Figure 3.
Effects of noise for 1, 2, and 4 days on endothelial NO-synthase protein expression and activity. (A–C) Endothelial NO synthase protein expression is increased after 4 days noise exposure and activating phosphorylation at Ser1177 is increased significantly at all time points measured. (D) eNOS S-glutathionylation as a surrogate marker for uncoupling of the protein was increased significantly at all time points of noise exposure. (E, F) Noise increased GTP-cyclohydrolase I (GCH-I) and dihydrofolate reductase (DHFR) expression leading to increased synthesis of the eNOS cofactor tetrahydrobiopterin (BH4) responsible for the coupling of the enzyme. Data are mean ± SD from n = 6–8 samples (pooled from 2 to 3 mice per sample) (A–C, E, F) and 7–10 samples (pooled from 2 mice per sample) (D).