[Effect of dopamine on small-intestinal motility in sheep].

The receptors involved in dopamine effect on the motility of the ileum were studied. The experiments were carried out on 3 sheep with chronic fistulas of the ileum and rumen. The contractions of the fistulated parts of the alimentary tract were recorded by the balloon method. Dopamine infused intravenously at a rate 28-38 micrograms.kg-1.min-1 inhibited the motility of the ileum. Domperidone (0.4-0.8 mg.kg-1) did not abolish this inhibiting influence of dopamine. Dopamine infused after propranolol (0.5-0.7 mg.kg-1) inhibited the motility of the ileum, however administrated after phentolamine (0.6-0.8 mg.kg-1) did not change its movements. It has been concluded that dopamine inhibits the ileum motility in sheep through alpha-adrenergic receptors.