Effect of ADP scavengers on GPVI-mediated platelet aggregation.

Washed, aspirin-treated human platelets were treated with an ADP scavenger system, creatine phosphate (10 mM), and creatine phosphokinase (40 U/mL), then challenged with various concentrations of convulxin (A), CRP (B), and collagen (C). Extent of aggregation was measured 210 seconds after the addition of the agonist in the absence (●) or presence (○) of the ADP scavenger system. The maximum aggregation extent in the absence of the ADP scavenger system was taken as 100% and the remaining values were normalized to this value. In the case of collagen, extent of aggregation in the presence of SC57101, a fibrinogen receptor antagonist, was taken as zero. Each data point is the mean ± SE of 3 measurements with different donors.