Inhibition by N-acetyl neuraminic (sialic) acid of platelet aggregation induced by different stimuli.

Addition of N-acetyl neuraminic acid (sialic acid, NANA) to citrated rat platelet-rich plasma significantly inhibited aggregation induced by near-threshold concentration of ADP, collagen or thrombin. In heparinized rat platelet-rich plasma aggregation of platelets induced by endotoxin or tumour cells of various origins was also inhibited by sialic acid. It is suggested that exogenous or endogenous sialic acid may act against various aggregating stimuli on the platelet membrane by masking a common factor through which various aggregating agents exert their effect.