Dual antiplatelet treatment with aspirin and a P2Y₁₂antagonist is similar to treatment with either drug alone. Representative photomicrographs showing the response to laser-induced injury in mouse cremaster arterioles 3 minutes after injury. All platelets are labeled with anti-CD41 (red), and degranulated platelets are labeled with anti–P-selectin (green; overlay of red and green is yellow). The fluorescence channels were binarized and are displayed overlaid on the bright-field channel. The response to injury is shown for mice treated with vehicle, aspirin alone, cangrelor alone, or aspirin and cangrelor. Scale bar, 10 µm. Arrows indicate the direction of blood flow.