Effects of sodium acetylsalicylate on thermoregulatory responses of rats to different ambient temperatures.

The effects of intraperitoneal administration of sodium acetylsalicylate (aspirin) on thermoregulatory responses (Ta) of 15, 22 and 29 degrees C were assessed. Intraperitoneal administration of aspirin produced dose-dependent hypothermia at both 15 and 22 degrees C. The hypothermia was brought about by cutaneous vasodilation (as indicated by an increase of the tail and foot skin temperatures). However, in the heat (29 degrees C), i.p. administration of the same amount of aspirin produced no change in rectal temperature, since the thermo-regulatory responses were unaffected by aspirin application at this Ta. Thus it appears that aspirin increases heat loss and leads to hypothermia in rats.