Effect of cast placement around carotid arteries on eNOS-GFP fluorescence. (A) Fluorescence of eNOS-GFP was imaged in the right carotid artery after the installation of a tapering cast (dashed line). The arrow indicates the position where the cast was situated (high shear stress region). The direction of the blood flow was from left to right. (B) Relationship between shear stress and eNOS-GFP fluorescence. Representative example of the relationship between the calculated shear stress and eNOS-GFP fluorescence along a linear segment of the carotid artery of an individual mouse. (C) Effect on eNOS-GFP fluorescence following downstream ligation of the carotid artery with a tapering cast or (D) placement of a nontapering cast. Arrows indicate the cast region, and dashed lines mark the site of ligation. (E) eNOS mRNA levels of the human transgene in the segments of the right carotid artery after the installment of a tapering cast: 1 mm immediately upstream of the cast (low shear stress), 1 mm in the cast (high shear stress), and 1 mm immediately downstream of the cast (oscillating shear stress), and in 1 mm of the contralateral control carotid artery (undisturbed shear stress); n = 3 groups (5 animals/group), *P < .05 versus low shear stress, †P < .05 versus undisturbed shear stress. All data are means ± SEM. Note that panel A is derived from the same picture as that in Figure 1C.