Modulation of platelet aggregation and protein release by aspirin. Equal volumes of platelets (2.5 × 108) were stimulated with ADP, TRAP, and collagen in the presence or absence of low-dose aspirin (20 μM). The aggregation response was plotted (mean ± standard deviation [SD] of 3 independent experiments using different donors) (A). Platelet releasate from a single representative donor was visualized using coomassie-stained (4%-20% acrylamide) and silver-stained (16% acrylamide) gels (B). Thromboxane levels in the platelet releasate (mean ± SD of 3 experiments) were plotted for each fraction (C).