The role of Lyn and Fyn in integrin-dependent stable platelet adhesion to VWF under shear stress. Washed wild-type, Lyn−/−, or Fyn−/− mouse platelets were loaded onto VWF-coated glass slides with mepacrine (10 μM). Wild-type platelets were also preincubated with DMSO, RGDS (1 mM), SFK inhibitor PP2 (10 μM), P2Y1 antagonist, A3P5P (0.5 mM), and P2Y12 antagonist, 2MeSAMP (10 μM), aspirin (1 mM), or the Syk inhibitor piceatannol (10 μM) for 2 minutes, before loading onto the VWF-coated glass slides. Platelets were then subjected to constant shear rate (800 s−1) for 5 minutes. After washing, adherent platelets were viewed and photographed as described in “Platelet adhesion under shear stress.” The number of adherent platelets/field were quantitated. Data (mean ± SD) were obtained from 10 randomly selected fields from each of 4 experiments. ###P < .001, compared with wild-type platelet. ***P < .001, compared with DMSO-treated platelet; P < .001, difference between ADP receptor antagonists and PP2; P < .01, difference between ADP receptor antagonists and Lyn knockout or between aspirin and PP2; P < .05, difference between aspirin and Lyn knockout.
