Leucine enkephalin noncompetitively inhibits the binding of [3H]naloxone to the opiate mu-recognition site: evidence for delta----mu binding site interactions in vitro.
Using quantitative methods, this study examined the hypothesis that delta-ligands are noncompetitive inhibitors at a population of mu-binding sites. Evidence is presented that with the defined set of in vitro assay conditions utilized, [3H]naloxone labels two binding sites: the mu binding site and a second site tentatively identified as a kappa binding site, and that leucine enkephalin is a noncompetitive inhibitor at the mu recognition site.
D000818:Animals; D001414:Bacitracin / Q000494:pharmacology; D001921:Brain / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D016308:Enkephalin, Leucine-2-Alanine; D007700:Kinetics; D009270:Naloxone / Q000378:metabolism*; D051381:Rats; D011957:Receptors, Opioid / Q000187:drug effects / Q000378:metabolism*; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu
D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D001414:Bacitracin; D009270:Naloxone; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine