Studies on the hormonal regulation of ion resorption in Schistocerca gregaria
department or school: Science, Faculty of
department or school: Zoology, Department of
data provider: DSpace
degree campus: UBCV
creator: Spring, Jeffrey Herbert
issued: 2010-03-15T18:13:15Z
issued: 1979
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: When isolated locust recta are short-circuited in 'Ussing-type' chambers, they exhibit an initial decline in short-circuit current (Isc) and transepithelial electropotential difference (PD) over the first two hours. Following this decline, recta remain in a steady-state condition for at least 4 h, during which these parameters decline only slightly. There is a factor present in the corpora cardiaca (CC) of schistocerca gregaria which causes the Isc and PD of short-circuited recta to increase. Maximum stimulation restores rectal Isc and PD to the levels observed immediately after removing this organ from locusts. Cyclic AMP causes a similar maximum increase in Isc and PD although the response exhibits a much shorter lag-time and a faster rate.of increase than with CC. The relationship between the logarithm of CC dose or cAMP concentration and the maximum ΔIsc is linear. Maximum stimulation is achieved with 0.05 pr CC or 0.3 mM cAMP, and the decline in Δlsc is dose-dependent and occurs over a matter of hours. Inhibitors of HCO₋₃/H+ and Cl- transport in vertebrates do not inhibit the stimulation of recta by CC or cAMP. Putative neurotransmitter substances and homogenates of flight muscle do not change rectal Isc or PD. Although homogenates of whole brains, ventral ganglia and rectal tissue cause small increases in Isc, the concentration of active factor is nearly three orders of magnitude greater in the CC. The unidirectional and net fluxes of ²²Na+ across short-circuited recta remain constant with time and are unaffected by the initial decline in Isc or by stimulation with CC or cAMP. Net ³⁶Cl- flux closely matches the Isc over the entire experiment, following the initial decline in Isc and rising when recta are stimulated with CC or cAMP. The stimulation of active net Cl- uptake is sufficient to account for the entire increase in Isc. Addition of CC to everted rectal sacs causes the levels of cAMP in this tissue to triple within 15 minutes. Removal of Cl- from the ba…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/21903
note: TODIES ON THE HORMONAL REGULATION OF ION RESORPTION IN SCHXSTOCERCA GREGARIA by J e f f r e y Herbert Spring B- Sc., U n i v e r s i t y of Waterloo, 1973 Mo Sc., U n i v e r s i t y of Waterloo, 1976 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOB OF PHILOSOPHY i n THE FACULTY OF GRADUATE STUDIES {Department of Zoology) We accept t h i s t h e s i s as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA May, 1979 © J e f f r e y Herbert S p r i n g In present ing t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree tha t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r re fe rence and s tudy. I f u r t h e r agree tha t permiss ion f o r ex tens ive copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s r e p r e s en t a t i v e s . I t i s understood tha t copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l ga in s h a l l not be a l lowed wi thout my w r i t t e n pe rm iss i on . Department of The U n i v e r s i t y of B r i t i s h Columbia 2075 Wesbrook P lace Vancouver, Canada V6T 1W5 Date DE-6 BP 75-51 1 E ABSTRACT When i s o l a t e d l o c u s t r e c t a are s h o r t - c i r c u i t e d i n *Ussing-type' chambers, they e x h i b i t an i n i t i a l d e c l i n e i n s h o r t - r c i r c u i t c u r r e n t (Isc) and t r a n s e p i t h e l i a l e l e c t r o p o t e n t i a l d i f f e r e n c e (PD) over the f i r s t two hours. F o l l o w i n g t h i s d e c l i n e , r e c t a remain i n a s t e a d y - s t a t e c o n d i t i o n f o r at l e a s t 4 h, d u r i n g which these parameters d e c l i n e only s l i g h t l y . There i s a f a c t o r present i n the corpora c a r d i a c a (CC) of s c h i s t o c e r c a g r e g a r i a which causes the I s c and PD…
has type: Thesis/Dissertation
is shown at: 10.14288/1.0100166
language: eng
degree discipline: Zoology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/21903