Adhesion of WT and GPV-deficient platelets to a collagen- or vWF-coated surface.

(A) Fluorescence-labeled anticoagulated whole blood (3.15% trisodium citrate) from GPV null (−/−) or WT (+/+) mice was perfused at 1500 seconds^-1 through glass microcapillaries coated with bovine type I collagen or at 3000 seconds^-1 through glass microcapillaries coated with bovine vWF. Platelet attachment was continuously monitored by fluorescence videomicroscopy, and the number of platelets adhering to the surface during the first 10 or 20 seconds of flow was determined off-line. Results are the mean values ± SEMs from 3 to 5 separate experiments. (B) Washed platelets from GPV null (−/−) or WT (+/+) mice resuspended in Tyrode-albumin buffer containing apyrase were incubated with collagen- or bovine vWF-coated microslides in the absence of flow. The number of adherent platelets was determined at indicated time points after fixation and labeling with phalloidin-TRITC. Results are the mean values ± SEMs from 3 separate experiments.