Hypothalamic neuronal histamine modulates physiological responses induced by interleukin-1[beta]. Kang, Masahiro, Hironobu Yoshimatsu, Seiichi Chiba, Mamoru Kurokawa, Ryuichi Ogawa, Yuichi Tamari, Mari Tatsukawa, and Toshiie Sakata. Department of Internal Medicine I, School of Medicine, Oita Medical University, Oita, 879-55 Japan
APStracts 2:0232R, 1995.
Dynamic involvement of hypothalamic histamine in ingestive behavior and thermogenesis induced by interleukin-1[beta] (IL-1[beta]) was examined in rats. Intraperitoneal injection of 0.12 nmol/rat IL -1[beta] decreased food and water intake, and elevated body temperature. However, depletion of neuronal histamine induced by intraperitoneal injection of 160 [mu]mol/rat [alpha] -fluoromethylhistidine, a suicide inhibitor of histidine decarboxylase (HDC), attenuated the suppressive effect of IL-1[beta] on food intake, facilitated the suppressive effect on drinking, and enhanced the elevating effect on rectal temperature. Intraperitoneal injection of 0.12 nmol/rat IL-1[beta] increased hypothalamic histamine turnover rate. The same dose of IL-1[beta] also increased activity of HDC and histamine-N-methyltransferase (HMT). These results suggest that IL -1[beta] may stimulate synthesis and release of hypothalamic histamine in presynaptic terminals by activation of HDC, and facilitate degradation of extracellular histamine by activation of HMT. These changes in the dynamics of hypothalamic histamine modulate IL -1[beta]-induced ingestive behavior and body temperature.

Received 22 December 1993; accepted in final form 13 June 1995.
APS Manuscript Number R694-3.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 August 1995.