Updated project metadata. Major depressive disorder (MDD) is considered as a neural circuit-based polygene syndrome that is mainly triggered by genetic susceptibility and stress factors. The present study employed the Wistar Kyoto (WKY) rat as an animal model with endogenous depression to further investigate the molecular basis of its genetic susceptibility to depression by performing quantitative protemoics analyses of the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), and hippocampus (Hip), respectively.