming  of the fish's  and t i s s u e  groups  samples  on t r o u t  chamber  behaviour taken.  rates  for8 were  were  det-  placed hours. made,  and  102  bowl  (a)  Swimming  Chamber  The  exercise  chamber  (diameter  speed  motor  velocities the  =  (Fig.16).  Continuous  Water  was  centre of  to  the  was  with  extremes  during  an  8  opposition  to  60  minutes  the  to  maintained  their thus  three well  or  intermittent. third  strated the  would  of  was  the  become  response  run  both  to  8  overhead  fish  of  PE  the  14 to  the  60  through bowl.  tubing  water  sampling.  relatively  experimental 16.5°C;  cm)  suspended  constant  temperature  maximum  was  change  1.8°C.  i n the  during  In  a  again  rotated  most  chamber of  each  two  relative  about hour  32  activity  the few  start, cases,  but a  d u r i n g water  visual  than fish  external  was  are  recorded not  swimming,  self-explanatory;  the  fish  demon-  to  periods  in  which  had  stopped  by  the  "not  swimming"  sampling,  stimulation.  less  swimming to  swimming,  and  swam  cm/second.  period  categories  20.5  trout  from  rapidly  p e r i o d s d u r i n g which of  at  Individual  categories:  first  at  run.  The  velocity  bouts  was  for periods ranging  hours.  to  swimming  active  airstone  chamber  entire  defined  The  hour.  an  and  was  the  current  animal  interrupted  trout  end,  refers  on  13.0°C.  position  one  the  length  Average  a maximum  the  a  =  of  permitted periodic  of  full  as  the  lid;  by  (diameter  variable  Conditions  the  of  port  addition  f o r the  Behaviour of  different  a l l experiments,  in  and  at  hour  Exercise  revolutions/minute  cues,  permitted rotation  dependent  15.2°C.  In  which  the  a i r temperature.  (b)  a  effected  ambient  observed  on  hinged  cm)  polyethylene  mounted  airstone  temperature  circular  =  A  13.5  a  depth  l i d allowed  aeration  the  adjacent  cm;  (kymograph)  plexiglass  through  40  comprised  As  fish  probably  these  in  103  F i g u r e 16  A drawing o f t h e s m a l l volume r e v o l v i n g chamber used f o r l o n g term e x e r c i s e o f t r o u t i n the experiments o f S e c t i o n I I .  104 swimming ment  to  bouts  "not  (c)  Weighing  The  weight  bucket The  of  water was  excess  taining  500  of  The  process  repeated.  ations,  the  end  weighing of  the  averaged, initial  on  a  to  dead  thorough have  drying  produced (d)  with  exactly  concentration and  then  was  to  of  was  and  was  an  weight  on  over  9  hours  stunned  to  of  the  fish;  from  2 71.5  of  animal  (as  stress  5 g  that  2 73.4  Procedures  to  an  experiment,  the  6 L  of  dechlorinated  =  1.61  ug/ml)  with  the  and  on  ion  plexiglass l i d .  -  25  the  were g  was ad-  determinations However  flux  (mean uC  v/ell  rates.  Groups  chamber  water 15  at  III) could  swimming  containing  ident-  o f water  Treatment  fresh  An  procedure,  g.  i n Section effects  determin-  section,  successive  the  i n g/100  the  amounts  to  and  measurements  this  variable  con-  and  animal  expressed  emphasized  sack  bucket  used  weight  a  to  closed  i n i t s aquarium. the  in  briefly  the  as  removed  plastic  the  recorded  experiment.  stapled  of  blockage  placed  back  ranged the  were  shaken  returned to  purposes  due  urinary  of  tared  bag  f o r the  undesirable  sealed  a  Duplicate  Experimental  Prior  hand,  be  surface  trout  by  I t must  inaccurate the  assign-  unchanged.  trout  start  completion  placed  change  adequate  relatively hering  the  and  A  the  The then  experiment. and  up  added  After  weight.  although  before  was  procedure  shams  fluxes.  water.  was  the  i t s r e c o v e r y tank  and  trout  fish  minutes),  experimental period  picked  water,  mis  of  water  hour  then  weighed.  ical  the  net  one  ( 1 - 2  category remained  changes  over  of  short  Procedure  a n a e s t h e s i a from  animal  remove  swimming"  groups  measures  without  extremely  the  treatment gross  were  of  was  filled  sodium Na  ,  105 (i)  Normal  the  acclimation  the  chamber  sary of  to  the  bowl  The  details  fish  to  water  the  A  of  port.  trout  to  chamber  animal.  Exactly  bowl,  samples  a water  were  taken  the  by  procedure  to  slip  then  then  varied 10  60  near  slowly  minutes (10  the  minute  was  into  neces-  the  outside  of  and  in  the  speed.  behaviour  of  the  addition  of  the  after  ml)  from  hands  direction  increments with  wet  generally  itself  rotated  gradual  directly  through  proposed  sample at  removed  position  was  attained  was  I t was  to  the  the  fish  allowed  in opposition  velocity  individual  and  f o r the  revolution.  The  tank  through  wait  desired  Trout«  drawn;  intervals  further  for 8  hours  22 to  measure  the  concentration decreased  decline of  the  of  as  above.  described  rinsed blood  from with  sampling, as  water,  the  the  as  f o r the  fish  was  dried  drawn  by  made trout  blow  measuring  on  paper  cardiac  and  period.  twice  hour  was  quickly  the  head,  towels.  puncture  immediately;  procedures  an  A  into  a  tissue  were  performed  I.  Urinary Blockage a  a  with  weighing,  stainless  swimming  was  and  by  centrifuged  and  one  and  group.  weighed  Trout.  After  p i n was  inserted  the  hour  chamber  normal  again  steel  cannula,  Exactly  to  stunned  the  sodium  radioactivity  experimental  were  hours,  in total  Water  the  behaviour 8  change  medium.  and  urinary  aquarium.  ul)  the  during  After  fresh (500  and  syringe  (ii)  of  fish's  chamber,  i n Section  minations,  85%  the  sample  heparinized  the  Na  external  approximately  Observations  removed  of  later, the  At  twice  fish  the  the  end  before  into  returned to trout  experimental  the  weight  of  blood  the and  was  a  deter-  the  stump  recovery transferred  protocol  followed  experiment, tissue  the  sampling.  106 Patency dyed  of the urinary  saline.  hydrostatic caused these  O f t h e 17  were  from  Sham  Trout.  the procedure through  checked  by  injection  to urinary  the build-up  papilla  i n 8.  animals  were  of  blockage,  of urine A l ldata  had from  discarded. These  experimental regime  mimicked  checked  subjected  rupture of the urogenital trout  ever,  was  fish  pressure resulting  (iii) same  c a n n u l a was  as t h e u r i n a r y  of plugging  several  firm  blockage  the urinary  tugs  post-experimentally  on  subjected group.  How-  c a n n u l a was  the tubing;  to ensure  to the  that  merely  the  catheter  i t had  remained  free-draining.  4.  Analytical  Procedures  Determinations tissue  water,  plasma  were  performed  were  done  on  of terminal  and water  as i n S e c t i o n  sodium,  I.  t h e T e c h t r o n Model  hematocrit, plasma and water  A l l flame AA  and  radioactivity  emission analyses  120 A t o m i c  Absorption  22 Spectrophotometer was  assayed  on d u p l i c a t e  to  1 ml w i t h  5.  Calculations  flux  (see Section  water  25  uL  and d r i e d  (a)  Sodium  Flux  The  method  described  rates  I ) .  Na  i n terminal  aliquots  under  which  a heat  plasma  had been  diluted  lamp.  Rates i n Section  i s complicated i n long  term  I for calculation experiments  of  by the  22 return In  of the labelled  the present study,  approached Computation of  isotope  the internal  35% o f t h e e x t e r n a l of influx  the radioisotope  Na  rate  would  the fish  specific  specific  without yield  from  activity  activity  compensation  a value  to the  inferior  of  after  water. sodium  8  hours.  for backflux to the  true  107 influx of  rate.  Maetz  during the  Thus  (1956)  long  term  theoretical  from  Maetz  that  the  two  to  i t was  determine  derivation The  (internal)  compartment  system  to u t i l i z e  ion influx  experiments.  (1956).  fish  necessary  The  of  this  analysis and  following equation  i s based  the water  between  rates  which  the  i n fresh  water  description  has on  equation  been  the  of  modified  assumption  (external)  represent  a l l i o n movements  a  occur.  Symbols: Na  Total quantity external water  ext  Na i n t  Quantity the f i s h  Qo  Total quantity external water  Qf  Total quantity external water  At 22  At  pf:  pf  Concentration (c.p.m./ml).  o f Na  22  the  i n a  :  Concentration of sample (ug/ml).  Fi  :  Na  influx  rate  (ug/minute).  Fo  :  Na  efflux  rate  (ug/minute).  Fn  :  Na  net  time  partment  t  the i s Na  flux  specific Q  , while  contained  i n  22 o f Na (c.p.m.) a d d e d t o t h e at time zero. 22 o f Na (c.p.m.) r e m a i n i n g i n t h e at t. 22 o f Na (c.p.m.) r e m a i n i n g i n t h e a t t h e e n d o f t h e e x p e r i m e n t (8 h r s ) .  Time p e r i o d o v e r which (60 m i n u t e s ) .  /ml  Na/ml  sodium(ug) c o n t a i n e d i n the a p a r t i c u l a r time t.  exchangeable sodium(ug) t.  Total quantity external water  Q  Na  of at  of at  rate  sodium  rate  terminal  i n a  i s  measured  plasma  sample  terminal  plasma  i n the  external  (ug/minute).  activity that  influx  of  of  sodium  the  internal  compartment  comi s  ext 22  Qo - Q. Thus o v e r A t , t h e amount Na i n t n a l c o m p a r t m e n t may b e e x p r e s s e d : x A t Fi x Q Na e x t  o f Na  entering  the  inter-  (1)  108 Conversely,  the  amount  (Qo Na  - Q) int  of  Na  22  leaving  the  internal  compart-  ment i s : Fo  x  x At  (2) 22  Thus  the  given  by  the  fresh  does  linear It  over  =  Fn Solution this  - ANa  At  of  in  At|  AQ At  to  note -  then  Q)  time  varies  of  and  thus  interval  with of  calculate  amount  Fo,  time  of in  equation  f l u x e s by The  net  sodium  an-exa  non-  (3).  numerical  flux  in  (3)  Fn  the  i s  con-  external  (3)  -Q ext for  that  -  Qo  Na  between  Fi  and  Fo (5)  (4)  and  (5)  for  produces  the  following  x  Fi  +  Qo Na  - Q int  Fo  x  and  substitution equation:  ( F i + 4 Na  ext) At  (6)  Fi —  - Q int  Qo Na  - Q int  be  deduced  during  (4)  Fo  —-  may  the  interval.  the  i s  ext  equation  solution  Fo  equals  integration  difference  Fi —  Na by  the  =  term =  ext  to  time  when  +  over  Na  At  diminishes:  represents  AQ  each  positive  Fn  (Qo  zero  i s therefore necessary  compartment  and  equal  over  e x p r e s s i o n s (1) and ( 2 ) : M Qo - Q : [_] Na ( Q io n-t Q ) x F o x A t  Fi rarely  fashion, preventing  sidered  of  F i x A t _ J|  (AQ)  •I  between t | +  Consequently,  resolution  and  e x t e r n a l Na  teleosts,  usually  periment.  total  ext x  water  not  in  difference  = I - NaQ  AQ In  change  4Na  (7)  ext _  A t Q Na  a  from short  i s negligible,  and  ext equation term  (5).  experiment,  equation  It  i s  the  simplifies  interesting quantity  to:  109  A2, Fi  which All  i s the  terms  =  -  Q Na  ext  relationship  i n equation  (8)  At  (7)  used  to  calculate F i i n Section  with  the  exception  o f Na  I.  i n t , are 22  readily  extractable  concentrations  from  Na  i n t must  since  Na  i n t i s large  the  may  be  terminal  vary  As  relative and  Na  Fn  varies  changes  to  Na  i n sodium  ext,  i n t may  be  during  i n Na these  and  Na  the  experi-  ext.  However,  slight  dev-  approximated  from  sample: Qo - Q f 22 , .. _ N aa / m l / m lp f p f  i n t 22  changes  to mirror  ignored,  plasma  Na  on  i n the water.  ment,  iations  data  (9)  X T  (b)  Na  Space  The  distribution  volume  of  radiosodium  (Vint)  was 22  calculated the  fish  plasma  as  after  i n Section 8  hours  I  and  from the  the  total  mount  radioactivity  of  o f Na the  i n .  terminal  sample: Vint  =  Qo Na  22  Qf /ml  (10) pf  110  RESULTS AND A.  DISCUSSION  II  Sodium F l u x Rates d u r i n g Extended E x e r c i s e The  r e s u l t s o f t h i s s e c t i o n were o b t a i n e d from  completely d i f f e r e n t  s e t o f rainbows from  I; t h e i r p h y s i c a l dimensions  those used  a  i n Section  are p r e s e n t e d i n T a b l e IX.  The  animals were g e n e r a l l y s m a l l e r and t h i n n e r (as m a n i f e s t e d the low c o e f f i c i e n t s o f c o n d i t i o n ) than the f i r s t  by  group  ( c f . T a b l e I I ) and many were i n prime b r e e d i n g c o n d i t i o n . These b a t c h d i f f e r e n c e s p r o b a b l y  accounted  f o r the  slightly  h i g h e r sodium i n f l u x r a t e s and plasma c o n c e n t r a t i o n s i n the p r e s e n t s t u d y . weights  observed  However T a b l e IX demonstrates t h a t body  and c o e f f i c i e n t s o f c o n d i t i o n d i d not v a r y  a n t l y among the t h r e e e x p e r i m e n t a l  groups o f t h i s  significsection,  t h e r e b y a g a i n a l l o w i n g comparison o f f l u x r a t e s between ments on a per 100 I t was a temporal  g body weight  basis.  the o b j e c t o f t h i s i n v e s t i g a t i o n t o measure on  b a s i s any p r o g r e s s i v e changes which o c c u r r e d i n  f l u x components i n response  t o l o n g term  p r e t a t i o n o f the r e s u l t s was factors.  been g r a p h i c a l l y p r e s e n t e d  swimming.  Inter-  however c o m p l i c a t e d by s e v e r a l  F l u x r a t e v a l u e s from  a typical  experiment  i n F i g . 17 t o i l l u s t r a t e  have  the  c u l t i e s encountered  i n e v a l u a t i o n o f d a t a and  analysis applied.  Individual trout exhibited variable  behaviour from  was  diffi-  the method o f  i n the e x e r c i s e chamber, swimming f o r p e r i o d s r a n g i n g  l e s s than one  ment.  treat-  hour to the e n t i r e e i g h t hours o f the e x p e r i -  C l a s s i f i c a t i o n of a p a r t i c u l a r hourly flux r a t e value  t h e r e f o r e dependent not o n l y on whether the animal  was  Ill  Table  IX.  P h y s i c a l dimensions  groups o f S e c t i o n I I .  Length  (g)  i n the t h r e e  Means - 1 s t a n d a r d  Normal N = 10 Body w e i g h t  of trout  error  Sham N = 10  186.92 - 5.42  treatment  U r i n a r y Blockage N ° 9  190.60 - 10.19  180.09 -  6.95  (cm)  28.84 - 0.40  28.73 -  0.57  28.42 -  0.35  Fork l e n g t h (cm)  27.70 - 0.39  27.38 ±  0.49  27.26 -  0.33  Max.depth (cm)  5.50 i  .08  5.52  -  .08  5.65  Coefficient of condition  0.882 -  .026  0.928 ± .036  0.889  d i f f e r e n c e s between c o r r e s p o n d i n g  values i n  w e i g h t x IQO3 ( fork length)  No  significant  different  groups  -  .11  -  .036  112  F i g u r e 17  R e s u l t s o f a t y p i c a l experiment o f S e c t i o n I I i l l u s t r a t i n g the method o f d a t a a n a l y s i s  applied.  B l a c k b a r s = sodium i n f l u x r a t e s ; d o t t e d b a r s = sodium e f f l u x r a t e s ; c l e a r b a r s = sodium net f l u x rates.  Below a p p r o x i m a t e l y 0.8  ug Na /ml, +  influx  r a r e became dependent on e x t e r n a l sodium concentration.  Fish 4 5 - S h a m ,180.6 g. 150  £  I - L ioo E £ u) Q50 x o  LU ( J  0.00 •50.0  i  •40.0 •30.0 •20.0 •10.0  a  0.0  DJ  -10.0  £ D O CO  -20.0 -30.0 -40.0  Swimming Behavior  s  w  i  m  ]st  -  s  w  ,  m  -  2 ^ n<  inter. inter. inter.  not not Q* swim. swim. swim.  n  2nd  subsequent Classification hour hour inter. inter. inter. hour hour hours swim. swim. recov. recov. recov. 0 8 Time (hours)  swimming o r  not,  but  on  the  measurement p e r i o d d u r i n g resting. trout  Inspection  had  hours of most o f the  of data  their  examples o f  time  at r e s t  had  swimming.  these  cases.  procedure  is illustrated  by  m e a s u r e m e n t was some f i s h  hours  after  presents  characteristic  hourly  The  than  the  A  the  effect  occurred  low  sodium  vestigation  of  the  interaction  rate revealed  greater on  that  0.8  that ug/ml,  concentration  in  the  of  d i d not  in  exter-  h i g h l y p o s i t i v e net  was  especially  the  outside  slope differ  of  prevalent  renal of  efflux. branchial  water.  In-  concentration  average e x t e r n a l  the  to  f u r t h e r problem  between sodium at  averaged.  equally  a marked d e p r e s s i o n  levels  17.  category  large diminutions  c a u s e d by  at  influx  hour  c o n t r i b u t e d more v a l u e s  did others.  from  hours  experiment o u t l i n e d i n F i g .  u r i n a r y b l o c k a g e g r o u p w h i c h s u f f e r e d no  influx  determinations  classification  t h e r e f o r e weighted  rate  of  three  hour recovery, second  the  some t r o u t ; t h e  there  three  swimming, s u b s e q u e n t  obviously  analysis evolved  a l l groups,  levels  by  g r o u p were t h e n  In  and  stabilized  no  spent  treatment  the  the  which  i n the  in  or  fish  animal  rates of  influx  rates of  first  for a particular  sodium c o n c e n t r a t i o n  flux  the  component  category  active  i n which  a flux  a particular  nal  been  of  mean a l t h o u g h  the  eight hours revealed  subsequent hours recovery.  values  Each h o u r l y  data  had  to  following self-explanatory categories:  and  in  flux  swimming, s e c o n d h o u r  every  the  Consequently,  recovery,  from  animal  F i g . 18  intermittent, f i r s t  the  time p r i o r  from experiments  a l l of  swimming,  All  the  Similarly,  were d i v i d e d i n t o t h e hour  of  i n s o d i u m movements a f t e r  exercise.  cessation of  first  which  swum f o r m o s t o r  marked v a r i a t i o n  length  the  sodium  regression  significantly  line  from  114  F i g u r e 18  R e s u l t s o f two experiments o f S e c t i o n I I . B l a c k b a r s = sodium i n f l u x r a t e s ; sodium e f f l u x r a t e s ;  clear  dotted bars =  b a r s = sodium net  flux  rates. Upper: Example  o f an animal which swam c o n t i n u o u s l y  for 8 hours.  Sodium  f l u x r a t e s had s t a b i l i z e d  by t h e t h i r d hour o f e x e r c i s e . Lower": Example  o f an animal which was  inactive for  most o f the e x p e r i m e n t a l p e r i o d .  Sodium  r a t e s had s t a b i l i z e d by the t h i r d hour termination of exercise.  flux  after  Fish 30 Sham, 181.8g. SWIM MING-  c J CO  0) O  or x E D O CO  +50.0-40.0 +30.0 +20.0-10.0 0.0 -10.0 -20.0 -30.0 -40.0 -50.0 -60.0 (8162) 0  fffs  D  n n  n  a  p  8  Time (hours)  Fish25 Normal,209.8g. SWIM.  +50.0 +40.0 ?3£ c + 30.0 E +20.0 +10.0 0.0 0 -10.0 O cr -20.0 X ' 3 -30.0E -40.0 2 -50.0 O CO -60.0 «/>  0  INTER. | +-  NOT SWIMMI NG  m  a a  D  2  3 4 5 Time (hours)  51  n  n  n  8  115 z e r o , whereas below t h i s positive correlation.  f i g u r e , there  existed a definite  In P a r t B o f t h i s s e c t i o n , i t has  shown t h a t the d a t a agrees w e l l w i t h a t y p i c a l Menten c u r v e order  ( c f . F i g . 20)  r a t e means between and if  ug/ml.  Comparison o f  w i t h i n groups was  a l l the components o f the  little  apply  e f f e c t on  averages had  t o net  directly  "velocity".  f l u x r a t e s , and  A s i m i l a r argument must  t o e f f l u x r a t e s i f the l a t t e r  Thus i t was  e x t e r n a l sodium c o n c e n t r a t i o n s  three  are  (back-transport)  necessary to d i s c a r d  l e s s than 0.8  d i s p l a y s the r e s u l t s o f the  average ug/ml. ( F i g . 17).  above a n a l y s i s f o r  the  treatment groups. Sodium e f f l u x r a t e s  i n the  shams and  ( F i g . 19)  were s l i g h t l y  thus net movements m a r g i n a l l y  r e l a t i v e t o the normals, but  the d i f f e r e n c e s were g e n e r a l l y These  s e t s o f t r o u t demonstrated e x t r e m e l y s i m i l a r t r e n d s r a t e v a r i a t i o n i n r e s p o n s e t o the s t a t e o f e x e r c i s e . regarding  f o r the p r e s e n t  the d a t a from the u r i n a r y  a number o f c o n c l u s i o n s  exchanges o f t h e s e two  higher  less positive  l a r g e enough t o o b t a i n s t a t i s t i c a l v a l i d a t i o n .  fish,  only  concentration  from the means a l l f l u x measurements taken at  F i g . 