Some Binding Characteristics of ³H—SCH 23390 — A Specific D1 Receptor Antagonist

Abstract

SCH 23390 ((R)-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5 phenyl-1H-3-benzazepin-7-ol) has been shown to have antipsychotic potential as shown in animal models of behavior (Iorio et al, 1981, 1983). SCH 23390 is the most specific D1 receptor antagonist known, as indicated in part by it weak blockade of ³H-spiperone or H-haloperidol binding (Iorio et al, 1983; Hyttel, 1983) and its potent blockade of dopamine sensitive adenylate cyclase (Iorio et al, 1983) and its potent displacement of the binding of H-cis-(Z)-piflutixol (Hyttel, 1983), which has similar affinities for D1 and D2 binding sites. These data suggested that radiolabelled SCH 23390 would uniquely bind to D1 receptor sites. This paper presents data showing some of the binding characteristics of ³H-SCH 23390 in rat striatal and cortical tissues.