Chronic administration of bacopa monniera increases BDNF protein and mRNA expressions: a study in chronic unpredictable stress induced animal model of depression.

ObjectiveaaThe present study aimed to investigate whether graded doses of Bacopa Monniera (BM) extract could produce antidepres sant-like effects in chronic unpredictable stress (CUS) induced depression in rats and its possible mechanism(s). MethodsaaRats were subjected to an experimental setting of CUS. The effect of BM extract treatment in CUS-induced depression was examined using behavioral tests including the sucrose consumption, open field test and shuttle box escape test. The mechanism underly ing the antidepressant-like action of BM extract was examined by measuring brain-derived neurotrophic factor (BDNF) protein and mRNA expression in brain tissues of CUS-exposed rats. ResultsaaExposure to CUS for 4 weeks caused depression-like behavior in rats, as indicated by significant decreases in sucrose consump tion, locomotor activity and escape latency. In addition, it was found that BDNF protein and mRNA levels in the hippocampus and frontal cortex were lower in CUS-treated rats, as compared to controls. Daily administration of the graded doses of BM extract during the 4-week period of CUS significantly suppressed behavioral changes and attenuated the CUS-induced decrease in BDNF protein and mRNA lev els in the hippocampus and frontal cortex. ConclusionaaThe results suggest that BM extract alleviates depression induced by CUS. Present study also confirms that 80 –120 mg/kg doses of BM extract have significantly higher antidepressant-like activity.