2 chloro n6 cyclopentyladenosine

[³H]-1,3-Dipropyl-8-cyclopentyl-xanthine ([³H]-DPCPX, specific activity 113.4 Ci · mmol⁻¹) was purchased from ARC, Inc. (St. Louis, MO). The Wheat Germ Agglutinin-Polyvinyl toluene (WGA-PVT) SPA beads (RPNQ0001) were purchased from PerkinElmer (Waltham, MA). Adenosine deaminase (ADA) was purchased from Boehringer Mannheim (Mannheim, Germany). 1,3-Dipropyl-8-cyclopentyl-xanthine (DPCPX, a selective hA₁R antagonist [23 (link)]), 8-cyclopentyl-3-N-[3-((3-(4-fluorosulphonyl)benzoyl)-oxy)-propyl]-1-N-propyl-xanthine (FSCPX, an irreversible hA₁R antagonist [24 (link)]), 2-chloro-N⁶-cyclopentyladenosine (CCPA, a selective hA₁R agonist [25 (link)]), N⁶-cyclopentyladenosine (CPA, a selective hA₁R agonist [25 (link)]), 5′-N-ethylcarboxamidoadenosine (NECA, a non-selective agonist for adenosine receptors [26 (link)]), and guanosine-5′-triphosphate (GTP) were purchased from Sigma (St. Louis, MO). BCA (bicinchoninic acid) protein assay kit was obtained from Pierce Chemical Company (Rockford, IL). LUF5834 (an hA₁R partial agonist) was synthesized in our laboratory as described previously [27 (link)]. Chinese hamster ovary (CHO) cells stably expressing the hA₁R were obtained from Prof. Steve Hill (University of Nottingham, UK). All other chemicals were of analytical grade and obtained from standard commercial sources.