Abstract
Our aim was to determine whether the newly described P2X1 antagonist NF449 [4,4′,4″,4″′-(carbonylbis(imino-5,1,3-benzenetriylbis(carbonylimino)))tetrakis-benzene-1,3-disulfonic acid octasodium salt] could selectively antagonize the platelet P2X1 receptor and how it affected platelet function. NF449 inhibited α,β-methyleneadenosine 5′-triphosphate-induced shape change (IC50 = 83 ± 13 nM; n = 3) and calcium influx (pA2 = 7.2 ± 0.1; n = 3) (pIC50 = 6.95) in washed human platelets treated with apyrase to prevent desensitization of the P2X1 receptor. NF449 also antagonized the calcium rise mediated by the P2Y1 receptor, but with lower potency (IC50 = 5.8 ± 2.2 μM; n = 3). In contrast, it was a very weak antagonist of the P2Y12-mediated inhibition of adenylyl cyclase activity. Selective blockade of the P2X1 receptor with NF449 led to reduced collagen-induced aggregation, confirming a role of this receptor in platelet activation induced by collagen. Intravenous injection of 10 mg/kg NF449 into mice resulted in selective inhibition of the P2X1 receptor and decreased intravascular platelet aggregation in a model of systemic thromboembolism (35 ± 4 versus 51 ± 3%) (P = 0.0061; n = 10) but without prolongation of the bleeding time (106 ± 16 versus 78 ± 7 s; n = 10) (N.S.; P = 0.1209). At a higher dose (50 mg/kg), NF449 inhibited the three platelet P2 receptors. This led to a further reduction in platelet consumption compared with mice injected with saline (13 ± 4 versus 42 ± 3%) (P = 0.0002; n = 5). NF449 also reduced dose-dependently the size of thrombi formed after laser-induced injury of mesenteric arterioles. Overall, our results indicate that NF449 constitutes a new tool to investigate the functions of the P2X1 receptor and could be a starting compound in the search for new antithrombotic drugs targeting the platelet P2 receptors.
Footnotes
-
This work was supported by Institut National de la Santé et de la Recherche Médicale, Association de Recherche et Développement en Médecine et Santé Publique, and Etablissement Français du Sang-Alsace.
-
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
-
doi:10.1124/jpet.105.084673.
-
ABBREVIATIONS: αβMeATP, α,β-methyleneadenosine 5′-triphosphate; NF449, 4,4′,4″,4″′-(carbonylbis(imino-5,1,3-benzenetriylbis(carbonylimino)))tetrakis-benzene-1,3-disulfonic acid octasodium salt; U46619, 9,11-dideoxy-11α,9α-epoxy-methanoprostaglandin F2α; MRS2179, 2′-deoxy-N6-methyl adenosine 3′,5′-diphosphate; TRAP-1, thrombin receptor activator peptide for protease-activated receptor-1; PGE1, prostaglandin E1; AR-C69931MX, N6-(2-methylthioethyl)-2-(3,3,3-trifluoropropylthio)-5′-adenylic acid monoanhydride dichloromethylenebis(phosfonic acid); PPACK, d-phenylalanyl-l-prolyl-l-arginine chloromethyl ketone dihydrochloride; RAM2, rat monoclonal antibody against mouse GPIIbIIIa; PRP, platelet-rich plasma; NF023, 8,8′-[carbonylbis(imino-3,1-phenylene carbonylimino)]bis(1,3,5-naphthalene-trisulfonic acid); NF279, 8,8′-(carbonylbis(imino-4,1-phenylenecarbonylimino-4,1-phenylenecarbonylimino))bis(1,3,5-naphthalenetrisulfonic acid).
- Received February 9, 2005.
- Accepted March 22, 2005.
- The American Society for Pharmacology and Experimental Therapeutics
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|