Accumulation of P2X1-expressing PMNs activated by ATP is required for fibrin generation. (A) The graph represents the median of Ly6-G–integrated fluorescence intensity (left) and the sum of the medians of Ly-6G–integrated fluorescence intensity (right) in WT mice (n = 21 thrombi, 4 mice) or P2X1^−/− mice (n = 26 thrombi, 4 mice) (P < .05). (B) Fibrin generation (green) at the site of injury for 29 thrombi in 3 WT mice and 30 thrombi in 3 in P2X1^−/− mice. Graphs represent median of fibrin-integrated fluorescence intensity (left) and the sum of the medians of fibrin-integrated fluorescence intensity in the 2 genotypes (right) (*P < .05).