Synergistic actions of enalapril and tempol during chronic angiotensin II-induced hypertension. Vascul Pharmacol 2007 Feb;46(2):144-51
Date
11/23/2006Pubmed ID
17112788Pubmed Central ID
PMC2746434DOI
10.1016/j.vph.2006.09.004Scopus ID
2-s2.0-33845561904 (requires institutional sign-in at Scopus site) 13 CitationsAbstract
Experiments were designed to test the hypothesis that antioxidant treatment would increase the anti-hypertensive actions of endogenous kinins during angiotensin converting enzyme (ACE) inhibition. Four groups of rats, all given angiotensin II (Ang II) for 2 weeks, were studied: 1) control, 2) enalapril, 3) tempol or 4) both tempol and enalapril. Ang II significantly increased systolic blood pressure (BP) when compared with the baseline (170+/-8 vs. 128+/-4 mm Hg, P<0.05). Neither enalapril nor tempol alone was able to attenuate the elevation in BP (165+/-7 and 164+/-6 mm Hg, respectively). In contrast, combined administration of tempol and enalapril prevented the increase in BP (137+/-5 mm Hg). Plasma 8-isoprostane increased in Ang II-infused rats when compared with control untreated rats (69+/-14 vs. 23+/-0.5 pg/ml, P<0.05). Tempol alone or tempol plus enalapril significantly attenuated the increase in plasma 8-isoprostane (29+/-6 and 34+/-7 pg/ml, respectively). In additional experiments, we used the bradykinin B(2) antagonist, icatibant to determine if increased B(2) receptor contributes to the anti-hypertensive effect of combined tempol and enalapril in Ang II-infused rats. Icatibant decreased the ability of this combination to lower arterial pressure. Additionally, a significant increase in B(1) receptor protein expression in renal cortex of Ang II-infused rats was observed compared to control suggesting that bradykinin receptor activation could account for the effect of enalapril to enhance the actions of tempol. These data support the hypothesis that combined reduction of superoxide along with enhanced endogenous kinins may facilitate blood pressure lowering in Ang II hypertension.
Author List
Elmarakby AA, Williams JM, Imig JD, Pollock JS, Pollock DMMESH terms used to index this publication - Major topics in bold
Angiotensin IIAngiotensin-Converting Enzyme Inhibitors
Animals
Antihypertensive Agents
Antioxidants
Blood Pressure
Bradykinin
Chronic Disease
Cyclic N-Oxides
Dinoprost
Disease Models, Animal
Drug Synergism
Drug Therapy, Combination
Enalapril
Hydrogen Peroxide
Hypertension
Male
Oxidative Stress
Rats
Rats, Sprague-Dawley
Receptors, Bradykinin
Spin Labels
Superoxides
Time Factors
