The effect of thrombin inhibition on light/dye–induced thrombus formation in cerebral vessels. Effect of treatment with a direct thrombin inhibitor on light/dye–induced thrombus formation in cerebral venules (A) and arterioles (B) of WT and β^s mice. WT→WT and β^s→WT received either hirudin (1 mg/kg) or ATIII (20 mg/kg) 5-20 minutes before the onset of light/dye–induced thrombosis, and the time taken for flow to cease was recorded in cerebral venules (A) and arterioles (B). Data are shown as the means ± SEM. *P < .05 compared with the corresponding WT→WT group; **P < .05 compared with the corresponding WT→WT group; ***P < .05 compared with the corresponding WT→WT group; #P < .05 compared with the corresponding β^s→WT group; ##P < .05 compared with the corresponding β^s→WT group; ###P < .05 compared with the corresponding β^s→WT group. n = 5-6 mice/group.