Table 1.
Basic Parameters.
Figure 1.
Ovariectomy impairs endothelium-dependent relaxation.
Time-dependent reduction of endothelium-dependent relaxations induced by acetylcholine (ACh, A) but not by sodium nitroprusside (SNP, B) in phenylephrine (Phe)-contracted ring with endothelium following ovariectomy. Results are means±SEM of 6–8 experiments. Statistical significance between control and OVX curves is indicated by *** p<0.001.
Table 2.
pD2 and Emax (%) for acetylcholine-induced relaxations.
Figure 2.
AT1R inhibitor and ROS scavengers acutely ameliorate OVX-related endothelial dysfunction.
Inhibitory effects of 30-min treatment with 3 µmol/l losartan (A), 100 µmol/l apocynin (B), 3 µmol/l losartan plus 100 µmol/l apocynin (C), and 1 mmol/l tiron plus 100 µmol/l DETCA (D) on ACh-induced relaxations. Results are means±SEM of 6–8 experiments. Statistical significance between OVX and drug-treated OVX is indicated by *** p<0.001.
Figure 3.
Chronic RAS blockade prevents endothelial dysfunction.
Concentration-response curves for ACh in aortae from control, OVX rats and OVX rats treated with enalapril (A, OVX+Ena) or valsartan (B, OVX+Val). (C) Lack of effect of HOE-140 on relaxations in aortae from OVX+Ena group. (D) Lack of effect of captopril on relaxations in OVX rats. (E) Phosphorylated levels of eNOS (p-eNOS) at Ser1177 in response to 1 µmol/l ACh and the total eNOS in aortae. Results are means±SEM of 6–8 experiments. Intensities were normalized to GAP(D)H and expressed relative to control. Statistical significance between OVX and treatment group is indicated by *** p<0.001. NS, no significance.
Figure 4.
Chronic RAS blockade reduces ACE expression and angiotensin II levels after ovariectomy.
Effects of chronic treatment of OVX rats with enalapril or valsartan on the protein level of angiotensin-converting enzyme (ACE) revealed by Western blot (A) and immunohistochemistry (B). Immunohistochemical staining of angiotensin II in the aortic vascular wall (C). Sections are counterstained with hematoxylin. Magnification ×400. Results are means±SEM of 4–6 experiments. Statistical significance is indicated by ** p<0.01 and *** p<0.001.
Figure 5.
Chronic RAS blockade decreases AT1R expression.
(A) Effects of chronic treatment with enalapril or valsartan on protein levels of angiotensin II type 1 (AT1R) and type 2 receptor (AT2R) in aortae of OVX rats. Aortic contraction induced by 100 nmol/l angiotensin II (B) and 60 mmol/l KCl (C) in the presence of 100 µmol/l L-NAME. Results are means±SEM of 4–5 experiments. Statistical significance is indicated by * p<0.05 and *** p<0.001.
Figure 6.
Chronic RAS blockade decreases oxidative stress.
Effects of chronic treatment with enalapril or valsartan on the protein expression of NAD(P)H oxidase subunits: gp91phox and p22phox (A), on ROS production as revealed by DHE fluorescent intensity (B), and on the protein level of nitrotyrosine (C) in rat aortae. Results are means±SEM of 4–5 experiments. Statistical significance is indicated by ** p<0.01 and *** p<0.001.