Imipramine treatment differentially affects platelet 3H-imipramine binding and serotonin uptake in depressed patients

Uptake of serotonin and 3H-imipramine binding in platelets of depressed patients were investigated simultaneously with changes in clinical state. Both V/sub max/ for serotonin uptake and B/sub max/ for 3H-imipramine binding were significantly lower in unmedicated depressed patients with respect to normal subjects. Successful treatment with imipramine led to a significant increase in B/sub max/ for 3H-imipramine binding, without significant change in V/sub max/ for serotonin uptake. B/sub max/ values increased to the normal range following complete, rather than partial clinical improvement. These data indicate that successful antidepressant treatment may increase the density of 3H-imipramine binding sites on platelets by a process which is independent of the uptake of serotonin. 29 references, 1 table