ALTERATION BY A PLASMA FACTOR(S) OF PLATELET-AGGREGATION IN UNMEDICATED UNIPOLAR DEPRESSED-PATIENTS

To investigate whether a plasma factor(s) modulates platelet aggregati on in unipolar depression, a series of assays were performed in which the platelet rich plasma of a male volunteer was preincubated with the plasma of either unmedicated unipolar depressed patients or age and s ex matched controls. Platelet aggregation was initiated by the additio n of a number aggregating agents (ADP, ADP/5-HT, adrenaline, noradrena line, collagen, thrombin and ristocetin) acting on different platelet membrane receptors. The plasma of depressed patients significantly red uced the platelet aggregatory response for each of the aggregating age nts used. Therefore, it is concluded that factor(s) which inhibit plat elet aggregation may be present in the plasma of unmedicated unipolar depressed patients.