Patterns of embolus blocking the MCA. a A representative picture showing the site of the embolus blocking the right MCA at the circle of Willis. After injection of clot, mice were transcardially perfused with saline and the brain was removed. b The position of embolus was confirmed by injection of clot labeled with fluorescent dye, marking blockage of the right MCA. c Identification of embolus positions (P) in brain 24 hours after ischemia. P1 (P1a–P1c together) indicates complete blockage of the MCA, P2 indicates that an embolus did not reach the MCA, P3 indicates that an embolus was lodged in the second branch of the MCA, P4 indicates that an embolus was lodged in the third branch of the MCA, and P5 indicates that no embolus was seen. Number of animals (n) in each position is shown in parenthesis. d Validation of embolus-induced MCA blockage by FITC-dextran infusion. A representative coronal section from a brain after venous infusion of FITC-dextran showing infarct area in the right MCA supplied regions (marked by dashed white lines) 24 hours after embolus-induced ischemia. Perfusion of FITC-dextran marks the microvessels in the unlesioned brain regions. In the peripheral part of the infarct cortex, high intensity of FITC-dextran indicates leakage of the 2,000 kDa macromolecule from microvessels into the infarct area. Section thickness, 100 μm; Scale bar, 800 μm.