Effects of specific inhibitors of 5‐hydroxytryptamine uptake on thermoregulation in rats.

Abstract

The effects of 2 inhibitors of uptake pump in serotonergic neurons, Lilly 110140 (3-(p-trifluoro methyl phenoxy)-N-methyl-3-phenylpropylamine hydrochloride) and chlorimipramine, on the thermoregulatory responses of unanesthetized rats to different ambient temperatures (Ta) of 8.degree., 22.degree. and 30.degree. C, were assessed. I.p. administration of either Lilly 110140 or chlorimipramine produced dose-dependent hypothermia at 8.degree. and 22.degree. C Ta. At 8.degree. C Ta, the hypothermia was due to a decrease in metabolic heat production. At 22.degree. C Ta, the hypothermia was brought about by both a decrease in metabolic heat production and an increase in cutaneous temperature of the tail and the footsole. However 30.degree. C Ta, there were no changes in rectal temperature in response to either Lilly 110140 or chlorimipramine application. Apparently, an increase in serotonergic receptor activity or in functional serotonin in brain decreases heat production and/or increases heat loss and leads to hypothermia in rats.