Once activated, these interleukins undergo exocytosis and bind to their respective receptors IL-1R and IL-18R, which are expressed by glial cells, subsequently inducing the synthesis and release of cytokines and thus leading to an increase in the levels of IL-1β, IL-6 and TNF-α, as seen in MDD [4,5,23,24]. This evidence concerns the gene TNF and major depressive disorder.