title: Synergistic disaggregation of platelets by the products of endothelial cells or their analogs.
abstract: It is known that some products of endothelial cells or their analogs can attenuate the platelet aggregation response and initiate the platelet disaggregation response. Since platelets are involved in the initiation of many clinically important occlusive vascular diseases, we hypothesized that the endothelial cell products act synergistically to disperse platelet aggregates. In this study we examined the synergistic platelet disaggregating effects among the products of endothelial cells. We used urokinase, prostaglandin I2 (PGI2), and sodium nitroprusside (SNP) (which is the chemical substitute as nitric oxide(NO)-donor) for endothelium-derived relaxing factor (EDRF). Platelet disaggregation rate was increased in a dose-dependent manner and decreased in a time-dependent manner, and the combined use of two or three agents had synergistic effects on platelet disaggregation. Furthermore, flow cytometric analysis showed decreases in the binding of fibrinogen to activated platelets by the addition of PGI2 or SNP. These data revealed that these products or their analogs could inactivate the activated platelets or aggregated platelets by detaching fibrinogen from platelets. In addition our data revealed that PGI2 and SNP can act synergistically with fibrinolytic agents. These findings suggest a potential strategy for improving the efficacy of thrombolytic therapy by a combination of these products or their substitutes.
authors.affiliation: The First Department of Internal Medicine, Hirosaki University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Takami
authors.forename: Y
authors.initials: Y
authors.lastname: Tamai
authors.forename: M
authors.initials: M
authors.lastname: Narita
authors.forename: K
authors.initials: K
authors.lastname: Mayama
authors.forename: A
authors.initials: A
authors.lastname: Munakata
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004730:Endothelium, Vascular / Q000737:chemistry / Q000378:metabolism*; D011464:Epoprostenol / Q000494:pharmacology; D005340:Fibrinogen / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007700:Kinetics; D009569:Nitric Oxide / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010959:Tissue Plasminogen Activator / Q000494:pharmacology; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology
chemical_list: D010975:Platelet Aggregation Inhibitors; D009599:Nitroprusside; D009569:Nitric Oxide; D000244:Adenosine Diphosphate; D005340:Fibrinogen; D011464:Epoprostenol; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator