Abstract
2-(Ar)alkoxyadenosines, which are agonists selective for the A2AAR in PC 12 cell and rat striatum membranes, are also agonists at the A2AR coupled to adenylate cyclase (AC) that mediates the inhibition of platelet aggregation. A panel of twelve well-characterized adenosine analogues stimulated human platelet AC and inhibited ADP-induced platelet aggregation at sub- to low-micromolar concentrations with a potency ranking CGS 21680 < adenosine < R-PIA. There were significant correlations between the ECso of anti-aggregatory activity and either the ECso of stimulation of platelet and PC 12 cell AC (r 2 = 0.66 and 0.67, respectively) or the K1 of inhibition of [3H]NECA binding to the rat striatum membranes (r 2 = 0.75). Likewise, platelet AC stimulation correlated well with stimulation of PC 12 cell AC and with [3H]NECA binding (r 2 = 0.94 and 0.91, respectively). Ten 2-(ar)alkoxyadenosines stimulated platelet AC at EC50s ranging between 0.16 and 2.3 μM and inhibited platelet aggregation at EC50s ranging between 2 and 30 μM. There were no correlations between the EC50s of anti-aggregatory activity and either the EC50s of the stimulation of platelet or PC 12 AC (r 2 = 0.08 and 0.06, respectively) or with the K1 of the inhibition of [3H]NECA binding to the A2aAR in rat striatum (r 2 = 0.02). The EC50s of the stimulation of platelet AC correlated with those of the stimulation of PC 12 AC (r 2 = 0.48), and also with the K1 of [3H]NECA binding (r 2 = 0.71). Each of the 23 adenosines completely inhibited platelet aggregation and thus, functionally, all behaved as full agonists. As stimulants of PC 12 cell AC, Group A and B analogues were equally efficacious. As stimulants of platelet AC, however, the efficacy relative to NECA ( = 1.0) of Group B analogues was significantly less than that of Group A analogues, 0.49 ± 0.2 vs. 0.72 ± 0.05, P±0.01. The partial agonist activity of Group B analogues at the platelet A2AR but full agonist activity at the PC 12 cell A2aAR, as well as the relatively low correlations between platelet AC stimulation and other indices of A2aAR agonist actlVlty, suggest the platelet receptor is not a typical A2aAR. Further, the lack of a correlation between the platelet anti-aggregatory and AC stimulatory activity suggests that (a) the 2-(ar)alkoxyadenosines might affect platelet aggregation by mechanisms other than AC stimulation or (b) that the stimulation of the platelet membrane AC by 2-(ar)alkoxy-adenosines does not correspond to the accumulation of cyclic AMP in intact platelets.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Born R, Cross MJ (1963) The aggregation of blood platelets. J Physiol 168: 178–195
Brackett LE, Daly JW (1993) Characterization of the A2b adenosine (ADO) receptor in NIH 3T3 bibroblasts. FASEB J7:A 693
Bruns RF (1980) Adenosine receptor activation in human fibroblasts. Nucleoside agonists and antagonists. Can J Physiol Pharmacal 58: 673–691
Bruns RF, Lu OH, Pugsley TA (1986) Charactenzation of the A2 adenosine receptor labeled by [3H]NECA in rat striatal membranes. Mol. Pharmacal 29:331–346
Cheng YC, Prusoff WH (1973) Relationship between the inhibition constant K1 and the concentration of inhibitor which causes 50 percent inhibition (I50) of an enzymatic reaction. Biochem Pharmacal 22:3099–3108
Cornfield LJ, Hu S, Hurt SD, Sills MA (1992) [3H]2-phenylaminoadenosine (3H]CV 1808) labels a novel adenosine receptor in rat brain. J Pharmacal Exp Ther 263:552–561
Cristalli G, Franchetti P, Orifantim M, Vittori S, Klotz K-N, Lohse MJ (1988) Adenosine receptor agonists: Synthesis and biological evaluation of l-deaza analogues of adenosine derivatIves. J Med Chem 31:1179–1183
Cristalli G. Eleuteri A. VIttori S, Volpini R, Lohse MJ. Klotz KN (1992) 2-Alkynyl derivatives of adenosine and N-ethyladenosine-5'-uronamide as selective agonists at A2 adenosine receptors. J Med Chem 35:2363–2368
Cusack NJ, Hourani SMO (1990) Subtypes of P2-purinoceptors: Studies using ATP analogues. Ann NY Acad Sci 603: 172–181
Daly JW, Padgett WL (1992) Agomst activity of 2- and 5'-substituted adenosine analogues and their N6-cycloalkyl derivatives at A1 - and A2-adenosine receptors coupled to adenylate cyclase. Biochem Pharmacol 43:1089–1093
Daly JW, Butts-Lamp P, Padgett W (1983) Subclasses of adenosine receptors rn the central nervous system: Interaction with caffeine and related methylxanthines. Cell Mol Neurobrol 3:69–80
Daly JW, Padgett WL, Secunda SI, Thompson RD, Olsson RA (1993) Structure-activity relationships for 2-substituted adenosines at A1 and A2 adenosine receptors. Pharmacology 46:91–100
Dionisotti S. Zocchi C, Varam K, Borea PA, Ongim E (1992) Effects of adenosrne derivatives on human and rabbit platelet aggregation. Correlation of adenosine receptor affinities and antiaggregatory activity. Naunyn-Schmiedebergs Arch Pharmacol 346:673–676
