Platelets derived from mice genetically deficient in α2β1 integrin and/or GPVI-FcRγ demonstrate critical roles for both receptors during platelet deposition on fibrillar collagen under flow. Whole blood from the specified mice was perfused over an immobilized collagen surface for 4 minutes. (A) Surface coverage area of platelets from α2β1–/– (▦), GPVI-FcRγ–/– (□), GPVI-FcRγ–/–; α2β1–/– (▪), and wild-type (▨) after flow. The results shown are the mean ± SEM (n = 6-11). Statistical significance (P < .01) was seen between the knockouts and the control at and between 400 and 1300 s–1. (B) Representative phase-contrast images after perfusion. The lines seen in the upper left portions of some panels are visual artifact and do not arise due to abnormalities in the collagen-coated surface.
