Oxygen Free-Radical Reduction of Brain Capillary Rubidium Uptake |
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Authors: | Warren D. Lo A. Lorris Betz |
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Affiliation: | Departments of Pediatrics and Neurology, University of Michigan, Ann Arbor, Michigan, U.S.A. |
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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. |
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Keywords: | Free radicals Brain capillaries Cerebral ischemia Na+ K+ -ATPase Blood-brain barrier Rubidium transport |
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