Effects of energy and protein restriction on acetylcholine sensitivity of rat isolated perfused heart.

Responses to acetylcholine of isolated perfused hearts obtained from rats which were acutely starved, chronically half-starved or protein-restricted were compared with those of paired control groups. Isolated hearts of totally starved rats showed no significant change in the responses elicited by 10 and 20 micrograms doses of acetylcholine as compared with paired controls. With 40 micrograms acetylcholine a significantly greater reduction (P less than 0.001) in heart rate and coronary flow was seen and the duration of the negative chronotropic action was significantly increased (P less than 0.05), as compared with controls. Isolated hearts of half-starved and protein-restricted rats responded to 10, 20 and 40 micrograms doses of acetylcholine with significantly greater reduction (P less than 0.001) in heart rate, coronary flow and increase in duration of negative chronotropic action (P less than 0.001) as compared to controls.