title: Opioid receptor types and subtypes: the delta receptor as a model.
abstract: Since the discovery of opioid receptors over two decades ago, an increasing body of work has emerged supporting the concept of multiple opioid receptors. Molecular cloning has identified three opioid receptor types--mu, delta, and kappa--confirming pharmacological studies that previously postulated the existence of these three receptors. The cloned opioid receptors are highly homologous and belong to the family of seven-transmembrane, G protein-coupled receptors. With the development of novel opioid ligands, subtypes of the mu, delta, and kappa receptors have been proposed, although the molecular basis of these subtypes has not been elucidated. In this review, we present the pharmacological data supporting the concept of multiple delta opioid receptor subtypes and offer hypothetical mechanisms which might generate these "subtypes."
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles 90024, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Zaki
authors.forename: E J
authors.initials: EJ
authors.lastname: Bilsky
authors.forename: T W
authors.initials: TW
authors.lastname: Vanderah
authors.forename: J
authors.initials: J
authors.lastname: Lai
authors.forename: C J
authors.initials: CJ
authors.lastname: Evans
authors.forename: F
authors.initials: F
authors.lastname: Porreca
mesh_terms: D017398:Alternative Splicing / Q000235:genetics; D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D003001:Cloning, Molecular; D004298:Dopamine / Q000378:metabolism*; D004347:Drug Interactions; D019204:GTP-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D051379:Mice; D009292:Narcotic Antagonists / Q000494:pharmacology; D011485:Protein Binding; D017465:Receptors, Opioid, delta / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D017473:Receptors, Opioid, kappa / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D000700:Analgesics; D009292:Narcotic Antagonists; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D019204:GTP-Binding Proteins; D004298:Dopamine