title: Direct inhibition of platelet function by organic nitrates via nitric oxide formation.
abstract: This study investigates the mechanisms of platelet inhibition by the nitrate esters isosorbide dinitrate, isoidide dinitrate, isomannide dinitrate, isosorbide 2-mononitrate and isosorbide 5-mononitrate as compared to the spontaneous nitric oxide (NO)-donor linsidomine, the active metabolite of molsidomine. Nitrates and linsidomine dose-dependently inhibited aggregation, ATP secretion and thromboxane formation of washed human platelets at a rank order of potency, identical with that for stimulation of cyclic GMP in cultured rat lung fibroblasts. While linsidomine (0.1 mM) caused a 3-fold platelet cGMP elevation, there was a weak (< or = 30%) but significant cGMP stimulation by organic nitroesters, which was tightly correlated with inhibition of platelet aggregation (r = 0.926, P = 0.008). Zaprinast (2 microM) potentiated, while methylene blue (1 microM) and oxyhemoglobin (10 microM) reversed the antiaggregatory effects. Linsidomine (0.5 microM-0.1 mM) dose-dependently released NO in a cell-free system. No spontaneous NO release was detected with organic nitroesters (0.1 mM). These data suggest that, to some extent, bioactivation of organic nitroesters occurs in platelets, resulting in platelet inhibition via the NO/cGMP system.
authors.affiliation: Institut für Pharmakologie, Heinrich-Heine-Universität Düsseldorf, FRG.
authors.forename: A A
authors.initials: AA
authors.lastname: Weber
authors.forename: H
authors.initials: H
authors.lastname: Strobach
authors.forename: K
authors.initials: K
authors.lastname: Schrör
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D016880:Anisotropy; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004952:Esters; D005347:Fibroblasts; D006801:Humans; D008168:Lung / Q000166:cytology / Q000187:drug effects; D008981:Molsidomine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009566:Nitrates / Q000378:metabolism / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D051381:Rats; D013931:Thromboxanes / Q000378:metabolism
chemical_list: D004952:Esters; D009566:Nitrates; D010975:Platelet Aggregation Inhibitors; D013931:Thromboxanes; D009569:Nitric Oxide; C002385:linsidomine; D000255:Adenosine Triphosphate; D008981:Molsidomine; D006152:Cyclic GMP