RADIORECEPTOR BINDING PROFILE OF THE ATYPICAL ANTIPSYCHOTIC OLANZAPINE

The affinities of olanzapine, clozapine, haloperidol, and four potenti al antipsychotics were compared on binding to the neuronal receptors o f a number of neurotransmitters. In both rat tissues and cell fines tr ansfected with human receptors olanzapine had high affinity for dopami ne D-1, D-2, D-4, serotonin (5HT)(2A), 5HT(2C), 5HT(3), alpha(1)-adren ergic, histamine H-1, and five muscarinic receptor subtypes. Olanzapin e had lower affinity for alpha(2)-adrenergic receptors and relatively low affinity for 5HT(1) subtypes, GABA(A), beta-adrenergic receptors, and benzodiazepine binding sites. The receptor binding affinities for olanzapine teas quite similar in tissues from rat and human brain. The binding profile of olanzapine was comparable to the atypical antipsyc hotic clozapine, while the binding profiles for haloperidol, resperido ne, remoxipride, Org 5222, and seroquel were substantially different f rom that of clozapine. The receptor binding profile of olanzapine is c onsistent with the antidopaminergic, antiserotonergic, and antimuscari nic activity observed in animal models and predicts atypical antipsych otic activity in man.