Effect of rectal distension on gallbladder emptying and circulating gut hormones

Background Abnormalities of upper gut motility, including a delay of gastri c emptying and small bowel transit, found in patients with constipation may be secondary to factors originating in the colon or rectum as a result of faecal stasis. The aim was to determine if stimulation of mechanosensory fu nction by rectal distension affects postprandial gallbladder emptying and r elease of gastrointestinal peptides participating in control of upper gut m otility. Materials and methods Eight healthy volunteers were studied with an electro nic barostat and a plastic bag positioned in the rectum. Intrabag pressure was maintained at minimal distension pressure + 2 mmHg on one occasion and on a pressure that induced a sensation of urge on the other. Gallbladder vo lume and plasma concentrations of cholecystokinin (CCK), pancreatic polypep tide (PP) and peptide YY (PYY) were measured before and after ingestion of a 450-kcal mixed liquid meal. Results Rectal distension enhanced maximum gallbladder emptying from 66 +/- 7% to 78 +/- 5% (P < 0.05). Distension tended to increase integrated plasm a PYY from 77 +/- 30 pM min to 128 +/- 40 pM min in the first hour after th e meal (P = 0.08) and it suppressed integrated plasma PP from 1133 +/- 248 pM min to 269 +/- 284 pM min in the second hour (P < 0.05). Integrated plas ma CCK concentrations were not significantly affected. Conclusion Mechanosensory stimulation of the rectum enhances postprandial g allbladder emptying and influences postprandial release of gut hormones inv olved in the regulation of gastrointestinal motility in healthy subjects. T hese mechanisms may play a role in the pathogenesis of the upper gastrointe stinal motor abnormalities observed in constipated patients.