Fig. (4).

BDNF is correlated with the occurrence of depression and its antidepressant effects. Stress reduces synaptic plasticity, neuronal survival, and nerve growth through BDNF-TrkB and downstream signaling pathways, thereby affecting hippocampal function and inducing depression. The antidepressant drugs restore hippocampal function by up-regulating the expression of impaired signaling pathways and produce antidepressant effects. Abbreviations: (BDNF: brain-derived neurotrophic factor, TrkB: tyrosine kinase receptor B, PLC-γ: phosphatase C-γ, PI3K: phosphatidylinositol 3-kinase, MAPK: mitogen-activated protein kinase, AKT: protein kinase B, ERK: extracellular signal-regulated kinase, IP3: inositol 1,4,5-trisphosphate).