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
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)