抄録
Galanin-like peptide (GALP), isolated recently from the porcine hypothalamus, is expressed predominantly in the arcuate nucleus (ARC), a feeding-controlling center. GALP is a peptide of 60 amino acids, in which residues (9-21) are identical to galanin (1-13). GALP shows a high affinity for galanin-receptor 2 (GalR2) than for GalR1. Therefore GALP is thought to be the endogenous ligand for GalR2. It is reported that intracerebroventricular (icv) injection of GALP stimulates food intake in rats. Functional relation between GALP and other feeding-regulatory peptides is not obvious. To determine which region in the hypothalamus is activated by GALP, we injected GALP into the nuclei and assessed orexigenic effects of GALP. GALP at 0.03 nmol injected into the dorso median nucleus (DMN) remarkably increased food intake, while that into the lateral hypothalamic area and the paraventricular nucleus had weaker or no effects. Following the study, we examined that which neurons are stimulated by icv GALP injection. GALP (0.3 nmol) icv injection expressed c-fos in the DMN, in which about 40% of NPY-containing neurons in the DMN co-expressed c-fos. GALP icv injection after BIBP3226 (Y1 receptor antagonist) icv injection did not stimulate food intake. These data suggest that an increase of food intake caused by icv GALP injection is mediated at least partly by an activation of NPY-containing neurons in the DMN. [Jpn J Physiol 54 Suppl:S206 (2004)]
