Chronic RAS blockade decreases AT₁R expression.

<p>(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.</p

Ovariectomy impairs endothelium-dependent relaxation.

<p>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.</p

Chronic RAS blockade decreases oxidative stress.

<p>Effects of chronic treatment with enalapril or valsartan on the protein expression of NAD(P)H oxidase subunits: gp91<i>^phox</i> and p22<i>^phox</i> (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.</p

pD₂ and E_max (%) for acetylcholine-induced relaxations.

<p>Initial tension developed by phenylephrine, pD₂ and E_max (%) for acetylcholine-induced relaxations in aortae from different groups. Results are means±SEM of 6–8 experiments. Statistical significance between (^a) control versus OVX and (^b) OVX versus acute or chronic treatment is indicated by *p<0.05, **p<0.01, and ***p<0.001.</p

Chronic RAS blockade reduces ACE expression and angiotensin II levels after ovariectomy.

<p>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.</p

Chronic RAS blockade prevents endothelial dysfunction.

<p>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.</p

AT₁R inhibitor and ROS scavengers acutely ameliorate OVX-related endothelial dysfunction.

<p>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.</p