Energy turnover in the normoxic and anoxic turtle heart

Peter Arthur, CE Franklin, KL Cousins, H Thorarensen, PW Hochachka, A.P. Farrell

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Abstract

We examined the possibility that the heart of the turtle Chrysemys scripta is an exceptional anaerobic performer, by measuring myocardial power output, lactate output, and estimated ATP turnover in perfused heart preparations. Over a range of myocardial power outputs at 5 and 15 degrees C we find that turtle hearts perfused with anoxic saline do not show a particularly outstanding ability to produce ATP anaerobically. Furthermore, at 15 degrees C anoxia reduced the ATP turnover rate to 50% of the normoxic rate. At 5 degrees C the anoxia-induced depression of ATP turnover was even more pronounced, being 4-fold lower than the normoxic rate. In addition, anoxia at 5 degrees C reduced the basal metabolic rate of the turtle heart. We conclude that long-term cardiac tolerance of hypoxia in this species is more likely related to metabolic depression rather than to an exceptional anaerobic performance. (C) 1997 Elsevier Science Inc.

Original languageEnglish
Pages (from-to)121-126
Number of pages6
Journal Comparative Biochemistry and Physiology. Part A: Molecular & Integrative Physiology
Volume117
Issue number1
Publication statusPublished - May 1997

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