Deletion of the GPIbα cytoplasmic tail impairs thrombosis in vivo. (A) Representative fluorescence images of platelets (green) with bright field images obtained from WT and 10aa^−/− mice (n = 5 mice per genotype) at the indicated times after laser-induced injury of endothelium (original magnification, ×200). Sum platelet fluorescent intensities after laser injury were calculated and plotted at 0.84-second intervals (n = 16 thrombi from 5 mice per genotype). Scale bar, 10 μm. (B) The area under curve (AUC) of fluorescent signal corresponding to platelet accumulation was calculated and plotted for each thrombus formed in WT and 10aa^−/− mice (n = 16 thrombi from 5 mice per genotype). (C) FeCl₃-induced mesenteric arteriole occlusion time in WT and 10aa^−/− mice (n = 14 mice per genotype). (D) Tail bleeding times in WT and 10aa^−/− mice (n = 15 mice per genotype). (E-F) Survival curve of WT and 10aa^−/− mice after intravenous injection of a mixture of U46619 and epinephrine (E, n = 14 mice per genotype) and PAR4-AP and epinephrine (F, n = 12 mice per genotype). Mann-Whitney U test in panels A-B,D; 2-tailed Student t test in panel C; log-rank (Mantel-Cox) test in panels E-F. Data are shown as mean ± SEM for panels A,C and median ± interquartile range (IQR) for panels B,D. ∗P < .05, ∗∗P < .01, and ∗∗∗P < .001.