Hydrogen peroxide has a role in the aggregation of human platelets

Abstract The aggregation of platelets induced by soluble and particulate stimuli is enhanced by the addition of minute amounts of H 2 O 2 . Externally added catalase strongly inhibits the aggregation induced by particulate stimuli and by phorbol myristate acetate (PMA). The addition of aminotriazole to stimulated platelets causes a significant inhibition of intracellular catalase. This indicates the formation of H 2 O 2 inside the platelets during activation. No effects were observed when the platelets were stimulated by the ionophore A23187.