Regulatory mechanism of colonic motility by the central nervous system

Abstract

We found that defecation was significantly promoted when an agonist of ghrelin was administered to rats. This unexpected finding motivated novel research focusing on the regulatory mechanism of colonic motility by the central nervous system, because the action site of the ghrelin agonist was the lumbosacral defecation center. In addition to the ghrelin agonist, noradrenalin, dopamine and serotonin were found to act on the spinal defecation center to enhance colonic motility. All of the monoamines were transmitters of the descending pain inhibitory pathways. Accordingly, we have proposed a novel concept that “the regulatory system of pain transmission and the regulatory system of colorectal motility are linked at the spinal cord”. In this review article, we summarize our recent findings on the central regulatory mechanism of colonic motility.