Local actions of trimebutine on canine gastrointestinal tract

The local actions of trimebutine on the circular muscle of canine gastrointestinal tract were studied after close intraarterial injection. The effects resembled those of metenkephalin at all sites. In stomach, trimebutine had no excitatory effects, but inhibited responses mediated by cholinergic post-ganglionic nerves. In small intestine, trimebutine stimulated the quiet gut by probably both neural and direct smooth muscle mechanisms, and it inhibited the field-stimulated phasic contractions. In large intestine, trimebutine had no excitatory actions and only weak inhibitory actions on the field-stimulated gut. Excitatory actions most likely seem to use the mu or delta receptors while inhibitory actions may focus on kappa opiate receptors.