Oxytocin and addiction: A review

Neuropeptides affect adaptive central nervous system processes related to o piate ethanol and cocaine addiction. Oxytocin (OXT), a neurohypophyseal neu ropeptide synthesized in the brain and released at the posterior pituitary, also is released in the central nervous system (CNS). OXT acts within the CNS and has been shown to inhibit the development of tolerance to morphine, and to attenuate various symptoms of morphine withdrawal in mice. In rats, intravenous self-administration of heroin was potently decreased by OXT tr eatment. In relation to cocaine abuse, OXT dose-dependently decreased cocai ne-induced hyperlocomotion and stereotyped grooming behavior. Following chr onic cocaine treatment, the behavioral tolerance to the sniffing-inducing e ffect of cocaine was markedly inhibited by OXT. Behavioral sensitization to cocaine, on the other hand, was Facilitated by OXT. OXT receptors in the C NS-mainly those located in limbic and basal forebrain structures-are respon sible for mediating various effects of OXT in the opiate- and cocaine-addic ted organism. Dopaminergic neurotransmission-primarily in basal forebrain s tructures-is another important biochemical mediator of the central nervous system effects of OXT. Tolerance to ethanol (e.g. hypothermia-inducing effe ct of ethanol) also was inhibited by OXT. (C) 1998 Elsevier Science Ltd. Al l rights reserved.