Effects of neuroleptic drugs on brain beta-endorphin immunoreactivity.

The effect of chronic haloperidol on brain beta-endorphin immunoreactivity was examined in rats. Chronic haloperidol resulted in significant reductions of beta-endorphin immunoreactivity within the striatum, but other brain regions were uneffected. When a variety of neuroleptic drugs were tested, fluphenazine, chlorpromazine and haloperidol resulted in comparable reductions in beta-endorphin immunoreactivity in the striatum. These findings suggest a functional interaction between beta-endorphin and dopamine systems in the striatum.