• equine;
  • ileocecal sphincter;
  • ileocecal reflux;
  • cecal distention

Recordings of intraluminal pressure at the equine ileocecal junction indicate the presence of a high-pressure zone of about 6 mm Hg over a distance of 5 cm. Both cecal distention by air and acidification of cecal contents by short-chain fatty acids elicited bursts of phasic pressure waves at the ileocecal junction. Phasic contractions contributed to the concomitant increase of tone at the ileocecal junction. Reflux of acidic cecal contents into the ileum was immediately counteracted by propagated phasic contractions. It appears that contractions propagated toward the cecum, rather than stationary contractions, contribute to the sphincteric properties at the ileocecal junction. The patterns of motor activity of the ileocecal region in species with a well-developed cecum suggest the additional presence of numerous propagated contractions of cecal origin.