Centrally administered galanin-like peptide modifies food intake in the rat: a comparison with galanin.

Galanin-like peptide (GALP) is a recently identified neuropeptide that shares sequence homology with the orexigenic neuropeptide, galanin. In contrast to galanin, GALP is reported to bind preferentially to the galanin receptor 2 subtype (GalR2) compared to GalR1. The aim of this study was to determine the effect of GALP on feeding, body weight and core body temperature after central administration in rats compared to the effects of galanin. Intracerebroventricular (i.c.v.) injection of GALP (1 micro g-10 micro g) significantly stimulated feeding at 1 h in both satiated and fasted Sprague-Dawley rats. However, 24 h after GALP injection, body weight gain was significantly reduced and food intake was also usually decreased. In addition, i.c.v. GALP caused a dose-related increase in core body temperature, which lasted until 6-8 h after injection, and was reduced by peripheral administration of the cyclooxygenase inhibitor, flurbiprofen (1 mg/kg). Similar to GALP, i.c.v. injection of galanin (5 micro g) significantly increased feeding at 1 h in satiated rats. However, there was no difference in food intake and body weight at 24 h, and galanin only caused a transient rise in body temperature. Thus, similar to galanin, GALP has an acute orexigenic effect on feeding. However, GALP also has an anorectic action, which is apparent at a later time. Therefore, GALP has complex opposing actions on energy homeostasis.