Modulation of heroin self-administration by neurohypophyseal principles

Neuropeptides related to hypothalomic-neurohypophyseal hormones affect intravenous heroin self-administration behavior in rats. Desglycinamide9, arginine8-vasopressin and pressinamide reduced, while oxytocin and its C-terminal tripeptide, prolyl-leucyl-glycinamide facilitated this behavior. The effectiveness of the vasopressin analogue appeared to be of a long term nature. The data indicate a modulating effect of these principles on the reinforcing efficacy of heroin.