Effects of bicarbonate on cardiac function in fish
department or school: Science, Faculty of
department or school: Zoology, Department of
data provider: DSpace
degree campus: UBCV
creator: Lo, Wing Man Mandy
issued: 2018-01-05T19:04:25Z
issued: 2017
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: An entirely novel mechanism to modulate heart rate was recently discovered in the Pacific hagfish (Eptatretus stoutii): a soluble adenylyl cyclase (sAC)-mediated pathway that increases cyclic adenosine monophosphate (cAMP) production upon stimulation by HCO₃₋ to increase heart rate. However, still unknown is whether this cardiac control pathway is present in other species as well. The objective of my study was to determine the effects of increasing extracellular [HCO₃₋] on the in vitro cardiac function of other fish species and whether the sAC-mediated pathway is associated with recovery of cardiac function during debilitating conditions. Exposure to severe hypoxia (100% N₂) and hypercapnic acidosis (7.5% or 15% CO₂) significantly decreased the heart rate of isolated, freely beating hearts and reduced the isometric tension (contractility) of electrically paced ventricular strips from Pacific lamprey (Lampetra richardsoni), Pacific spiny dogfish (Squalus suckleyi), Asian swamp eel (Monopterus albus), white sturgeon (Acipenser transmontanus), zebrafish (Danio rerio), and starry flounder (Platichthys stellatus). Spontaneous recovery in heart rate or contractility was not observed during severe hypoxia or hypercapnic acidosis for any of the species tested. Addition of HCO₃₋ (up to 50 mM) was associated with a complete and dose-dependent recovery of control heart rate in lamprey, dogfish, and swamp eel hearts during severe hypoxia, and in dogfish, sturgeon, and swamp eel hearts during hypercapnic acidosis. A partial recovery of control heart rate was observed in lamprey and zebrafish hearts during hypercapnic acidosis. However, HCO₃₋ had no effect on the heart rate or contractility in flounder hearts and had little to no effect on restoring control contractility in dogfish, swamp eel, and flounder ventricular strips. The addition of KH7 (sAC blocker) abolished the HCO₃₋-induced recovery of heart rate during severe hypoxia only in the lamprey heart. Thus, the sAC-mediated…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/64280
note: EFFECTS OF BICARBONATE ON CARDIAC FUNCTION IN FISH by Wing Man Mandy Lo B.Sc. Hons., University of British Columbia, 2015 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in The Faculty of Graduate and Postdoctoral Studies (Zoology) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) December 2017 © Wing Man Mandy Lo, 2017 ii Abstract An entirely novel mechanism to modulate heart rate was recently discovered in the Pacific hagfish (Eptatretus stoutii): a soluble adenylyl cyclase (sAC)-mediated pathway that increases cyclic adenosine monophosphate (cAMP) production upon stimulation by HCO3- to increase heart rate. However, still unknown is whether this cardiac control pathway is present in other species as well. The objective of my study was to determine the effects of increasing extracellular [HCO3-] on the in vitro cardiac function of other fish species and whether the sAC-mediated pathway is associated with recovery of cardiac function during debilitating conditions. Exposure to severe hypoxia (100% N2) and hypercapnic acidosis (7.5% or 15% CO2) significantly decreased the heart rate of isolated, freely beating hearts and reduced the isometric tension (contractility) of electrically paced ventricular strips from Pacific lamprey (Lampetra richardsoni), Pacific spiny dogfish (Squalus suckleyi), Asian swamp eel (Monopterus albus), white sturgeon (Acipenser transmontanus), zebrafish (Danio rerio), and starry flounder (Platichthys stellatus). Spontaneous recovery in heart rate or contractility was not observed during severe hypoxia or hypercapnic acidosis for any of the species tested. Addition of HCO3- (up to 50 mM) was associated with a complete and dose-dependent recovery of control heart rate in lamprey, dogfish, and swamp eel hearts during severe hypoxia, and in dogfish, sturgeon, and swamp eel hearts during hypercapnic acidosis. A partial recovery of control heart rate was observed in lamprey and zebrafish hearts during…
has type: Thesis/Dissertation
date issued: 2018-02
is shown at: 10.14288/1.0362871
language: eng
degree discipline: Zoology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/64280