Abstract
Diphenylene iodonium is an inhibitor of the enzyme NADPH-oxidase and prevents the generation of oxygen-derived free radicals in neutrophils (Cross and Jones, 1986). Here we show that diphenylene iodonium (0.25-2 microM) inhibited, according to the dose, thrombin-induced platelet-aggregation in human washed platelets and ADP-induced platelet aggregation in platelet-rich plasma. At the concentrations which inhibited platelet aggregation diphenylene iodonium did not alter platelet concentrations of cAMP or cGMP but enhanced the anti-platelet activity of iloprost, sodium nitroprusside or cultured endothelial cells. These findings highlight the importance of free radicals as platelet pro-aggregatory agents.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Diphosphate / pharmacology
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Biphenyl Compounds / pharmacology*
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Cyclic AMP / metabolism
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Cyclic GMP / metabolism
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Endothelium, Vascular / cytology
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Free Radicals
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Humans
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Iloprost / pharmacology
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In Vitro Techniques
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Leukocytes / drug effects
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Leukocytes / enzymology
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NADH, NADPH Oxidoreductases / antagonists & inhibitors
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Nitroprusside / pharmacology
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Onium Compounds / pharmacology*
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Platelet Aggregation / drug effects*
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Platelet Aggregation Inhibitors*
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Thrombin / pharmacology
Substances
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Biphenyl Compounds
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Free Radicals
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Onium Compounds
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Platelet Aggregation Inhibitors
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diphenyliodonium
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Nitroprusside
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Adenosine Diphosphate
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Cyclic AMP
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NADH, NADPH Oxidoreductases
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Thrombin
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Cyclic GMP
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Iloprost