Figure 2.

Effect of histamine on leukocyte rolling and P-selectin expression in vWf-deficient mice. (A) Mice were injected intraperitoneally with histamine, and 15 min later mesenteric venules were observed through intravital microscopy. Numbers of rolling leukocytes (L. Number) and their velocity (L. Velocity) were measured in vWf +/+ (black bars) and vWf −/− (gray bars) mice (n = 7). *, P < 0.0001 compared with vWf +/+. (B) Mouse mesentery from wild-type (vWf +/+) or vWf-deficient (vWf −/−) mice were collected before (unstimulated) and 15 min after (stimulated) treatment, fixed, sectioned, and stained for P-selectin. No staining can be seen in the resting mesenteries of either genotype. Staining becomes bright brown in vWf +/+ but not in vWf −/− mesentery after histamine treatment.