Chronic imipramine reduces [3H]SCH 23390 binding and DA-sensitive adenylate cyclase in the limbic system.

[3H]SCH 23390 binding and dopamine (DA)-stimulated adenylate cyclase activity were measured in brain membrane preparations from rats chronically treated with imipramine (10 mg/kg twice daily for 14 days). [3H]SCH 23390 binding sites were decreased by 27% in the limbic system but only 14% in the striatum. The responsiveness of adenylate cyclase to DA was reduced by 38% in the limbic system but was not modified in the striatum. Concomitant treatment with alpha-methyltyrosine (alpha-MPT) (50 mg/kg daily for 14 days) prevented the imipramine-induced reduction in both [3H]SCH 23390 binding sites and the responsiveness of adenylate cyclase to DA.