Corticosterone selectively attenuates 8-OH-DPAT-mediated hypothermia in mice.

The 5-HT1A agonist 8-OH-DPAT produces a hypothermia in mice mediated by somatodendritic 5-HT1A receptors, that is attenuated by antidepressants and corticosterone. The present study investigated if the effect of corticosterone is specific to the serotonergic system or a non-specific effect on thermoregulation. Administration of corticosterone for 3 d had no effect on dopaminergic (apomorphine) or adrenergic (clonidine) hypothermic challenges. However in addition to 8-OH-DPAT, nicotine-induced hypothermia was attenuated by corticosterone. Administration of the selective nicotinic antagonist mecamylamine had no effect on 8-OH-DPAT-induced hypothermia, although nicotine-induced hypothermia was attenuated by the selective 5-HT1A antagonist WAY-100635. This demonstrates a serotonergic-nicotinic interaction in the generation of hypothermia in mice and is consistent with corticosterone selectively attenuating somatodendritic 5-HT1A receptor function.