GRIK2 and mood disorder: Activation of these receptors by fluoxetine triggers several signalling cascades [75, 76], and induces transactivation of epidermal growth factor receptors (EGFR), which, in turn, recruits MAPK/ERK or PI3K/AKT downstream cascades to regulate expression of several genes (such as Ca2+-dependent phospholipase A2, cPLA2, subtype 2 of adenosine deaminases acting on RNA’s, ADAR2, or subtype 2 of kainate receptors, GluK2) related to mood disorders [77].