title: Hypothalamic neuronal histamine modulates adaptive behavior and thermogenesis in response to endogenous pyrogen.
abstract: Homeostatic involvement of hypothalamic neuronal histamine in adaptive behavior and thermogenesis was investigated when interleukin-1 beta (IL-1 beta), one of the endogenous pyrogens, was infused peripherally in rats. IL-1 beta decreased food and water intake and elevated body temperature. Depletion of neuronal histamine in the hypothalamus induced by alpha-fluoromethylhistidine, a suicide inhibitor of the histamine synthesizing enzyme histidine decarboxylase (HDC), attenuated the suppressive effect of IL-1 beta on food intake, facilitated the inhibitory effect on water intake, and enhanced its thermogenic effect. Simultaneously IL-1 beta increased activity of HDC and histamine-N-methyltransferase (HMT), a neuronal histamine catabolizing enzyme. Pretreatment with indomethacin completely blocked those increases in turnover of neuronal histamine induced by IL-1 beta. Hypothalamic prostaglandin E2 (PGE2) activated by peripheral IL-1 beta, but not peripheral PGE2, increased both activities of HDC and HMT. Ginsenoside Rg1, a major component of panax ginseng, modulated the suppressive effects of IL-1 beta on ingestive behavior, resulting in a lowering of body temperature. The findings suggest that the effects of IL-1 beta on ingestive behavior and thermogenesis may be modulated by dynamics of hypothalamic neuronal histamine through activation of hypothalamic PGE2 which is elevated by peripheral IL-1 beta.
authors.affiliation: Department of Internal Medicine I, School of Medicine, Oita Medical University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sakata
authors.forename: M
authors.initials: M
authors.lastname: Kang
authors.forename: M
authors.initials: M
authors.lastname: Kurokawa
authors.forename: H
authors.initials: H
authors.lastname: Yoshimatsu
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects*; D002491:Central Nervous System Agents / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D004365:Drugs, Chinese Herbal; D004435:Eating / Q000187:drug effects; D036145:Ginsenosides; D006632:Histamine / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D007375:Interleukin-1 / Q000494:pharmacology*; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D012503:Saponins / Q000494:pharmacology
chemical_list: D002491:Central Nervous System Agents; D004365:Drugs, Chinese Herbal; D036145:Ginsenosides; D007375:Interleukin-1; D012503:Saponins; D006632:Histamine; D015232:Dinoprostone; C035054:ginsenoside Rg1