Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 336, Issue 2, pp 204–210 | Cite as

8-Cyclopentyl-1,3-dipropylxanthine (DPCPX) — a selective high affinity antagonist radioligand for A1 adenosine receptors

  • Martin J. Lohse
  • Karl-Norbert Klotz
  • Jutta Lindenborn-Fotinos
  • Martin Reddington
  • Ulrich Schwabe
  • Ray A. Olsson


The properties of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) as an antagonist ligand for A1 adenosine receptors were examined and compared with other radioligands for this receptor. DPCPX competitively antagonized both the inhibition of adenylate cyclase activity via A1 adenosine receptors and the stimulation via A2 adenosine receptors. The K1-values of this antagonism were 0.45 nM at the A1 receptor of rat fat cells, and 330 nM at the A2 receptor of human platelets, giving a more than 700-fold A1-selectivity. A similar Al-selectivity was determined in radioligand binding studies. Even at high concentrations, DPCPX did not significantly inhibit the soluble cAMP-phosphodiesterase activity of human platelets. [3H]DPCPX (105 Ci/mmol) bound in a saturable manner with high affinity to A1 receptors in membranes of bovine brain and heart, and rat brain and fat cells (KD-values 50–190 pM). Its nonspecific binding was about 1 % of total at KD, except in bovine myocardial membranes (about 10%). Binding studies with bovine myocardial membranes allowed the analysis of both the high and low agonist affinity states of this receptor in a tissue with low receptor density. The binding properties of [3H]DPCPX appear superior to those of other agonist and antagonist radioligands for the A1 receptor.

Key words

Adenosine receptors Adenylate cyclase Phosphodiesterase Xanthines Radioligands 












XAC (“xanthine amine congener”)

8-{4-[([{(2aminoethyl)amino}carbonyl]methyl)oxy]phenyl-1,3-dipropyl-xanthine. 8-Cyclopentyl-1,3-dipropylxanthine is abbreviated DPCPX (from 1,3-dipropyl-8-cyclopentylxanthine)


