Butyrophenone influences on the opiate receptor.

Interaction of neuroleptic drugs with the opiate receptors was investigated by inhibition of the stereospecific binding of 3H-naloxone. Benperidol and pimozide, with IC50's of 0.3-0.5 muM, were more potent than the classical opiates meperidine and propoxyphene. A systematic structure-activity relationship was evident with the basic opiate structure of a benzene and a piperidine ring preserved in active compounds. No correlation between neuroleptic activity and binding to the opiate receptor was demonstrated.