title: Introduction of alkynyl chains on C-8 of adenosine led to very selective antagonists of the A(3) adenosine receptor.
abstract: Some 8-alkynyladenosines were synthesized and evaluated for their adenosine receptor activity, utilizing radioligand binding studies (A(1), A(2A), A(3)) or adenylyl cyclase activity assays (A(2B)). Furthermore, the maximal induction of guanosine 5'-(gamma-thio)triphosphate ([35S]GTPgammaS) binding to G proteins and the inhibition of NECA-stimulated binding, in membranes of CHO cells which express the human A(3) receptor, were used to determine the intrinsic activity of these nucleosides at the A(3) adenosine receptor. The results showed that these new adenosine derivatives are very selective ligands for the A(3) receptor subtype and behave as adenosine antagonists, since they do not stimulate basal [35S]GTPgammaS binding, but inhibit NECA-stimulated binding. This is the first report that adenosine derivatives, with unmodified ribose moiety, are adenosine receptor antagonists.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Camerino, 62032, Camerino, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Volpini
authors.forename: S
authors.initials: S
authors.lastname: Costanzi
authors.forename: C
authors.initials: C
authors.lastname: Lambertucci
authors.forename: S
authors.initials: S
authors.lastname: Vittori
authors.forename: K
authors.initials: K
authors.lastname: Klotz
authors.forename: A
authors.initials: A
authors.lastname: Lorenzen
authors.forename: G
authors.initials: G
authors.lastname: Cristalli
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology*; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000032:analysis / Q000378:metabolism; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D016466:CHO Cells; D006224:Cricetinae; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D058915:Purinergic P1 Receptor Antagonists; D011869:Radioligand Assay; D012680:Sensitivity and Specificity
chemical_list: D058915:Purinergic P1 Receptor Antagonists; D019830:Adenosine-5'-(N-ethylcarboxamide); D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D000241:Adenosine