BDNF and colitis: Exposure to stressors induces the secretion of adrenocorticotropic hormone from the pituitary gland, which the stimulates the excretion of cortisol (corticosterone) from the adrenal gland through the hypothalamic–pituitary–adrenal axis and activates NF-κB signaling [30,31], while serotonin and BDNF levels decrease in the central nervous system and gastrointestinal tract, resulting in DA with neuroinflammation and colitis [32,33].