The anorectic effect of neuropeptide AF is associated with satiety-related hypothalamic nuclei

Neuropeptide AF (NPAF), a member of the RFamide family, is encoded by the same gene as neuropeptide FF (NPFF), which causes short-term anorexia. However, reports on the role of NPAF on appetite-related process are lacking. Thus, i.c.v. injections of 4.0, 8.0 and 16.0 nmol NPAF were administered to chicks to observe its effect on food and water intake. Chicks treated with 8.0 and 16.0 nmol i.c.v. NPAF decreased both their food and water intake. Additionally, all doses of NPAF injected caused a similar reduction in whole blood glucose concentration 180 min after injection. In a second experiment, chicks that received i.c.v. NPAF had an increased number of c-Fos immunoreactive cells in the dorsomedial, paraventricular (magnocellular and parvicellular parts) and ventromedial nuclei. The arcuate nucleus and lateral hypothalamic area were not affected. In a third experiment, NPAF-treated chicks exhibited fewer feeding pecks and spent less time perching, whereas they spent an increased time in deep rest. Other behaviours, including exploratory pecking, escape attempts, defecations, distance moved, and time spent standing, sitting and preening, were not affected by NPAF injection. We conclude that NPAF causes anorectic effects that are associated with the hypothalamus.