FOS and major depressive disorder: In Figures 3A–O, the results from the Western blot and qRT-PCR showed that after the model of depression was constructed, the expressions of the A1 adenosine receptor, Bcl-2, and PI3K were downregulated, and those of Bax, P38 MAPK, cFos, and ADAR2 were upregulated (Figures 3A–O, P < 0.001).