Dehydration attenuates panting response to intraventricular 5-hydroxytryptamine in the rabbit.

Panting response and a fall in rectal temperature following intraventricular injection of 5-hydroxytryptamine (5-HT) were significantly reduced in dehydrated rabbits as compared with normally hydrated animals. The vasomotor heat loss response to 5-HT was essentially similar in both groups. These as well as earlier findings suggest that dehydration may modify signals generated in brain thermoregulatory centers controlling evaporative but not the vasomotor heat loss.