BDNF and major depressive disorder: Therefore, reduced astrocytes in the limbic regions of the brain and decreased function of astrocytes, such as reduced levels of BDNF and 5-HT1A observed by others and by us, may be associated with glucocorticoid overproduction induced by stress (Chatterjee and Sikdar, 2013), and FLX treatment improves CUMS-induced depression-like behaviors, which may be associated with an increase in the number of astrocytes and with an enhancement in the function of astrocytes reflected by increased levels of BDNF and 5-HT1A.