Figure 3.
Effects of low dose (LD) and high dose (HD) of glucocorticoid (GC) on nitric oxide synthase (NOS) pathway. Experiments were performed on thoracic aortic rings harvested at the end of the treatment period (21 days after the onset of arthritis) of adjuvant‐induced arthritis (AIA) rats treated with saline (vehicle), or a low dose of prednisolone (0·1 mg/kg/day, GC‐LD) or a high dose of prednisolone (10 mg/kg/day, GC‐HD). Cumulative concentration‐response curves of acetylcholine (Ach) were obtained after incubation or not with NW‐nitro‐L‐arginine methyl ester (L‐NAME) at 10−4 mol/l (a–c). Expression of endothelial nitric oxide synthase (eNOS) (f,g) and its phosphorylated form at serine 1177, P‐eNOS (d,e), were evaluated in aortas by Western blotting. Values from the concentration–response curves are the mean ± standard error of the mean (s.e.m.) (n = 7–15 rings from 7–15 rats per group), compared by two‐way analysis of variance (anova) for repeated measures. Values from immunoblots are the mean ± s.e.m. (n = 6 rats per group), compared by the Mann–Whitney U‐test. *P < 0.05; ***P < 0·001.