title: Mechanisms involved in the antiplatelet activity of 8-methyl-4-(1-piperazinyl)-7-(3-pyridinylmethoxy)-2H-1-benzopyran-2-one (RC414).
abstract: The effect on human platelets of 8-methyl-4-(1-piperazinyl)-7-(3-pyridinylmethoxy)-2H-1-benzopyran-2-one (RC414) was tested in vitro by measuring aggregation induced by several agonists, cAMP and cGMP levels, cAMP phosphodiesterase and PKC activities and [Ca2+]i. The RC414 effect on nitric oxide production was also evaluated. RC414 in a dose-dependent manner inhibited aggregation both in platelet rich plasma and in washed platelets. It was particularly effective in platelets challenged by collagen, ADP and thrombin: IC50 values are 0.51 +/- 0.12 microM, 0.98 +/- 0.36 microM and 1.00 +/- 0.15 microM, respectively. RC414 increased cAMP levels, through the specific inhibition of the cAMP high affinity phosphodiesterase (IC50 = 1.73 +/- 0.35 microM). RC414 reduced [Ca2+]i transients and PKC activation induced by thrombin. In addition RC414 was able to increase nitric oxide formation involving the stimulation of constitutive nitric oxide synthase enzyme. In conclusion, RC414 exerts its powerful anti-platelet activity by increasing cAMP intracellular levels and nitric oxide formation.
authors.affiliation: Department of Experimental Medicine, Biochemistry Section, University of Genoa, Viale Benedetto XV 1, 16132 Genova, Italy. leoncini@unige.it
authors.forename: Giuliana
authors.initials: G
authors.lastname: Leoncini
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Signorello
authors.forename: Debora
authors.initials: D
authors.lastname: Bruzzese
authors.forename: Mario
authors.initials: M
authors.lastname: Di Braccio
authors.forename: Gian Carlo
authors.initials: GC
authors.lastname: Grossi
authors.forename: Giorgio
authors.initials: G
authors.lastname: Roma
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism; D001120:Arginine / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D002867:Chromones / Q000737:chemistry / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D004347:Drug Interactions; D006801:Humans; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000378:metabolism; D010879:Piperazines / Q000737:chemistry / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology
chemical_list: D002867:Chromones; D010879:Piperazines; D010975:Platelet Aggregation Inhibitors; C484743:RC414; D009569:Nitric Oxide; D001120:Arginine; D000242:Cyclic AMP; D011493:Protein Kinase C; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D013917:Thrombin; D006152:Cyclic GMP; D002118:Calcium