Fig 8. Tempol reduces protein S-nitrosylation and cardiac contractility.

(A) Representative Western blots showing protein S-nitrosylation in hearts homogenized prior (basal, B), or after stimulation with isoproterenol (10nM, 3-min, Iso), in control conditions or after 20-min treatment with tempol (100μM). Homogenized tissue was submitted to the biotin-switch assay and SDS-PAGE. The same membrane is shown stained for biotin (left) and for total protein (right), as detailed in the legend to Fig 3. (B) Densitometric analysis of the normalized biotin/total protein signal for 8 similar experiments. Two-way ANOVA indicated significant effect of tempol (p<0.0001) and interaction (p<0.05). (C) Cardiac contractility determined in the same hearts immediately previous to homogenization. Two-way ANOVA indicated significant effect of tempol (p<0.01), and isoproterenol (p<0.001) without significant interaction. * p<0.05, ** p<0.01 vs. respective Basal; †, p<0.01 vs. corresponding Control value.