Perlapine: relationship between stimulation of prolactin secretion and antipsychotic activity.

Perlapine is a dibenzohetereopine compound chemically related to clothiapine, loxapine, and clozapine. Although the latter three compounds are antipsychotic, perlapine has not been reported to be antipsychotic. Nevertheless, all four drugs increase rat plasma prolactin levels. The order of potency is loxapine, perlapine, clothiapine, and clozapine. These results suggest that either perlapine should be reexamined for antipsychotic properties or there are hitherto unsuspected discrepancies between the dopamine receptors relevant to antipsychotic activity in man and those that regulate prolactin secretion in the rat.