BDNF and major depressive disorder: Acupuncture at “Baihui” (GV 20) and “Yintang” (EX-HN 3) can effectively reverse chronic stress-induced down-regulation of BDNF mRNA and protein expression in the frontal cortex and hippocampus of rat models of depression, contributing to its anti-depressive-like actions by protecting neuronal regeneration [50].