FIGURE 3.

Down-regulation of ADP-induced platelet aggregation by P18, P24, and Ap2A. WP (3 × 10⁸ platelets/ml) were preincubated for 2 min in the absence (control) or in the presence of increasing concentrations (1, 5, and 10 μm) of P18 (black squares), P24 (black rhombuses), or Ap2A (black triangles) and then incubated for 3 min with 2.5 μm ADP. Results are expressed as percentage of inhibition relative to controls and are the mean ± S.D. of at least three different experiments, performed on platelets from different donors.