Nociceptin/orphanin FQ inhibits stress- and CRF-induced anorexia in rats

The purpose of this study was to examine whether nociceptin/orphanin FQ (NC ), the endogenous ligand of the opioid receptor-like 1 (ORLI) receptor, is able to block hypophagia induced by either stress or central administration of corticotropin releasing factor (CRF) in rats. A marked reduction in foo d consumption was observed following exposure to 15 min intermittent electr ic footshock 60 min physical immobilization or after intracerebroventricula r (i.c.v.) injection of CRF (0.1-1.01 mug/rat). i.c.v, pretreatment with NC (0.1-2.0 mug/rat) completely abolished the hypophagic effect induced by st ress or by i.c.v. CRF injection. The same i.c.v. doses of NC did not modify food consumption in food deprived rats and did not modify the anorexic eff ect induced by lipopolysaccharide, suggesting that the effect of NC is sele ctive for anorexia induced by stress or CRF. These findings provide origina l evidence that NC attenuates stress-induced anorexia, presumably by acting as a functional CRF antagonist. NeuroReport 12:1145-1149 (C) 2001 Lippinco tt Williams & Wilkins.