PTGS2 and major depressive disorder: While results from a previous study have indicated that pro-inflammatory cytokines could activate the p38 MAPK protein leading to decreased synaptic availability of serotonin and depressive-like behavior (Adzic et al., 2018), we found that inhibition of Cyclooxygenase-2 (COX-2)-mediated inflammation could suppress p38 activation in this animal model of depression (Song et al., 2018).