Loss of rat cerebral cortical opiate receptors following chronic desimipramine treatment.

The characteristics of central opiate and beta-adrenergic receptors were studied after giving the tricyclic antidepressant desimipramine (DMI) to rats. Administration of DMI for 1 or 7 days did not alter cortical opiate or beta-adrenergic receptors. However, after 21 days of treatment there was a significant subsensitivity of both these receptors in the cortex. A specific loss of receptor sites for opiate binding was detected with no change in affinity. After a similar time of treatment, opiate receptors in the corpus striatum and hippocampus were the same as the controls. The data suggest that change in cortical opiate receptors may be important in the mechanism of action of antidepressants.