19  influx  been determined  (exchange d i f f u s i o n ) o r i n d i r e c t l y  l i n k e d to i n f l u x r a t e s .  zero-  therefore v a l i d  o v e r t h a t p a r t o f the c u r v e where " s u b s t r a t e " had  Michaelis-  which tends t o approach the  r e l a t i o n s h i p a f t e r 0.8  been  may  groups.  be  two  of flux Disblockage  drawn from the  sodium  F i r s t l y , branchial  sodium  i n f l u x r a t e e x h i b i t e d remarkable s t a b i l i t y over the e x p e r i - ' mental p e r i o d .  The  only  statistically  gence i n t h i s parameter o c c u r r e d and  2nd  hour r e c o v e r y  values  significant  diver-  between 1 s t hour swimming  i n the normals, and  between  the  not  116 F i g u r e 19  Sodium f l u x r a t e s , measured a t e x t e r n a l c o n c e n t r a t i o n s g r e a t e r than 0.8 ug/ml, under d i f f e r e n t e x e r c i s e cond i t i o n s i n normal ( 1 0 ) , sham ( 1 0 ) , and u r i n a r y b l o c k a g e (9) t r o u t . B l a c k b a r s = sodium i n f l u x r a t e s ; d o t t e d b a r s = sodium e f f l u x r a t e s ; c l e a r b a r s = sodium n e t flux rates. V e r t i c a l l i n e s represent 1 standard error o f each mean. Each average i n c l u d e s a l l a c c e p t a b l e d a t a i n t h e c a t e g o r y ; thus i t was p o s s i b l e f o r a s i n g l e f i s h to c o n t r i b u t e more than one v a l u e t o t h e mean i n c l a s s i f i c a t i o n s 3, 4, and 7. S t a t i s t i c a l Comparisons: (Numbers r e f e r t o means o f e x e r c i s e c o n d i t i o n s as l a b e l l e d a t t h e head o f t h e graph.) Normal: I n f l u x Rate. F = 1.59, n . s . 6  5  7  4  3  2  1  E f f l u x Rate. F = 13.90, p < . 0 0 5 6  7  5  3  4  2  1  Net F l u x Rate. F = 4.59, p < .005 1 Sham:  2  4  5  3  7  6  I n f l u x Rate. F = 1.61, n.s. 4  5  6  Efflux 6  4  2  3  1  7  Rate. F = 5.63, p < . 0 0 5 5  3  7  2  1  Net F l u x Rate. F = 6.62, p < . 0 0 5 1  2  4  3  5  7  6  Urinary B l o c k a g e : I n f l u x Rate. F = 1.94, n . s . 7  6  Efflux 5  2  5  4  2  1  Rate. F = 0.20, n.s. 7  1  6  4  Net F l u x Rate. F = 1.52, n.s. 7  —  6  4  5  2  1  A = significantly different normal v a l u e (p < .05)  from c o r r e s p o n d i n g  B = significantly different sham v a l u e (p < .05)  from c o r r e s p o n d i n g  C = significantly different v a l u e s (p < .05)  from b o t h normal and sham  = not s i g n i f i c a n t l y d i f f e r e n t v a l u e s (p y .05)  from o t h e r c o r r e s p o n d i n g  2  1  3  Hour  2" Hour  Swimming  Swimming  Subsequent Hours Swimming  n=9  n=4  n=11  1  s t  d  7  5  6  Intermittent  1 Hour Recovery  2 Hour Recovery  n=12  n=7  n=6  s t  nd  Subsequent Hours Recovery n=20 NORMAL  M  r r  a  1-1  n=10  CO  n=8  n=16  n=!5  2  n=6  a  n=6  n=14  g 3C+ +  SHAM  "5+20 I? in  +10  <  0  OS  .3  . 1  a  f  g -1C+ -20f |-3C+ O  i A A  CO  n=9 +30  n=9  n=3  n  + 10 0  •i  lbs;  i  -10 -20 -30  _ cc  _ C B  n=4  n=4 URINARY BLOCKAGE  No Dato  +20  n=5  — A A  B C  a  1 B  intermittent shams.  As  istical  the  and  data,  hours  differences  confirmation^were  meaningful ical  subsequent  these  treatments, in  and  were  not  i t seems  not  An  unfortunately  contribution  of  data  iated  with  in  prolonged  subsequent  to  swimming,  at  recovery  the  of  but  by  the  third  ations  in  net  flux  that  associated entation was  of  which  whose  to  low  the  the  rate  to  (one may  hour) now  exercise.  was,  however,  significantly  subsequent  rates  followed  hours a  experiments  of  activity.  designed  to  overcome  the  with  short  periods  of  swimming  through  through  This  reduction was  originally  s i t u a t i o n over  sodium  exchange  uously  throughout  of  data the  the  of 8  hours,  #30  Vari-  exercise ( F i g . 18)  provide  to  net  test,  sodium the  the the  exercise,  excellent  occurred  same  factor  negative  interval. which  deficit  implem-  apparently  for  first  The  prolonged  efflux rate,  responsible  i n i t i a l  trout  during  adaptation  the  the  post-exercise  able  confirmed.  vulner-  similar pattern. were  mechanisms  the  condition.  i s  compensatory  extended  during  to  assocwas  be  v e l o c i t y , and  greatest  The  factors  prevailing exercise  and  statistunequal  such  were  any  mean.  trout  elevation  balance  at  ( F i g . 19)  the  with  1  trends  spurious  recovery  following  declined  these  of  stat-  two  general  the  therefore  entirely  of  represented  conclusion  out\v-ard m o v e m e n t s  levels  namely  least  period  influence  they  influx  and  This  efflux rate  swimming  hypothesis  sodium  exercise I.  Unidirectional hour  term  Section  Sodium able  branchial  short  established to  of  the  any  sources  the  borderline  between  concomitant  single  of  with  augmentation  is  from  that  figures  only  consistent  concordant  effects  insensitivity  attained  doubtful  variation.  recovery  swam  The contin-  illustration  118  of  this  the of  first the  over  hour  second  It  was  may  greater  ence  hour  which  negative  despite By  five  group,  be  the  than was  the  of  This  by  of  short  rapid  for a  an  disruption nature of  increase  minimum  (Fig.  intervals  i n oxygen  irregular  efflux  19)  observed  i n the It  must  discussed  above  and  and  shams  least  f o r the  hours  category  swimming,  of  the  next  a  probably explainable  of  category,  swimming  Such  of  compensatory  activity,  into  activity  the  which,  have  been  of  recovery efflux  with  increase  i n net  branchial experiments  of  emphasized  were  thus  efflux  whole  Section that  the  a  the  the  exhibited  recovery  by  a  return  somewhat  lower  to net  through  during  recovery  was  I. sodium  efflux  measurements sum  with  flux.  flux  parameter  organism  represented  net  characterized  associated  similar  be  were  large  responsible  hour  positive  the  through  the  a maximum  a  current  combined  during  second  by  produces  phenomenon  could  to  which  value  of  differ-  flux  groups  A  the  was  at  intermittent  return  rest.  by  outward  returned  Both  greater  of  had  element.  a  reduction  the  (Brett,1964),  the  #30  loss  maintained throughout  that  intermittent  the  i n the  efflux  hours  uptake.  was  net  persisted  i n the  Subsequent  sodium  the  bursts  of  fish  uptake  accompanied  slightly  which  of  effect  consisted  deficit  reduction  hour,  subsequent  reflected  during  exercise.  rate  i n the  possible  third  i n F i g . 19  trout  increases  large  noted  of  by  a  of  that  extremely high  This  hours  efflux  value.  was  producing a pronounced  situation  behaviour  followed  efflux  environment.  balance  following  normal  to  component.  a positive  the  sodium  o f measurement  electrolyte  the  moving to  phenomenon;  of  rates  f o r the  branchial  and  normals renal  contributions. rainbows  were  constituent rate  performed  determinations  distributed moderate fidence from  data,  between  significant conditions other  sequent also  two  animal  throughout  Rejection  fish  was  sodium  one e x c e p t i o n ,  On  this  basis,  nature  however,  o n e may  have  of ligated trout  of fish,  rate,  values  across  the g i l l  showed  s i m i l a r magnitude  came  Thus  epithelium  exercise  means o f  o f t h e subwhich  from  a  single  low i n f l u x  rates  movement o f  of urinary  blockage  to that  was that  the inward  and s t a b i l i t y  con-  no  to the fact  characteristically  the experiment.  showed  anomaly,  ascribed  i n the average  demonstrated  sodium  c a n be  lone  only  calculated  different  the exception This  well  some  group, o r comparable  with  value.  was  o f t h e means  to either  flux  criterion.  and e x h i b i t e d  influx  respect  each  o f many  level  (Fig. 19).  rates  of  unfortunately  measurements  o f net flux  which  the role  d i f f e r e n t experiments  recovery  o f the four  to ascertain  external  the treatment  sets  hours  true  three  with  variation with within  occluded  the ligated  i n the representative  the remaining  urinary  responses.  ug/ml  variability.  Branchial  the  from  b y t h e 0.8  acceptable  with  i n order  i n the observed  necessitated The  The experiments  of the  animals unligated  fish. Sodium cases  significantly  either  or both  extremely the  efflux rates  than  o f the other  constant  assumption  lower  under  i s taken  influx,  was  unaffected  changes  i n whole  body  o f the occluded  two  the corresponding treatments,  different activity that  trout  branchial  by urinary  but  unidirectional losses  values  i n most for  remained  conditions.  sodium  occlusion,  were  efflux, then  during  I f like  the observed prolonged  120 swimming  must  component sodium  efflux  of urinary  ation.  was  this  X  during  to recovery  levels  of  Section  of  the rate  This  conclusions  I which  o f sodium  discrepancy  could  of  rates  i n the normals  of  these  two  component  calcul-  of exercise  but had  and  sub-  sham  discharge  which  (Table  Section  through during  was  subsequent  X)  of  hours  the estimate  section. electrolyte calculated  sodium  outputs  Table  XI  observed by  at various  with  discharge efflux  were  an  i n Section  subtraction  speeds,  increased  extremely  calculated i n the  c o m p a r e s t h e maximum I I I with  o f the sodium  renal  directly  and  sodium  loss  swimming, low  relative  present  discharge  the urinary efflux  efflux  rainbows  diuresis during was  branchial  hypothesis.  measured of  variations  individuals.  for this  of the urine  a c t u a l l y d i d occur  of renal  representative  a significant  support  analysis  of this  sodium  of the calculated renal  cogent  associated  exercise.  i . e .i f the efflux  i n the ligated  c o n t r o l l e d swimming  the magnitude  not  not evident  and  the kidney  during  include  provides  There  were  results  augmentation  i f the branchial  rainbows shams;  the  significant  d i d i n fact  I I I ,urinary  rest,  through  and  with  the g i l l s  explained  o f the v a l i d i t y  collection  recovery.  be  a very  across  occluded  groups  assessment  rates  to  from  of this  seriously disagree  efflux  of urinary  but  of  the renal  the third  demonstrated  effluxes  In  by  means  the results  hour  excretion  approximated by  efflux  indicate that  the f i r s t  be  efflux  swimming. These  An  could  sodium  presents  i n the renal  the urinary  conditions  estimates  high  basis,  blockage  Table  These  decreased of  On  different  means.  sodium  attributed to variation  alone.  under  traction  be  rate  of the  release of the  121  T a b l e X. exercise  Urinary conditions  branchial  efflux  mean w h o l e  sodium  efflux  rates  o f shams u n d e r  e s t i m a t e d by s u b t r a c t i o n  rate  o f the urinary  animal e f f l u x  rate  1st  hour  swimming  21.72  2nd h o u r  swimming  14.88  Calculated  u r i n a r y sodium e f f l u x r a t e (ug/100 g/minute) •  s u b s e q u e n t h o u r s swimming  5.82  intermittent  3.39  1st  hour r e c o v e r y  7.53  2nd h o u r r e c o v e r y  1.25  subsequent  6.86  urinary  hours recovery  an e f f l u x  blockage f i s h  a v e r a g e o f 2nd h o u r  rate  equal  swimming  from t h e  o f t h e shams.  condition  in  o f t h e mean  blockage group  Exercise  * Computed a s s u m i n g  different  f o r subsequent hours  t o 13.81 ug/100 g / m i n u t e ,  and i n t e r m i t t e n t  values.  swimming the  122  Table  XI.  during maximum  Comparison o f calculated  swimming urinary  i n shams  with  reported  sodium discharge  U r i n a r y Sodium efflux rate. (ug/100 g/minute) 6.86  renal  direct  i n Salmo  Conditions  sodium e f f l u x  measurements  of  gairdneri•  Method  control (subsequent h o u r s swimming)  rates  Reference  calculation  present Section  study II  * 21.72  * 14.88  1,95  3.51  2.61  2.83  1 s t hour u p t o 32  swimming cm/sec.  "  "  2nd hour u p t o 32  swimming cm/sec.  "  "  control  * *  *  direct measurement  present Section  1 s t h o u r swimming - 21.4 c m / s e c .  "  "  1 s t h o u r swimming - 32.1 c m / s e c .  "  "  1 s t h o u r swimming - 42.8 c m / s e c .  "  "  1.43  control  5.35  1 hour a f t e r acute hypoxia  0.30  control  study III  direct measurement  Hunn  (1969)  direct measurement  Hunn and W i l l f o r d (19 70)  * 3.38 4.71  *  Maximum ments .  6 hours after MS 2 2 2 anaesthesia *2 h o u r s a f t e r methyl pentynol anaesthesia  urinary  sodium l o s s  "  "  "  "  under d i f f e r e n t  experimental  treat-  123  urinary number  blockage of  other  loss  of  Salmo  been  included  fish  from  the  corresponding  d i r e c t measurements  gairdneri  response  the  work  of  Willford,1970).  These  data  indicate  rising  the  first  over and  urinary 15%  of  from  in  half  second  sodium the  although  hours  loss  not  low;  possible  presently.  the  of  hour  have of  the  terminal  Table  XII.  which  at  isotope  8  1967;  branchial derived  • The hours  probably  for  Lahlou  was  and  very  figure  chasing  component  fish  from  the  tissue  space  an  similar fresh  al.,1969).  were will  of  water Both  the  teleosts Na  22  of  the  of  the  g/min.  been  to  shams during that  In  addition,  the  reduction  largely  loss.  been  few  advanced  probably  for  and  analysis  summarized  normal  administration  to  be  procedure  equilibrium  about  abnormally  I.  have  the  suggest,  than  identical  Section  has  the  branchial  ug/100  sodium  samples  external  30  weighing  comp-  evidence,  swimming  would  has  animals, most  nearly  of  more  This  responsible  activity  than  efflux rate  in  sodium  and  during  that  irregularity  mechanism  represented  "intact" et  of  radiosodium after  suggests  non-occluded  a  Hunn  no  movement.  branchial  renal  calculations  for  with  A  stresses  rather  the  approximately  prolonged  blood  Nibelle,1969) reported  been  hour  as  value.  maximum  that  associated  swimming,  one  efflux during  in  various  blockage  this  The  compensatory  Data of  for  gills.  during  on  urinary  to  account  strongly  efflux rate  the  unknown  active  of  cause  therefore  observed the  in  at  first  probably  the  efflux rate  exercise,  Consequently,  variations  would  can  conclusive,  efflux rates  occurred  of  of  (Hunn,1969;  organism  u n i d i r e c t i o n a l outward  sodium a  whole  Hunn  sham  rainbow  of  value  other  the  in trout,  radio-  (Mayer  and  measurements  (Maetz,1956;  Motais,  d i s t r i b u t i o n volumes  124 Table X I I .  T e r m i n a l measurements o f i n t e r n a l sodium and water  l e v e l s , radiosodium  spaces, h e m a t o c r i t s , and weight changes  the e x p e r i m e n t a l p e r i o d .  Means - 1 s t a n d a r d  Normal  Sham  N = 10 Plasma sodium concentration (mEq/L)  144.75 ± 5.23  error. Urinary  N = 10 132.62 ± 10.05  106.69 ± 3.87  p-^ „== n . s .  Pl< P  33.82 ± 1.83  2 < .05  Pi P 2  89 ,957.50 ± 6 ,629.68 p < 1  .001  34.39 ± o. 78  29.86 ± 1.43 p^ = n.s.  T o t a l e x c h a n g e - I l l , 4 2 6 . 00 ± 5,867. 11 able i n t e r n a l sodium (ug/100 g)  blockage  N = 9  -  22 Na space (ml/100 g)  over  " n.s. < .02  84,399.90 ± 3.808.42  .05  .01 Pi < P " n.s. 2  "96.19 ± 0.26 Plasma water concentration '(ml/100g plasma)  95.90 ± 0.27  96.38 ± 0. 31  p^ = n . s .  l P p  2  Hematocrit  {%)  28.05 - 3 . 1 7  33.75 ± 2.56  = n.s. - n.s.  28.49 ± 3.86  p^ = n.s.  P l = n.s. 2 = n.s. P  Weight change (g/lOOg i n i t i a l weight)  -  -2.57 ± 1 . 0 5 l~  p  +8.57±0.93 p  l~ " P < .001 2  T i s s u e water concentration (ml/lOOg/tissue)  81.047 ± 0.530 81.851 ± 0.570 P  x  =• n . s .  83.899 ± 0.257 _ P< .oui n  1  P  2  < *  0 1  e q u a l s s i g n i f i c a n c e w i t h r e s p e c t t o c o r r e s p o n d i n g normal v a l u e p  2  e q u a l s s i g n i f i c a n c e w i t h r e s p e c t t o c o r r e s p o n d i n g sham v a l u e  and  plasma  normals, The  sodium  although  effective  internal  products  associated  with  accompanying  Section could  an  a  result i s  (Hirano,  personal  ed  a  sodium  Salmo not  yet  sodium  this  of  urine  whole  deficit body  in  the  of  both  efflux  shams  of A  of  the  very  as  trout. under  renal  losses.  urinary  cannula  exhibited  significant  weight  most  gain  wall  of  animal  is  a  secondary  tubular  thus  the negate  slightly  exercise  as  re-  of  drain  reflected  not  during  demonstrat-  augmenting  However did  probably studies  that  and  The  have  trout  intact  would  the higher  conditions elevation  noted  earlier,  i n t e r f e r e with extended  amounting  be  g i l l  efficiency  further  therefore  changes  the  produced  may  and  the  have  the  may  in  bladder  possible  catheter  thereby  recorded  the  series with  i t was  cannulated  rates  isolated  increases  urinary  across  72  the  discussed  unpublished  in  to  during  D.J.Randall) the  up  permeability  and  in  itself.  procedures  (Lederis,1970)  to  in  for  The  Recent  by  confirmed  increase.  therefore  normally  function,  the  efflux  i s  soon  out  i t s function  mechanism  ( F i g . 19)  branchial  presence  pattern  of  It  As  sodium  nature  capacity  The as  reabsorptive  sodium  the  activity  retention.  bladder  of  the  exchangeable  branchial  al.,1969).  permeability  although  conservation  sodium  et  communication  transport  operative  r e s p i r a t o r y exchange  leakage  this  total  e l e c t r o l y t e balance  in  than  statistically  effective  of  shams  significant  increase  understood.  absorptive  a  intermittently.  gairdneri,  was  and  contractile in  urine  the  anaesthesia  greater  releases  in  parameters,  show  in  (Houston  from  these  however  elevation  period I,  bladder  222  lower  difference  of  Disturbances  a f t e r MS  recovery  were  neither  sodium, d i d  decrease. hours  levels  to  the  exercise. a  net  water  126 e n t r y o f about 1% body volume per hour o c c u r r e d i n t h e u r i n a r y b l o c k a g e animals ( T a b l e X I I ) . (Shams underwent a 2.5  g/100  g weight r e d u c t i o n over t h e e x p e r i m e n t a l p e r i o d ; a  s m a l l e r but s i g n i f i c a n t weight l o s s a s s o c i a t e d w i t h extended swimming was  o b s e r v e d under more c a r e f u l l y c o n t r o l l e d  i n Section I I I ) .  conditions  On autopsy, t h e l i g a t e d f i s h e x h i b i t e d some  d i s t e n s i o n o f the u r o g e n i t a l p a p i l l a e a l t h o u g h the volume cont a i n e d i n t h e b l a d d e r i t s e l f d i d not appear t o be l a r g e . seems p r o b a b l e t h a t the a c c u m u l a t i o n o f u r i n e i n t h i s continued only u n t i l  the g l o m e r u l a r f i l t r a t i o n  pressure.  have been a c c e l e r a t e d by the known c o n t r a c t i l i t y  o f the b l a d d e r ( L e d e r i s , 1 9 7 0 ) . water was  organ  i t s h y d r o s t a t i c p r e s s u r e , r e f e r r e d back t o  the k i d n e y t u b u l e s , opposed T h i s e f f e c t may  It  Thus most o f the i n f l u x e d  p r o b a b l y not removed from the b l o o d by t h e k i d n e y .  Plasma water c o n c e n t r a t i o n was  however o n l y m a r g i n a l l y  (and  n o n - s i g n i f i c a n t l y ) e l e v a t e d i n the l i g a t e d t r o u t and h e m a t o c r i t remained s i m i l a r t o t h a t o f the o t h e r two g r o u p s .  The i m p l e -  m e n t a t i o n o f some mechanism t o p r e v e n t e x c e s s i v e e x p a n s i o n o f the i n t r a v a s c u l a r volume was  therefore indicated.  ly significant  o f t i s s u e water l e v e l s s u g g e s t e d  augmentation  t h a t t h i s compensation  The  extreme-  i n v o l v e d a c c u m u l a t i o n o f the s u p e r f l u o u s  water i n e i t h e r o r b o t h the i n t r a c e l l u l a r phases o f the e x t r a v a s c u l a r s p a c e .  