Rectosigmoid motility response to sham feeding in irritable bowel syndrome. Evidence of a cephalic phase

Rectosigmoid pressure recordings by means of open-ended perfused catheters were performed on 21 patients with the irritable bowel syndrome (IBS). Motility indexes were calculated in resting conditions, after sham feeding, after a meal, and after 0.5 mg neostigmine intravenously. Each step of stimulation caused a significantly increased motility index compared with the previous step (p less than 0.01). The increase in rectosigmoid pressure activity after sham feeding indicates the existence of a cephalic phase in the postprandial motor response of the colon in IBS.