INCREASED SEROTONIN PLATELET UPTAKE AFTER TIANEPTINE ADMINISTRATION IN DEPRESSED-PATIENTS

Tianeptine is a new antidepressant drug reported to enhance serotonin (5-hydroxytryptamine [5-HT]) uptake in rat brain. The effect of tianeptine on 5-HT platelet uptake was studied in 10 depressed patients treated for 28 days. Tianeptine increases V(max) of 5-HT platelet uptake during treatment without inducing any change in K(m). As early as 2 hr after the first administration, V(max) increased significantly (+23%, alpha = 0.01). Although of a lesser magnitude, 5-HT platelet uptake remains increased after chronic administration (+14% on day 10 and +13% on day 28). This suggests that tianeptine affects 5-HT platelet uptake sites, either directly or via an action on modulators of 5-HT uptake. These results, in contrast with the action of other tricyclic antidepressants, confirm the original action of tianeptine on 5-HT platelet metabolism.