Comparing the mRNA levels in the brain stem of stressed rats with Tianeptine and Sertraline administration

Since the discovery that antidepressants work in part by potentiating the actions of 5-HT within the serotonergic system the effects these drugs elicit on the serotonin transporter (SERT) protein have been an area of active research. The aim of the present study is to understand the mechanism of action of tianeptine and sertraline in relation to its effects on the expression of SERT gene and SERT protein in the brain stem of stressed rats. Albino Wistar rats were divided into two groups (n=12) i.e. saline and drug. Each group was further divided into two equal groups, stressed (Forced Swim Test-FST) and unstressed. Tianeptine and sertraline were administered to rats orally for 4 weeks prior to subjecting them to forced swim test and decapitation. Tianeptine increased the expression of SERT gene though the protein is reduced in the brain stem in stress. On the contrary sertraline decreased the expression of SERT gene but increased the protein in the brain stem. The increase in swimming time in FST by both the drugs indicates stress alleviating effects. It can be concluded that Tianeptine prevents stress induced changes through its effect on the serotonergic system, including SERT mRNA and protein. Sertraline complies to the reuptake inhibition property by reducing SERT gene expression. Results are discussed specifically, how changes in SERT expression following chronic antidepressant treatment may contribute to the therapeutic benefits of antidepressants. Keywords: Antidepressants; Serotonin transporters; Stress; Serotonergic system; SERT gene expressio