Nociceptin/orphanin FQ and drugs of abuse.

Nociceptin/orphanin FQ (NC) binds with high affinity to the opioid receptor-like1 (ORL1) receptor. NC has been reported to block opioid-induced supraspinal analgesia, and it has been proposed that it may represent a functional antiopioid peptide in the control of brain nociceptive processes. The wide distribution of NC and of its receptors in the central nervous system suggests, however, that it may be involved in the control of a variety of biologic functions. Increasing evidence indicates that it may influence the rewarding and reinforcing properties of drugs of abuse. NC has been shown to abolish the rewarding properties of ethanol and morphine in the place conditioning paradigm, to reduce ethanol consumption in alcohol-preferring rats and to inhibit stress-induced alcohol-seeking behavior. These findings suggest that drugs directed at central NC receptors may represent an interesting approach to the treatment of ethanol and opiate abuse.