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  1. Bauer AC, Schwabe U (1980) An improved assay of cyclic 3′,5′-nucleotide phosphodiesterases with QAE-Sephadex columns. Naunyn-Schmiedeberg's Arch Pharmacol 311:193–198Google Scholar
  2. Berne RM, Rall TW, Rubio R (1983) Regulatory function of adenosine. Martinus Nijhoff, Den HaagGoogle Scholar
  3. Böhm M, Brückner R, Neumann J, Schmitz W, Scholz H, Starbatty J (1986) Role of guanine nucleotide-binding protein in the regulation by adenosine of cardiac potassium conductance and force of contraction. Evaluation with pertussis toxin. Naunyn-Schmiedeberg's Arch Pharmacol 332:403–405Google Scholar
  4. Bruns RF, Daly JW, Snyder SH (1980) Adenosine receptors in brain membranes: Binding of N6-cyclohexyl[3H]adenosine and 1,3-diethyl-8-[3H]phenylxanthine. Proc Natl Acad Sci USA 77:5547–5551Google Scholar
  5. Bruns RF, Daly JW, Snyder SH (1983) Adenosine receptor binding: Structure-activity analysis generates extremely potent xanthine antagonists. Proc Natl Acad Sci USA 80:2077–2080Google Scholar
  6. Bruns RF, Lu GH, Pugsley TA (1986) Characterization of the A2 adenosine receptor labeled by [3H]NECA in rat striatal membranes. Mol Pharmacol 29:331–346Google Scholar
  7. Bruns RF, Fergus JH, Badger EW, Bristol JA, Santay LA, Hartman JD, Hays SJ, Huang CC (1987) Binding of the A1-selective antagonist 8-cyclopentyl-1,3-dipropylxanthine to rat brain membranes. Naunyn-Schmiedeberg's Arch Pharmacol 335: 59–63Google Scholar
  8. De Lean A, Hancock AA, Lefkowitz RJ (1982) Validation and statistical analysis of a computer modeling method for quantitative analysis of radioligand binding data for mixtures of pharmacological receptor subtypes. Mol Pharmacol 21: 5–16Google Scholar
  9. Dunwiddie TV (1985) The physiological role of adenosine in the central nervous system. Int Rev Neurobiol 27:63–139Google Scholar
  10. Glowinski J, Iversen LL (1966) Regional studies of catecholamines in the rat brain. J Neurochem 13:655–669Google Scholar
  11. Hoffman BB, Michel T, Brenneman TB, Lefkowitz RJ (1982) Interactions of agonists with platelet α2-adrenergic receptors. Endocrinology 110:926–932Google Scholar
  12. Honnor RC, Dhillon GS, Londos C (1985) cAMP-dependent protein kinase and lipolysis in rat adipocytes. I. Cell preparation, manipulation, and predictability in behaviour. J Biol Chem 260:15122–15129Google Scholar
  13. Jacobson KA, Ukena D, Kirk KL, Daly JW (1986) [3H]Xanthine amine congener of 1,3-dipropyl-8-phenylxanthine: An antagonist radioligand for adenosine receptors. Proc Natl Acad Sci USA 83:4089–4093Google Scholar
  14. Klotz K-N, Cristalli G, Grifantini M, Vittori S, Lohse MJ (1985) Photoaffinity labeling of A1 adenosine receptors. J Biol Chem 260:14659–14664Google Scholar
  15. Lee KS, Reddington M (1986) 1,3-Dipropyl-8-cyclopentylxanthine (DPCPX) inhibition of [3H]N-ethylcarboxamidoadenosine (NECA) binding allows the visualization of putative non-A1 adenosine receptors. Brain Res 368:394–398Google Scholar
  16. Linden J, Patel A, Sadek S (1985) [125I]Aminobenzyladenosine, a new radioligand with improved specific binding to adenosine receptors in heart. Circ Res 56:279–284Google Scholar
  17. Lohse MJ, Lenschow V, Schwabe U (1984a) Two affinity states of R1 adenosine receptors in brain membranes: Analysis of guanine nucleotide and temperature effects on radioligand binding. Mol Pharmacol 26:1–9Google Scholar
  18. Lohse MJ, Lenschow V, Schwabe U (1984b) Interaction of barbiturates with adenosine receptors in rat brain. Naunyn-Schmiedeberg's Arch Pharmacol 326:69–74Google Scholar
  19. Lohse MJ, Ukena D, Schwabe U (1985) Demonstration of R1-type adenosine receptors in bovine myocardium by radioligand binding. Naunyn-Schmiedeberg's Arch Pharmacol 328:310–316Google Scholar
  20. Lohse MJ, Klotz K-N, Schwabe U (1986) Agonist photoaffinity labelling of A1 adenosine receptors: Persistent activation reveals spare receptors. Mol Pharmacol 30:403–409Google Scholar
  21. Londos C, Cooper DMF, Wolff J (1980) Subclasses of external adenosine receptors. Proc Natl Acad Sci USA 77:2551–2554Google Scholar
  22. McKeel DW, Jarett L (1970) Preparation and characterization of a plasma membrane fraction from isolated fat cells. J Cell Biol 44:417–432Google Scholar
  23. Papesch V, Schroeder EF (1951) Synthesis of 1-mono and 1,3-disubstituted 6-aminouracils. Diuretic activity. J Org Chem 16:1879–1890Google Scholar
  24. Peterson GL (1977) A simplification of the protein assay method of Lowry et al. which is more generally applicable. Anal Biochem 83:346–356Google Scholar
  25. Schwabe U, Trost T (1980) Characterization of adenosine receptors in rat brain by (−)[3H]N6-phenylisopropyladenosine. Naunyn-Schmiedeberg's Arch Pharmacol 313:179–187Google Scholar
  26. Schwabe U, Lenschow V, Ukena D, Ferry DR, Glossmann H (1982) [125I]N6-p-Hydroxyphenylisopropyladenosine, a new ligand for R1 adenosine receptors. Naunyn-Schmiedeberg's Arch Pharmacol 321:84–87Google Scholar
  27. Schwabe U, Ukena D, Lohse MJ (1985) Xanthine derivatives as antagonists at A1 and A2 adenosine receptors. Naunyn-Schmiedeberg's Arch Pharmacol 330:212–221Google Scholar
  28. Smellie FW, Davis CW, Daly JW, Wells JN (1979) Alkylxanthines: Inhibition of adenosine-elicited accumulation of cyclic AMP in brain slices and of brain phosphodiesterase activity. Life Sci 24:2475–2482Google Scholar
  29. Van Calker D, Müller M, Hamprecht B (1978) Adenosine inhibits the accumulation of cyclic AMP in cultured brain cells. Nature (Lond) 276:839–841Google Scholar
  30. Walseth TF, Johnson RA (1979) The enzymatic preparation of [α-32P]nucleoside triphosphates, cyclic [32P]AMP and cyclic [32p]GMP. Biochim Biophys Acta 526:11–31Google Scholar
  31. Weishaar RE, Cain MH, Bristol JA (1985) A new generation of phosphodiesterase inhibitiors: multiple molecular forms of phosphodiesterase and the potential for drug selectivity. J Med Chem 28:537–545Google Scholar
  32. Williams M, Braunwalder A, Erickson TJ (1986) Evaluation of the binding of the A-1 selective adenosine radioligand cyclopentyladenosine (CPA), to rat brain tissue. Naunyn-Schmiedeberg's Arch Pharmacol 332:179–183Google Scholar

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Martin J. Lohse
    • 1
  • Karl-Norbert Klotz
    • 1
  • Jutta Lindenborn-Fotinos
    • 1
  • Martin Reddington
    • 2
  • Ulrich Schwabe
    • 1
  • Ray A. Olsson
    • 3
  1. 1.Pharmakologisches Institut der Universität HeidelbergHeidelbergFederal Republic of Germany
  2. 2.Max-Planck-Institut für PsychiatrieMartinsriedFederal Republic of Germany
  3. 3.Departments of Internal Medicine and BiochemistryUniversity of South FloridaTampaUSA

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