The Potential Role of Brain Gut Peptides in the Antidepressant Effects of Exercise Based on the Theory of “Brain-Gut Interaction”

Accumulating evidences have indicated that the interaction between the brain and the gastrointestinal tract plays an important role in human health and behavior. Bain-gut axis is a two-way response system mediated by neuro-endocrine between the brain and the intestine. Brain-gut peptides are the indispensable pysiological and molecular basis for the function of the brain-gut axis. Abnormal expression of brain-gut peptides in peripheral and central nervous system mediates stress response, gastrointestinal hyperactivity/deficiency, appetite and feeding abnormalities, itestinal microecological imbalance, etc., and thus leads to depression,anxiety, gastrointestinal diseases and metabolism diseases. The secretion and release of brain-gut peptides in chronic stress model animals or depressed patients are abnormal, and the levels of brain-gut peptides changes following antidepressant drug treatment.These results suggest that brain-gut peptides may be a new biomarker of depression. Exercise can regulate the abnormal expression of peripheral or central brain-gut peptides(such as ghrelin, neuropeptide Y, cholecystokinin, Peptide YY, Gastrin Releasing Peptide),and then affect monoamine neurotransmitter levels, HPA axis activity, neurotrophic factors expression, neuroplasticity, neuronal apoptosis, neurotoxic substances metabolism, epigenetics and so on in order to exert an antidepressant effect.