Reversibility of the TRAP-induced decrease of the platelet surface expression of GPIb. A total of 15 μmol/L TRAP (•) was added at t = 0 minutes to Orgaran anticoagulated whole blood (+ dRGDW) at 37°C. As a control, no agonist (○) was added. The samples were fixed with 1% paraformaldehyde at the indicated time points. The binding of the GPIb-specific MoAb 6.20 at t = 0 minutes (before TRAP was added) was assigned 100 arbitrary units of fluorescence. Data are the mean of two separate experiments.