Central neural mechanisms underlying stress-induced defecation

Abstract

Research using rodents in recent years has advanced our understanding of the mechanisms by which the central nervous system regulates colorectal motility and defecation. It has been demonstrated that the spinal defecation center regulates motility of the distal colon and rectum via the pelvic nerve, and that its function is modulated by multiple monoamines and peptides. In particular, evidence that a descending neural pathway, involving the hypothalamus, the medullary raphe nuclei, and the spinal defecation center, is involved in defecation induced by acute psychological stress is of significant importance. These findings provide a basis for the concept of the gut-brain axis and are also useful for understanding the mechanisms underlying stress-related defecation disorders. In this review, we summarize the multi-level regulatory mechanisms of colorectal motility and defecation, as well as the central neural circuits involved in the control of defecation during psychological stress, including our recent findings.