Disaggregation of platelet aggregates formed by the action of thrombin in the presence of hydrogen peroxide.
The aggregation and change in the intracellular Ca2+ concentration induced by thrombin (0.005-0.22 U/ml) in the presence of H2O2 (0.05-0.6 mM) was investigated. Under the chosen experimental conditions (incubation time of platelets with H2O2 not more than 15 sec), H2O2 neither accelerated nor inhibited the thrombin-induced platelet aggregation. However, platelet aggregates formed by the action of thrombin in the presence of H2O2 were unstable and disaggregated. Disaggregation was abolished by catalase added after thrombin. The disaggregation effect was dose-dependent; the process of disaggregation was confirmed by electron microscopy. Hydrogen peroxide did not influence thrombin-induced increase in the intracellular Ca2+ concentration, but dose-dependently accelerated Ca2+ extrusion from the platelet cytoplasm.
Loiko
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Department of Biochemistry, Belarusian State University, pr. F. Skoriny 4, Minsk 220050, Belarus. Loiko@bsu.by
Samal
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Lapsha
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D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007700:Kinetics; D010974:Platelet Aggregation / Q000187:drug effects*; D013917:Thrombin / Q000494:pharmacology*
D006861:Hydrogen Peroxide; D013917:Thrombin; D002118:Calcium