Effect of venlafaxine on hippocampal BDNF levels in depression-induced rats

Although antidepressant drugs have been used for  approximately 60 years, very little is known about their  effect mechanism. Structural abnormalities, particularly  in the hippocampus, are observed in brain structures of  depressed patients.  The correction of these abnormalities with  treatment suggests that major depressive disorders may  be associated with a decrease in cellular elasticity and  structural plasticity, and antidepressant treatments may  provide benefits by treating these disorders. In this  study, we aimed to investigate the effect of venlafaxine  treatment on the brain-derived neurotrophic factor  (BDNF) and BDNF levels in the hippocampus of  depression-induced rats by using the chronic mild stress  (CMS) model.  In this study, 30 eight-week-old, Wistar albino  male rats were divided into three groups. The first group  received venlafaxine (20 mg/kg) with CMS, the second  group a placebo with CMS, and the third group only a  placebo (n = 10) for four weeks. At the end of the four week  period, BDNF levels in hippocampus tissues were  measured.  The measurements showed that the BDNF levels  of the depressed group were significantly lower than  those of the control group. In our study, the  hippocampal BDNF levels of the venlafaxine administered  group were similar to those of the control  group and significantly higher than those of the  depressed group.  In conclusion, these findings show that the BDNF,  which has an important function in neuroplasticity,  plays a role in depression pathophysiology, and  venlafaxine prevents the BDNF decrease observed in  depression. This latter result supports the view that  depression treatment prevents the long-term  complications of the disorder.