Motilides accelerate regional gastrointestinal transit in the dog

Motilides have prokinetic effects on the upper gut during fasting, increasing the strength of antral contractions and stimulating gastroduodenal phase 3 sequences. Effects on the distal gut, and postprandially, are less well documented.

To evaluate dose-response effects of motilin and erythromycin on gastric emptying, small bowel and colonic transit in the dog using a validated scintigraphic technique.

For gastric emptying and small bowel transit, 99mTc labelled beads were added to a meal of dog chow (450 kcal). Regional colonic transit was measured by 111In labelled beads placed in a capsule which dissolved and released radiation into the proximal colon. Scintiscans were taken at regular intervals and indices of whole-gut transit were calculated. Drugs were given by slow intravenous administration.

In the doses used, motilin accelerated regional colonic transit but did not hasten gastric emptying or small bowel transit. Single or repeated doses of motilin had similar effects on colonic transit. Erythromycin accelerated gastric emptying, small bowel transit and regional colonic transit.

Motilin receptors are apparently present in the canine small bowel and colon. Postprandially, motilides accelerate transit in the distal gut.