Figure 4.

Effects of chronic ET_A receptor blockade (black) on aortic ET-1 content and vascular function in isolated aortic rings of apoE-deficient mice compared with untreated animals (white). Endothelin blockade reduced aortic ET-1 protein content comparable to levels of C57BL/6 mice (a). NO-mediated endothelium-dependent relaxation to acetylcholine was normalized by treatment with the ET_A antagonist LU135252 (b) and inversely correlated with vascular ET-1 protein content. Sensitivity to exogenous NO as assessed by relaxations to sodium nitroprusside was slightly enhanced (c). Analyses were performed on n = 8–10 (a) and n = 8 (b and c) from each group. P < 0.0001 control vs. untreated.