title: Antioxidant effect of captopril and enalapril on reactive oxygen species-induced endothelial dysfunction in the rabbit abdominal aorta.
abstract: BACKGROUND
  Reactive oxygen species (ROS) are known to be related to cardiovascular diseases. Many studies have demonstrated that angiotensin-converting enzyme inhibitors have beneficial effects against ROS. We investigated the antioxidant effect of captopril and enalapril in nitric oxide mediated vascular endothelium-dependent relaxations.
  
  
  METHODS
  Isolated rabbit abdominal aorta ring segments were exposed to ROS by electrolysis of the organ bath medium (Krebs-Henseleit solution) after pretreatment with various concentrations (range, 10(-5) to 3×10(-4) M) of captopril and enalapril. Before and after electrolysis, the endothelial function was measured by preconstricting the vessels with norepinephrine (10(-6) M) followed by the cumulative addition of acetylcholine (range, 3×10(-8) to 10(-6) M). The relevance of the superoxide anion and hydrogen peroxide scavenging effect of captopril and enalapril was investigated using additional pretreatments of diethyldithiocarbamate (DETCA, 0.5 mM), an inhibitor of Cu/Zn superoxide dismutase, and 3-amino-1,2,4-triazole (3AT, 50 mM), an inhibitor of catalase.
  
  
  RESULTS
  Both captopril and enalapril preserved vascular endothelium-dependent relaxation after exposure to ROS in a dose-dependent manner (p<0.0001). Pretreatment with DETCA attenuated the antioxidant effect of captopril and enalapril (p<0.0001), but pretreatment with 3AT did not have an effect.
  
  
  CONCLUSIONS
  Both captopril and enalapril protect endothelium against ROS in a dose-dependent fashion in isolated rabbit abdominal aortas. This protective effect is related to superoxide anion scavenging.
authors: Department of Medicine, Sicho Subcenter, Seocheon County Public Health Center, Korea.
authors: Ji Hoon
authors: JH
authors: Kim
authors: Hyuck
authors: H
authors: Kim
authors: Young Hak
authors: YH
authors: Kim
authors: Won-Sang
authors: WS
authors: Chung
authors: Jung Kook
authors: JK
authors: Suh
authors: Sung Jin
authors: SJ
authors: Kim
keywords: Angiotensin-converting enzyme inhibitors; Captopril; Enalapril; Reactive oxygen species; Vasodilation