title: [(3)H]8-Ethyl-4-methyl-2-phenyl-(8R)-4,5,7,8-tetrahydro-1H-imidazo[2,1-i]-purin-5-one ([(3)H]PSB-11), a novel high-affinity antagonist radioligand for human A(3) adenosine receptors.
abstract: This study describes the preparation and binding properties of [(3)H]PSB-11, a novel, potent, and selective antagonist radioligand for human A(3) adenosine receptors (ARs). [(3)H]PSB-11 binding to membranes of Chinese hamster ovary (CHO) cells expressing the human A(3) AR was saturable and reversible. Saturation experiments showed that [(3)H]PSB-11 labeled a single class of binding sites with high affinity (K(D)=4.9 nM) and limited capacity (B(max)=3500 fmol/mg of protein). PSB-11 is highly selective versus the other adenosine receptor subtypes. The new radioligand shows an extraordinarily low degree of non-specific binding rendering it a very useful tool for studying the (patho)physiological roles of A(3 )ARs.
authors.affiliation: Pharmaceutical Institute, University of Bonn, Kreuzbergweg 26, D-53115 Bonn, Germany. christa.mueller@uni-bonn.de
authors.forename: Christa E
authors.initials: CE
authors.lastname: Müller
authors.forename: Martina
authors.initials: M
authors.lastname: Diekmann
authors.forename: Mark
authors.initials: M
authors.lastname: Thorand
authors.forename: Vita
authors.initials: V
authors.lastname: Ozola
mesh_terms: D000818:Animals; D016466:CHO Cells; D002384:Catalysis; D006224:Cricetinae; D006801:Humans; D006865:Hydrogenation; D007093:Imidazoles / Q000138:chemical synthesis / Q000494:pharmacology*; D007700:Kinetics; D008566:Membranes / Q000378:metabolism; D058915:Purinergic P1 Receptor Antagonists; D011687:Purines / Q000138:chemical synthesis / Q000494:pharmacology*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000494:pharmacology*; D043684:Receptor, Adenosine A3
chemical_list: C438613:8-ethyl-4-methyl-2-phenyl-4,5,7,8-tetrahydro-1H-imidazo(2,1-i)purin-5-one; D007093:Imidazoles; D058915:Purinergic P1 Receptor Antagonists; D011687:Purines; D019275:Radiopharmaceuticals; D043684:Receptor, Adenosine A3