Fleysher MH (1972) N6-substituted adenosines: Synthesis, biological activity, and some structure-activity relationships, J Med Chem 15:187–191
Hamilton HW, Taylor Md, Steffen RP, Haleen SJ, Brum RF (1987) Correlation of adenosrne receptor affinities and cardiovascular actIvity. Life Sci 41:2295–2302
Haslam RJ, Cusack NJ (1981) Blood Platelet receptors for ADP and for adenosine. In: G Burnstock (ed) Purinergic receptors. Chapman and Hall. New York, pp 223–285
Haslam RJ, Rosson OM (1975) Effects of adenosine on levels of adenosine cyclic 3',5'-monophosphate in human blood platelets in relation to adenosine incorporation and platelet aggregation. Mol Pharmacal 11:528–544
Hutchison KA, Nevins B, Perini F, Fox IJ (1990) Soluble and membrane-associated human low-affinity adenosine-binding protein (adenotin): Properties and homology with mammalian and avian stress proteins. Biochemistry 29:5138–5144
Kusachi S, Thompson RD, Olsson RA (1983) Ligand selectivity of dog coronary adenosine receptor resembles that of adenylate cyclase stimulatory (Ra) receptors. J Pharmacol Exp Ther 227:316–321
Lohse MJ, Elger B, Lindenborn-Fotinos J, Klotz K-N, Schwabe U (1988 a) Separation of solubilized A2 adenosine receptors of human platelets from non-receptor [3H]NECA binding sites by gel filtratron. Naunyn-Schmiedebergs Arch Pharmacal 337:64–68
Lohse MJ, Klotz KN, Schwabe U, Cristalli G, Vittori S, Orifantini M (1988 b) 2-Chloro-N6-cyclopentyladenosine: a highly selective agonist at AI adenosine receptors. Naunyn-Schmiedebergs Arch Pharmacal 337:687–689
Londos C, Cooper DMF, Wolff J (1980) Subclasses of external adenosine receptors. Proc Natl Acad Sci USA 77:2551–2554
Martin PL (1992) Relative agonist potencies of C2-substituted analogues of adenosine: eVIdence for adenosine A2b receptors in the guinea pig aorta. Eur J Pharmacal 216:235–242
Niiya K, Thompson RD, Silvia SK, Olsson RA (1992) 2-(N’-aralkylidenehydrazino) adenosines: Potent and selective coronary vasodilators. J Med Chem 35:4562–4566
Olsson RA, Kusachi S, Thompson RD, Ukena D, Padgett W, Daly JW (1986) N6-substituted N-alkyladenosine-5’-uronamides. J Med Chem 29: 1683–1689
Prasad RN, Bariana DS, Fung A, Savic M, Tietje K, Stein HH, Brondyk H, Egan RS (1980) Modification of the 5’ position of purine nucleosides. 2. Synthesis and cardiovascular propertIes of adenosine-5’-(N-substituted) carboxamides. J Med Chem 23:313319
Robins MJ, Uznanski B (1981) Nucleic acid related compounds. 34. Non-aqueous diazotization with tert-butyl nitrite. Introduction of fluorine, chlorine and bromine at C-2 of purine nucleosides. Can J Chem 59:2608–2611
Snedecor OW, Cochran WO (1967) Statistical methods, 6th ed. Iowa State Umversity Press, Ames, Iowa
Stehle OH, Rivkees SA, Lee JJ, Weaver DR, Deeds JD, Reppert SM (1992) Molecular cloning and expression of the cDNA for a novel A2-adenosine receptor subtype. Mol Endocrinol 6:384–393
Thompson RD, Secunda S, Daly JW, Olsson RA (1991) Activity of N6-substituted 2-chloroadenosrnes at A1 and A2 adenosine receptors. J Med Chem 34:3388–3390
Ueeda M, Thompson RD, Arroyo L, Olsson RA (1991 a) 2-Alkoxyadenosines: Potent and selective agomsts at the coronary artery A, adenosine receptor. J Med Chem 34: 1340–1344
Ueeda M, Thompson RD, Arroyo L, Olsson RA (1991 b) 2-Aralkoxyadenosines: Potent and selective agonists at the coronary artery A2 adenosine receptor. J Med Chem 34: 1340–1344
Ueeda M, Thompson RD, Padgett WL, Secunda S, Daly JW, Olsson RA (1991 c) Cardiovascular actions of adenosrnes, but not adenosine receptors, differ in rat and guinea pig. Life SCI 49: 1351–1358
Ukena D, Bohme E, Schwabe U (1984) Effects of severa15'-carboxamide derivatives of adenosine on adenosine receptors of human platelets and rat fat cells. Naunyn-Schmiedebergs Arch Pharmacol 327:36–42
Ukena D, Olsson RA, Daly JW (1987) Definition of subclasses of adenosine receptors associated with adenylate cyclase: interaction of adenosine analogs with inhibitory A1 receptors and stimulatory A2 receptors. Can J Physiol Pharmacol 65:365–376
Van Calker D, Muller M, Hamprecht B (1979) Adenosine regulates via tv-o separate receptors, the accumulation of cyclic AMP in cultured bram cells. J Neurochem 33:999–1005
Watson S, Abbott A (1992) Adenosme receptors. Trends Pharmacol Sci, Receptor Supplement 3
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Cristalli, G., Vittori, S., Thompson, R.D. et al. Inhibition of platelet aggregation by adenosine receptor agonists. Naunyn-Schmiedeberg's Arch. Pharmacol. 349, 644–650 (1994). https://doi.org/10.1007/PL00004904
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/PL00004904