Document Detail


The effects of catecholamines on ventilation in rainbow trout during hypoxia or hypercapnia.
MedLine Citation:
PMID:  1906629     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study assessed the effects of experimentally elevated plasma catecholamine levels on gill ventilation in rainbow trout (Oncorhyncus mykiss) exposed to various external ventilatory stimulants. Trout were exposed to hypoxia (water PO2 (PwO2) = 90 Torr) or hypercapnia (water PCO2 (PwCO2) = 4.5 Torr) for 30 min. These conditions caused gill ventilation volume (Vw) to increase by 2.3- and 1.5-fold, respectively, but did not stimulate release of catecholamines into the blood. While the stimulus (hypoxia or hypercapnia) was maintained, fish were given a bolus injection (0.3 ml), followed by intra-arterial infusion (0.6 ml.h-1), of a catecholamine mixture (2 x 10(-5) mol.l-1 adrenaline + 5 x 10(-6) mol.l-1 noradrenaline) to mimic the physiological concentrations and ratios of these catecholamines observed under more severe hypoxic or hypercapnic conditions. In hypoxic fish, this treatment caused a significant, but transient (5 min) depression of ventilation while during hypercapnia, the administration of exogenous catecholamines caused a more prolonged hypoventilatory response. These hypoventilatory responses occurred despite a catecholamine-induced blood acidosis (a potential ventilatory stimulant). To assess the importance of initial Vw and/or blood respiratory status on catecholamine-mediated hypoventilation, these experiments were repeated under hyperoxic (PwO2 = 640 Torr) hyperoxic hypercapnic (PwO2 = 510 Torr, PwCO2 = 4.8 Torr) or normoxic (PwO2 = 151 Torr) conditions in which Vw was either depressed (3.9-fold during hyperoxia) or unaffected. Intra-arterial infusion of catecholamines did not affect Vw under either of these experimental conditions. These results demonstrate that during a respiratory challenge, such as hypoxia or hypercapnia, physiologically relevant levels of circulating catecholamines can depress Vw and therefore do not support a stimulatory role for circulating catecholamines in the control of ventilation in fish.
Authors:
R Kinkead; S F Perry
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Respiration physiology     Volume:  84     ISSN:  0034-5687     ISO Abbreviation:  Respir Physiol     Publication Date:  1991 Apr 
Date Detail:
Created Date:  1991-08-20     Completed Date:  1991-08-20     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0047142     Medline TA:  Respir Physiol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  77-92     Citation Subset:  IM    
Affiliation:
Department of Biology, University of Ottawa, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Animals
Anoxia
Carbon Dioxide / physiology*
Catecholamines / blood,  physiology*
Female
Hypercapnia
Male
Oxygen / physiology*
Respiration / physiology*
Sodium Chloride / pharmacology
Trout / physiology*
Chemical
Reg. No./Substance:
0/Catecholamines; 124-38-9/Carbon Dioxide; 7647-14-5/Sodium Chloride; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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