eNOS uncoupling in the aortas of old rats.

<p>(<b>A</b>) Immunoblotting analysis of eNOS-dimers and –monomers in the aortic endothelium of young and old rats. Ponseau S staining served as loading control. Quantification of the eNOS-dimer/monomer ratio is shown in the lower panel. n = 3 in each group. (<b>B</b>) Confocal microscopic <i>en face</i> detection of DHE staining for cytoplasmic superoxide anion production followed by counterstaining with DAPI for endothelial nuclei in the intact thoracic aorta segments from young and old rats, which were treated with or without L-NAME (1 mmol/L, 1 hour). Shown are representative images from a young and an old rat. (<b>C</b>) Quantification of the fluorescence intensity from three animals in each group. Scale bar = 50 µm. *p<0.05, **p<0.01, ***p<0.001 between indicated groups.