| Abstract: | Belke, Darrell D., Lawrence C. H. Wang, and Gary D. Lopaschuk. Effects of hypothermia on energy metabolism in rat and Richardson's ground squirrel hearts. J. Appl.Physiol. 82(4): 1210-1218, 1997. Glycolysis,glucose oxidation, palmitate oxidation, and cardiac function weremeasured in isolated working hearts from ground squirrels and ratssubjected to a hypothermia-rewarming protocol. Hearts wereperfused initially for 30 min at 37°C, followed by 2 h ofhypothermic perfusion at 15°C, after which hearts were rewarmed to37°C and further perfused for 30 min. Functional recovery in groundsquirrel hearts was greater than in rat hearts after rewarming.Hypothermia-rewarming had a similar general effect on the variousmetabolic pathways in both species. Despite these similarities, totalenergy substrate metabolic rates were greater in rat than groundsquirrel hearts during hypothermia despite a lower level of work beingperformed by the rat hearts, indicating that rat hearts are lessefficient than ground squirrel hearts during hypothermia.After rewarming, energy substrate metabolism recovered completely inboth species, although cardiac work remained depressed in rat hearts.The difference in functional recovery between rat and ground squirrelhearts after rewarming cannot be explained by general differences inenergy substrate metabolism during hypothermia or after rewarming. |
