Alterations in lipid peroxidation of thrombin-stimulated rat platelets treated with beta-adrenoceptor blocking drugs.

Thrombin-stimulated formation of malondialdehyde in isolated rat platelets was time- and dose-dependent and occurred in parallel with thromboxane B 2 production and platelet aggregation. β-Adrenoceptor blocking drugs inhibited thrombin-stimulated malondialdehyde formation according to their liposolubility in the rank order of potency: atenolol < practolol < oxprenolol < metipranolol ≃ alprenolol ≃ propranolol. In platelets pretreated with β-blockers and stimulated with thrombin, a positive correlation was found between malondialdehyde formation and inhibition of aggregation, arachidonic acid liberation from membrane phospholipids as well as thromboxane production