Tianeptine: a novel atypical antidepressant that may provide new insights into the biomolecular basis of depression.

Tianeptine, an atypical antidepressant patented and developed by Servier, enhances the synaptic reuptake of serotonin, without affecting norepinephrine and dopamine uptake, while it lacks affinity for neurotransmitter receptors. This mechanism for an antidepressant is apparently paradoxical, since the currently employed antidepressants enhance serotonin by inhibiting its breakdown or by inhibiting monoaminergic reuptake. Although tianeptine has been shown to reduce central 5HT availability and to indirecty modulate central adrenergic and dopaminergic systems and to indirectly inhibit cholinergic hyperactivity, its antidepressant action is believed to be more directly related to central neuronal remodeling and restoration of neuronal plasticity. In reliable animal models of depression tianeptine has been shown to prevent neurodegeneration and decreases in hippocampal volume in response to chronic stress. These effects on neuroplasticity are suspected to involve the normalization of the hypothalamic-pituitary-adrenal axis and modulatory effects on excitatory amino acids and N-methyl-D-aspartate receptors. Together with a body of related studies, these data provide further support for the hypothesis that depression may involve dysregulation of pathways controlling cellular resilience and that treatment should be directed towards the reversal thereof. Importantly, tianeptine is not anxiogenic and has also been shown to be effective in treatment-resistant depression, which may lead the way to a major breakthrough in the treatment of depression.