LOCAL-REGULATION OF ILEAL TONE IN HEALTHY HUMANS

We previously showed that a meal induced, in the human terminal ileum, a delayed tonic relaxation, which could be related to the ileal deliv ery of meal residues and/or endogenous secretions released by a meal. In this study, we assessed the effects of some components of the ileal contents on its motor activity. In six healthy subjects, we studied i leal tonic and phasic motility in response to the infusion into the te rminal ileum of different isotonic solutions: saline, glycochenodeoxyc holic acid (GDCA), triglycerides, and short-chain fatty acids (SCFA). Tonic activity was not modified by saline, whereas it was significantl y decreased by GDCA and triglycerides (maximal increase in intrabag vo lume 139 +/- 7% and 152 +/- 16%, respectively, P < 0.01), and signific antly increased by SCFA (maximal decrease in intrabag volume 72 +/- 4% , P < 0.01). No significant change of phasic activity was evidenced wi th either solution. We conclude that I)bile acids and triglycerides no t absorbed in the more proximal gut could be involved in the ileal rel axation occurring after eating and 2) local stimulation of chemorecept ors is of importance in the regulation of ileal motility.