Capsaicin impairs preoptic serotonin-sensitive structures mediating hypothermia in rats.
In an attempt to elucidate the possible mechanisms involved in the development of the thermoregulatory disturbances induced by systemic capsaicin treatment, the effects of 5-HT injected into the preoptic region or into the cisterna magna on the body temperature and on tail skin vasodilation were studied in control and capsaicin-treated rats. Intracisternal 5-HT elicited a comparable decrease in body temperature in both groups of animals. In contrast, intrapreoptic injection of different doses of 5-HT-induced tail skin vasodilation and hypothermia in the controls, but not in the capsaicin-treated rats. It is suggested that changes in the sensitivity of preoptic warm-responsive structures to 5-HT may contribute essentially to the specific thermoregulatory impairment brought about by systemic capsaicin treatment.
D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001833:Body Temperature Regulation / Q000187:drug effects*; D001931:Brain Mapping; D002211:Capsaicin / Q000494:pharmacology*; D008297:Male; D011301:Preoptic Area / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology* / Q000502:physiology; D012867:Skin / Q000098:blood supply; D014664:Vasodilation / Q000187:drug effects
D012701:Serotonin; D002211:Capsaicin