Effect of [D-Ala2,MePhe4,Gly-ol5]enkephalin and [D-Ala2,D-Leu5]enkephalin on ion and amino acid transport in rabbit ileum.
The selective mu-opioid agonist [D-Ala2,MePhe4,Gly-ol5]enkephalin (DAGO) (10 microM) reduced the short circuit (Isc) and the L-valine induced increase of the transepithelial potential difference and Isc(delta Vms and delta Isc) measured in-vitro in rabbit ileum, with a mechanism antagonized by naloxone (1 microM). [D-Ala2,D-Leu5]enkephalin (DADLE) (10 microM) had no significant effect on the transepithelial potential difference (Vms), Isc, delta Vms and delta Isc. In the ileum deprived of the serosa and muscolaris, DAGO reduced the delta Vms and delta Isc, but not the Vms and Isc, suggesting localization of the receptors responsible for this latter effect in the myenteric plexus and/or the muscularis mucosae. These preliminary results suggest that in the rabbit ileum opioids influence electrolyte and amino acid transport and these effects may be at least partly mediated by mu-receptors.
Meyer
G
G
Dipartimento di Fisiologia e Biochimica Generali, Università di Milano, Italy.
Botta
G
G
Tavani
A
A
Algeri
S
S
Cremaschi
D
D
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine; D004745:Enkephalins / Q000494:pharmacology*; D007082:Ileum / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D009270:Naloxone / Q000494:pharmacology; D011817:Rabbits; D014633:Valine / Q000494:pharmacology
D000596:Amino Acids; D004745:Enkephalins; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D009270:Naloxone; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; D014633:Valine