title: Novel selective antagonist radioligands for the pharmacological study of A(2B) adenosine receptors.
abstract: The adenosine A(2B) receptor is the least well characterized of the four adenosine subtypes due to the lack of potent and selective agonists and antagonists. Despite the widespread distribution of A(2B) receptor mRNA, little information is available with regard to their function. The characterization of A(2B) receptors, through radioligand binding studies, has been performed, until now, by using low-affinity and non-selective antagonists like 1,3-dipropyl-8-cyclopentylxanthine ([(3)H]DPCPX),(4-(2-[7-amino-2-(2-furyl)-[1,2,4]triazolo-[2,3-a][1,3,5]triazin-5-ylamino]ethyl)-phenol ([(3)H]ZM 241385) and 3-(3,4-aminobenzyl)-8-(4-oxyacetate)phenyl-1-propyl-xanthine ([(125)I]ABOPX). Recently, high-affinity radioligands for A(2B) receptors, [N-(4-cyanophenyl)-2-[4-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8-yl)-phenoxy]acetamide ([(3)H]MRS 1754), N-(2-(2-Phenyl-6-[4-(2,2,3,3-tetratritrio-3-phenylpropyl)-piperazine-1-carbonyl]-7H-pyrrolo[2,3-d]pyrimidin-4-ylamino)-ethyl)-acetamide ([(3)H]OSIP339391) and N-benzo[1,3]dioxol-5-yl-2-[5-(1,3-dipropyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-yl)-1-methyl-1H-pyrazol-3-yloxy]-acetamide] ([(3)H]MRE 2029F20), have been introduced. This minireview offers an overview of these recently developed radioligands and the most important applications of drugs towards A(2B) receptors.
authors.affiliation: Department of Clinical and Experimental Medicine, Pharmacology Unit and "Interdisciplinary Center for the Study of Inflammation (ICSI),", Ferrara, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Gessi
authors.forename: Katia
authors.initials: K
authors.lastname: Varani
authors.forename: Stefania
authors.initials: S
authors.lastname: Merighi
authors.forename: Edward
authors.initials: E
authors.lastname: Leung
authors.forename: Stephen
authors.initials: S
authors.lastname: Mac Lennan
authors.forename: Pier Giovanni
authors.initials: PG
authors.lastname: Baraldi
authors.forename: Pier Andrea
authors.initials: PA
authors.lastname: Borea