%0 Journal Article
%T Effects of reactive oxygen species and neutrophils on endothelium-dependent relaxation of rat thoracic aorta
%A Viktor Bauer
%A Ru ena Sotn¨ªkov¨¢
%A Katar¨ªna Dr¨¢bikov¨¢
%J Interdisciplinary Toxicology
%@ 1337-9569
%D 2011
%I 
%R 10.2478/v10102-011-0029-3
%X Reactive oxygen species (ROS) are produced in different metabolic processes including the respiratory burst of neutrophils accompanying local inflammation. The aim of this study was to analyze the effects of N-formyl-methionyl-leucyl-phenylalanine (FMLP)-activated neutrophils, isolated from the guinea pig peritoneal cavity, on isolated rings of a large (conduit) artery, the rat thoracic aorta. FMLP-activated neutrophils enhanced the basal tension increased by ¦Á1-adrenergic stimulation. In phenylephrine-precontracted aortae, they elicited marked contraction, while in noradrenaline-precontracted rat aortal rings they caused a biphasic response (contraction-relaxation). To eliminate interaction of activated neutrophils with catecholamines, in the subsequent experiments the basal tension was increased by KCl-induced depolarization. Activated neutrophils evoked a low-amplitude biphasic response (relaxationcontraction) on the KCl-induced contraction. Not only the acetylcholine- and A23187-induced relaxations but also the catalase sensitive hydrogen peroxide (H2O2) elicited contractions were endothelium-dependent. Even though the acetylcholine-induced relaxation was changed by activated neutrophils and by the ROS studied, their effects differed significantly, yet none of them did eliminate fully the endothelium-dependent acetylcholine relaxation. The effect of activated neutrophils resembled the effect of superoxide anion radical (O2 -) produced by xanthine/xanthine oxidase (X/XO) and differed from the inhibitory effects of Fe2SO4/H2O2-produced hydroxyl radical ( OH) and H2O2. Thus O2 - produced either by activated neutrophils or X/XO affected much less the endothelium-dependent acetylcholine-activated relaxation mechanisms than did  OH and H2O2. In the large (conduit) artery, the effects of activated neutrophils and various ROS (O2 -,  OH and H2O2) seem to be more dependent on muscle tension than on endothelial mechanisms.
%K ROS
%K neutrophils
%K aorta
%U http://versita.metapress.com/content/y79w757um1jx150v/?p=ed2aaf5eb7ee4089a485a1d7cf55796a&pi=3