and  extracellular  Plasma sodium l e v e l s were  d r a s t i c a l l y d e p r e s s e d d e s p i t e t h e apparent s t a b i l i t y o f plasma volume and t o t a l exchangeable i n t e r n a l sodium. t h e r e f o r e appear t h a t the removal o f e x c e s s water v a s c u l a r compartment was sodium which was  accompanied  I t would from the  by a r e d i s t r i b u t i o n o f body  reflected in a significant  r a d i o s o d i u m space r e l a t i v e t o the shams.  expansion of the As sodium  appears t o  be  effectively  salmonids into  the  interstitial  immediately  the  expense  of  postulated Infusion  sodium  across  (Bourguet  et  the  this  involved  both  At  least  in  by  the  (Morris  of  sodium  normal ment  of  sodium igation of  the  plasma the  and  did two  not,  influx  the  of  this  ion  constancy  of  occurred  at  The  in  the  the  of  however,  unidirectional  was  the  and  the  separate  auratus  the  efflux  of  efflux. mediated the net  through  across  both  isolated  proportional  fluid  (Richards inferior  occurred  inward  opposite  the  net  occurred  solution. relative  components  to  the  at  This  to and  concentrations a  up-  parameters  flux  inversely  latter  increased  t  and  through  from  depletion  sodium  (Mayer  f  directly  resulting  uptake  solution  augmentation  planeri  of  while  were  rate  net  occurred  alone,  have  blockage  anguilla  response  perfusion  flux  urinary  hypertonic  perfusion  there  while the  a  sodium  sodium  levels  could  efflux  stimulated  levels  net  gairdneri of  levels  branchial  responses  depression  of  sodium  component  sodium  electrolyte,  concentrations  in  goldfish, Carassius  former  of  internal  sodium  have  well  eel,Anguilla  experimental  Salmo  At  the  the  influx  concentration  Fromm, 1970).'  of  The  Bull,1970). of  may  of  ammocoete,, L a m p e t r a  influx  movement the  saline  administration  i n plasma  to  net  maintain  i n plasma  occurred  and  goldfish,  response  hemibranchs the  have  g i l l s  the  The  milieu  hypotonic  while  the  and  of  help  depression  inhibition  changes  elevation  to  the  of  injections. in  the  effect.  elevation  take  drop  a]..,1964)  Nibelle,1970), reversed  to  a  space  homeostasis.  profound for  intracellular  Toews,1969)  fluids  plasma  responsible  trout.  the  extracellular  of  This  earlier  from  (Houston,1964;  the  been  excluded  to  movehigh invest-  contributions observed  128 effects.  The  branchial in  vivo;  Influx  sodium the  was  associated  onent  to  of  rainbow  trout  is  not, however  and  renal net  sodium  through Indeed from  could  accompany  the  and  exchanges. its  use  occlusion inating efflux  in  from  Conclusions  experiments  other  measured  light  may comp-  e f f l u x would to  sodium  decrease  such  a  efflux  be  water s o d i u m  i n plasma  induced  species,  moving  of  mechanism proposed  of  the  must  be  massive  an  and  renal  with  the  General  of  that  involved  in to  discrimthe  sodium  Evidence of  reduction  branchial  adjustive  Discussion.  on  The  majority  compensatory  this  based  exercise. the  the  sodium  suspect.  contributions  swimming,  mechanism  to  uninformative  prolonged  extremely  disturbance  associated  gravely  therefore  during  the  be  behaviour  extended  in  to  flux  sodium  during  and  appear  about  loss  considered  gills  outward  of  depletion  this  respect  sodium  be  the  plasma  homeostasis  variation, including  nature  in  with  were  branchial  would  rate  will  an  s o u r c e s , however, i n d i c a t e d  possible  Thus  branchial  efflux  The  sodium  in passive the  parameter.  consequences  Holmes,1959)  changes  plasma  across  existence  blockage  technique  between  efflux  stable  ligation.  i t s likely  (e.g.  the  the  that  remarkably  reductions by  of  internal hydroelectrolyte  procedure  in  by  The  depression  urinary  unsatisfactory  the  decrement  caused  of  ( F i g . 19).  reinforced  urinary  by  decline  permeability.  explain  true  transport  some the  be  t  alterations in  gradient  Hence  in  indicate  blockage  concentration  would  study  with  simply  branchial  i s  of  present  unaffected  alone.  levels,  the  apparently  occur  expected  of  influx  same  modification normally  data  in  function.  phenomenon  12  B.  The C o n c e n t r a t i o n As  hourly each The  each  flux  ition  able  over  the ex-  the net fluxes o f the animals  a t a wide  seemed sodium  variety  i n Part influx  a l l hourly  level  the particular  are  presented  levels  below  correlation at  sodium  range,  with  levels  ationship  over  ug/ml  t h e whole  isolated  frog  whole  skin  ammocoetes  than  this  using  figure.  (Sutcliffe  and B u l l , 1 9 7 0 ) ;  rainbow  trout  whole  means  intervals,  at  sodium  positive was  not true  The  form  was  similar  systems  of the r e l to that  - e.g.  isolated  crayfish  and t h e p e r f u s e d et  to  value f o r  (Shaw,1959);  and Shaw,1968);  (Kerstetter  avail-  sodium  of the  this  o f sodium-transporting  et al.,1962);  a l l  assigned water  an o b v i o u s  I t  Consequent  influx  earlier,  concentration range  crustaceans  (Morris  anaesthetized  T h e mean  As noted  cond-  between  (Ussing,1949b;Kirschner,1955);  (Frazier  gammarid  ambient  at the midpoints  demonstrated  greater  for a variety  bladder  plotted  that  parameters.  external concentrations;  observed  toad  period.  rate  r a t e were  o f the average  i n F i g . 20. 0.8  influx  The  (Fig. 19).  the interaction  (231) o f these  level  levels.  to the exercise  of the trout  trout.  produced  II indicated  insensitive  o f sodium  the basis  ug/ml  sodium  and b r a n c h i a l i n f l u x  on  0.2  of Section  to analyze  categories over  o f water  treatment  valid  values  A  was  p a i r e d measurements  each  values f o r  effected  p e r i o d by  movement  individual  e x t e r n a l c o n c e n t r a t i o n changes  or experimental  external  2 30  eight  29  sodium  therefore  over  entailed  from  presented  branchial  section  Fluxes  obtained  measurements results  i n this  r a t e measurements, sodium  o f B r a n c h i a l Sodium  were  perimental  ly  experiment  unidirectional large  Dependence  whole  gills  al.,1970).  of  130  F i g u r e 20  The r e l a t i o n s h i p between b r a n c h i a l sodium  influx  r a t e and e x t e r n a l sodium c o n c e n t r a t i o n .  A l l data  from normal, sham, and u r i n a r y b l o c k a g e t r e a t m e n t groups has been averaged o v e r 0.2 ug/ml sodium concentration  intervals.  Means - 1 s t a n d a r d e r r o r  are p l o t t e d a t the m i d p o i n t s o f each i n t e r v a l . line  f i t t e d t o the p o i n t s was g e n e r a t e d by t h e  Kirschner  (1955) equation: where  Fi  The  = Fi(max). H o Ks + |Na] o  Hsra]o = F  i  Fi(max) Ks  e x t e r n a l sodium  concentration  " = maximum sodium influx rate S  o  d  i  u  m  i  n  f  l  u  x  r  a  t  = half-saturation constant  V a l u e s f o r Fi(max) and Ks were o b t a i n e d from a Lineweaver-Burke p l o t o f t h e d a t a .  e  EXTERNAL SODIUM CONCENTRATION  (jjg/ml )  131 Kirschner carrier  (1955),  w i t h which sodium  developed ted  assuming  a theoretical  nature  tration  of influx  the  implication  complexed  the  simple  diffusion  and  the  relationship  Fi  = F i ( m a x ) . [Na] o Ks + [Na] o  a  specific  transport process,  d e s c r i b i n g the  frog  g r a d i e n t between i n t e r n a l  the  i n the  relationship  through  of  skin.  and  rate  When t h e  e x t e r n a l media  c o n s t i t u e n t of the  e q u a t i o n may  limi-  concen-  is  large,  be  ignored  becomes  where  [Na] o = e x t e r n a l s o d i u m concentration Fi  =  sodium  influx  rate  F i ( m a x ) = maximum s o d i u m rate Ks  w h i c h has  a form  equation  relating  centration. 1934)  of  A  identical enzymatic  double  the present  w h i c h were used JNaJo's.  to the  data y i e l d e d  to generate  This theoretical  values  i n Fig.20.  influx  across  the  cribed  by  Kirschner equation.  the  The gills  d e m o n s t r a t e d ,in the Lampetra p l a n e r i , (Kerstetter pointed  et  out,  the  data with  may  exist  through  i s the  line  fitted  c o n c e n t r a t i o n dependence o f of intact  the g i l l s  of  i s nothing  Salmo g a i r d n e r i Similar  Burke,  to  the  sodium  i s well  the  about  the K i r s c h n e r r e l a t i o n s h i p ,  and  des-  been  ammocoete  a n a e s t h e t i z e d rainbow As  Ks  different  a c c o r d has  pallipes.  singular  considering potential  con-  f o r Fi(max:) and  aJL.,1970; K i r s c h n e r , 1 9 7 0 ) .  there  and  d e s c r i b i n g F i at  which d e s c r i b e the process  also  (Lineweaver  values  crayfish, Astacus  and  Michaelis-Menten  r a t e to substrate  plot  a curve curve  half-saturation constant  familiar  reaction  reciprocal  =  influx  Shaw  (1959)  coincidence other  trout has  of  expressions  more a c c u r a t e l y ( e . g .  difference).  However,  the  132  correspondence based  on  a  to  The  and  the  Table ment in  other Ks  XIII  Fi(max)  of  other  systems.  this  study  obviously  affinity must  be  times the  relative noted  lower  same  These  to  that  than  experimental  The  present  the  rainbows  the  of  in  a  needle  held  sewn  area  and  requirements effect  i s  maximum  influx  rate  metabolic  curve by  the  present  from  on  a  the  of  the  the  sodium  and  small  30  to  in  a  differ-  while  the  distinctly  MS  perfused  222  at  100  cavity.  to  for  Fi(max).  state,  portion of  ml/minute  Such  the  a  sys-  normal  satisfy  the  gas  (Davis  and  Cameron,1970).  account  for  the  weight  resulting  permeability  i s  investigations.  used  inadequate  Ks.  influx  trout  sodium  extremely  were  buccal  animal  observed  in  normal  workers  the  body  high  study  respective  down  sufficient  depression  elevated  some way  the  probably of  latter  dependence in  was  assort-  K e r s t e t t e r e t _ a l . ( 1 9 70)  arisen  a  an  However, i t  dissimilarities  into  branchial  have  the  mEq/L)  rainbow  extremely  animals.  of by  upside  involved only  well  other  derived  g/hour)respectively.  of  an  mechanisms.  (0.014  system  These  have  general  uEq/100  relatively  would  in  ug/ml  transport  lesser have  0.32  general  gairdneri  from  value  condition.  through  The  were  a  transport  Salmo  K e r s t e t t e r et. a l . ( 1 9 70)  fish  exchange  for  system  and  values  conditions of  anaesthetized a #15  of  limited  with  obtained  were  sodium  demonstrated  Ks  with  trout  unphysiological  tem  The  d i s c r e p a n c i e s may  ent  value  figures  that  that  species,  active  (58.40  these  rate  (Kirschner,1955),  ( F i g . 20)  g/minute  compares  saturable  carrier  data  ug/100  a  reported  and  present  22.38  suggest  complexing  similarity  from  does  i n  difference  basis, while from If  trout  the  anaesthesia the  could  concentration  g i l l  i s  characteristics  of  determined the  membranes  133  Table and  XIII.  half  systems  Summary  o f maximum  sodium  saturation concentrations i n a variety  of  Ks  Fi(max)  (mEq/L  (uEg/lOOg/hour  .014  influx  (Ks) f o r sodium  (Fi(max)) uptake  animals. Preparation  58.40  rates  Reference  whole i n t a c t rainbow trout,Salmo gairdneri  present  study  0.46  33.30  g i l l s o f perfused, anaesthetized rainbow trout,Salmo gairdneri  Kerstetter (1970)  0.26  36.00*  w h o l e ammocoete, Lampetra p l a n e r i  Morris (1970)  and  Bull  0.13  45.00* ,  sodium d e p l e t e d whole ammocoete, Lampetra p l a n e r i  Morris (1970)  and  Bull  0.25  97  whole crayfish, Astacus pallipes  Shaw  isolated frog s k i n , Rana s p .  Kirschner  isolated bladder, marinus  toad Bufo  Frazier (1962)  amphipod Gammarus  crustacean, pulex  S u t c l i f f e and Shaw ( 1 9 6 8 )  amphipod Gammarus  crustacean, duebeni  S u t c l i f f e and Shaw ( 1 9 6 8 )  4.3  20  200  0.15  0.5  *  ^1000  corrected  from  an a p p a r e n t  typographical  error  et  a l ,  (1959)  (1955)  et a l  i n the paper.  134 through as  which  apparently  then  an  g i l l The  acclimated the  see  of  were  of  1970)  ammocoete  that  a  in  have be  Indeed  low  smaller  sodium than  inhabiting Thus  the  the  species  may  also  influences  on  the  There centration and  reflect  dependence a l l were  acclimation  and  those.,  here.  used  this  only of  was  determined very  ug/ml  .09  of  or  K e r s t e t t e r jet a l .  about  10  times  and  Bull  with  was  by  hand,  and  Shaw  (1968)  exhibit  races  Ks  sodium  information  living  values  the dilute  this  demonstrated in  streams  considerably  the  species perennially  the  ion  i s more  the  results  abundant. of  the  j i l . ( 1 9 70)  on  perhaps  even  or  the  same  genetic  stocks.  few  However  have  in  of  adaptational  at  influx  elevated  duebeni  low mEq/L;  pretreatment  experimental  limited  were  contains  Morris  Kerstetter et  obtained  Ks.  by  Gammarus  a  i n -  reduced  experimental  exist  from  sodium  i n which  of  trout  al.,1962),  of  other  other  that  2.0  study.  quantitative difference in and  which  carrier,  Ks  concentrations of  et  the  measured  than  The  the  Sutcliffe  environments  study  with  were  the  rainbows  concentration  that  the  raised  which  water,  present  amphipod  those  present  fish,  on  (Frazier  have  to  rates  tap  markedly  procedure.  with  the  shown  Fi(max),  of  also  level  sodium  with  resistance resulting  could  flux  binding  bladder  (generally less  solutions;  races  toad  diffusion  Vancouver  to  could  that  before  Stainer,1966)..  preadapted  (1968,  pass  the  sodium  ion  and  than  in  i n which  this  higher  must  perfusion  and  Holmes  in  water  nature  levels  ion  occurs  increase  efficient  by  the  other  measurements  influx sodium  media  in  "intact"  of  fresh  concentrations  considerably  comparison ( F i g . 21)  of  the  does  the  of  greater trout  conwater  the than  curve  emphasize  the  135  Figure  21  Comparison  of  the  concentration  sodium  influx  in  ported  in  goldfish  the  the  the  eel  (4),  and  redrawn  from  data  (1)  present  the  the  (2),  presented  (a  the  broken  (5).  Maetz  (3)  Morris  line)  through  (1956).  (4)  Chester  (5)  Maetz  and  et  Bull  Jones a l .  et  (1970). a l .  (1967  (1969).  b).  with  of  branchial  that  re-  ammocoete  Lines  have  (3), been  in:  equation.  (2)  (1)  lamprey  ( F i g . 20).  determination  (1955)  trout  k i l l i f i s h  study  extrapolated direct  rainbow  dependence  This  curve  beyond  the  use  the  of  has  region  been of  Kirschner  60.0  EXTERNAL SODIUM CONCENTRATION (jjEq / m l )  136 extremely uptake  high  from  anguilla,  efficiency  dilute  the  of  solutions  planeri.  g o l d f i s ^ Carassius  auratus,  trend  parallel  which  may  to  that  of  indicative  data  however,  a  to  system  the  of  gairdneri  similar  a  high  the  lamprey  (1956)  rate  down  sodium  Anguilla  and  Maetz  show*  for  eel,  heteroclitus,  The  Salmo  of  animal's  relative  k i l l i f i s h , Fundulus  ammocoete/Lampetra  be  this  on  the  limited  to  0.1  affinity  uEq/ml ,  transport  mechanism. The effect  possible  in  the  gills  Arguments  for  this  branchial  flux  teleosts gills  and  did  oxygen  not  been  teleosts,  for  20  of  -  40% /  amphipods  presence rates  marked  the 0.2  by  in  ug/ml for  influx  admittedly  a  is  the  group  seems  and  problem, of  trout  abnormal  These animals  is  of  not  of  fresh  reason  accounts  fresh  water  gammarid  criterion  for  unidirectional  concentration,or  a  abolished.  the  efflux  alone  were  ranges  as  efflux  values  but  has  various  general  sodium  the  definite  the  high  their  regions  of  covariation  influx  to  I.  water  across  evidently  of  A  Section  fresh  sodium  no  exchange  concentration rates.  sodium  of  in  diffusion  extremely  other  mechanism  external  pursue  the  branchial  Shaw,1968).  when  sodium  to of  (Shaw,1959)  in  on  proportion  there  efflux  blockage  the  sodium  process  changes  further  urinary  and  based  in  exchange  proposed  diffusion  in  Such  ;  was  efflux  priori,  pallipes  this  reduction  described ated  of  with  To  the  normal  sodium  relative  increase  exist.  a  trout  Exchange  (Sutcliffe  of  were  trout  that  a  the  crayfish Astacus  over  fact  but,  not  of  of  demonstrated  i t could  flux  phenomenon  apparently  why  the  rainbow  permeability.  previously water  of  rates  the  occurrence  were  rates  (70)  averaged  previously were  produced  generby  the  137 only  treatment  exclusively fish  were  group  branchial  identical  seems u n l i k e l y t h a t i f the  present, use  of  loss  -  was  efflux rate  dependence  of  the  i s extremely  Kerstetter  et  present  study  of  branchial  flux  rates  least  on  influx-efflux  and  that  of  the  was animal.  was  data  positive  branchial  same  sod-  range.  This  diffusion.  similar correlation of  i n their  perfused  trout  the q u a l i t a t i v e nature  linkage,  Kerstetter  to  concentration  the  exchange  due  concentration  and  obtained  and  the  concentration  suggestive  Thus,at  of  linear  parameters over  uni-  earlier,  condition  p a r a l l e l e d the  these  addition,  the  approximately  have  preparations. curve  loosely  In as  adequate  of  of efflux,  perhaps  Over  were  ( F i g . 19), i t  discussed  a l . (1970)  unidirectional  influx  the g i l l s ,  f o r which  external  influx  inasmuch  exercise  an  rates  trauma.  i n F i g . 22.  prevailed  influx  rainbows  by  depletion  ug/ml)  which  the  movements  d i f f u s i o n component  across  the  sodium  normal  affected  sodium  between  As  advantageous  sodium  1.50  there  relationship  pattern  been  are presented  (0.10  available,  ium  of  of  exchange  insensitive to  results  interval  those  have  e f f e c t o f plasma  apparently The  to  thise data  measured  in origin.  the  would  directional the  i n which  the  et  results  a l . ( 1 9 70)  of  are  of  the  the i n  good  agreement. Assuming contribute the  f o r the present  to branchial  sodium  efflux concentration  external sodium  sodium  leak  polation diffusion  should  across  yielded  transfer,  dependence  the g i l l s  of  exchange  line  then  diffusion  the  of  of 2.3  ( F i g . 22)  to  mediated  The  ug/100  f o r the  e f f l u x , which  should  be  of  zero  ligated fish. g/minute  does  extension  approximate the non-carrier  a value  component  that  extra-  stable  simple  over  the  138  Figure  22  The  r e l a t i o n s h i p between  rate for  and  urinary  over  0.2 -  Means of  each  polated of  external  the  blockage  ug/ml 1  to  0  calculation  from  The  external  Fig.  are  presented  i s  have  efflux  level  of for  been  at  values  averaged  the  has for  i n Table  curve  included  line  A l l  intervals.  plotted  fitted  sodium  dependence 20  only  concentration  error  interval.  sodium  concentration.  animals  sodium  standard  concentration rate  sodium  branchial  midpoints  been the  purposes  XIV.  sodium  extra-  The influx  comparison.  05  , 1.0  1.5  EXTERNAL SODIUM CONCENTRATION  2.0 ( jjg/ml )  2.5  3.0  139 relatively tered ent  in  narrow  the  study.  mechanisms  trout  could  to  be  the  been  arbitrarily  used  in  The  data  Section  20)  and  results  note  that  number  in  idea  5 of  fold  The  presented  of  the  chasing.  presented sodium  are  Kerstetter diffusion a  conclusion  problem ation  of  of  in  that  both  of  Bryan  argued  that  in  i s  planeri,  flux  and  the  linkages  has  average  agreement  that  the  lines).  with  through  permeability  lend*  credence  effective  perm-  increased  oxygen  during  the  idea  the  hour support  diffusion  referring claimed  but  in  one  about  in  the  trout.  