8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) dose-dependently induced hypothermia in mice. The 5-HT sub(1A) receptor partial agonists, buspirone, gepirone and ipsapirone, also dose-dependently ...induced hypothermia. The 8-OH-DPAT temperature response was antagonized by the 5-HT sub(1) receptor antagonists quipazine, ( plus or minus )-propranolol, ( plus or minus )-pindolol, spiroxatrine and metitepine but not by 5-HT sub(2) (ketanserin) or 5-HT sub(3) (MDL 72222, GR 38032F) receptor antagonists. The response was also antagonized by the dopamine D sub(2) receptor antagonists, haloperidol and BRL 34778. No other catecholamine or muscarinic receptors were involved in mediating the response. Destruction of 5-hydroxytryptamine (5-HT)-containing neurons with the neurotoxin, 5,7-dihydroxytryptamine, abolished the response to 8-OH-DPAT indicating that the 5-HT sub(1A) receptors involved were located on 5-HT neurones.
