α Granule release during thrombus formation in vivo is impaired in VAMP-7^−/− mice. (A) Platelet-specific anti-CD42b antibody conjugated to DyLight 649 (0.1 μg/g body weight) and anti-PF4 monoclonal antibody conjugated to Alexa Fluor 488 (0.5 μg/g body weight) were infused into the mice. Representative binarized images of the appearance of fluorescence signals associated with PF4 (green) and platelets (red) after laser-induced vessel wall injury in wild-type and VAMP-7^−/− mice are shown. (B) Median integrated platelet fluorescence intensity in wild-type (light red) and VAMP-7^−/− mice (dark red). (C) Median integrated PF4 fluorescence intensity at the injury site in wild-type (light green) and VAMP-7^−/− mice (dark green) are plotted vs time. Wild-type mice, n = 28; VAMP-7^−/− mice, n = 23.