• The specific binding of tritiated (3H)-clonidine, an α2-adrenergic receptor agonist, to platelet membranes was measured in normal subjects and in patients with major depressive disorder. The number of platelet α2-adrenergic receptors from the depressed group was significantly higher than that found in platelets obtained from the control population. Treatment with tricyclic antidepressant drugs led to significant decreases in the number of platelet α2-adrenergic receptors. These results support the hypotheses that the depressive syndrome is related to an α2-adrenergic receptor supersensitivity and that the clinical effectiveness of tricyclic antidepressant drugs is associated with a decrease in the number of these receptors.
García-Sevilla JA, Zis AP, Hollingsworth PJ, Greden JF, Smith CB. Platelet α2-Adrenergic Receptors in Major Depressive DisorderBinding of Tritiated Clonidine Before and After Tricyclic Antidepressant Drug Treatment. Arch Gen Psychiatry. 1981;38(12):1327-1333. doi:10.1001/archpsyc.1981.01780370029003