The mPVN mediates blockade of NPY-induced feeding by a Y5 receptor antagonist: a c-FOS analysis

To identify the site(s) of NPY Y5 receptor (Y5R) mediation of NPY-induced f eeding, we employed c-Fos immunostaining and a selective Y5R antagonist (Y5 R-A), CGP71683A, in adult male rats. Intracerebroventricular (icv) administ ration of NPY stimulated feeding and c-Fos-like immunoreactivity (FLI) in t he dorsomedial hypothalamus, supraoptic nucleus and the two subdivision of the hypothalamic paraventricular nucleus (pPVN), the parvocellular (pPVN), and magnocellular (mPVN). YSR-A on its own, injected either intraperitoneal ly or icy, neither affected feeding nor FLI in hypothalamic sites. However, YSR-A pretreatment suppressed NPY-induced food intake and FLI serectively in the mPVN. Taken together with our previous similar finding of YIR involv ement, these results suggest that NPY receptor sites concerned with feeding behavior reside selectively in the mPVN and Y1 and Y5 receptors are either coexpressed or expressed separately in those target neurons that promote a ppetitive drive. (C) 2001 Elsevier Science Inc. All rights reserved.