Orphanin FQ nociceptin blocks acquisition of morphine place preference

Orphanin FQ/nociceptin (OFQ/N) suppresses the activity of the dopaminergic mesolimbic reward pathway yet reportedly fails to produce conditioned place aversion or preference. The present study sought to determine if this pept ide could attenuate the development of morphine place preference. Male rats were administered OFQ/N (3 to 30 nmol intracerebroventricularly) during th e induction of morphine (3 mg/kg subcutaneously) place preference. Animals receiving 3 or 10 nmol (but not 30 nmol) OFQ/N showed significant reduction s in the development of place preference to morphine. (C) 1999 Elsevier Sci ence B.V. All rights reserved.