[Antioxidants, lipid peroxidation, and receptor-dependent increase in Ca2+ concentration in human platelets]

Content of tocopherol and total antiradical activity of hydrophobic antioxidants were estimated in human blood platelets. Two hydrophobic antioxidants--tocopherol and ubiquinone were detected in hexane extracts of thrombocytes using thin-layer chromatography. After incubation of thrombocytes with N-ethyl maleimide content of malonyl dialdehyde was increased and of tocopherol--decreased, receptor-dependent increase of Ca2+ concentration in cytoplasm was potentiated, while the Ca(2+)-blocking effect of nitroglycerol was decreased. Nitroglycerol did not inhibit the N-ethyl maleimide effect on content of malonyl dialdehyde in blood platelets. Addition of exogenous vitamin E to thrombocytes did not affect the receptor-dependent increase of Ca2+ concentration. Ascorbic acid inhibited the receptor-dependent increase of Ca2+ concentration. The data obtained suggest that nitrates may be used more rationally in combination with antioxidants and/or inhibitors of cyclooxygenase.