Year: 1986
Type: article
Abstract: Experiments were designed to determine the effects of oxygen-derived free radicals on the production and biological activity of endothelium-derived relaxing factor or factors released by acetylcholine. Rings of canine coronary arteries without endothelium (bioassay rings) were superfused with solution passing through a canine femoral artery with endothelium. Superoxide dismutase caused maximal relaxation of the bioassay ring when infused upstream, but not downstream, of the femoral artery; this effect of superoxide dismutase was inhibited by catalase. Infusion of acetylcholine relaxed the bioassay rings because it released a labile relaxing factor (or factors) from the endothelium. When infused below the femoral artery, superoxide dismutase and, to a lesser extent, catalase augmented the relaxations to acetylcholine. Superoxide dismutase, but not catalase, doubled the half-life of the endothelium-derived relaxing factor(s). This protective effect of the enzyme was augmented fivefold by lowering the oxygen content of the perfusate from 95 to 10%. These data demonstrate that: superoxide anions inactivate the relaxing factor(s) released by acetylcholine from endothelial cells and hyperoxia favors the inactivation of endothelium-derived relaxing factor(s).
Authors: G. M. Rubanyi, P. M. Vanhoutte
Institution: Mayo Clinic
Language: English
Subfield: Physiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W1838917319