Salmo  that  premature  work  exchange  conceivable  (1968,  of  was  1970)  Such  the operalso for  the  somewhat c i r c u i t o u s  crayfish, similar  the  until  epithelium  Bull a  to  gairdneri g i l l s .  The  and  and  to  those  sodium  exchange  level  influx  to  branchial  Morris  ug/ml  fitted  branchial  solved.  the  1.5  i s encouraging  therefore  recently in  of  both  the  It  original  probable,  for  I  ligated  r e s t i n g rainbows  rainbow  exist  I.  (1960)  data  the  where  excellent  of  to  XIV.  for  the  encoundiffer-  concentration  l i e on  presumably  has  does  mechanism  Lampetra  the  the  (1970),  very  point  means  for  presumptive  Section  (This  epithelium  back-transport  ammocoete, fashion,  seems  this  discussed  have  with  sodium  22.  Section  et. j a l . ( 1 9 7 0 ) , of  level  changing  present  t r a n s f e r system Kirschner  in  about  in  However  here  sodium  (pp.68,69)  branchial  in parallel  water  a  sodium  contribution of in  i n Table  are  assumptions  the  external  i t corresponds  ( F i g . 22)  I  of  exchange  represents  Section  to  a  and  as  figures  exercise.  eability  20  chosen and  sodium  for  presented  during the  Figs.  efflux  are  of  branchial  I  these  calculated a  of  range  Consequently,  computed  from  (Fig.  concentration  Astacus to  those  fluviatilis, of  the  140  Table to  XIV.  total  assuming  branchial  sodium  External  Total  Total  influx  Net  diffusion  efflux  flux  t o be  mechanisms  blockage  caused  concentration  diffusion  diffusion  of different  i n urinary  linkage  transport  Exchange Simple  exchange  sodium  Exchange Active  Efflux  contribution  a l linflux-efflux  diffusion.  Influx  Calculated  by  equals  trout  exchange 1.50  =  +  14.3  ug/100  =  +  4.2  "  =  +  18.5  "  =  -  14.3  =  -  2.3  =  -  16.6  +  1.9  it  ug/ml.  g/minute  141 present  study  transporting  were  caused  sodium  ions  external  sodium  actively  transporting  (by  simple  demands sodium not  place  diffusion)  that pump  true,  outward  f o r most  transport served  could  gills  cannot  study  or that await  offer  walled  free  i n series  leakage  i n the  flux  i t seems  with  of efflux.  roles  while  across  e t al_. ( 1 9 7 0 ) .  i s measured  back-  t o t h e obdefinitive  diffusion  Salmo  and  gairdneri  the present  Such  i n which during  active  filamental  However,  of either  o f experiments  to take  that  o f exchange  linkages  efflux  i s probably  i s thought  contribution  up  the active  this  likely  high  system  inter lamellae  the result  solution  a  respiratory,lamellae  a minimal  of Kerstetter  Such  In the teleost,  Thus  from  be bound  and t h e measured  occur  dependence  i n sodium  would  At  assessments  sodium  efflux  inhibition  of  transport.  organism  utility  inhabiting  scarce  i s clear;  system  i n such  the  be  the relative  b e made  The  could  augmented.  only  the results  a sodium  active  would  of the passive  concentration  back-transport  to  ions,  back-  diffusion.  of the carrier  i s situated  about  by simple  external  (Conte,1969).  statements  must  more  diffusion  the thin  apparatus  epithelium  leaving  (Kirschner,1955).  through  uptake  levels,  by an u n s a t u r a t e d c a r r i e r  i n fact  exchange  an environment  however  merely  adapted  forms  1966;  Motais,1967) Such  sodium  which  i s extremely  o f an exchange  t h e remnant  i n fresh  process characteristic  o f many  f o r an  diffusion  i s not immediately "obvious.  represent  diffusion  where  t h e advantage  a situation  water  salinities.  o f a b a c k - t r a n s p o r t mechanism  euryhaline  i s important  a mechanism,  water  of  of the sea  teleosts  ( M o t a i s &t a l . ,  i n adaptation  as p r o p o s e d  I t  t o lower  by Motais  et-  a l .  (1966)  organizes  efflux  may  external salt  to  on e n t r y  f r e s h water  ( 1 9 70)  continue  sodium  ions  across  exchange  balance.  ally  proposed ions  some  may  (net transport),  available  internal  Under  mostly  -  minimal  sodium  regulatory  normal  disadvantage  which  of the carrier animal.  external carrier, hydrogen  diffusion  number o f c a r r i e r acutely  entail  and o f f e r  sites  acidotic  the system would  a l .  origin-  or  o f exchange  et  of acid-  where of a  a  of  to that  (no n e t t r a n s p o r t )  during  of  through  the presence  similar  scarce.  uptake  i n regulation  circumstances  to the  adaptation  Kerstetter  the mediation  a large  exchanges  occurs  (Ussing,1949b),  o f protons  cost  then  the existence  to keep  sodium  maintenance  ions  g i l l  system  i s extremely  f o r which  role  through  then  for excretion  conditions.  some  skin  sodium  the trout  ions,  This  i f the active  that  excessive  during  sodium  a mechanism  can exchange,  ions  allow  play  for the frog  either  that  evidence,  Imagining  with  medium.  the trout  to hydrogen  diffusion  base  would  i n which  speculate  provided  dilute  so  of the  preventing  t o be b e n e f i c i a l  environments  exchange  of the g i l l s  by reduction  thereby  a more  also  have  sodium  into  o n e may  external coupled  lowered  concentration,  presumably  However  "leakiness"  instantaneously  sodium  loss  could  be  the inherent  no  would only  effect a  osmo-  143  SUMMARY  1.  Branchial  periods  of  sodium  up  to  8  uptake hours  II  remained  and  constant during  during  r e c o v e r y from  swimming extended  exercise. 2.  Whole  first  organism  hour  of  exercise  Unidirectional hour  of  during  evidence  3.  third  was  second  rate  hour  level  a  4.  Alterations  5.  The  the  i n whole of  fish  exercise  group  animal.  further  reduction  implemented  activity. during  i t increased  the  slightly  rate.  sodium  net  flux  rates  of  the  i n efflux rate  non-  under  urinary  unaffected  by  the  exercise  condition  the  efflux rates  was  values  for renal  that  e v i d e n c e was  subtraction of  shams  of  efflux rates  losses  depressed  due  the  of  the  effect of of  the  different exercise  of of  unrealistically during  suggested  ligated trout renal  blockage  mean  yielded  presented which  sodium  most  the  sodium  branchial  with  This  the  high  rates  of  rate  of  from  Consequently,  second  (branchial)  group  6.  penalty  ligated.  influx  mechanism  osmotic  influx  body  than  the  swimming.  p a r a l l e l e d changes  However,  to  lower of  urinary  the .  conditions.  this  Further  a  not  during  during  compensatory  the  below  were  hours  recovery a f t e r which  efflux rate  treatment  reduce  slightly  sets  different  to  a  highest  declined  levels  subsequent  demonstrated  of  to  occluded  and  reached  was  which  movements  indicative of  exercise  Efflux  and  efflux rate  i n trout  outward  swimming, the  during  sodium  activity.  that  were  the  abnormally  occlusion.  variation  i n whole  conditions  of  the  animal  efflux  unligated  fish  144 has 7.  been  attributed  Branchial  sodium  catheterization 8.  Whole  bearing normal  open  9.  The  10.  losses  over  increases decrease and  lower  Urinary  water  water  the  the  11.  the  experimental  sodium  however,  o f plasma a  net  the  to  elevation  sodium  levels.  cribed  by  the  of  similar  situations.  reflected i n sodium  sig-  contents.  of both branchial  and  period  a pronounced  accompanied  and  tissue  change  space this  movement  of  water  of  water  sodium  levels,  relegation  was  from  have  of branchial  and  water  of  levels  excess  apparently  the plasma  been  sodium  a  large  compartment.  l e v e l s may  of  These  prevented a  sodium  gain  significant  markedly.  shift  extra-vascular  by  Plasma  the  which  net  into  The  responsible  efflux rates  for i n  fish. sodium This  influx  rate  (1955)  These  affected  Ks  by  dependence  equation  equation) with  g/hour.  was  concentration  Kirschner  Michaelis-Menten uEq/100  trout  that  very  exercise was  in  to  exhibited  shams  i n terms  depression  blockage  relative  various  d i d not  volume;  o f plasma  Branchial  urinary  elevated  concentrations.  extravascular  by  by  cannulation.  interpreted  postulated  58.40  under  ascribed  e x t r a - c e l l u l a r but  renal  groups  i n radiosodium space  accompanied  reduction  (shams)  two  of  slightly  l i g a t e d animals suffered  were  to  unaffected  i n t e r n a l exchangeable  following  i n plasma  increase  the  total be  hematocrit,  effects  the  efflux rates  e f f e c t may  renal  source.  was  was  catheters  However  higher  rate  efflux rate  i n efflux rate  nificantly This  influx  urinary  fish.  a branchial  or blockage.  organism  responses  to  external  was  well  (analogous to and  des-  the  =  .014  mEq/L  F i max  values  were  indicative of  an  =  145 extremely  efficient  solutions  i n the rainbow  12.  Branchial  urinary sodium  fusion Salmo  sodium  occlusion levels.  although  system  This  mechanism gairdneri.  rates,  alone,  as  were  phenomenon  not conclusive,  uptake  from  dilute  trout.  efflux  group  f o r sodium  was  determined  also  dependent  considered  of the presence of  f o r sodium  i n the g i l l s  from  of  an  the  on  external  indicative, exchange  fresh  water  difadapted  SECTION  THE  EFFECT  III  OF  WATER  EXERCISE BALANCE  INTRODUCTION  The to  assess  fluxes ial  experiments  the  effect  across  the  the  sodium  g i l l s  in  metabolic  designed  as  regulation mental time, only  a  during  the a  work  small  was  and  designed  shifts  in  the  branch-  compromise  caused  by  the  part-  of  exercise.  The  present  investigation of Because for  the  animals,  but  study flux  necessary  only  preliminary  water  a  in  short  a  was and  experi-  period  nature  yielded  sodium  and  good  of  involved  deal  of  information. As  branchial  the  blood  carrier  been  components  of  this  and and  flux.  had  not or  occurring  unlikely that  sodium  balance  distribution  desirable  conditions  changes  extremely  flow  net  purpose  swimming  e f f e c t s on  mediated  previously  atory  were  of  available  of  sections  particular,  somewhat  number  two  general,  activity. were  first  in  complementary  facilities  useful  both  demands  III  balance  respiratory/osmoregulatory  icular  by  on  of  ON  simple to  small  permitted any  direct  during any  could  alterations be  diffusional  separate  The  of  the  volume  the  fluxes,  i t  in had  unidirectional system  measurement  carrier  manifested  imposition  exercise.  in  of  necessitated of the  However,  mediated  standard respiri t is  processes  are  '  147 directly  involved  determination adequate this  of  In ment  the  measure  substance  enters  i n water  of  at  across  1962;  Fromm,1968),  net  water  this  under  that  of  of  1964;  would  provide  ations  in  were  order  urine  rainbow  flow  the in  the  oxygen  of  reduction  the  present  net  allowed net  a  branchial  further  hydromineral to  occur  pursue  in g i l l  swimming  durations  ation.  The  decrease  i n blood  data  information  that  the  permeability, were  volume  also  and  of  weight  determined  obtained  prolonged  question  as  a  increase  Use  of  deter-  water  entry  respirometer such gas  which  data and  in  water limit-  Section  exercise.  In  compensatory  changes  at  measures  of  provided  affords  compensatory  permeability  during  entry  simultaneous  swimming  the  fresh  the  system.  hoped  about  in  water  urine  q u a n t i t a t i v e r e l a t i o n s h i p between  further  equivalent  drink  branchial  in  animal  accompanying  experimental  I t was  be  branchial of  pathway,  the  simplifying  without  conditions b).  that  not  collection  and  (Bentley,  single  should  does  environ-  (Evans,1967;  a  taken  further  study  consumption  Stevens,1968 a  trout  permeability  volume  to  the  impermeable,  flow  equals  Consequently,  postulated  to  being  urine  Gordon,1969)  branchial  (Brett,  II  and  provide  from  intestine  the  of  and  skin  the  gained  state,  controlled exercise  exchange  and  water  steady  The  should  time.  is  flux.  Consequently  permeability  assumption  technique  minations  branchial  i f the  species.  limitation  alone  Thus  so  estimates  g i l l s .  through  (Shehadeh  this  the  and  water  teleosts, gills  the  eliminated  water  situation in  the  at  is  kidney. a  of  particular  Evans,1967),  maintains  flux  effective  f r e s h water  and  to  the  a  Potts  the  net  exchange  different water  explanation  i n plasma  regul-  for  sodium  the  levels  148 measured  during In  collection sodium data  + +  addition of urine  efflux  )  XI).  A  losses  have  teleosts  I I and have  under  urine  analysis  Urine measured  previously  precluded.  to solve two  exchange  several  sections,  swimming.  brief  summary  (Na , K , +  Mg *  +  +  further  information  flows  and r e n a l i o n  i n any  fresh  on  water  conditions.  o f water  an o p p o r t u n i t y  noted.in  fluxes  through  f o r examining  of the respiratory/hydroelectrolytic  had  during  provided  determination  use o f sodium  first  samples  urinary  interpretation of the  been  cation  exercise.  fluxes, the  mensuration o f  already  been  and gas  aided  c o n t r o l l e d swimming  the  served  direct  extensive  during  provided  I.  water  results  not previously  Thus  istics  The  of the collected function  of  allowed  fairly  kidney  i n Section  to relating  rate.  of Section  (Table Ca  activity  some  collection character-  adjustment  which  as t h e t h e o s m o r e g u l a t o r y v a r i a b l e Furthermore  problems  and p r o v i d e d  the investigation  r a i s e d by  the results  information  on  renal  o f the physiology  149  METHODS I I I  Experimental  Animals  Experiments bow  trout  180  g.  prior tank  (Salmo The  were  to experimentation  during  this  with  time,  pellet.  Vancouver  Urine  Flow  1.  Operating  Aquarium  versus  described  1/10,000  MS  222  concentration Cannulae 190  (length  tubing  weights  and  papillae  45  i n Section  cannulae. sealed  only  into  7 -  were I.  carried  90  3  weeks  holding  at 7 a  to  8°C;  commercial  out at the  and March,  19 7 0 .  Experiments  catheters  by  constructed  from  o f these  fish,  This  these  PE  222  temperature. 60  and  o f t h e low  i n diameter  animals  body  a of the many  originally  and  free-draining  of the operation, s t i l l  PE  the urogenital  modifications,  patent  while  MS  necessitated  t i p and  o f t h e 18 both  fact  i n a  water  because  box  performed  higher  However,  completion  a metabolism  The  the colder  Despite  failed;  was  anaesthetized  10°C.  small.  5 exhibited  Following  concrete  February  of the proximal  attempts  f o r at least  f r e s h water  were  trout  immaturity  extremely  from  rain-  Cannulations  I on  cm)  immature  ranging  gallon  of urinary  of the catheter.  catheterized,  was  =  i n length  cannulation  250  necessitated  sexual  were  reduction flanges  as  indoors  Consumption  solution at  was  weights  during  and  i n Section  sexually  fed regularly with  Oxygen  Procedure  on  oxygenated  were  Implantation as  kept i n a  fully they  with  A l l experiments  Public  I.  performed  gairdneri)  animals  supplied  trout  were  the  fish  anaesthetized.  150  Recovery through  2.  was the  aided  by  Urine  production  determined  and  during  samples  Terminal  water  -flow  of  300  ml/min.  System  aneously  Urine  a  chamber.  Experimental  then  directing  and  during  controlled  were  weighing  rest  consumption  i n metabolism  levels  collected and  oxygen  for  measuring  of  was  boxes  swimming  later  ionic  carried  were  simult-  (5  fish)  activity  (4  fish).  analysis. out  as  in  Section  I. (a),Metabolism Resting sealed  i n blackened  43.1  cm;  with  fresh  boxes fish  a  width  to  water  change with  measurements  plexiglass  8.6 at  cm; 7  -  depth 8°C.  restricted position.  the  aid of  #21  needle  piercing  The  catheter  i n c u r r e n t and  water  flow  oxygen  box. mined  rate  (80  were  a  (Radiometer differential  -  8.2  cm)  A  moveable  l e d out  the  by  water  by  pressure  mixing  did  not  could  box in  the  through  be  attachment  the  thermostatted  oxygen  micro-electrode  conversion  contents  by  withdrawal  means  i n water  of  permitted  effluent  rear  (P02's)  to  the  chamber  oxygen  oxygen  of  measurement  of  Copenhagen);  chambers.  rear  the  at  the  visually  Representative  chambers  the  allow  The  and  =  flushed in  the  via  gravity.  samples  ml/min)  (length  partition  beneath  stopper  drained  200  of  trout  continually  but  placed  from  chambers  rates  determinations.  ensured  Partial with  -  =  movements,  rubber  taken  metabolism  mirrors  excurrent  consumption  samples  a  were  Opercular  u r i n a r y c a t h e t e r was  chamber. of  -  permitted  counted The  state  Boxes  of  each  were  deter-  system  of  differential  of  temperature  P02*s  to  dependent  151 solubility  factors  allowed calculation  o f oxygen  consumption  rates.  from  (b)  Respirometer  Data  at various  trout  originally that  exercised used  described  irometer inside ated  levels  by B r e t t  diameter  motor  propelled  speed  from  (1968 a).  (1964)  cm)  through  of velocities. t h e pump,  allowing  0 t o 45.7 cm/sec.  water  or sealed  In the l a t t e r  t h e chamber  bubble  The a n t e r i o r  were  covered with  black plastic;  cue rear to  encourage  extended the  i n this  system,  (i)  Resting Trout. chambers  be  tank  60  needle  of was flushed  consump-  connecting samples  o f t h e swimming  generally using  i t as a  A metal  grid  by  a  at the  voltage  catheter  and brought  drained  visual  a t a low  through  tube  oriented  The u r i n a r y  o f PE  was  out through rubber  siphon.  Procedures Catheterized  f o r up  4 days,  variation  electrified  the cannula  Experimental  the f i r s t  trout  recircul-  electric  o f oxygen  exercise.  v i a a #21  (c)  metabolism  During  2 0 cm  be  continually  header  thirds  performance.  a further  t o p o f t h e chamber  stopper;  in  swimming  with  two  during  of the respirometer could  cm;  o f the system  be e i t h e r  end o f the p l a s t i c ,  to maintain position  70  speed  to  the resp-  f o r m a t i o n when w a t e r  withdrawn.  the posterior  =  could  continuous  a small  were  under  water  f o r measurement  case,  prevented  (length  The volume  with  to  taken  similar  In b r i e f ,  A variable  The r e s p i r o m e t e r c o u l d  tions.  tube  which  2 3.75 L . fresh  were  T h e d e s i g n was  (Fig.23).  of a plexiglass  = 13  a t a range  activity  a t 7 - 9 ° C . i n t h e swimming r e s p i r o m e t e r  by Stevens  consisted  o f swimming  urine  t o 8 days was  fish  after  collected  were  maintained  operation. from  5  fish  a s 24  152  Figure  23  A  diagram  of  experiments  the of  swimming  Section  respirometer  III.  used  in  the  water inflow  header tank  water sampling p u r i n e collection water overflow ^•chargeable grid  variable speed electric motor^  b l a c k plastic f  pump  153  hour  samples.  ascertained 48  60  -  duction  5  hour  bolic  were  rate  operative  orient  itself  the  start  and  of  following  an  one  lengthy However,  fish  with  at  trout  latter On  during  animals  the  fish  least  5  fifth  was  the  the  and  were first  urinary  urine  pro-  post-operative  measured  over  determinations  of  a meta-  out.  was  Between  gently  chamber.  The to  experiment.  and  8th  postanaes-  left  overnight  to  During  this  time,  respiro-  at  the  a  velocity  trout  urinary  drain  5th  and  f r e s h water  swimming.  the  transferred, without  respirometer  which  allowed  3  rates  Unfortunately,  each  into  as  cm/sec. cm/sec. cm/sec. cm/sec. cm/sec. cm/sec. cm/sec. cm/sec. cm/sec. cm/sec.  (#59),  breaks  production swimming  of  opercular  least  were  then  10.7  of  cm/sec,  continuously  catheter  for at  Trout  would  the  was  l e d out  2 hours  of  before  subjected  to  the  regime: 10.7 21.4 10.7 21.4 32.1 10.7 21.4 32.1 42.8 10.7  For  the  Trout.  the  current  without  chamber  on  which  fish  to  further  quantified.  swimming  flushed  the  be  Swimming  the  minimum  patent  carried  a  a  and  cannulation.  during  days,  was  on  production  were  to  accustom  the  not  period  thesia,  not  urine  (ii)  meter  after  could  the  consumption  periodically  hours  catheters  day,  Oxygen  near  possible occurred  regime  were  - • -  3 3 3 15 3 3 15 15 3 3  the  swimming  the  beginning  shifts during  hours hours hours minutes hours hours minutes minutes hours hours regime and  i n the these  imposed  was  end  base  interrupted for  of  the  line  intervals,  consecutively  experiment.  rate  of  periods on  each  urine of  of  the the  other  154  3  animals  mental  tested  period  of  Total each  60  during was  also  sealing  15  organism  (30  -  55  takes  during  beat  for  no  below at  calculation  enough  to  quantify  the  were  periods. the  experi-  periods,  Oxygen  consumption  length  of  time  sufficient  in  chamber  the  was  the PO  P0  in  2  10  and  end  of  accurately.  by  15%  on  duplicate closure  Oxygen periods  Opercular  upwere  rates  r e g u l a r l y throughout  mirrors  placed  under  for  respirometer  each  rates.  increment  -  the  analyses  ?  metabolic  counted  by  for  and  intervals  velocity  aid of  measured  hour  Hg.  of  and  treatment  beginning  minutes  frequencies  2  mm  15  with  continuous  one  time  120 the  of a  P0  the  experiments  a  collected  3 hour  each  the  At  drawn  allowed  great  tail  over  reduce  fall  samples  period  not  to  the  was  intermediate  minutes).  permitted water  minute  to  during  production  respirometer  the  #65)  hours.  section of  determined the  #63,  21.75  urine  minute the  (#55,  the  and  the  respiro-  meter.  3.  Analytical  Procedures  Urine vials, the  samples  measured  with  a  vials  at  -12°C.  performed  in  duplicate  with  appropriate  (Harleco);  the  flame  later  Sodium  1/600  with mode  of  distilled of  the  and  120  a l l  then  frozen  in  A l l assays  curves  were  constructed  prepared  Atomic  standards  Absorption  determinations.  Aliquots water  polyethylene  analyses.  calibration  AA  for  in Urine.  small  commercially  Model  used  in  syringe,  ionic  against  Techtron  (i)  emission  for  was  collected  Hamilton  dilutions  Spectrophotometer  diluted  were  and  of  read  spectrophotometer  each at  sample  5890  8  were  on  (calibration  the  range  =  0  -  1.0  (ii) were  ascertained  known  flame 200  of  each  calcium  flame  were ug  K /ml  of  and  sample and  high  mode  1/250  the  instrument  assayed  uEq  sodium and  of  and  0 - 2 0  K  /L.  levels  unknowns  against Because  on  potassium  were  swamped  with  of  with  101%.  This  Na /ml  swamping, analyses 100  only were  uEq The at  photometer  &  over  ug  ion  c o u l d be  on  of  and  f o r the  spectral  different,  reported  emission  a  but  Na  30%  of  identically  and  +  of  additions  analytically  effects  over  a  revealed that  after  both  stand-  and  (approximately  that,  422 7 8  swamp  made  the  tests  interference at  was  recovered  indicates  dilution  to,potentiate  unknowns  +  calcium  range  same  93 K  -  +  remained.  Calcium  calibration  range  of  /L.  remainder 2852  of  a  performed + +  200  correction  amounts  minimal  Ca  a  However,  evidence  shown  both  phosphate  samples  been  thus  concentration) to  diluted,urine  have  The  for determination of  (Teloh,1958);  No  of  i n Urine.  utilized  potassium  (Teloh,1958). known  Magnesium  was  emission  effect  constant  nesium  range  standards  swamp.  +  calcium  -  emission  diluted  i n the  both  diluted  depressant  0  were  Calcium  Sodium  total  flame  concentrations  +  ions.  of  the  Potassium  Na /ml.  (1/60)  100  i n Urine.  interference  (iii)  ards  on  curves  emission,  ug  +  Samples  calibration the  Na /ml.  Potassium  7 6 6 4 8.  at  ug  on a  of  each  the  dilution  atomic  calibration  was  analyzed  a b s o r p t i o n mode range  of  0  -  80  of uEq  for the Mg  + +  magspectro-  /L.  As  a.  the  unknowns  had  a l r e a d y been  swamped  (200  ug  K /ml)for  c a l c i u m measurements,  the  similarly  fortified  precaution.  +  as  a  safety  magnesium  Na  /ml;  100  standards However,  ug  were sodium,  156  potassium, the  and  phosphate  spectral absorption  ion of  apparently  magnesium  do  not  interfere  in  urine  (Dawson  this  study  was  with  and  Heaton,1961). As urine  the  volume  samples.  not  have  into  with  The  negligible,  volume  and  by  a  ml)  would  represent  period,  and  but,  hours  measured in  ically  axis  at  vals  over  mixing  rate  of  urine  flow.  Thus  necessary  of  elapsed from  collected  and  each of  a  periods.  composition variations in would  sample  was was  values ionic  new  then  two  been  at  the  the  production  was  the  was graph-  end the  of  of time  time  inter-  measured the  production  of  minute  volume  The  associated  somewhat  sample  refer  to  was  catheter  60  i t s  set  swimming  would  produced  r e f e r r e d to  representative content  to  volume  formed.  Unfortunately, spanned  been  dropped a  the  that  to  was  moment  hourly  urine  volume  defining  sample  often  have  urine  perpendicular  urine  have  cannula  cumulative  thereby  each  The  of  during  Cumulative  time. the  excreted  hourly  deposition  one  an  i t was  samples  process.  volume  Thus  points,  levels  to  the  any  may  period,  these  at  rates,  composition  which  formed  in  urine  the  flow  of  activity  corresponding  However  urine  point  T h u s any  urine  correlate  ureter  siphon,  low  composition  creating  of  f o l l o w i n g manner.  these  collected  vial  bladder.  by  and  volume  ionic  of  the  ducts  drained  to  collected  exact  subtracted  sample  in  was  collecting  catheter  previously.  against  each  the  urine  the  at  ionic the  plotted  the  of  uptake,  of  the  factor  (0.35  time  as  collecting  delayed  purpose  oxygen  accumulated  the  2 - 3  primary  mid-  times  speeds,  neither with  dampened  by  condition.  different this  157  II.  Weight  Change  Weight fluxes meter  v s . Swimming  changes  i n trout  swum  ately  measured  f o rvarious  a t 32.1 c m / s e c .  animals.  were  Duration  lengths o f time  were  performed  70 t r o u t  held  i n t h e 250 g a l l o n  determinations  were  made  2 - 3  The animals  experimentation weight  i n this were  to prevent  changes.  as an i n d i c a t i o n  and i n i d e n t i c a l l y  Experiments  times.  Experiments  Water  sets of  of  fish  as 151  was  f o r 6 days  control  approxim-  concrete tank;  starved  faecal  handled  each  used  prior  to  evacuation contributing  temperature  throughout  water  i n the respiro-  on a b a t c h  study,  of  to  the study  was  7 - 8°C. For the  water,  weighing,  placed  on a b e d o f paper  thoroughly  dried  to  container  a tared  weighing (length of  entry The  released  was  with  accurate  to-0.1 For  from  for  fresh  at least  with  rarely  Total showed  change  tank  that  added  .05 g .  The  styrofoam 12 cm)  sack.  chamber  fitting  the  shape  The bag c o n t a i n e d  staples  immediately  struggled  weighing  time  after  i n the apparatus. and  was  the weighing  water.  8 hours  measurements,  to individual  (5 o r 10 g a l l o n )  oxygenated  a plastic  then  gently  about  60  procedure  seconds. was  g.  weight  the holding  aquaria  fish  was  to the nearest  =  from  and g e n t l y b u t  The animal  depth  sealed  was r e m o v e d  r e t u r n e d t o i t s aquarium  water.  dead  7 cm;  with  towels,  of a light  Animals  finally  under  =  a n d was  of the fish.  trout  Tests  consisted  and l i n e d  ml o f water  seconds.  and weighed  30 cm; w i d t h  the fish  500  f o r 15  container =  an u n a e s t h e t i z e d t r o u t  blackened  served with The animals  to recover  from  fish  were  and covered  a constant were this  transferred  left  supply  of  fully  undisturbed  initial  handling.  158 Then and  individual returned  to  After  this  their  chambers  seconds).  (15  seconds),  60  minutes at  inactive rod At  to the  from  in  then  they  4  the  the  experimental  Control  were  then  undisturbed 60  minutes  as  before.  fish  seconds  returned  until or  4  After  -  an  holding During  the 8  to  netted for  appropriate  the  de-scaled  trout  were  rejected.  g/100  g  for  at  course  when  and  were  Weight  weight.  an  least of  the  the  of  as  from  finally 1,  avoid  not  5,  15,  30,  stress,  the  electrified;  tail  the  removed  cm/sec.  with  non-swimmers  an  were  trout  aluminum discarded.  was  removed  before.  from  the  their  experiment,  noticeably  original  as  To  was  recuperation.  and  period  period,  weighed  hours),  tank  on  Chronic  and  seconds),  tunnel  weighed,  respirometer  10.7  term).  tapped  were  the  at  swimming  water  respirometer  set  aquaria,  hours  animals  (15  (long  gently  end  v?ere  t r i a l .  hours  their  further 8  was  cm/sec.  swimming.  5  from  airdipped to  desired  of  were  air for  general  8  a  velocity  induce of  for  quickly  21.4  -  netted  experimental  the  rear  fish  the  the  for  or  the  and  were  tanks  Water  cm/sec.  grid  the  interval,  (5  32.1  trout  their  aquaria  and  experimentals.  individual sample they  24  time  were  animal  hours a  sacrificed; were  (1,  However, and 5,  removed  was  study,  changes  tanks  few  and  the  next  became  from  expressed  30,  weighed  to  the  fish  results  left 15,  returned before  held  as  these  159  RESULTS  Before several  points  A  portion  major  ation  of  oxygen for  the  and  oxygen  internal under that of  the  presentation of  data  of  through water  is  laminar  not  which  which  flux  and  occurs  transfer  diffusional  transport  the  of  by  such  discrepancies  ability) water  and  that  (diffusional  whether  in  net  calculated  and  pore  pores  from  osmotic  assumed  representative the  of  osmotic by  size  membranes  gradient, both  quasi-  and  important.  bounding have  (osmotic flux  permeability  of  postusystems perme-  labelled  i t i s not (Pos),  Evans, the  been  biological  present,  simple  increases,  (Davson,1964;  layer  a);  the  the  equation)  gross  resp-  (Randall,1970  transfer  At  invariant  been  movement,  i n many  the  between  across  House,1966)  water  permeability^  t e l e o s t s , the  an  unstirred  account  measured  are  increasingly less  lated  directly  again  to  gradients  essentially  proceeds  As  (Dainty  between  water  properties  Poiseuille  in question for  water  the  membrane to  and  i t has  Under  the  an  permeability  concentration  b)  membrane  through of  consider-  diffusion  becomes  influence  to  simple  (Davson,1964).  water  devoted  transfer  occurs.  a porous  clarified.  oxygen  on  results,  be  remain  of  the  first  substances  true  dependent  flow  1969b)and  by  necessarily is  As  will  both  However  (described  flow  of  of  branchial  conditions,  fluxes  through  flow  bulk  been  water.  milieux  exercise  diffusional  The  has  Randall,1967  epithelium  of  section  (Stevens  permeabilities.  nature  i n t e r p r e t a t i o n must  this  external  III  discussion  to  measured  same  and  permeability  different  iratory  DISCUSSION  r e l a t i o n s h i p between  and  the  AND  as  clear  160 measured in  sea  by  urine  water,  ability  (Ed)  through  pores  Xiphister  Evans any  the  relating  of  (Hirano,  or  through  the  largely  reduce  -  the  flow  Pholis  and yet  study,  the  two  to  the  animal  negated  condition. in trout  bladder  the  volume  by  of  papilla the  inaccuracy  itself  have  been  intervention  W i l l f o r d , 1 9 7 0 ) , so  there  Hunn  at  the  finally  et  exists  alter  Such  the  may  The  are  the  alteration g i l l s .  on  the  urine  through Holmes  flow  and  would  thus  respect  similar  al.,1968;  comp-  functions  with  in  released  cannulap  results  no  simor  observed  fluid  (Fromm,1963;  of  effective  any  the  obtained  Hammond,1969;  in  to  data  thus  r e a b s o r p t i v e mechanism  in vivo.  A l l previous  and  may  which  serve  i n the  make  i n comparing  D.J.Randall)  of  to  surfaces  represent  a  species,  possible  may  presence  from  marine  substances,  sodium to  wall  but  permeabilities.  to  bladder  gunnelis  urine productions  data, m u s t  the  fish  relationships,  the  that  by  intertidal  permeable  present and  affected  water  Pd  rate  perme-  agreement,  diffusional  that  urogenital  Enomoto,1967; and  fair  Pos  communication  trout  i n t r o d u c i n g ' some  of  simple  and  drinking  diffusional  the  i t i s not  of  the  importance  personal  osition  osition  about  consumptions  however,  In  fresh  that  structure  i s possible  isolated  normal  in  both  concluded  two  phenomenon  or  r e s p i r a t o r y / o s m o r e g u l a t o r y adjustment It  be  of  water  simple  layers.  were  permeabilities  parameters  the  Pd  range  oxygen  branchial  the  and  statements  remains,  fresh  (Evans,1967)  Consequently  ultaneous  of  Pos  membrane  teleosts.  be  complex  unstirred  (1969b) h a s  about  fact  or  a wide  definite  not  a more  atropurpureus  of  in  i s representative of or  (Evans,1969a ) survey  production  and  to  the  comp-  techniques  Stainer,1966;  Hunn,1969;  comparative  Hunn  information  161  on  this  of  urine  of  the  that  point.  Until  after  i t leaves  bladder  will  reabsorption  occurring  at  ation  high  and  errors  volume  small  purposes  of  and  this  and  water  salmonids  ed  that  after  this  elevation  of  Measurements (Fig.  25)  present  from  a  in  the  to  a  of  222  g i l l s .  corresponding  the  Oxygen level to  a  by  vasculariz-  Consequently the  bladder  nature;  uptake about  45  Trump  in  Hunn  associated  and  presumably have  with  Hickman seems  after  stabilization  of  an  functions  in  the  and  to  suggest-  period.  respiratory  cannulation of  fresh  phenomenon  (1969)  ventilation  hours  the  urinary catheteriz-  demonstrated  therefore  and  are  for  Trump  result  respiratory/osmoregulatory  similar  rate  adjustment  had  operation urine  declined (Fig.  25)  production  24). Determinations  resting  indeed  disregarded.  and  and  activity however,  i f  post-operative  hypothesis  diuresis"  of  i s  ( F i g . 24)  the  organ,  permeability, and  collection  vivo  i t s poor  in  to  the  anaesthesia  supported  disturbance  during  in  correlated this  permeability  flow  "Laboratory  constant  (Fig.  MS  has  Hickman  uptake  urine  b)  the  likely,  Hammond,1969;  i n water  stress.  oxygen  after  (1969).  increase  augmented  study  been  repeatedly  (1969  seems  from  systematic have  normal  this to  for  ratio.  subsequent  been  Evans  immediate  branchial,  has  due  collection  they  diuresis  by  area  (R.M.Holmes,1961;  W i l l f o r d , 1 9 70). an  surface  relatively  handling  the It  ions  minimal  direct  study,  marked  ation  with  by  developed  animal,  and  be  to  are  unknown.  water  a l l , would  probably  the  remain  of  introduced  A  methods  state values  post-operative  day.  of  (Table The  urine  flow  and  XVI)  were  performed  mean  oxygen  metabolic on  consumption  rate the  was  for fifth  extremely  162  Figure  24  The  decline  anaesthesia point  i n urine and  interval. values  catheterization  represents  sample p l o t t e d  flow with  the  at the  Different  flow  lost.  a f t e r MS  midpoint  222  in 5 trout.  calculated  from  o f the  One  72  Each  a 24  hour  collection  symbols have been used  from d i f f e r e n t a n i m a l s .  s a m p l e was  time  - 96  for hour  o o  o<  X  z o  < o<  ZD  z z  oo <  u  /  /  <  LU  I CN  I  / •4  O/JB  O  / I  _JL_  O NO  O  _L_  o  CN  ( Ji| /  6>I/|LU  )  M O  T d 3NlcJPl  163  Figure  25.  The  decline  ventilation  oxygen  consumption  (lower  MS  anaesthesia  and  222  The  r  in  5  points  96  -  120  of  Table  XVI.  in  each  (upper  figure)  with  catheterization  represented  hours  rate  by  black  figure  are  figure) time  after  in  trout.  3  triangles the  and  at  resting  rates  164  Table  XV.  Means  ~  P h y s i c a l dimensions  1 standard  of the trout  weight  Length Fork  length  weight  and  XVI.  minations Fish  were  Weight  8 t  11.82  24.80  -  0.54  23.80  -  0.53  4.93  -  0.10  (cm)  of  1.056"-  0.036  x IOO3  length)  Resting  ventilation  =  144.50  (cm)  depth  Coefficient condition  Table  (g)  (cm)  Maximum  (fork  i n Section I I I .  error. N  Body  used  rate made  state  values  f o r 5 trout on t h e f i f t h  Ventilation  rate  of urine  flow,  i n metabolism day a f t e r  *  (operc.closures/min.)  Oxygen  oxygen  boxes.  uptake, Deter-  cannulation. * consumption Urine  (ml/kg/hour)  (ml/kg/hr)  #55  166.7  52.9  34.95  2.76  #59  152.0  55.8  23.47  3.26  #63  120.1  58.6  46.39  2.48  #64  105.7  53.1  32.41  3.15  #65  138.9  63.6  69.57  2.78  Mean - 1 standard  56.8 ±  1.99  41.36 -  7.94  2 . 8 9 "- 0 . 1 4  error  *  mean  of at least  X  over  5  hours  5 determinations  over  5 hours  flow  f o r each  fish  x  165  similar  to  the  gairdneri  of  the  flow  urine  resting  this  state  ted  means  and  XVI  when  of  are  comparable  be  a  as  described  rate  but  rates,  fact  (#55,  beat  the  when  "resting"  XVI)'.  speeds  in  a  metabolic  same  reported for Holmes  determined Thus  be  the  to  given  urine  water  and  i n much values  standard further  larger  presen-  ..rates  consider-  production to  of  the  oxygen  of  are  with  effects  are  increased  times  uptake  associated  tabulated  about  hours  12  their  oxygen  i n the  uptakes  observed  slightly  in  that  the  i n salmon  boxes  (Brett,  (spontaneous to  Consequently the  deter-  sub-swimming  difficult  at  the  metabolism at  "restlessness" extremely  XVII.  initial  greater than  days  and  with  i n Table  despite  exercise.  only  flow  respiration  Firstly,  3  been  i n urine  in  uptake  t u n n e l have  the  changes  commenced,  high  in  The oxygen  5  respirometer  ventilatory  note.  after  subjected  trout's  experiment  animals  swimming  interruptions  already spent  was  were  this  protocol  worthy had  and  #65)  alterations  exercise.  disappear with  rate  on  and  i n the  caused  effect  associated Such  to  regime  have  to  #63,  Lengthy  Similarly  are  activity). tend  fish the  i n the  and  will  Salmo  Furthermore  (Fromm,1963;  those  #59,  frequency,  are  oxygen  (Table  1964)  may  obvious  sections  that  mined  no  points  chamber  #59  responses  tail  Several  to  data  previously.  had  different  size  for  5°C.  those  considered basal  These  animals  fish  metabolic  than  at  Hunn,1969).  standardized exercise  of  measured  (1968)  lower  similar  rate  presented.  to  regime  Rao  observations relating  Four  but  were  may  (cf.Brett,1962).  uptake  by  (Hammond,1969;  i n Table  ation  weight  trout  Stainer,1966) salmonids  standard metabolic  lowest  eliminate average swimming  Table  XVII.  during  each  Tail hour  beat  frequencies  o f t h e imposed  Velocity (cm/sec)  10.7  swimming  10.7  T.B.F. ( t a i l beats/min) N = 12  -  -  Ventilation rate (closures/min) N = 12  ,.63.0 ± 2.4:  ^63.5 ± 2.7  Oxygen Consumpt i o n (ml/kg/hr) N  . -,128.35 ± 24.74  Continuation  regime:  of  Velocity (cm/sec) T.B.F. ( t a i l beats/min) N = 12 Ventilation rate (closures/min) N  =  ±  32.1  ±  124.6 4.1  ±  (T.B.F.),  116.14 22.67  89.8 1.8  124.2 2.0  regime.  10.7  -  ±  86.7 ± 2 . 4  1 standard 21.4  77.8 ± 1 2 . 