METABOLIC STATE OF THE INSITU PERFUSED TROUT HEART DURING SEVERE HYPOXIA

Peter Arthur, JE KEEN, PW Hochachka, A.P. Farrell

Research output: Contribution to journalArticle

Abstract

An in situ perfused heart preparation was used to study the effects of severe hypoxia in the rainbow trout, Oncorhynchus mykiss. Hypoxic trout hearts were capable of generating similar power outputs and ATP turnovers to normoxic counterparts at subphysiological work regimes. However, lactate efflux was 35-fold higher and glycolytic rate was calculated to be >10-fold higher in hypoxic than in normoxic hearts. The surprising ability of trout hearts to withstand severe hypoxia appears to be related to the rapid removal of lactate and associated protons from the heart. An increase in power demand to normal in vivo levels caused rapid failure in hypoxic hearts. Failure was caused by a decline in stroke volume (contractility) and was not a consequence of heart rate deterioration. Hypoxia caused marked declines in the concentration of creatine phosphate but not ATP, and we suggest that an increase in intracellular phosphate was the primary cause of failure.

Original languageEnglish
Pages (from-to)R798-R804
Number of pages7
JournalAmerican Journal of Physiology
Volume263
Issue number4
Publication statusPublished - Oct 1992

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