Hypothermia in the rat induced by the potent serotoninergic agent 8-OH-DPAT

The potent, centrally acting 5-HT receptor agonist 8-OH-DPAT was shown to induce a clearcut hypothermic response in naive and PCPA-pretreated conscious rats, maintained at 22 degrees C. PCPA pretreatment decreased the threshold dose of 8-OH-DPAT required to cause hypothermia, indicating that a sensitisation of 5-HT-receptor dependent mechanisms was involved. The results are discussed with reference to recent 5-HT receptor subclassification. It is suggested that body temperature measurements in the rat might provide a simple in vivo physiological means of studying central serotoninergic mechanisms, including 5-HT receptor sensitivity modification.