Studies on pig blood platelet responses to peroxynitrite action

The action of peroxynitrite (ONOO-) on pig blood platelet function was stud ied. Incubation of washed blood platelets with ONOO- (0.062-2 mM) caused st rong, dose- and time-dependent inhibitory effects on adhesion of resting an d thrombin-stimulated platelets to collagen and on platelet aggregation ind uced 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 a cid method but did not cause any changes in blood platelet proteins as dete rmined by SDS-polyacrylamide gel electrophoresis.