GRIA4 and major depressive disorder: To address whether changes in neuronal activity are due to synaptic damage in CRS-induced depression-like behaviors, Western blotting and qPCR assays were used to measure the levels of NMDARs (GluN1, GluN2A and GluN2B) and AMPARs (GluA1, GluA2, GluA3 and GluA4) in dHIP and vHIP.