April 1, 1997Journal of Applied Physiology16 citations
Effects of hypothermia on energy metabolism in rat and Richardson’s ground squirrel hearts
Key Result
Functional recovery after hypothermia-rewarming was greater in ground squirrel hearts than in rat hearts, despite similar general effects on metabolic pathways.
Structured PICO
Does hypothermia-rewarming affect energy metabolism and cardiac function differently in rat and ground squirrel hearts?
P
Population
Isolated working hearts from ground squirrels and rats subjected to a hypothermia-rewarming protocol.
I
Intervention
Hypothermia-rewarming protocol (perfused initially for 30 min at 37 degrees C, followed by 2 h of hypothermic perfusion at 15 degrees C, after which hearts were rewarmed to 37 degrees C and further perfused for 30 min)
C
Comparator
Comparison between ground squirrel hearts and rat hearts
O
Outcome
Glycolysis, glucose oxidation, palmitate oxidation, and cardiac functionsurrogate
Ground squirrel hearts show better functional recovery after hypothermia-rewarming compared to rat hearts, which cannot be explained by general differences in energy substrate metabolism.
Abstract
Glycolysis, glucose oxidation, palmitate oxidation, and cardiac function were measured in isolated working hearts from ground squirrels and rats subjected to a hypothermia-rewarming protocol. Hearts were perfused initially for 30 min at 37 degrees C, followed by 2 h of hypothermic perfusion at 15 degrees C, after which hearts were rewarmed to 37 degrees C and further perfused for 30 min. Functional recovery in ground squirrel hearts was greater than in rat hearts after rewarming. Hypothermia-rewarming had a similar general effect on the various metabolic pathways in both species. Despite these similarities, total energy substrate metabolic rates 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. After 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 after rewarming cannot be explained by general differences in energy substrate metabolism during hypothermia or after rewarming.