Fibrinogen binding and ADP receptor function are needed for thrombus stability under flow. (A) Human blood was flowed over VWF/collagen at 1000 s–1 for 4 minutes. Thrombi were formed on coverslips (i). These were then perfused again for 10 minutes with PPACK-anticoagulated plasma containing indicated antagonists: vehicle (ii), fibrinogen-depleted plasma (iii); AR-C69931MX (30 μM) (iv), wortmannin (1 μM) (v), MRS2179 (100 μM) (vi), and AR-C69931MX plus MRS2179 (vii). Representative phase-contrast images (180 × 180 μm) are given after secondary perfusion (n = 3-5). (B) Histograms of features obtained by image analysis; estimated numbers of platelets per feature were 1 to 2, 2 to 8, 8 to 40, 40 to 130, and more than 130, as indicated. Secondary perfusion was with control plasma, fibrinogen-depleted plasma, or plasma plus AR-C69931MX (χ2 analysis). Data are shown as mean ± SEM (n = 3–5).
