The nociceptin/orphanin FQ system as a target for treating alcoholism

Nociceptin (known also as orphanin FQ) is the most recently discovered member of the endogenous opioid peptide family, albeit nearly 15 years ago. Nociceptin renders or influences many behavioral, psychological and neurobiological processes, including memory, anxiety, stress and reward. Since its discovery, results of a steady stream of studies have suggested that endogenous nociceptin might be involved in responses to addictive drugs, and that targeting the nociceptin system may be beneficial in treating addictions. The current review summarizes and critically appraises those studies, particularly those that point to an application in treating alcoholism. Overall, most, studies suggest that the endogenous nociceptin system has a physiological role in mediating or regulating behavioral responses to alcohol, and that activating nociceptin receptors suppresses ongoing alcohol consumption or reinstatement of responding for alcohol. These findings encourage the development of therapies targeted at the nociceptin system for the treatment of alcoholism in humans, though a minor number of studies showing continuous activation of the nociceptin receptor can produce increased, rather than reduced, alcohol consumption emphasize the necessity of further investigation.