NTRK2 and major depressive disorder: Third, we examined the effects of the TrkB antagonist ANA-1223, 24, 29, 30 and the TrkB agonist 7,8-DHF23, 24, 30, 31 on behavioral abnormalities (for example, depression and behavioral sensitization) and dendritic changes in the VTA–NAc circuit after METH withdrawal.