GRM2 and major depressive disorder: mGluR2/3 antagonists, including MGS0039, LY341495 and LY3030371,display fast and sustained antidepressant-like responses in depression models (Campo et al. 2011; Chaki et al. 2004; Dwyer et al. 2013; Fukumoto et al. 2016; Joffe et al. 2020; Koike et al. 2013b; Podkowa et al. 2015), compared to the conventional antidepressants which have a substantial delay in the therapeutic onset.