title: L-histidine stimulates sympathetic nerve activity to brown adipose tissue in rats.
abstract: Hypothalamic neuronal histamine is involved in the central regulation of energy expenditure through the activation of sympathetic nerves innervating brown adipose tissue (BAT). The present study examined the effect of L-histidine, a precursor of neuronal histamine, on BAT sympathetic nerve activity in rats. Infusion of histamine at a dose of 1 nmol/rat into the third cerebroventricle significantly increased BAT sympathetic nerve activity as compared with the effect of phosphate buffered saline (P < 0.05). Intraperitoneal (i.p.) injection of L-histidine (0.3 mmol/rat) also significantly increased BAT sympathetic nerve activity as compared with the effect of PBS (P < 0.05). Pretreatment with an i.p. bolus injection of 224 micromol/kg alpha-fluoromethylhistidine, a suicide inhibitor of the histamine synthesizing enzyme histidine decarboxylase, blocked the stimulatory effect of l-histidine on BAT sympathetic nerve activity. These results indicate that L-histidine regulates BAT sympathetic nerve activity through its conversion into neuronal histamine in the hypothalamus.
authors.affiliation: Department of Internal Medicine I, School of Medicine, Oita Medical University, 1-1 Idaigaoka, Hasama, Oita 879-5593, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Yasuda
authors.forename: Takayuki
authors.initials: T
authors.lastname: Masaki
authors.forename: Seiichi
authors.initials: S
authors.lastname: Chiba
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kakuma
authors.forename: Toshiie
authors.initials: T
authors.lastname: Sakata
authors.forename: Hironobu
authors.initials: H
authors.lastname: Yoshimatsu
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000502:physiology*; D000320:Adrenergic Fibers / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D006639:Histidine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D006639:Histidine