Affiliation:
1. Department of Biology, Portland State University, PO Box 0751, Portland,OR 97207-0751, USA
2. Department of Biological Sciences, Idaho State University, Pocatello, ID 82309-8007, USA
Abstract
SUMMARYAll of our previous work, and that of other investigators, shows that the trout heart only partially recovers following brief exposure to severe hypoxia or anoxia (i.e. it is hypoxia-sensitive). However, in preliminary studies, we found evidence to suggest that rainbow trout reared at a farm in Oregon (USA)have a significant degree of inherent myocardial hypoxia tolerance. To evaluate whether hearts from these trout are indeed hypoxia-tolerant, and thus to determine whether intra-specific variation in rainbow trout myocardial hypoxia tolerance exists, we measured in situ cardiac function and monitored myoglobin and lactate dehydrogenase (LDH) release (both indices of myocardial damage) in hearts that were exposed to varying durations(10–30 min) of severe hypoxia (PO =5–10 mmHg). There was a strong positive relationship between the duration of severe hypoxia and the degree of post-hypoxic myocardial dysfunction. However, the resulting dysfunction was modest, with hearts exposed to 30 min of severe hypoxia recovering 77% of their initial maximum cardiac output. Furthermore,myoglobin was not detected in the perfusate, and ventricular LDH activity did not vary in response to the duration of severe hypoxia. These data (1)indicate that trout from this farm have extremely hypoxia-tolerant hearts; (2)suggest that considerable intra-specific variation exists in trout myocardial hypoxia tolerance; and (3) provide preliminary evidence that trout hearts are not irreversibly damaged, but are merely `stunned', following brief periods(10–30 min) of severe hypoxia.
Publisher
The Company of Biologists
Subject
Insect Science,Molecular Biology,Animal Science and Zoology,Aquatic Science,Physiology,Ecology, Evolution, Behavior and Systematics
Reference40 articles.
1. Anthony, A., Ackermann, E. and Strother, G. K.(1959). Effects of altitude acclimation on rat myoglobin. Changes in myoglobin content of skeletal and cardiac muscles. Am. J. Physiol.196,512-516.
2. Apstein, C. S., Gravino, F. N. and Haudenschild, C. C.(1983). Determinants of a protective effect of glucose and insulin on the ischemic myocardium. Circ. Res.52,515-526.
3. Arthur, P. G., Keen, J. E., Hochachka, P. W. and Farrell, A. P. (1992). Metabolic state of the in situ perfused trout heart during severe hypoxia. Am. J. Physiol.263,R798-R804.
4. Axelsson, M., Farrell, A. P. and Nilsson, S.(1990). Effects of hypoxia and drugs on the cardiovascular dynamics of the Atlantic hagfish Myxine glutinosa.J. Exp. Biol.151,297-316.
5. Bailey, J. R., Sephton, D. H. and Driedzic, W. R.(1990). Oxygen uptake by isolated perfused fish hearts with differing myoglobin concentrations under hypoxic conditions. J. Mol. Cell. Cardiol.22,1125-1134.
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