title: Oxygen free-radical reduction of brain capillary rubidium uptake.
abstract: Free radicals are proposed to play a role in the injury following cerebral ischemia in which cerebral edema is a prominent feature. To determine whether free radicals might alter the movement of ions and water across the blood-brain barrier, we examined their effect on brain capillary transport. Rat brain capillaries were isolated, incubated with a system that generates free radicals, and various capillary transport systems were studied. Rubidium uptake was reduced 74% whereas rubidium efflux, glucose transport, and capillary water space were unchanged. The results following the addition of radical scavengers indicated that hydrogen peroxide or a related free radical was the toxic species. These data suggest that free radicals can impair capillary endothelial cell mechanisms that help maintain homeostasis of electrolytes and water in brain.
mesh_terms: D019325:3-O-Methylglucose; D000079:Acetaldehyde / Q000378:metabolism; D000493:Allopurinol / Q000494:pharmacology; D000621:Aminoisobutyric Acids / Q000378:metabolism; D000818:Animals; D002196:Capillaries / Q000378:metabolism; D002560:Cerebrovascular Circulation; D004305:Dose-Response Relationship, Drug; D005609:Free Radicals; D006861:Hydrogen Peroxide / Q000378:metabolism; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000378:metabolism; D008297:Male; D008757:Methylglucosides / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012413:Rubidium / Q000097:blood* / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013997:Time Factors; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D000621:Aminoisobutyric Acids; D005609:Free Radicals; D007042:Hypoxanthines; D008757:Methylglucosides; D019325:3-O-Methylglucose; C017911:2-(methylamino)isobutyric acid; D019271:Hypoxanthine; D000493:Allopurinol; D006861:Hydrogen Peroxide; D014969:Xanthine Oxidase; D000254:Sodium-Potassium-Exchanging ATPase; D000079:Acetaldehyde; D012413:Rubidium; D010100:Oxygen