L-histidine stimulates sympathetic nerve activity to brown adipose tissue in rats.
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.
Yasuda
Tohru
T
Department of Internal Medicine I, School of Medicine, Oita Medical University, 1-1 Idaigaoka, Hasama, Oita 879-5593, Japan.
Masaki
Takayuki
T
Chiba
Seiichi
S
Kakuma
Tetsuya
T
Sakata
Toshiie
T
Yoshimatsu
Hironobu
H
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
D006639:Histidine