Contribution of nitric oxide to the endothelial function. Dose–response relaxation curves to acetylcholine (ACh) in Sham (A), non-treated 2K1C hypertensive (B) and sildenafil-treated 2K1C (C) mice with and without blockade of nitric oxide synthase (NOS) with L-NAME. Bar graphs show the area under the curve derived from the dose–response curves to ACh (D), the maximum response (Rmax) (E) and pEC50
(F). Values are the means±SEM. **p < 0.01 and #p < 0.05 compared to the group indicated by the line; two-way ANOVA (A, B and C) and one-way ANOVA (D, E and F).