7  78.3 ± 1 3 . 1  58.0 ±16.0  61.6 3.0  ,79.0 ± 3.2  ±  150.62 26.27  ±  ±  75.3 3.0  119.20 13.78  10.7  124.3 3.7.  ±  ±  and oxygen  21.4  32.1  ±  Means  rates,  21.4  ,101.55 - 19.21  32.1  ±  ventilation  62.8 2.0  109.74 9.14  ±  98.28 9.30  10.7  ,  ±  66..8 1.1  ±  ±  10.7  ±  144.6 4.5  ±  60.8 1.8  ±  102.2 2.7  113.72 12.60  ±  98.14 9.17  ±  299.81 6.05  63.2 2.4  112.97 7.41  42.8  64.1 1.4  ±  10.7  -  ±  10.7  fish.  10.7  -  92.0 3.2  for 4  71.6 3.5  ±  ±  error  consumptions  ±  90.97 12.35  ±  42.8  *  133.0 4.4  ±  62.2 2.3.  42.8  ±  96.7 8.2  137.8 3.5  ±  84.0 8.9  12  Oxygen consumpt i o n (ml/kg/hr) N = 4  ±  222.06 14.29  ±  232.24 27.29  ±  248.38 19.69  ±  139.63 19.81  ±  ±  272.35 9.11  ±  296.56 5.03  Table  XVII.  Continuation  (Continued) of  regime:  Velocity (cm/sec)  10.7  T.B.F. (tail beats/min) N = 12  10.7  10.7  -  Ventilation rate (closures/min) N = 12  ±  66.6 1.5  Oxygen consumpt i o n (ml/kg/hr) N - 4  ±  92.61 6.93  -  ±  ±  61.4 1.4  81.50 12.97  ±  61.5 2.1  94.46 ±14*70  speed  (21.4  cm/second),  consumption uptakes 42.8  at  associated the  two  cm/second  by  Rao  at  15°C.  were  (1968)  at  The  i n fact  Rao  (1968)  in  the  present  1962)  at  5°C.  study  taining  a particular  was  probably  to  The  averaged  #55,  #63,  a  during  periods  proportional deficit  two  the  with  data  #65  a  of  the  similar  the  A  the  oxygen  (Brett, was  of  maindrop  exercise debt  consumptions  values,  again  consumptions are  being  now  the  flux  consumption.  illus-  approximately  branchial  may  of  increased  demonstrated  addition,  animals  of  markedly  i n water  cost  experiment  been  trout  activity.  augmentation  has  that  trailing  oxygen  oxygen  conclusion  i n oxygen  end  i f any,  increment.  In  alterations  the  but  ascertained  precipitous  "resting"  production  activity  for individual  at  and  throughout  the  The  spontaneous  flows  balance.  changes  elevate  regime,  initial  velocity with  sections;  i n general,  urine  exercise,  the  water  below  Urine  associated  esponded of  to  branchial  that,  of  the  size  cm/second  effect  by  l i t t l e ,  the  42.8  This  created  levels  of  at  observed  same  appear  speeds.  original  end  here  the  and  those  the  in  oxygen  metabolic rates  velocity.  diminution  and  active  greatly  to  of  therefore  drag  The  consumptions  swimming  the  due  i n F i g . 26.  to  the  would  slightly  trated  first  to  By  actually  trout  to  indicated,however, that  incurred.  were  maximum  swimming  decrease  cm/second  comparable  measured  approached  which  rate  the  (32.1  f o r rainbows  I t would  low  catheter  periods  speeds  than  attributable  meb'abolic  were  a  behaviour.  velocities  metabolic rates  urinary  in  restless  9°C.)  these  at r e l a t i v e l y  probably  -  greater  by  with  highest 7°  at  probably reflecting  be  data  (urine  sodium in  the  extended reveals flow)  corr-  Consideration  i s particularly  convincing  168  Figure  26  Simultaneous changes uptakes during regime o f  the  Section  in urine  continuous III.  averaged responses of Crosshatching broken  line  hour o f  the  value  of  the  first  fish  Each bar t r o u t #55,  urine  exercise  inclusion #65.  flow  of  oxygen  swimming  represents #63,  and  the  #65.  of exercise.  bar  f o r the  interval the  and  imposed  indicates periods  on  mean w i t h o u t  flows  initial  represents  extremely  The  the  diuretic  I VELOCITY (cm/sec.)  OXYGEN CONSUMPTION (ml/kg/hour)  1  URINE FLOW (ml/kg/hour)  169  of  this  versus  point. urine  Fig. 27 presents plots  production  determination  during  there  a highly  the  existed  two  in the  line  metabolism  lines  Thus  fitted  over  active  a range  interpreted defined  by  effect  have  linear  i n terms the  a  of  urine  commersonii. movements  a  relatively  This  flow  that  reductions  of  imposed  the  on  the  oxygen  of  of  and  and  water  i n the  indicative water  to  between  entry  taken  were  in  an  results  water  being  and  are largely  necessary  Beatty  (1968)  temperature  gas  depen-  Catostomus and  water  contribution  across  with  almost  The  sucker,  the  noted  experiments.  fluxes  f o r the  that  be  sub-standard to  Mackay  correspondence  the  agreement  blood perfusion  white  between  of  flow values  i n good  permeability  explanation  total  I t may  relationship.  uptake.  trout  correlation  swimming  from  each  intercepts  urine  the  branchial  oxygen  and  were  uptakes  g i l l  For  positive  XVI)  oxygen  simultaneous  individuals.  from  positive  swimming  whole  swimming  dealt  with  close more  inspection complex  osmotic  general  occasionally a  to  regime.  consumption  the  net  of  gills  non-  i s  unimportant.  reveals  within  data  production  However,  were  the  similar  i s perhaps  diffusional  fish  (Table  oxygen  f o r each  slopes  consumption  pattern  certain  suggested  dence  of  the  between  metabolic rates,  approximately  to  swimming  boxes to  flux)  significant  varied  s t a n d a r d oxygen  the  the  parameters,although  regression that  (water  of  seen  the  penalty  in drastic  period  f  F i g . 28  data  interactions, of  Such  i n a more  The  former  general  short  presents three  terra of  individual  may  be  with  super-  compensations  modification  and  from  associated  exercise,  relationship.  regime.  first;  of  the  of  urine  trend effect more  flow  over may  the be  pronounced  170  Figure  27  The  relationship  urine in  flow,  considered  3 rainbows  regime.  1  hour  oxygen  consumption  a measure  subjected  Each  simultaneous a  between  to  a  continuous  point, (except  determination  o f water  x's)  of  the  and  influx,  swimming  represents two  factors  a over  period.  ® = d a t a from f i r s t 6 hours o f the regime. The l a b e l l e d p o i n t (21.45 m l / k g / h r ) r e p r e s e n t s an e x t r e m e l y d i u r e t i c v a l u e n o t e d i n F i g . 28, a n d was not i n c l u d e d i n the c a l c u l a t i o n o f the r e g r e s s i o n line or correlation coefficient. O  =  data  from  middle  A  =  data  from  final  x =  Fish  #65:  water  #55:  #63:  =  6 hours  =  =  =  p<  influx  0.742,  =  p <  influx  0.744,  water r  influx  0.783,  water r  Fish  hours  of of  the the  regime. regime.  v a l u e o b t a i n e d f r o m t h e same t r o u t a t r e s t a m e t a b o l i s m box ( T a b l e X V I ) ; n o t i n c l u d e d the c a l c u l a t i o n o f the r e g r e s s i o n l i n e or correlation coefficient.  r Fish  9  p<  1.12  in in  +  0.031(oxygen  uptake)  +  O.OlKoxygen  uptake)  +  0.019(oxygen  uptake)  .001 2.55 .001  =  1.72 .001  URINE FLOW  (ml/kg/hour)  171  Figure  28  Three high  examples urine  flows  drastically during  ~  This  trout  with  pattern  activity  at the start  reduced  continued  associated —  o f t h e phenomenon  These  efflux  -  t o be  Crosshatching  "adapted"  indicates periods  of  arrows) were  not  consumption.  at the  the typical  are not already  the  were  changes  v a r i a t i o n s i n oxygen  of renal water  extremely  of exercise  (as i n d i c a t e d by  sivimming.  i s thought  which  i n which  oTiset  response to  o f "  of  swimming.  exercise.  OXYGEN CONSUMPTION (ml/kg/hrj  VELOCITY (cm /sec.) O P O N  o  c  b»  w  > L  •—  po  URINE FLOW (ml/kg/hr)  172  examples urine  of this  discharges  dramatically were  occurred  in  reduced  As w i l l  b e shown  presently,  this  and t i m i n g  water  to that  mechanism.  That  occasionally  i n the present  activity  sufficient ability  this  observed have  study  been  This  probably  initially  very  appears  caused  be r e l a t e d  high  similar  efflux i n  by a  common only  t o the spon-  at the "resting"  behaviour  the postulated  the imposition  changes  d i u r e s i s was o b s e r v e d may  were  metabolic  f o r sodium  by t h e animals  t o swimming.  before  was  compensation  exceptional  exhibited  to induce  influx  This  I I ; t h e t w o e f f e c t s may  prior  The  effect  high  interval  alterations of  declined.  velocity  o f an e x e r c i s e  any marked  subsequently  taneous  extremely  with  branchial  Section  cases,  by the end o f the period.  because  magnitude  In such  at the beginning  not associated  rate.  but  phenomenon.  lowering  may  have  been  of branchial  o f the experimental  perme-  exercise  situation. A during  more  prolonged  individual  fish  illustrated be  seen  the that fit  final  animal.  tend  data  different lower  middle, The water  was  from  to fall  F o r each  straddle below  elevation  lines  i t .  i s best i t can  of the  regression  i t ; while  line;  the values  One may  of  speculate  be p o s s i b l e  to  o f s i m i l a r slope but  to the values  a n d e n d o f t h e swimming per unit  trout,  influx  of  effect  6 hours  t h e common  a v a i l a b l e , i twould  regression  entry  This  the first  l i e above  9 hours  were  27.  o f water  by the response  protocol.  of Fig. taken  f o rcurtailment  suggested  the entire  generally  6 hours  progressively beginning,  over  the middle  i f enough three  activity  the points  regime  from  tendency  by t h e p l o t s  that  swimming those  general  oxygen  recorded protocol  uptake  at the f o r each  obviously  173 decreased ation  as  will  swimming  be  phenomenon  further  weight  branchial  with  the  on  the  alterations  of  an  aquaria) only  be  caused  i n weight  estimates the  it  seems  of  mean  not  handled  results and  of  impose  further  set of  from  two  (resting  from  the  However  amounted  to  balance  the  decrease to  and  minutes.  observed  positive 15  to  a  Fluctuations  over  in control  as  however  60  state; the  minutes there  following  v a l u e s were  was  exercise,  much  3%  i n terms  time  of  of  increased.  weights the  hours  a  variability  increase  occurred only  of  than  f o l l o w e d by  values, the control  generous  exercised  because  3 - 7  could  Consequently,  swimming  minute  greater than  and  negative  decrement  1  experimental  significantly 30  after  balance;  minute  Between  response  very  minutes.  of  separate  excretion  less  net  triphasic  in  efflux,  shifts  water  animals  environment;  water  f o r 60  weight  i n weight  a l l weight  a  swum  stress  experimentals  losses.  factors  l i t t l e  control  Increase  represent net  "metabolic"  as  the  precaution, the  controls  water  of  (Evans,1969b),  interpret  become  further  a  to  sensitivity  to  rise  returned  known  to  changes  legitimate  large  5  the  flux  fish  exhibited  the  gain  The  this  performed  of  trout  in  to  were  water  i n F i g . 29.  latter  of  decline  movements.  rapid  As  The  could  and  the  water  The  trout.  the  of  designed  cm/second)  by  electrolytes,  of  was  presented  Further consider-  mechanism  handling effects  identically  32.1  are  decrease of  at  course Due  to  ascertained.  (swimming  possible  experiments  time  procedure  increased.  Discussion.  exercise.  possible  also  the  change  permeability  experimental  was  to  General  elucidate  associated  as  devoted  i n the  The  experience  did  until  30  animals a  very  slight  of  activity.  smaller  magnitude  174  Figure  29  Changes to  i n body  original,  values  previously) at  for  determined  i n t h e swimming  the determinations  standard  (relative 8  exercise  respirometer  to the handling  alone  hours  (controls).  durations (experi-  necessary Means  -  error.  minutes  Control:  trout  at least  to various  and i n response  Statistical in  o f rainbow  i n response  32.1 c m / s e c .  mentals)  1  weight  Comparisons:  (Numbers  o f t h e r e s p e c t i v e means F =  2.29, p <  30  1  15  refer  to the  times  on t h e graph.)  .05  5  240  60  Experimentals: F  =  240  A  =  sample means  12.54, 1  times  60  p <  .005  30  a t which  15  5  control  are significantly  and  different  experimental ( p < .05)  +1.00-T  TIME ( minutes)  175 but mimicked t h e o s c i l l a t i o n s o f e x p e r i m e n t a l s u n t i l post-handling.  30 minutes  I t seems p r o b a b l e t h a t t h e e f f e c t s o f h a n d l i n g  were v e r y s i m i l a r b u t l e s s s e v e r e than those o f swimming. After  30 minutes,  controls returned to their i n i t i a l  which was m a i n t a i n e d through The  further a c t i v i t y  weight  ( 3 - 7 hours).  d a t a must be i n t e r p r e t e d i n terms o f d i f f e r e n c e s  between n e t water i n f l u x a c r o s s t h e g i l l s through t h e u r o g e n i t a l p a p i l l a .  and n e t water  efflux  The l a r g e magnitude o f t h e  v^eight l o s s a f t e r 1 minute i n d i c a t e d t h a t i t was p r o b a b l y caused m a i n l y by a b l a d d e r emptying  effect,  a l t h o u g h an  increase i n glomerular f i l t r a t i o n rate r e s u l t i n g  from  an i n i t i a l  "overshoot" i n systemic blood pressure at the onset o f e x e r c i s e may have c o n t r i b u t e d t o t h e enhanced water e f f l u x . (1969.) has demonstrated  Hammond  i n t h e l a k e t r o u t , S a l v e l i n u s namaycush^  t h a t p r e s s o r e f f e c t s can markedly e l e v a t e u r i n e f o r m a t i o n . The  f o l l o w i n g weight  produced  g a i n and f i n a l weight  by i n e q u a l i t i e s o f i n f l u x and e f f l u x , b u t i t i s n o t  c l e a r whether t h e former, changing. respect.  l o s s must have been  t h e l a t t e r , o r both p r o c e s s e s were  The u r i n e p r o d u c t i o n d a t a i s i n f o r m a t i v e i n t h i s A f t e r 60 minutes o f swimming, t h e n e t weight  loss  r e l a t i v e t o t h e g a i n a t 30 minutes was 1.13 g/100 g.  Even i f  no i n f l u x o c c u r r e d a f t e r  situ-  30 minutes,  a highly unlikely  a t i o n , the u r i n e p r o d u c t i o n over the f i r s t must have exceeded 11 ml/kg.  hour o f swimming  I t i s probable that the a c t u a l  r a t e was much h i g h e r .  T h e r e f o r e t h e weight  change  were o b v i o u s l y behaving  as t h e examples o f F i g . 28 which  underwent a much g r e a t e r d i u r e s i s d u r i n g t h e f i r s t hours o f swimming than d u r i n g subsequent t h e r e was l i t t l e ,  i f any, augmentation  hours.  animals  one o r two In such  of urine production  cases  176 during  the  first  type  of  response  cise  in  the  to  their  which ming on  with  did  not  spontaneous have  runs.  prior  minutes  The  other to  activity  hand,  been  type  of  urinary response  appearing  of  high  emptying  effect).  decrease  while  pronounced  60  start  of  branchial  (except  for  the  progressed,  phenomenon  gain  resulting  measured  at  similar, output  A  a  had,  aquaria  the  "naive" model  influx  a  are  and  water  and  caused  by  compensatory bladder tended  weight  to  at  a  between  after net  than  60  body  des-  during  high  overshoot eventual  water  those  graphically  balance  at  after  situation soon  initial  an  the  loss  hours  i s presented  subsequent  falls,  weight  4 - 8  scheme  an  net  the  overcompensated  balance  trout  F i g . 28,  29)  finally  rate  of  (Fig.  producing  reached  tentative  adaptation, as  swim-  group  influx  i n the 1  was  turnover  interpretation  initially  parameter  the  thereby  ?  maintained.  in renal  to  initial  higher  an  exer-  in  without  water  a  features of  efflux  influx  set  above  of  respirometer  data  was  balance hov;ever,was  The  delay  minutes  new  in  a  The  This  exercise main  30  This  were  change  renal  the  this  attributed  darkened  and  originally  be  change  illustrated  eventually rose,  swimming  f  cribing  weight  and  swimming  weights  lower and  that  i n the  entry  minutes. content  As  water  As  again  in  developed. 5  function  efflux  original  be  between  diuresis.  minutes.  the  may  the  b r a n c h i a l water  renal  onset  x^eight  resting  integrating  extremely  the  exercise prior  the  by  increment  the  quietly  may  fact  experience  to  of  at  The  swimming.  explanation  for  them  Thus  elevation  occur  and  experimentals  following  an  exercise.  commonly  "adapted"  obligatory  the  of  urinary catheterized trout  could  the  15  in  Fig.  water of  30.  influx,  the  equilibrium  177  Figure 30  A t e n t a t i v e model of the temporal changes occurring i n water i n f l u x and e f f l u x of the rainbow t r o u t during the onset and continuation of e x e r c i s e . has been assumed that the animal i s not already "adapted" to swimming.  It  WATER FLUX RATES  (RELATIVE UNITS;  178 between  influx  that  the  as  "adapted" water  and  animal  to  movement  final  are  in  water  (Fig.  this  flux  so  now  further  the  per  that  in  model  I t may new  in  and  to  hypothesized i t becomes renal  some m a n n e r  alterations the  be  balance,  branchial  linked  decline  into  coupled  of  the  unit  oxygen  uptake  triphasic  weight  fluctuation  correlated  with  and  protein  plasma exercise  a  reciprocal  triphasic  concentrations ascertained  concluded  that  since  the  haemoglobin  to  protein  plasma  individual ential g i l l s  rates and  the  of  out  present of  decline one  volume content  the  work,  hour  of by  the  ( F i g . 29). during offers  and  blood this  several  decrease  renal  rise  reported  the  would losses  the  beginning  a).  Stevens  by  the  i n -  i n plasma  sodium  levels  Section loss  I  can  through  a  decrease  benefits  resulting  to  also  observed reduced  ions  to  rates.  a  of  basis  modified  of  to  the  efflux  water  tend  differ-  across On  their  renal  in  maintenance  obvious  and  haemoglobin  during  tissues.  influx  and  blood  be  be  in  caused  may  may  concentration  change  the  the  at  (1968  were  explanation  exercise  basis,  not  into  significant  extended  did  effects  into  volume  The  electrolytes  branchial  of  movement  exercise  osmoregulatory  plasma  the  b r a n c h i a l water  i n blood  explained  minutes  water  of  ratio  concentration  fluctuations,  equalities  an  i n -  previously  response  Stevens  be  been  ( F i g . 29)  g a i r d n e r i by  over  demand.  progressive  Salmo  The  has  discussed  of  change  metabolic  in  of  and  fluxes  represent  components  27). The  of  reaches  with  gradual  corporated  rates.  exercise  simultaneously A  efflux  the  by  60  plasma in  water  trout.  concentration  compensate  for  now  the  suffered during  On of augmented  swimming  179 and thus h e l p t o p r e s e r v e t h e c o n s t a n c y  o f the i n t e r n a l medium  Haemoconcentration would e l e v a t e the b l o o d oxygen c a p a c i t y and t h e r e f o r e f a v o u r a b l y a l t e r the r e l a t i o n s h i p between oxygen t r a n s p o r t and c a r d i a c work.  total  In a d d i t i o n t h i s  effect  would i n c r e a s e t h e b u f f e r i n g c a p a c i t y o f the b l o o d j and t h e r e f o r e s e r v e t o reduce activity.  The  unfavourable  a c i d o s i s a s s o c i a t e d w i t h g r e a t e r muscular  accompanying r i s e  i n b l o o d v i s c o s i t y would be  i n i t s e l f , but would p r o b a b l y be o f f s e t by  o v e r a l l decrease  i n systemic r e s i s t a n c e to blood flow  t e d t o accompany e x e r c i s e i n t r o u t  (Stevens, 1968  calcula-  a).  The  volume r e d u c t i o n o f the c i r c u l a t o r y compartment d u r i n g c o u l d be  activity  f a c i l i t a t e d by an i s c h e m i a o f "white" muscle p o s t u -  l a t e d by Stevens was  the  presented  (1968  b), and  f o r which some l i m i t e d  i n Section I.  