Inhibition of the Ca sup 2+ -ATPase of vascular smooth muscle sarcoplasmic reticulum by superoxide radicals

Conference · Fri Mar 15 04:00:00 EST 1991 · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)

OSTI ID:5213564

Suzuki, Yuichiro; Ford, G D ^[1]

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1. Medical College of Virginia, Richmond (United States)

The effect of oxygen free radicals generated by hypoxanthine plus xanthine oxidase on the Ca{sup 2+}-ATPase of sarcoplasmic reticulum from bovine aortic smooth muscle were studied. Exogenous hypoxanthine plus xanthine oxidase produced an hypoxanthine concentration dependent inhibition of the Ca{sup 2+}-ATPase. The inhibition could be completely blocked by superoxide dismutase but not by either mannitol or deferoxamine. Direct addition of reagent hydrogen peroxide in the {mu}M range did not cause significant inhibition. These results suggest that superoxide is the primary damaging species. Additionally, 1.16 {plus minus} 0.17 mU/g wet wt of xanthine oxidase activity were detected in the post-nuclear supernatant of bovine aortic smooth muscle, suggesting the existence of a possible intracellular source of superoxide. This value was calculated to be approximately 5 mU/ml by using a usual value of vascular smooth muscle cellular volume. Thus the level of endogenous xanthine oxidase resident in vascular smooth muscle is comparable with the level of exogenous xanthine oxidase used in the present study. These findings suggest a potential role of xanthine oxidase-generated superoxide in free radical injury to vascular smooth muscle.

• OSTI ID: 5213564
• Report Number(s): CONF-9104107--
• Conference Information: Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Journal Volume: 5:5
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID ANHYDRASES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
ATP-ASE
BIOLOGICAL EFFECTS
CALCIUM COMPOUNDS
CATTLE
CELL CONSTITUENTS
DOMESTIC ANIMALS
ENDOPLASMIC RETICULUM
ENZYME ACTIVITY
ENZYMES
HYDROLASES
INHIBITION
MAMMALS
MUSCLES
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PHOSPHOHYDROLASES
PROTEINS
RADICALS
RUMINANTS
SARCOPLASMIC RETICULUM
SUPEROXIDE DISMUTASE
SUPEROXIDE RADICALS
VERTEBRATES