Motilides accelerate regional gastrointestinal transit in the dog

Background: Motilides have prokinetic effects on the upper gut during fasti ng, increasing the strength of antral contractions and stimulating gastrodu odenal phase 3 sequences. Effects on the distal gut, and postprandially, ar e less well documented. Aim: To evaluate dose-response effects of motilin and erythromycin on gastr ic emptying, small bowel and colonic transit in the dog using a validated s cintigraphic technique. Methods: For gastric emptying and small bowel transit, Tc-99m labelled bead s were added to a meal of dog chow (450 kcal). Regional colonic transit was measured by In-111 labelled beads placed in a capsule which dissolved and released radiation into the proximal colon. Scintiscans were taken at regul ar intervals and indices of whole-gut transit were calculated. Drugs were g iven by slow intravenous administration. Results: In the doses used, motilin accelerated regional colonic transit bu t did not hasten gastric emptying or small bowel transit. Single or repeate d doses of motilin had similar effects on colonic transit. Erythromycin acc elerated gastric emptying, small bowel transit and regional colonic transit . Conclusions: Motilin receptors are apparently present in the canine small b owel and colon. Postprandially, motilides accelerate transit in the distal gut.