Atropine, Diazepam, and Physostigmine: Thermoregulatory Effects in the Heat-Stressed Rat.

摘要

For several years we have been interested in the effects of anticholinergic and anticholinesterase drugs on physical, physiological, and thermoregulatory responses to heat and exercise. Atropine, the prototype of anticholinergic drugs, inhibits evaporative cooling in man by suppressing sweat production and in rats by reducing saliva secretion which is behaviorally spread for evaporative cooling. Both sweat and saliva secretions are cholinergically regulated, and both are analogously inhibited by atropine in man. We have previously reported that administration of atropine (A) to unrestrained, sedentary, heat-stressed rats resulted in a dose-dependent increase in heating rate. Additionally, we have demonstrated that the decrements in treadmill endurance and increments in heating rate of physostigmine (PH)-treated running rats can both be restored to control levels by pretreating the animals with A and diazepam (D). Our objective in the present work was to determine if the administration of D+PH to A-treated unrestrained, sedentary, heat-stressed rats could improve their thermal tolerance. The combination of A+D+PH not only restores PH-induced performance and thermoregulatory decrements of rats exercised in a moderate environment, but also reduces A-induced heat tolerance. Reprints. (kt)