[Inhibitory and excitatory effects of methionine-enkephalin in the isolated rabbit ileum].
Methionine-enkephalin first inhibited and then stimulated the spontaneous rhythmic activity of the rabbit isolated ileum. The inhibitory effect of methionine-enkephalin was antagonized by naloxone. On the contrary, atropine did not change significantly either the inhibitory or the stimulatory action of this peptide. Furthermore, methionine-enkephalin inhibited the peristaltic reflex of the rabbit isolated ileum as well. Naloxone completely antagonized the inhibition of peristalsis produced by methionine-enkephalin. On the other hand, acetylcholine reversed only the propulsive activity and the back pressure, but not the peristaltic movements of the longitudinal muscle previously abolished by methionine-enkephalin. It appears, therefore, that only the inhibitory effects of methionine-enkephalin are mediated through opioid receptors in the intestine.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D005260:Female; D007082:Ileum / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D009270:Naloxone / Q000494:pharmacology; D010528:Peristalsis / Q000187:drug effects; D011817:Rabbits
D009270:Naloxone; D004744:Enkephalin, Methionine; D001285:Atropine; D000109:Acetylcholine
Effet inhibiteur et excitateur de la méthionine-enképhaline sur l'iléon isolé de Lapin.