Approaches to the study of oxidative stress in the nervous system.
Item
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Title
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Approaches to the study of oxidative stress in the nervous system.
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Identifier
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AAI8820902
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identifier
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8820902
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Creator
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Slivka, Adam.
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Contributor
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Adviser: Gerald Cohen
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Date
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1988
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Neuroscience
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Abstract
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These experiments explore and develop methodology to study the interactions between peroxides, glutathione, and hydroxyl radicals ({dollar}\sp\cdot{dollar}OH) during oxidative stress in the nervous system.;A biochemical approach was developed to detect {dollar}\sp\cdot{dollar}OH. The products of {dollar}\sp\cdot{dollar}OH attack on dopamine were identified: the products were 2-hydroxydopamine, 5-hydroxydopamine, and 6-hydroxydopamine. Identification of these products provides an investigative approach to study {dollar}\sp\cdot{dollar}OH in dopamine neurons.;Other experiments utilized a histochemical method to study the localization of a cellular antioxidant, reduced glutathione (GSH). GSH staining was distributed heterogeneously in brain, with a relative absence in neuronal somata. Low levels of GSH in neuronal somata would make them susceptible to oxidative stress.;The histochemical technique, along with biochemical analyses, were applied to a model of cerebral ischemia (unilateral ligation of the common carotid artery in Mongolian gerbils). Ischemia depleted tissue GSH without a concommitant rise in oxidized GSH (GSSG); levels of free cysteine were elevated in ischemic tissue. The depletion of GSH in ischemic tissue is most likely due to autolytic breakdown.;The metabolism of catecholamines in ischemic brain may result in oxidative stress. Examination of tissue and extracellular levels of dopamine and metabolites in ischemic striata showed an acute release of dopamine; oxidative metabolism of dopamine by monoamine oxidase was still supported in ischemic tissue. However, the release and metabolism of dopamine were not causally related to the depletion of GSH, as pretreatment of animals with alpha-methyl-para-tyrosine, to deplete catecholamines, or pargyline, to inhibit monoamine oxidase, failed to protect against ischemia-induced GSH depletion. Hydroxylated dopamine products were not found in ischemic tissue.;Biochemical and histochemical techniques were also used to examine glutathione in human and monkey brain. Previous studies indicated that human brain contained primarily GSSG. We demonstrated that levels of GSSG are extremely low when compared to GSH in both human and monkey brain, similar to that seen in tissues from other species.;Lastly, a protocol for repeated administration of a glutathione synthesis inhibitor (buthionine sulfoximine) was found to lower levels of glutathione in the central nervous system of preweanling mice. Previous studies report that brain is resistant to buthionine sulfoximine-induced depletion of glutathione. This protocol provides an approach to study aspects of glutathione physiology and pharmacology in the nervous system.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
