Rats treated chronically with dopamine receptor blockers [haloperidol, trifluperazine] apparently had an increase in striatal 3H-dopamine binding and adenylate cyclase activity as manifestations of receptor supersensitivity. Increase in binding and in adenylate cyclase activity were reversed by chronic L-dopa treatment, presumably by increasing the supply of specific ligand (dopamine). Deliberate receptor sensitivity manipulation may be useful as treatment for patients with conditions involving disturbances in receptor sensitivity such as tardive dyskinesia and insulin resistant diabetes.