Objective—To examine the effects of various doses of mosapride, a 5-hydroxytryptamine 4 receptor agonist, on motility of the small intestine and cecum in horses by use of electrical activity and to determine the dose that provides the optimal response.
Animals—6 healthy adult Thoroughbreds.
Procedure—Electrical activity of the small intestine and cecum was recorded before and after mosapride administration by use of an electrogastrograph. Mosapride (0.5, 1, 1.5, and 2 mg/kg) was dissolved in 200 mL of water and administered orally to horses through a nasogastric tube. Three hours after drug administration, mean amplitude of electrical activity calculated for a period of 30 minutes was expressed as the percentage of the mean amplitude of electrical activity for a period of 30 minutes before drug administration.
Results—Mosapride administered orally increased the percentage of the mean amplitude of electrical activity in the small intestine and cecum in a dosedependent manner. Mean ± SD values differed significantly for 1, 1.5, and 2 mg/kg (127.0 ± 12.5%, 137.7 ± 22.2%, and 151.1 ± 24.0%, respectively) in the small intestine and for 1.5 and 2 mg/kg (130.1 ± 34.5% and 151.6 ± 45.2%, respectively) in the cecum.
Conclusions and Clinical Relevance—Analysis of results of this study clearly documents that mosapride promotes motility in the small intestine and cecum of horses and that the optimal orally administered dosage is 1.5 to 2 mg/kg. Therefore, mosapride may be useful for treatment of horses with gastrointestinal tract dysfunction. (Am J Vet Res 2005;66:1321–1323)