INJECTIONS OF NOCICEPTIN INTO NUCLEUS-ACCUMBENS SHELL OR VENTROMEDIALHYPOTHALAMIC NUCLEUS INCREASE FOOD-INTAKE

THE novel opioid receptor ORL1 is widely distributed throughout the CN S of the rat, and is present in high densities in several brain region s known to participate in the control of food intake. We injected a re cently identified endogenous agonist of this receptor, nociceptin, int o two of these feeding-related areas. Microinjections of nociceptin (2 .5-25 nmol) into either the ventromedial hypothalamic nucleus or the n ucleus accumbens shell significantly increased food intake in rats. We believe this to be the first report of a specific effect of nocicepti n on a motivated behavior.