Regulation of food intake by neuropeptide Y in goldfish

In mammals, neuropeptide Y (NPY) is a potent orexigenic factor. In the pres ent study, third brain ventricle (intracerebroventricular) injection of gol dfish NPY (gNPY) caused a dose-dependent increase in food intake in goldfis h, and intracerebroventricular administration of NPY Y1-receptor antagonist BIBP-3226 decreased food intake; the actions of gNPY were blocked by simul taneous injection of BIBP-3226. Goldfish maintained on a daily scheduled fe eding regimen display an increase in NPY mRNA levels in the telencephalon-p reoptic area and hypothalamus shortly before feeding; however, a decrease o ccured in optic tectum-thalamus. In both fed and unfed fish, brain NPY mRNA levels decreased after scheduled feeding. Restriction in daily food ration intake for 1 wk or food deprivation for 72 h resulted in increased brain N PY mRNA levels. Results from these studies demonstrate that NPY is a physio logical brain signal involved in feeding behavior in goldfish, mediating it s effects, at least in part, through Y1-like receptors in the brain.