title: Inhibition of the antisecretory effects of [D-Ala2,D-Leu5]enkephalin in the guinea-pig ileum by a selective delta opioid antagonist.
abstract: The novel opioid antagonist [diallyl-Tyr1,(CH2)S-Phe4,Leu5]enkephalin (M154,129) was examined for its ability to block the antisecretory effects of [D-Ala2,D-Leu5]enkephalin (DADLE) in isolated mucosal segments of the guinea-pig ileum, actions mediated predominantly through the delta opiate receptor. DADLE reduced transepithelial potential difference and short-circuit current (ED50 18 nM); these effects were competitively antagonized by M154,129 with a Ke value of 746 nM. These results are consistent with others demonstrating M154,129 is a relatively selective although not highly potent blocker of delta opiate receptors.
mesh_terms: D000818:Animals; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D011957:Receptors, Opioid / Q000187:drug effects; D017465:Receptors, Opioid, delta
chemical_list: D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; C036405:ICI 154129