Effects of hypothermia on energy metabolism in rat and richardsonos
ground squirrel hearts.
Belke, Darrell D., Lawrence C. H. Wang, and Gary D. Lopaschuk.
Departments of Pharmacology and Pediatrics, Department of
Biological Sciences, University of Alberta, Edmonton, Alberta,
Canada, T6G 2S2
APStracts 3:0551A, 1996.
Glycolysis, glucose oxidation, palmitate oxidation and cardiac
function were measured in isolated working hearts from ground
squirrels or rats subjected to a hypothermia-rewarming protocol.
Hearts were perfused initially for 30 minutes at 37oC, followed by 2
hours of hypothermic perfusion at 15oC, after which hearts were
rewarmed to 37oC and further perfused for 30 minutes. Functional
recovery in ground squirrel hearts was greater than in rat hearts
following rewarming. Hypothermia-rewarming had a similar general
effect on the various metabolic pathways in both species. Despite
these similarities, total energy substrate metabolic rats were
greater in rat than ground squirrel hearts during hypothermia despite
a lower level of work being performed by the rat hearts, indicating
that rat hearts are less efficient than ground squirrel hearts during
hypothermia. Following rewarming, energy substrate metabolism
recovered completely in both species, although cardiac work remained
depressed in rat hearts. The difference in functional recovery
between rat and ground squirrel hearts following rewarming cannot be
explained by general differences in energy substrate metabolism
during hypothermia or following rewarming.
Received 7 August 1996; accepted in final form 22 November 1996.
APS Manuscript Number A753-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996