Antiparkinsonian drug doses and neuroleptic receptors.

The clinical potency of 3 drugs, apomorphine, N-propylnorapomorphine, and bromocryptine, have been found to be closely correlated to their potencies in competing for 3H-haloperidol and 3H-spiroperidol both of which label the dopamine receptor. This correlation indicates that the direct binding assay may be used to predict clinical potencies of anti-parkinsonian drugs, and indicates that agonists as well as antagonists compete potently for 3H-neuroleptic binding.