T h i s t i s s u e i s i n any  evidence case  l a r g e l y anaerobic; i f i n f a c t i t continued to r e c e i v e a blood s u p p l y d u r i n g swimming, t h e r e would o c c u r a  disadvantageous  r e l e a s e o f l a c t a t e i n t o the c i r c u l a t i o n , which would t e n d t o i n h i b i t oxygen uptake by haemoglobin a t the g i l l s . i n plasma volume d u r i n g p r o l o n g e d  A  decrease  e x e r c i s e would t h e r e f o r e  seem t o p l a y an i n t e g r a l r o l e i n the p h y s i o l o g i c a l  adjustment  p f the f i s h t o the i n c r e a s e d m e t a b o l i c demands o f swimming. C a t i o n l e v e l s were measured i n a l l h o u r l y u r i n e sample from the f o u r e x e r c i s e d t r o u t .  As noted p r e v i o u s l y (p. 156)  the method o f sample c o l l e c t i o n p r o b a b l y dampened c o n c e n t r a t i o n change a s s o c i a t e d w i t h d i f f e r e n t presented i n Table XVIII  t h e r e f o r e r e p r e s e n t s average  f o r each hour e s t i m a t e d from time  ( e . g . F i g . 31).  e x e r c i s e c o n d i t i o n s ; the  data  ion level  the c u r v e s o f c o n c e n t r a t i o n v e r s u s  Because o f l a r g e magnitude d i f f e r e n c e s  between the samples from d i f f e r e n t  a n i m a l s , ranges  r a t h e r than  Table  XVIII.  Urine  Means  and ranges  cation  10.7  each  hour  10.7  21.4  10.0 5.5-19.5  10.8 5.5-18.5  9.3 4.0-13.8  8.5 4.8-11.3  0.95 0.62-1.17  0.95 0.62-1.29  0.89 042-1.40  0.94 0.70^1.44  U r i n e Na* (uEq/ml)  o f t h e imposed  swimming  regime.  I  5.43 3.20-8.35  7.04 3.83-10.17  +  during  5.45 2.01-8.62  Urine flow fal/kg/hr)  •Urine K (uEq/ml)  and flows  for 4 fish.  10.7  Velocity (cm/sec)  levels  10.49 4.20-20.21  21.4  6.26 4.00-8.35  21.4  6.75 5.40-10.06  10.7  4.33 ' 3 .3 0 - 5 . 3 3  9.5 4.8-15.0  9.5 5.5-14.0  9.5 5 .5-13.0  1.00 0.65-1.31  1.00 0.60-1.32  1.01 0. 5 8 - 1 . 4 0  Urine Ca (uEq/ml)  +  +  0.96 0.30-1.27  0.99 0.30-1.24  1.06 0.30-1.40  l.|18 0.95-1.75  1.37 0.80-2.05  1.39 0.70-1.95  1.33 0. 7 2 - 2 . 0 3  Urine Mg (uEq/ml)  + +  0.51 0.15-1.01  0.56 0.15-1.30  0.57 0.05-1.26  0.(83 0.50-1.20  1.15 0.30-1.62  1 . 36 0.21-2.28  1.31 0. 2 8 - 2 . 4 7  32.1  32.1  32.1  Continuation Velocity (cm/sec)  10.7  Urine flow (ml/kg/hr) Urine Na (uEq/ml)  o f regime:  +  Urine K (uEq/ml)  +  5.32 3.50-9.27  10.7  5.27 3.55-10.06  10.89 5.20-24.86  10.84 5.90-23.09  6.48 5.07-7.50  10.7  4.48 2.60-6.2 5  10.7  4.22 2. 8 0 - 6 . 2 5  9.6 5.8-13.0  9.4 4.5-14.7  9.5 13.8-16.5  8.5 3.0-14.3  8.5 6.5-10.5  9.3 7.5-10.5  9.9 7.5-11.8  0.99 0.45-1.36  0.98 0.35-1.44  1.05 0.26-1.74  1.'07 0.42-1.74  1.01 0.60-1.47  0.99 0.68-1.36  1.01 0. 6 0 - 1 . 4 3  Urine Ca (uEq/ml)  +  +  1.20 0.66-1.93  1.15 0.56-2.07  1.15 0.50-2.11  1.15 0.60-»2.07  1.26 0.62-2.17  1.32 0.73-2.32  1-. 31 0. 8 0 - 2 . 4 0  Urine Mg (uEq/ml)  + +  1.15 0.35-2.34  1.00 0.32-2.10  0.86 0.35-1.70  0.'97 0.25-1.90  1.25 0.20-2.45  1.39 0.38-2.90  1.33 0. 5 4 - 2 . 6 0  \  Table  XVIII.  Continuation Velocity (cm/sec)  o f regime: 10.7  Urine flow (ml/kg/hr) Urine Na (UEq/ml)  (Continued)  +  Urine K (uEq/ml)  42.8  3..48 .97--4. 2 50  7..68 5 . 40--11 .10  1 0 ..5 9.5--11 .5  9,,4 8 .6--10 .00  42.8  7 .91 5 .50 - 1 1 .50  42.8  10.7  10.7  6.84 5.30-7.70  2.40 1.40-3.09  2.23 1.20-2.95  9 .0 7.5 - 1 1 .2  8.3 7.0-10.0  15.3 12.0-18.0  17.4 12.7-19.0  1..17 1 .00- - 1 . 32  1..11 0. 9 7-- 1 . 22  1 .13 1 .05 - 1 . 15  1.16 0.98-1.38  1.17 1.06-1.30  1.20 1.05-1.38  Urine Ca (uEq/ml)  +  +  1..38 0 .83--2. 22  1..13 0. 66-- 1 . 85  1 .04 0 .60 - 1 . 56  1.09 0.55-1.90  1.46 0.63-3.11  1.65 0.77-3.11  Urine Mg (uEq/ml)  + +  1..14 0 .46- - 1 . 70  0..62 0. 25-- 1 . 00  0 .54 0 .19 - 1 . 0 0  0.73 0.20-1.67  1.54 0.33-4.03  1.66 0.50-4.03  +  1 0 .7  2 .62 2.00 -3.60  —  standard Such of  errors  diversity  teleost  have  been  o f values  urinary  presented between  i o n data  as estimates  individuals  (Hammond,  1969;  of  variability.  i s characteristic Hunn  and W i l l f o r d ,  1970). Sodium, tions the  i n "resting"  ranges  1963;  effects  potassium  relation  levels  varied only  d i d not always  these  two d i v a l e n t c a t i o n s  study, the of  Similar oscillations  trout  these  tubular  have  i n fact  this  that  the tubular  f o r apparent  tubule;  t o volume  fluct-  changes  epithelial  cell  m  that  fluctuationsi n  The data  are  o f calcium  Hickman  of  i n the urine o f  (Hammond,1969).  the transport  a n d Trump  o f t h e two  suggestive  a n d mag-  (1969) electro-  i s e f f e c t e d by  ATP r e q u i r i n g s y s t e m s .  i s not clear.  and magnesium  simultaneous  associated with  temporal  sodium  and g e n e r a l l y i n  observed  i n the active transport  proposed  mechanism  been  of the ions.  the proximal  part  i n the concentrations  namaycush  i fnot identical,  reason  have  v a r i a t i o n s were  across  related,  of  Salvelinus  reabsorption  l y t e s through  the  f  some c o u p l i n g  nesium  correspond  volume  o f swimming;  the latter  Calcium  large  (Fromm,  as u r i n e  animals,  flow.  demonstrated  31).  lake  during  within  a tendency f o r  termination  moderately  i n urine  (Fig.  the  upon  well  and W i l l f o r d ,  to fall  In individual  to alterations  which  minerals  was  concentra-  species  Hunn  there  pronounced  regime.  fell  forthis  Hunn,1969;  occurred  more  concentrations,however, uations  workers  o f a l l four  become  and magnesium  cm/second)  of exercise  The r e v e r s e  the exercise  and  (10.7  by other  periods  concentrations  increased.  of  calcium,  and Stainer,1966;  During  these  samples  reported  Holmes  19 70). the  potassium,  closely  However,  fluctuations i n the activity  182  Figure  31  Changes single of  of  trout  Section  lesser with  over  III.  extent,  urine  exercise levels,  cation  concentrations  in  the  swimming  Variations potassium  volume  however, of  in  sodium,  l e v e l s were  a l t e r a t i o n s under  conditions.  independently  continuous  Calcium  fluctuated urine  urine  flows  in or  and  from  a  regime and  to  a  associated different  magnesium  synchrony, exercise  but conditions.  183 The present cise  electrolyte  study  was  indicate that  somewhat  flow  and  the  different  (R.M.Holmes,1961), (Hunn  concentration  severe  rates  were  that  hypoxia In  associated  (Hunn,1969),  marked  concentrations;  the  Diuretic  involving increased  reflect  states profound  functions exercise eration fish are  well  of  in  water  by  tubular  at  discharges  in  salt  ations  of  strating  a  diuresis ion  similar  (Holmes  fish,  are  and  thought  to  water  net  magnitude  of  urinary the  renal  observed  only  lower  lower  at  urine  high  glome-  electrolyte  be  an  It  diuresis relative  a  efficiency  to  by i s  urinary  production  of  perturbinteresting as  demon-  smolting  fish,  concen-  example  considered  Smolting  alter-  Increased  to  be  in resting  The  uncomplicated  may  exagg-  minimal  decrease  seem  an  Such a l t e r a t i o n s  mechanisms.  rainbows  of  have  previously  increased  therefore  The  merely  (Hammond,1969).  Stainer,1966).  branchial As  creating  transport  type  to  probably  reabsorptive  functions.  tends  (Hunn,1969)  non-smolting  duals  reduced  flows  swimming  tubular  that  thereby  urine  during  "water"  however,  with  high  electrolyte  rate.  represent  filtration  in  levels  Trump,1969).  conservation  rates,  high  simple  a  changes  and  ion  be  handling  anaesthesia  mineral  can  exer-  swimming.  filtration  normally  Hickman  during  the  situations,  increases  urine  to  or  in  with  after  latter  tubular  glomerular  v a r i a t i o n s which  clearance  note  in  reabsorption,  trations  to  as  in  diuresis,however,appears  mediated  rular  occurred  disturbances  (Hammond,1969;  ations of  as  occurring  a l l these  with  opposite  observed  diuresis associated  from  Willford,1970).  changes  like  indivi-  resting  because  of  permeability.  noted efflux  (Table of  XI)  sodium  loss,however  there during  (2.0  -  4.0  occurred  an  swimming.The ug/100  g/minute)  184 was  small  relative  (28.50ug/100 across renal the  the  branchial  averaged  summarized  volume  in  26  fact  Fig.  32.  was  magnesium  nounced  due  to  mechanism  for  the  gradual  loss  under  of  entirely  dependent  from  tended Thus  renal  deficit of  branchial  for  the  in  the  minerals. declines  on  the  been  to  in  exercise  be  urinary  of  urine  will  remain  Fig.  32  potassium,  data.  Increases  were  less  of  the  noted  sodium (10.7  of  reabsorptive that  and  there  potassium  cm/second)  over  in urine  compensatory the  water  reduce may  latter  be  the  effect  mechanisms  permeability urinary  simply  adjustment.  a  in  exercise  decreases  the  this  pro-  concomitant that  with  and  which  of  permeability  ions  on  ( F i g . 32)  argued  to  of  been  nature,  independent  activity I t may  measured;  largely  exercise  were  elevated  have  this  sodium  present  g/minute)  protocol  reduce  adaptation  during  in  #65  Comparison  excretion, with  implementation  exercise  least  The  cations  dependent  reabsorption  experimental  previously  the  at  ug/100  #63,  "resting" conditions  duration  has  #55,  diuresis of be  unidirectional  III).  a l l four  variations that  these  the  a  (12.14  (Table  to  should  occurred  transpired rates  efflux  (Hammond,1969).  and  It  In  confirmed  apparently  simultaneous  animals  tubular  calcium  which  of  indicates that,  relationship  net  common  excretion  stable  the  epithelium  percentage  relatively Fig.  in  or  responses  salt as  either  g/minute)  l o s s was  urinary  to  flow.  resulted  the  component  secondary  were  during  of  the  of  ex-  g i l l s . mineral  consequence  185  Figure  32  The  net  renal  continuous bar #63,  swimming  represents and  exercise.  excretion  #65.  the  of  regime averaged  four of  cations  Section  III.  responses of  Crosshatching  during  indicates  the  Each  trout  #55,  periods  of  VELOCITY(crn/sec)  URINARY  ELECTROLYTE  LOSS  (yEq/kg/hour)  ( yg/ ]00g./min.)  186  SUMMARY  1.  Post-catheterization  of  oxygen  All 2.  consumption  three Urine  parameters flow,  markedly  respirometer. ponded 3.  In  from  with  had  influxes The  oxygen  in  to  at  beginning  after  1  the 2  response  was  ^adapted"  to  branchial  water  water  Weight  of  water  changes balance  triphasic  a  net  the  of  and  the  unit  In  to  a  corres-  change  consumptions  rates,  fish  which  from  an  uptake  of  high  the  water  urine  as  reduced  indicated were  to  that  not  extremely  tended  water  greatly  declined.  regime  correl-  branchial  were  experiments  subsequently  and  exchanger.  cases,  period  exercise  oxygen  positive  reduce  few  swimming  oxygen  imposed  entry,  swimming  covariation  branchial  resulted  which  a  generally  significant  occurred  a  operation.  water  in  oxygen  i n d i c a t i v e of  of  after  high  In  a l l ani-  decrease  swimming  over  exper-  increased.  5.  time  of  per  exercise  metabolic  characteristic of  entry  entry  duration  highly  Weight  exercise,  branchial  range  exercise.  hours.  of  trout.  uptake. a  of  hours  flux  elevations  rainbow  45  of  active  apparently  flows  ience  a  in  with  by  i n water  over  r e s u l t s were  during  the  periods  permeabilities  or  measure  nearly  permeability  mals,  a  oxygen  exhibited  Compensations  this  stabilized  during  changes  associated  ventilation rate  Alterations  sub-standard  ation.  4.  and  individual trout,  water  and  d i u r e s i s was  considered  increased  III  was  were in  determined  trout  fluctuation in prolonged;  gain  by  30  an  which body  and  were  loss a  exercise  "naive"  weight  i n i t i a l  minutes,  during  was (1  final  to  decrement  measures  swimming.  observed  minute)  as  was  as  swimming  followed  below  A  with  resting  187  level  by  60  reduction 6.  over  The  main  at  branchial output  by  water  (net  water  following  of  lower  body  a  This  volume  net and  exercise  in  Sodium  swimming urine  without  (net  exit  increase  in  Section  I.  did  augmented a  simple  branchial  The  defined (2.0  -  compared  "water"  of  and  ug/100 to  and  urine  exercise  although  net  rise  for  the  rate  and  in  blood  noted  during  to  during  decrease  at  high  calcium  and  fluctuations  volume a l t e r a t i o n s . thus  appeared  by  to  rep-  elevated  disturbances  functions. cations  this Renal  associated  sodium  and  decrease  simultaneous  a l l four  potassium.  g/minute)  branchial  the  However  uncomplicated  of  swimming,  sodium  turnover  d i u r e s i s r e s u l t i n g from  excretion  during  for 4.0  output  electrolyte reabsorptive  urinary  increased  urine  flows.  to  renal  equilibrium  collected  tended  underwent  correspond  permeability,  tubular  10.  always  low  rate  high of  overcompensates  levels  but  not  in  sodium  stable at  bladder  i n i t i a l  influx  for  generally increase  an  swimming.  rest.  were  and  water  modification  in  further  inform-  of  immediate  higher  in urine  which  resent  a  levels  concentrations  The  at  potassium  flows  flow  during  eventual  and  magnesium  9.  an  account  plasma  urine  loss);  decline  during  can  slight  exercise.  trout  an  (net  and  than  deficit  are:  set  very  t e n t a t i v e model  eventually  loss);  and  with  appreciable  subsequent which  a  of  unexercised  activity  content  water  a  of  rate  entry  water  of  only  hours  data  scheme  influx  efflux  water  change  this  onset  accumulation  between  3 - 7  previously  gain);  urinary  occurred  construction  the  the  There  weight  features  emptying  8.  of  permitted  regulation  7.  the  Integration  ation  in  minutes.  loss  trend  which was  sodium  with rate  were only  well  efflux  activity (12.14  measured  was  ug/100  small g/minute).  188  GENERAL  The oxygen  uptake  rainbow and  present  trout  water  across were  movements their  exercise,  mechanisms fluxes  swimming.  The  animals  minutes),  and In  transport at  rest,  the  efflux This is ion  i s  eliminated loss.  lamellae  During  and  g i l l s .  effect  on  the  through  increased  the  in  blood  also  Fig.  during  to  small  the  active  the  initial  of  a  a  swimming,  the  circulatory perfusion  thus This  elevates  the  total  r e d i s t r i b u t i o n of  carrier  mediated  sodium  that  a  g i l l .  Thus  large  exchange  simple  influx  gas  the  served  lamellae. of  a  water  small  which  urinary  cardiac  output  respiratory  exchange  blood  both  diffusional  enhanced  of  un-  back-  element,  with  from  hours).  epithelium  together  of  ( 5 - 1 5  respiratory  constant  kidney  (3  influx  small  walled  penalty  conclusions  trout  comprises  these  previously  assumed the  the  reduce  activity  exercise  sodium  extended  to  and  of  in  osmotic  for  interlamellae  thin  site  33  been  pathways;  the  the  initial  transfer  a  During  in  adapted  surface  inferences  in  increases  elevations  invoked  negligible in  and  across  similar  alleviate  i t has  sodium  fresh  branchial  important  is  the  gradients.  thus  rest,  generated  occurs  area  causes  the  sodium  filamental  water  "adaptation"  component  presumably  of  apparently  models,  branchial  diffusion  by  after  that  with  summarized at  these  of  and  most  been  exercised  were  demonstrated  the  activity  hydromineral  have  gills  through  of  data  the  has  associated  direction  the  study  DISCUSSION  has  transport  no  capacity apparent  mechanisms  of  189  Figure  33  Models  summarizing  balance  i n the  Animals  are  onset  of  by  arrows;  the of  animal  trout  illustrated  thin  the  of  flux  i s not  volume flux  latter  rate. already  and  after  and  changes  represents been  "adapted"  to  study. the  after  r a t e s by  I t has  water  in this  shortly  minutes),  and  the  sodium  presented  rest,  Blood  arrows  size  at  ( 5 - 1 5  exercise.  dicated  the  rainbow  activity  prolonged  nitude  i n f o r m a t i o n on  are  i n -  thick the  assumed  magthat  swimming.  Respiratory Lamellar Pathway  Filamental Pathways  Blood Volume  j White'Muscle  =Water Flux  RESTING  •=Sodium Flux  Active Transport  Simple Diffusion  Exchange Diffusion  SWIMMING ( 5-15 minutes)  SWIMMING (after 3 hours )  inary Loss  1 9 0  supplied  by  the  diffusional  filamental  loss  creating  a  elevated  without  increased the  sodium  blood  pattern  that  at  tions  of  the  renal  sodium  state  o f water  charge  now  had space  net  the  by  increase  systems  of  sodium The  an  was  opment  of  the  at  g i l l s .  an  and  influenced  by  have  the  The  urinary  e f f e c t was  "white"  dis-  the  (through  muscle.  effective  and  In  permeability  between that  functioning  this  apparently  levels  compensations  presented  with  largely with salt  and  water  different exercise  concept  the  Before  reducing  accommodation  the  increased  the  both  of  the  other  necessary  to  pre-  balance.  dealt  of  of  the  invariant.  an  however,  sodium  reduc-  levels.  again  thereby  to  returned  resting  osmoregulation,  compromise  discussions  under  that  similar  diuresis.  This  ischemia  indicated  water  i n terras  animal  the  and  thesis  obtained the  be  influx,  exercise,  have  entry;  attained  i n plasma  exchanger  this  the  volume.  r e s p i r a t i o n and  could  this  and  to  o f water  was  branchial  resting  results  sodium  accompanies  below an  permeability  thereby  An  compensatory  d i f f u s i o n are  rate  equilibrium  the  dynamics  the  excretion  loss)  of  exchange  equals  branchial  demands  of  and  output.  remains  the  greatly  prolonged  However  of  augments  surface,  i s also  i n renal  After  swimming.  movement  lamellar  probably  hydromineral  water  summary,  serve  of  flow  markedly  entry  change  results.  but  the  Water  blood  exceeded  accompanied  of  g i l l  transport flow  the  volume  outward  Urine  i o n across  appreciable  i n branchial  Active  the  deficit.  start  diffusional  blood  of  pathways,  of  the  individual  evaluation balance  conditions,  of  the  situation and  with  a respiratory/osmoregulatory  intent  of  this  general  sections  discussion  data of devel-  compromise i s to  provide raised ample and  a  more  by  the  speculative results.  evidence  ion  that  limiting  activity of  mechanism  implies  g i l l  factors  both  will  be  on  convenient of  and  as  increased  a  have  the  presence  of  the  the  way  a  the  of  whether  enactment  deficit  system  activity  ask  water  similar  osmotic  for  a  natures  of  Finally,  some  i n which  branchial  of  of  detection  mediator  possible  a  water  to  both  these  suggestions  will  permeability  branchial  of  water  loss  the  evidence  obligations  across  the  hydromineral  of  ions  was  present  gills  as for  the  parallel  balance,  studies  a  have  osmoregulation  on  exert  the  secondary of  the  utilized  and  and  thus  ion pro-  respiratory  indicated, can  of  exercise  variable  variables,  in  effects  while  permeability  penalties  i t is  efflux  during  i n v e s t i g a t i o n has  dependent  the  secondary  greater  apparently  elevated  hand,  phenomena)  the  on  permeability  and  e s s e n t i a l l y independent  recent of  Thus  on  the  The  gills)  exchange  other  branchial  of  osmoregulation.  gas  the  consequence  exchange  Two  in  on  the  surface.  and  exchange  changes  penalties  as  interaction of  at  urinary  exchange  balance.  turn  (occurring  influx  gas  no  to  the  and  hamper  pertinent  restrict  water  r e s u l t i n g from  exchange  vides  in  provided  uptake  to  the  consider  and  primary  problem  and  primary  respiration  were  ion  to  (occurring  sodium  oxygen  problems  has  Secondly,  actual  discussing  hand,and  terms  study  exchange.  