Stress, a common factor in the development of depression and depressive-like behaviors, causes to activate the M1 phenotype of microglia and synthesize pro-inflammatory cytokines (IL- 6, IL- 1β and TNF-α) and oxidative mediators (ROS and NO), and these mediators are abundant in depressed patients [1, 52, 88]. This evidence concerns the gene TNF and depressive disorder.