What is the function of motilin in the rabbit gastrointestinal tract?

抄録

Motilin was isolated from the extract of the porcine duodenal mucosa as a gastrointestinal (GI) motility-stimulating peptide. Although responsiveness of motilin in GI tract is different depending on experimental conditions (in vivo, in vitro), GI regions and species, it has been demonstrated that motilin is a physiological mediator of phase III of migrating motor complexes (MMCs) in the stomach, at least in humans, dogs, house musk shrews (suncus), monkeys, and opossums. Since the discovery of motilin, rabbits have been used for in vitro research. Although small intestinal MMCs in rabbits have been observed in vivo, their characteristics are different from those in humans and dogs probably due to the lack of hunger periods and it is still unknown whether motilin regulates intestinal MMCs or not. The density of motilin receptors is highest in colonic enteric neurons and the responsiveness of motilin is highest in the colon. These findings are own characteristics of rabbits and it is possible that motilin regulates colonic motility related to defecation or caecotrophy, but this possibility has not been clarified at present. Further in vivo functional studies with measurements of colonic motility and plasma motilin are needed to understand the physiological role of motilin in regulation of GI motility in rabbits.