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December 1981

Depressed Patients Have Decreased Binding of Tritiated Imipramine to Platelet Serotonin 'Transporter'

Author Affiliations

From the Clinical Psychobiology Branch, National Institute of Mental Health, Bethesda, Md (Drs Paul, Rehavi, and Goodwin); the Laboratory of Bioorganic Chemistry, National Institute of Arthritis, Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Md (Dr Skolnick); and the Department of Behavioral Medicine and Psychiatry, University of Virginia School of Medicine, Charlottesville (Dr Ballenger).

Arch Gen Psychiatry. 1981;38(12):1315-1317. doi:10.1001/archpsyc.1981.01780370017001

• The high-affinity tritiated (3H) imipramine binding sites are functionally (and perhaps structurally) associated with the presynaptic neuronal and platelet uptake sites for serotonin. Since there is an excellent correlation between the relative potencies of a series of antidepressants in displacing 3H-imipramine from binding sites in human brain and platelet, we have examined the binding of 3H-imipramine to platelets from 14 depressed patients and 28 age- and sex-matched controls. A highly significant decrease in the number of 3H-imipramine binding sites, with no significant change in the apparent affinity constants, was observed in platelets from the depressed patients compared with the controls. These results, coupled with previous studies showing a significant decrease in the maximal uptake of serotonin in platelets from depressed patients, suggest that an inherited or acquired deficiency of the serotonin transport protein or proteins may be involved in the pathogenesis of depression.