Chronic electroconvulsive shock and desimipramine reduce the degree of inhibition by 5-HT and carbachol of forskolin-stimulated adenylate cyclase in rat hippocampal membranes.

The degree of inhibition of forskolin-stimulated adenylate cyclase activity by 5-HT and by carbachol in hippocampal membranes was significantly reduced after administration of either chronic ECS (10 days) or desimipramine (10 mg/kg i.p. for 3 weeks). A single ECS had no effect on the 5-HT response and slightly augmented the carbachol response. These results parallel previous observations on the effects of ECS and antidepressants on behavioral responses to 5-HT1a agonists and on muscarinic receptor number, and indicate the possible involvement of these receptors in the mechanism of action of antidepressant drugs.