Exploring the brain-gut axis in irritable bowel syndrome: Specific emphasis on stress and melatonin

Abstract

Stress can influence brain and bowel functions causing dysregulation of brain-gut axis in irritable bowel syndrome (IBS). Melatonin, a pineal hormone, could have many functions on brain-gut axis and IBS related symptoms. Thus, a series of animal and human studies were done in the present thesis to investigate the brain-gut axis and put specific emphases on stress and melatonin in IBS. The results showed stress changed gut function in rats and human. Dysfunctional central pain modulating mechanisms under stress conditions were observed in IBS patients compared with healthy controls. Furthermore, in rat, melatonin significant alleviated stress induced defecation. In IBS patients, melatonin attenuated abdominal pain and increase rectal pain threshold despite the absence of improvements in sleep disturbance and psychological distress. These findings suggested that stress plays an important in the dysregulation of brain-gut axis, thus could causing IBS. Moreover, melatonin could be a promising candidate for the treatment of IBS.