NTRK2 and major depressive disorder: Eight proteins (p-AKT, p-ERK12, GluA1, p-MEK1, p-MEK2, p-P38, Syn1 and TrkB) in the AKT and MAPK signaling pathways were significantly altered in at least one depression model, while three proteins (p-mTOR, p-P70S6K, PSD95) in the mTOR signaling pathway were not altered.