Biochem/physiol Actions

Perospirone (SM-9018) is a typical neuroleptic (antipsychotic) agent that displays high affinity for 5-HT2, D2 and 5-HT1A receptors (Ki = 0.61, 1.4 and 2.9-1.8 nM, respectively), moderate affinity for alpha 1 and D1 receptors (Ki = 17 and 41 nM, respectively), while exhibiting much reduced affinity for alpha 2 (Ki = 408 nM) and little affinity toward muscarinic, opiate, glutamate, phencyclidine, benzodiazepine or GABAA receptors (Ki >1 µM). SM-9018 antagonizes both D2-dependent (e.g. methamphetamine-induced hyperactivity, apomorphine-induced stereotypy) and 5-HT2-mediated (e.g. tryptamine-induced clonic seizure) activities in vivo, while exhibiting very low cataleptogenic and central depressant activities commonly observed with two other neuroleptics, haloperidol and chlorpromazine.