title: Dihydroetorphine is a mu-receptor-selective ligand.
abstract: The selectivity to opioid receptors of dihydroetorphine, a potent analgesic with only mild physical dependence, was investigated using radioligand binding assay and its analgesic activity in mice determined. The relative affinity ratio of dihydroetorphine to mu-, delta- and kappa- opioid receptors was 333:1:1. The analgesic effect of intracerebro-ventricular injection in mice could be antagonized by the mu-antagonist beta-funaltrexamine but could not be antagonized by delta- and kappa-selective antagonists naltrindole and norbinaltorphimine. We conclude that dihydroetorphine is a selective ligand for the mu-opioid receptor.
authors.affiliation: Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, China.
authors.forename: D X
authors.initials: DX
authors.lastname: Wang
authors.forename: X Q
authors.initials: XQ
authors.lastname: Lu
authors.forename: B Y
authors.initials: BY
authors.lastname: Qin
mesh_terms: D000701:Analgesics, Opioid / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005048:Etorphine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D007276:Injections, Intraventricular; D051379:Mice; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D017465:Receptors, Opioid, delta / Q000187:drug effects*; D017473:Receptors, Opioid, kappa / Q000187:drug effects*; D017450:Receptors, Opioid, mu / Q000187:drug effects*
chemical_list: D000701:Analgesics, Opioid; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D005048:Etorphine; C034765:18,19-dihydroetorphine