Fig. 1. Effects of heme oxygenase-1 (HO-1) induction, zinc protoporphyrin IX (ZnPP), bilirubin, and carbon monoxide on lipopolysaccharide-induced V^P/V^Rvalues, indicating platelet rolling velocity referred to erythrocyte velocity, in the periendothelial regions of the mesenteric venules. HO-1 was induced with hemin 12 h before the experiments. The data are expressed as mean ± SD of four to eight experiments in each group. *P < 0.05 as compared with the hemin-untreated control; †P < 0.05 as compared with the hemin-untreated lipopolysaccharide group.