title: Bombesin-induced poikilothermy in rats.
abstract: The effect of ambient temperature (Ta) on the rectal temperature (Tre) response to intraventricular injection of bombesin has been evaluated in conscious adult male rats. At Ta = 4 degrees C, bombesin (50 ng-1 microgram) caused a marked hypothermia which was dose-dependent both in terms of the magnitude and of the duration of the response. The bombesin-induced hypothermia was reduced at Ta = 24 degrees C, whereas at Ta = 31 or 33 degrees C, the peptide (1 microgram) failed to affect Tre.AtTa = 36 degrees C, bombesin 1-10 micrograms induced an elevation in Tre. The hyperthermia observed at high Ta could be reversed to hypothermia by transferring rats to cold. The analogs [d-Trp8]bombesin or [d-Leu13]bombesin, tested under the same conditions, failed to produce significant changes in Tre. These findings demonstrate that bombesin appears to act in the brain as a poikilothermic agent by disrupting thermoregulation at temperatures below or above thermoneutrality.
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001833:Body Temperature Regulation / Q000187:drug effects*; D001839:Bombesin / Q000031:analogs & derivatives / Q000494:pharmacology*; D008297:Male; D010455:Peptides / Q000494:pharmacology*; D051381:Rats
chemical_list: D010455:Peptides; D001839:Bombesin