considered. the  certain  modified. In  one  be  of  could  of  the  therefore  permeability;  advanced  could  the  gas  i n t e r n a l misalignment  change  be  i t is  necessities  e f f e c t on  compensatory  Firstly,  elevations  regulation;  osmoregulatory  treatment  at  however, least  that  severe  on  192 secondary Salmo  e f f e c t s on  gairdneri,  nilotica, oxygen a  performed  consumption  variety  swimming at  and  of  zero  in  this  tion  devoted  ities  to be  was  penalty  oxygen of  regulatory  on  cost.  gills  active  a  with  of  As  the  did of  exercised  in  different  metabolic  osmoregulation total  not  oxygen in  rate  equalled  consump-  other  salin-  water,  this  figure  change  with  increasing  osmoregulation  across  uptake  greater  the  gills.  functions  concomitant  would  not  an  favour  ( 1 9 71)  cause sodium  role  of  not  by  rose This  is  an  was  in greater  obvious  elevations  in  have  Paralichthys  in  this  influx  increased did  not  through  serving  perfusion  the of  the  ion  that  in  Salmo appear  Indeed,  the  respiratory of  the  influx.  demonstrated  lethostigma,  osmo-  central  transporting  active  least  change  i t would  constant.  decreased  fact  of  i n d i c a t i o n , at  important,  flow  augmentation  some  back-transport  remained  blood  pathways  Randall  the  i s probably  filamental  flounder,  of  fresh  provides  Branchial  sodium  of  study  sinus  and  of  the  salinity.  regulation  cost  flux  and  the  Tilapia  i n which  several  that  r e s p i r a t i o n caused  trout,  exercise.  lamellae  cost  For and  to  isosmotic  osmoregulatory  present  rainbow  diversion  an  the  the  with  at  found  proportion  rest,  (1969)  with  permeability. The  that  the  at  the  secondary  gairdneri  in  that  Thus  demand  during  studies  lowest  (1968)  experiments  measured  calculated.  metabolic  the  were  Rao  acclimated  hydroelectrolyte  20%  to  Beamish  idential  animals  Both  speeds.  proportion  for  almost  medium,  approximately  branchial  and  assumption  could  swimming  Farmer  salinities  a l lv e l o c i t i e s the  metabolism.  of  speeds.  Through  oxygen  in  induced  the  cells  Wood southern  anaemia,  a  treatment  thought  distribution a  decreased  the  similar rate  g i l l s .  branchial passive  The sodium  yet  influx.  of  trout  linear  in  rising  oxygen  uptake,  in  at  the  the  less  than  because increase  can  and an  to  that  there  (1969)  to  regulation  was  more  cost  a  e f f e c t on  such  a  imp-  with rate  and  probably  given that  swimming exercise  prevented A  the  cost  swimming  fresh  Rao  water.  calculated  the  subtraction between  speed  mean  was  condition the  of  (1968) is  uptake  would  necessary  somewhat  that  of  oxygen  phenomenon  of  difference  in  hydromineral  reports  from  the  of  that  the  through  of  influx.  permeability.  exercise  a  electrolytes  by  workers  less  expense  filtration  inhibition  in  far  The  seem  primary  as  be  of  c o n s u m p t i o n , and  no  solution  these  some  considerations  is  reduction  changes.  evidence  for  across  elevation  therefore,  of  support  effective g i l l  isosmotic  devoted  consumption optimal  oxygen  limiting  existence,  a  caused  initial  well  an  glomerular  direct  the  osmoregulatory  water  primary  is"provided  that  to  have  osmoregulatory in  of  both  exercise,  e n t r y , however, i n c r e a s e d  would,  reabsorption  The  that  Beamish  noted  for  blood  transport  may  as  compensatory  increase  a  which  with  no  oxygen  indication exchange  the  during  through  effect  water  exists  gills.  that  by  proportion  There regulation  same  branchial  overcomes  mechanism  the  in  sodium  exercise  fashion  factor  increases  a  of  elimination  tubular  mediated  apparently  reduced  water  active  occurring  deficit  ortant  the  those  Branchial  partially  renal  changes  carrier  achieve  approximately only  of  produce  to  permeability,  expensive active  to  oblique  oxygen and  the  However  Farmer  same  in  i t must  oxygen  consumption  of  cost  the  standard  and  of  be  osmo-  swimming  194  metabolic been of  rates;  derived  as  the  stated  osmoregulation  was  not  rather  his  their  i s largely  animals  activity  to  come  anaerobically  effect  of  that  of  on  trout.  branchial  reasonable  may  least  partially  volume  changes,  mechanism exercise  debt  Rao at  not  the  to are  a primary  compared  into  may in  hydromineral  corrected  by  permeability  cost  of  no  the  not  exist,  favour  as  apparently exists  should  depressant  i s built  phenomenon  oxygen  repayment  environments  i s weighted  metabolic  crit-  allowed  both  inasmuch  the  thus  particular  exercise  uptake  this  a  debt  and  This  (1968)  cost but  /  oxygen  devoted  isosmotic or  the  computed an  i n which  after  oxygen  there  for reducing  of  gas  imbalance and  blood  parallel  a  certain  which  must  level. The  responsible effects  while  that  permeability  amount  compromise  seems  at  state  the  That  that  assumed  fact t h a t  and  previously  disequilibria.  whether  exchange, be  and  had  object  g i l l  experiments  water  clearly  the  the  their  the  produced  fresh  more  animals  steady  swimming  osmoregulation  physiology i.e.  a  could  greater than  the  by  However  in  One  fact  into  of  demonstrate  in  negated  level.  fish  above.  osmoregulatory  during the  between  osmoregulation  increasing  uptake any  of  because  further  compounding icism  was  manifested than  cost  misalignment f o r the  during  Firstly,  a  initiation  swimming  direct of  an  with  responsive receptors  to  the  changes  i n renal  of  activity  sensing of  characteristics arrangement,  detection  compensatory may  act  i n one  environment  osmoreceptors i n plasma  i n the  osmotic  arterioles  may  of  two  ways.  hydromineral occur.  Such  hypothalamus  pressure, and  be  osmoregulatory  disturbances i n the  internal  afferent  system  the  and  left  volume  atrial  wall in  sensitive  mammals  evidence system tonic  to  that  may  an  analogous,  exist  in  of  the  plasma;  demonstrated changes but  by  in  (Bourguet served  that  the  of  effects of  loads  a  produced  goldfish;  however  involved  in  the  same  diuresis  the  jections  the  postulated  could  well  caused  levels were  is  greater  lactin on  a  activity  and  Fromm  for  secretory  factor  by rate on  medium  a  on  the  of  (160  mEq  However  Sage  isolated  concentrations  from  have  mannitol  in-  stimuli  effects  circulatory  whose  This  which  pituitary  (112  mEq  para-  +  fresh  study  revealed  Na /L)  paralactin in  ion  secretions  economy.  recent  in  al.,1964).  of  outflux  perfused  saline  overall  sp.  +  obThe  specific  (1968)  Na /L);  the  pressure,  respectively  et  organs  medium  sodium  neither  anguilla.,  observed  Xiphophorus dilute  by  the  action  flux  tonicity  (1970)  resulting  of  hyper-  equilibrium  osmotic  electrolyte  work  or  Carassius  concentrated  (Bourguet  the  and  by  or  Nibelle  endocrine  the  same  antidiuresis  direct  controlling  Ball,1968). (1970)  the  ionic  mediated  elucidation  that  of  the  and  diuresis  water  cultured  concentrated  (Ensor  by  supported  cells  important  and  the  responsible  concept a  on  a  hypotonic  electrolyte  and  responses  workers  of  different,  unidirectional  the  (volume)  dilute  prevented renal  goldfish,  the  eel, A n g u i l l a  and  osmotic  These  be  the  limited  into  internal  in  exists  of  were  Mayer  described  qualitatively  restore  space  been  Infusion  injections  a_l.,1964).  similar  to  has  there  branchial  responses  disturbance et  of  tending  mannitol  administration  the  solutions  extracellular  the  although  alterations  directions  variations, Moreover,  teleosts.  chloride  auratus ^produced in  pressure  (D.M..Woodbury, 1 9 6 5 ) .  sodium  rates  blood  of  hemibranchs  is  than an  water Richards of  Salmo  196 gairdneri  suggested  branchial  sodium  seem the  to  exist  function  discrete  to  some  internal  were  slight  the  above  tended  possible  change(s)  in  plasma  relative  rise a  mechanisms  shown  second  type  swimming, designed into the  the for  by  scheme,  and  also  be  ponsible  the  for.the  an  ity  of  large  The  stimulatory  tentative  prior  the  The  present  to  dependent  to  on  may  It  in  increased  of  anterior  of  (Nakano  perhaps upon  in  the the  during been  entry  catecholamines,  levels  adaptation  to  adjustment.  of  adrenaline  Tomlinson,1967) and  would  without  the  electrolyte on  i f  Thus  alterations.  internal  the  i n mammals  hypothesis  efflux  functional  occur  detected,  catecholamines  this  be  and  exercise  hypophysis  volume  osmoregulatory  permeability to  blood  that  circulatory  "disturbance"  levels  cardiovascular the  swimming  reductions  for  in  induced  sodium  having  which  indicates  swimming  operation.  well  than  study  sodium  is possible for  sensitive  other  during  the  elevate  mechanism  be  disturbances  due  were  adaptation  effect  support  intrinsic  would  exercise  workers  branchial  automatic  of  does  to  d r a s t i c changes  during  internal  offers  activity  system  occurring  would  instrumental the  noradrenaline  would  causes,there  levels  addition,plasma  largely responsible  In  on  necessarily  experimental  which  salinities.  are  a  attendant  In  these  more  exercise, such  not  e l e c t r o l y t e s e n s i t i v e system the  concentrations  actual salt  monitoring  the  detection  different factors  and  r e s t i n g values  deviation  of  plasma  composition  to  above  reduction,  the  disarrangement.  investigations.  to  of  plasma  sites.  hy d r o e l e c t r o l y t i c changes  of  Whatever  certain tissues  second  that  action  detection  receptor The  direct  fluxes.  some of  a  (Russel,  be  res-  The  plan  necesslevels.  secretory provides 1965);  197  pituitary  hormones  are  of  great  importance  in teleost  osmo-  regulation. In ation  in teleosts  dependent of  the  ment,  recent  on  an  water  systems,  array  and  process  secretions  branchials these  and  than  imposed  in fish  anterior  octapeptides,  Consequently, which  reduce  trout  are  owing  discussion  observed  the  be  not  to  a  of  compensatory  effects,  of  major  interrenal  t o be i n no  of way  actions  not  corticotropin  (A.C.T.H.)  pituitary;  two  endocrine organs  of  understood that  thyroid  the  ultimo-  laid  i n water  the  which  in The  three and  f o l l -  the  systems  salt  balance;  of  other  defined. Cortisol  are  anterior  seems  released  stimulation  are  adjustments  in  intervention  been  in  at present.  si^imming  the  down  roles  roles,  of  control  as  possible  the  the  such  exact  of  and  exert  their  importance,  from  much  endocrine  source.  yet  g l a n d , p r o b a b l y under  to  pattern  each  of  a  prolactin"),  the  precludes the  have  because  environ-  be  definite  importance  osmoregulatory  the  main  suggest  single  Adrenocorticosteroids, be  Three  secretions  well  the  whose  to  agents,  but  naive to  Perhaps  aqueous  known  embroider  consider  treatment  now  and  will  known  function  appears  osmoregulatory problems  attributable  presently  hormones  are  osmoregul-  pituitary-adrenocortical  Other  influences,  i t would  the  ("fish  are  renin,  u r o p h y s i s may  economy  by  i n mammals.  the  hormone,  hydroelectrolyte  this  stress  demonstrated  that  e n d o c r i n e mechanisms.  hydromineral metabolism. growth  clear  exceedingly intricate  of  of  become  adenohypophysial paralactin  hormone,  by  i t has  ion regulation  neurohypophysial over  i s an  severe osmotic  more- c o m p l e x  axis,  years,  lobe  thought  from  to the  of  adreno-  of  the  to  be  linked  198 in  a negative  Plasma  Cortisol  gairdneri would to  feedback levels  (Donaldson  seem  a prime  swimming;  r e l a t i o n s h i p (Chester increase  candidate  however  none  efflux  rate  and water  adrenal  this  work  doses in  i s now  function  efflux  i n sea water  Cortisol  on  augment  Carassius  observed  weight  in  the trout  i t  would  is  not involved  and  may  onset during  without This  gain  (Figs.  appear  i n fact  that  carbohydrate  29  and  action  30).  i s perhaps  metabolism.  pump,  water;  however  on  balance  of overriding  and  and  o f the of  swimming  evidence,  to  problems  the mobilization of  i t has  goldfish,  (Lahlou  present  adjustment  the  A.C.T.H.  i n the  few m i n u t e s  and  promoting  pituitary-interrenal  to water  However  maintains  diuresis  Thus,  high  investigations  i s reminiscent  the f i r s t  the anterior  contribute  that  although  sodium  permeability  accompanying  during  invest-  osmoregulatory  Furthermore,  i n the osmoregulatory  of activity. swimming  i n fresh  water  latter  sodium  adrenalectomy  Cortisol  i n fresh water.  branchial  auratus  Giordan,1970).  that  of the active branchial  efflux  are i n  indicated  to  recent  /  influx  adaptation  of the unphysiologically  anguilla using surgical  and  hormone  effects  i n fact  More  have r e v e a l e d  normal  i n the  and Butler,1963),  administered.  therapy,  this  i n the present  deleterious  because  al.,1969).  i n branchial  noted  the trout  generally  suspect  the eel, Anguilla  effect  on  (Holmes,1959* Holmes  o f hormones  Cortisol  no  permeability)  s t e r o i d s were  homeostasis  (reductions  et  i n Salmo  thus  o f i t s demonstrated  the compensations  studies  and  f o r involvement  with  Early  exercise  and M c B r i d e , 1 9 6 7 ) ,  accord  igation.  during  Jones  axis  exercise, at the  Cortisol  importance  i n  199  Paralactin, physis, been  or  shown  largely et  at  mammalian to  water  as  "all  an  ance  or  to  Ensor fish  and  the  survival  elevate  ionic could  swimming  in trout.  However  and  kansae  water  (Potts  and  Neurohypophysial  rather  than  the  the  of  sodium  o f major  sodium  and  at  which  prolactin  Cortisol,  least  plains  (Ball, import-  loss  mammalian  A.C.T.H.  and  i n  homeostasis be  permeability,  Giordan,1970)  for life  i n  effects,  branchial  branchial  Maetz It i s  i t s function,  augmented  like  (e.g.  lies  have  presumably  essential  mechanism",  hormone  paralactin),  sodium,  Ball,1969).  i s not  to maintain  adenohypo-  i t s action,  teleosts  the  (Lahlou  Fundulus  of  permeability  Consequently this  i n reducing  of  that  teleost  mimics  B a l l , 1968;  prolactin  gills  the  efflux  i n a variety  nothing  presumably  fish  passive  through simple  accompanies (and  the  from  which  i n a l l species,and  across  1969).  b;  that  modulation, efflux  prolactin  gills,  a,  evident  fresh  limit  the  aJL.,1967  now  originating  tends  i n the  gold-  k i l l i f i s h  Fleming,1970). octopeptides  are presently  disputed  osmoregulatory function  i n fresh  They  produce  branchial  sodium  influx  unidirectional  fluxes  (e.g. Motais  may  an  and  Julien,1961) or  and  M a e t z , 1964;  (e.g.  Maetz  diuresis much  of  of both  Maetz  et  (Holmes,1961; this  doses  of  a l . , 1964b); a n d  e_t j a l . , 1 9 6 4 b ; L a h l o u a n d  to  arises  from  adequately control  of purely  teleostean  and  isotocin).  Neither  are  i n agreement  with  the  of  the  either  teleosts.  a  G i o r d a n , 1970)  Hammond,1969).  disagreement  investigators ical  elevation  water  of  diuresis or  an  I t i s probable the  failure  stress  principles reported  compensations  or  use  of  antithat  many  physiolog-  (arginine  salt  (Maetz  vasotocin  balance  observed i n  effects  the  200 present  study,  influence  on b r a n c h i a l  investigation in  fact  sodium  suggested  careful  a  glomerular  of  only  was  a direct  eability.  Lahlou  demonstrated  greatly  Carassius principles  almost  while  efflux  immediately  (Hammond,1969)), influence Ensor  within  disagreement  vasotocin  than  (1968),  however  i t would  4 hours.  t o t h e time  These courses  water  have  perm-  recently  o f t h e same  exchange o f  disequilibrium One may  primarily  prolactin  to  reduces  The former after  agent  limit passcan  act  injection  of the paralactin  on t h e b a s i s  seem  secondary  possible.  15 m i n u t e s course  urine  o f neurohypophysial  serves  the g i l l s .  b u t t h e time  i s ill-defined;  and B a l l  effects  (less  water  infusion  weight  or a  however,  quite  adenohypophysial across  or  the decreased  o f hydromineral  remains  reduction  Unfortunately  p h a r m a c o l o g i c a l doses  The i m p l i c a t i o n  demonstrated  by a  i n branchial  (1970),  control  intravascular  entry  whether  the branchial  arginine  who  vasotocin.  water  (1969) h a s  o f Hammond  entirely  o f t h e hormone  and Giordan  therefore  that  almost  further  The most  namaycush,  a decrease  i n the correction  influx  sodium  from  may  t o be t h a t  o f arginine  at least  auratus.  act to  following  effect  depress  exercise  conjecture  ive  that  vasotocin  Salvelinus  rate,  of  Perks  appears  not conclude  resulting  worthy  techniques.  branchial  renal  seems  during exercise.  mediated  amounts  so could  phenomenon  during  trout,  d i d n o t measure  variation  hormone  study  filtration  nanogram  Hammond  prudent  the gills  balance  o f neurohypophysial  movements  arginine  antidiuresis,  in  water  that  on t h e lake  problem  sodium  more  across  water  marked  flow  with  fluxes  (1969)  b u t t h e whole  to exert  latencies  o f t h e work o f permeability  do n o t o f f e r  o f compensatory  serious  phenomena  201  observed  in  the  The g i l l  tissue  hormone this the  mechanism raises  action  effective  possibilities and  permeability  organic  ammocoete,  reducing and  (Potts  (Potts  in  secretion  of  mucus  effective  by  Moreover,  stimulates  mucus  but  action not  on  19 7 0 ) .  may  Finally  allowing  calcium  s i m i l a r to  1964;  Newstead,1967),  ions  plains A  the  and  exists at  the  i t s effect  found  fixed closer  the  in  the  during a  easily Three  cations  such  cell  in  the  apposition  Bull,1968)  the in  and  stimulated involved  Secondly, cells  passive  loss  of  Fundulus  be  (see  may of  in  the  change the  that  exchange  paralactin  Ball,1969); sodium  (Lahlou  and  cytoplasmic  pillar  are  sodium  evidence  of  on  of  Furthermore,  resistance  on  water  anions  could  gills  nature  depress  hormonally  some  myofilaments  to  of  of  practical.  k i l l i f i s h ,  permeability of  and  divalent  and  metabolism  distance  scope the  reduced  (Morris  the  involvement  are  of  the  manner  which  known  epidermal  water  which  been  on  dependent  most  branchial  explain  on  and  swimming.  production  an  not  and  the  sodium  during  there  branchial  are  act  the  Fleming,1970).  cation  diffusion  surface.  this  long  planeri  changes  to  repulsion  and  in  beyond  Firstly,  Fleming,1970).  divalent  permeability  the  about  structure  costly  have  of  exchange  and  cell  agents  speculate  which  therefore  Lampetra  water  may  advanced.  administration  alteration  the  by  are  reduction  least  magnesium  molecules  branchial  the  be  structure  external  kansae  seem  may  which  Changes of  endocrine questions  one  permeability  would  calcium  which  However  modification  reversible  membrane  by  membranes  exercise.  synthetic  the  on  study.  fundamental  discussion.  extended  as  present  smooth cells  efflux Giordan,:  filaments,  muscle  (Rhodin,  of  respir-  the  202 atory  lamellae  traction on  may  o f these  the overlying  permeability; peptides  be  suggested.  elements  could  epithelium  t h e known  on smooth  I t i s possible i n some  and b a s a l  stimulatory  muscle  offers  that  v/ay a l t e r t h e  lamina  action  a possible  to reduce  of  contension their  neurohypophysial  mediation  effect.  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