BDNF and major depressive disorder: Although the obese animals showed marked depression-like behavior, there was no difference in the expression of genes related to depression or memory such as BDNF and NT-3, which are neurotrophins and mainly associated with increased neurogenesis and cell proliferation (61,62) and NR2B, CRHR2 e NR3C1, receptors for glucocorticoids and therefore mediate response to stress (63).