Studies on pig blood platelet responses to peroxynitrite action

The action of peroxynitrite (ONOO(-)) on pig blood platelet function was studied. Incubation of washed blood platelets with ONOO(-) (0.062-2 mM) caused strong, dose- and time-dependent inhibitory effects on adhesion of resting and thrombin-stimulated platelets to collagen and on platelet aggregation induced by thrombin. The platelet responses were measured 10 s after addition of peroxynitrite to platelets ('zero time') and after 60 min incubation of platelets with ONOO(-). Exposure of blood platelets to peroxynitrite (60 min) brought about platelet lipid peroxidation assessed by the thiobarbituric acid method but did not cause any changes in blood platelet proteins as determined by SDS-polyacrylamide gel electrophoresis.