Ginsenoside Rg3 modulates spatial memory and fear memory extinction by the HPA axis and BDNF-TrkB pathway in a rat post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a serious mental disorder that can develop after exposure to extreme stress. Korean red ginseng, whose major active component is ginsenoside Rg3 (Rg3), is a widely used traditional antioxidant that has anti-inflammatory, anti-apoptotic and anxiolytics effects. This study investigated whether the administration of Rg3 ameliorated the memory deficit induced by a single prolonged stress (SPS) in rats. Male rats were dosed with Rg3 (25 or 50 mg/kg) once daily for 14 days after exposure to SPS. Rg3 administration improved fear memory and spatial memory might be involved in modulating the dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis and monoamine imbalance in the medial prefrontal cortex and hippocampus. It also increased the reduction in the brain-derived neurotrophic factor (BDNF) and tropomyosin-related kinase B (TrkB) mRNAs expression, and the ratio of p-Akt/Akt in the hippocampus. Thus, Rg3 exerted memory-improving actions might be involved in regulating HPA axis and activating BDNF-TrkB pathway. Our findings suggest that Rg3 could be useful for preventing traumatic stress, such as PTSD.