Thermoregulatory responses following injection of 5-hydroxytryptamine into the septohippocampal complex in rats.
The present study investigated the change in thermoregulatory responses following microinjection of 5-hydroxytryptamine (5-HT) into the lateral septum and the hippocampus of unanesthetized, unrestrained rats. Intraseptal injection of 5-HT (5 to 20 micrograms) caused a dose-related fall in core temperature (Tb), which was associated with a decrease in heat production (HP). As the decrease in HP can not completely account for the magnitude of the decrease in Tb, increase in heat loss may also be involved in the 5-HT-induced hypothermia. In contrast to observed changes following intraseptal injection, no significant change in either Tb or HP was observed after microinjection of the same doses of 5-HT into the hippocampal areas, indicating that the hypothermic response to intraseptal injection of 5-HT is site specific. Further, the hypothermic response to intraseptal injection of 5-HT was only attenuated by systemic pretreatment with cyproheptadine, but not by naloxone or scopolamine, indicating that the hypothermic response is mediated by 5-HT receptor, but not by endogenous opioid and cholinergic systems.
Cui
Y
Y
Department of Zoology, University of Alberta, Edmonton, Canada.
Lee
T F
TF
Wang
L C
LC
D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects*; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D003533:Cyproheptadine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D008845:Microinjections; D009270:Naloxone / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012601:Scopolamine / Q000494:pharmacology; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013238:Stereotaxic Techniques
D012702:Serotonin Antagonists; D003533:Cyproheptadine; D012701:Serotonin; D009270:Naloxone; D012601:Scopolamine