Neuromediated action of beta-casomorphins on ion transport in rabbit ileum.
beta-casomorphins (beta-CMs) are opioid peptides derived from milk beta-casein. The beta-casomorphin analog beta-[DAla2,4, Tyr5] CM-5-NH2 reduced short-circuit current (lsc) and stimulated electrolyte absorption by an opioid effect in rabbit ileum in vitro. This effect was inhibited by 10(-7) M tetrodotoxin, 10(-6) M epinephrine and 10(-5) M naloxone. Atropine in the 10(-7)-10(-5) M range and 10(-5) M hexamethonium did not inhibit the action of the peptide on lsc. In comparison the muscarinic effect of 10(-3) M carbachol was inhibited by atropine in the 10(-8)-10(-5) M range. These results indicate that the action of the beta-casomorphin analog was neuromediated and suggest that this peptide acted on the submucosal plexus located on the blood side of the intestinal epithelium. A physiological role of the food-derived beta-CMs peptides implies the passage of the active sequences from the lumen to the blood side of the intestine.
Tomé
D
D
INSERM U. 290, Hôpital Saint-Lazare, Paris, France.
Ben Mansour
A
A
Hautefeuille
M
M
Dumontier
A M
AM
Desjeux
J F
JF
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004558:Electric Stimulation; D004723:Endorphins / Q000494:pharmacology*; D004837:Epinephrine / Q000494:pharmacology; D018738:Hexamethonium; D006584:Hexamethonium Compounds / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000187:drug effects; D007413:Intestinal Mucosa / Q000187:drug effects / Q000502:physiology; D007477:Ions; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D011817:Rabbits
D004723:Endorphins; D006584:Hexamethonium Compounds; D007477:Ions; D009270:Naloxone; D018738:Hexamethonium; C021968:beta-casomorphins; D001285:Atropine; D002217:Carbachol; D004837:Epinephrine