Effects of sulpiride treatment on the levels of immunoreactive beta-endorphin in rat hypothalamic nuclei.

The effects of sulpiride, a specific dopamine receptor antagonist, on the levels of immunoreactive beta-endorphin (ir-beta-END) in discrete hypothalamic nuclei of rats were investigated. Single injections of sulpiride significantly decreased the levels of ir-beta-END in the nucleus arcuatus, nucleus paraventricularis and median eminence. Repeated injections of sulpiride significantly increased the levels of ir-beta-END in the nucleus arcuatus, nucleus periventricularis and median eminence. These findings suggest that beta-endorphinergic neurons are under dopaminergic control.