Tianeptine, a selective enhancer of serotonin uptake in rat brain

Tianeptine is a tricyclic agent provided with antidepressant activity in experimental models and in clinical trials. In vitro tianeptine and its two principal metabolites have no effects on monoamine uptake, release or neurotransmitter receptor binding. The biochemical effect of tianeptine in vivo after acute or repeated treatment indicates an enhanced serotonin uptake in cortex and hippocampus but not in mesencephalon, with no effect on noradrenaline or dopamine uptake. This enhanced serotonin uptake is not due to decrease in serotonin release, but is related to increase in the Vmax of the uptake carrier for serotonin. The fact that enhancers as well as inhibitors of serotonin uptake are provided with antidepressant activity challenge simple conclusion as to their mechanism of action. The possibility that increased serotonin uptake after repeated treatment may be related to the antidepressant activity exerted by these drugs, and drugs enhancing serotonin uptake might have antidepressant activity, with an earlier onset, is proposed.