Atropine-Induced Cutaneous Vasodilation Decreases Body Temperature during Exercise,

Systemic atropine enhances forearm cutaneous blood flow FBF but depresses forearm sweating m sub s in warm environments, as previously shown in our laboratory. To further examine thermoregulatory consequences of this increased FBF, four healthy males were studied during 30 minutes of seated exercise. Esophageal T sub es and mean skin T sub sk temperatures, m sub s metabolism M, heart rate HR and FBF were measured during control and following 2 mg im atropine. All eight skin temperatures increased with atropine which implies widespread cutaneous vasodilation. The enhanced sensible heat loss with atropine during constant intensity exercise caused T sub es to decrease, resulting in a further significant m sub s depression. The decreased central drive did not result in peripheral vasoconstriction, suggesting that the dilation was peripherally controlled and non-responsive to the thermoregulatory controller. Keywords Cholinergic blockade.