Tianeptine decreases both serotonin transporter mRNA and binding sites in rat brain

In situ hybridization histochemistry and quantitative autoradiography were used to evaluate the effects of repeated administration of the serotonin reuptake enhancer, tianeptine. Tianeptine (10 mg/kg twice daily, for 14 days) significantly reduced both the expression of serotonin transporter mRNA and serotonin transporter binding sites labeled by [3H]paroxetine in rat dorsal raphe nucleus. In median raphe nucleus, tianeptine did not change either expression of serotonin transporter mRNA or binding. This effect, which is similar to a reported effect for serotonin reuptake inhibitors, may help to explain the antidepressant effect of tianeptine.