Potentiation of beta-endorphin effects by proglumide in rats.

The effects of proglumide, a cholecystokinin (CCK) receptor antagonist, on the analgesia and catalepsy induced by beta-endorphin were investigated in rats. Proglumide itself produced a slight analgesia but no catalepsy. Combined intracerebroventricular administration of beta-endorphin and proglumide produced marked potentiation of the analgesic and cataleptic effects of beta-endorphin. The results suggest that endogenous CCK may have an antagonistic effect on the actions of beta-endorphin in the brain.