The hypoxic threshold for maximum cardiac performance in rainbow trout Oncorhynchus mykiss (Walbaum) during simulated exercise conditions at 18° C
Abstract:Perfused rainbow trout Oncorhynchus mykiss hearts exposed to simulated exercise conditions (hypoxia, hyperkalemia and acidosis) at 18° C experienced complete failure of maximum cardiac performance at oxygen tensions <5·6 kPa and partial failure at <6·7 kPa. This hypoxic threshold, which occurred in the presence of maximal adrenergic stimulation (500 nM adrenaline), is unusually high compared with previous results at a colder acclimation temperature. Cardiac failure was primarily due to significant decreases (P < 0·05) in heart rate rather than cardiac stroke volume at all hypoxia levels tested.
Document Type: Research Article
Affiliations: Department of Zoology and Faculty of Land and Food Systems, 2357 Main Mall, UBC, Vancouver, B. C., V6N 1W2 Canada
Publication date: 2007-09-01