Ethanol-induced hypothermia in the rat

Ethanol (0.5-3.2g x kg-1 i.p.) caused a dose-dependent fall in body temperature in rats. A dose of 1.5g x kg-1 i.p. led to a fall of 1.6 +/- 0.20 degrees C over 60 min at an environmental temperature of 18 +/- 1 degrees C. There was no evidence of acute tolerance when the hypothermic response was elicited by the same dose of ethanol (0.7--20.0g x kg-1 i.p.) 24 h later; indeed the second response was consistently, although not significantly, greater than the first. Behavioral thermoregulatory studies indicated that the fall in temperature after ethanol is due, at least in part, to a downward setting in the thermoregulatory set point. These results suggest that the rat may be a suitable animal model for a study of accidental hypothermia following ethanol ingestion and exposure to low environmental temperatures.