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It is the general hypothesis that the primary mode of action of ethanol is the alteration of membrane structure and function including the conformation of receptors and ion channels essential for neurotransmission and signal transduction. However, the issue of whether ethanol affects (Na+K)-ATPase under physiological conditions remains unsettled. In this study, adult mice were treated with a daily dose of 5 g/kg of ethanol for 28 days. The RNA was isolated from brain and the (Na+K)-ATPase mRNA level was determined using Northern blot analysis. We have found an increased expression of (Na+K)-ATPase -subunit in the chronically treated alcohol group as compared with that of controls. This result was further substantiated by increased protein phosphorylation as well as increased specific activity of this enzyme in the synaptosomal plasma membrane after chronic ethanol administration. Thus we have demonstrated that ethanol may directly affect (Na+K)-ATPase in vivo, leading to the increased synthesis of this enzyme through adaptive mechanisms. 相似文献
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Recently we have demonstrated that extracellular ATP acts as an excitatory neurotransmitter and enhances cell death in the
presence of ferrous ions. By using a newly developed cis-parinaric acid fluorescence technique, we demonstrated that ATP,
in a dose dependent manner, enhanced the increased membrane lipid peroxidation in PC12 cells when cells were incubated with
micromolar FeCl2/DTP. P2 purinoceptor agonists, α,β-methylene ATP and 2-methylthio-ATP, induced PC12 cell lipid peroxidation, but to a lesser extent
than ATP. ATP-induced Ca2+ influx via P2 purinoceptor activation significantly increased the intracellular Ca2+ concentration, which may have triggered a free radical generating cascade(s), and led to membrane lipid peroxidation and
cell death. Since oxidative stress has been implicated in certain neurodegenerative diseases such as aging, extracellular
ATP may contribute to neuronal cell death by an oxidative mechanism involving lipid peroxidation. 相似文献
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Earl P. Wixom 《Arts Education Policy Review》2013,114(4):37-39
Abstract Shoshana Zuboff. In the Age of the Smart Machine: The Future of Work and Power. New York: Basic Books, 1988, 468 pp. $11.95 paperback. George Gilder. Microcosm: The Quantum Revolution in Economics and Technology. New York: Simon &; Schuster, 1989. 426 pp. $19.95 hardcover. Loren Baritz. The Good Life. New York: Alfred A. Knopf, Inc., 1988. 361 pp. $19.95 hardcover. Miles Orville. The Real Thing: Imitation and Authority in American Culture, 1880–1940. Chapel Hill: University of North Carolina Press, 1989. 382 pp. $14.95 paperback. Peter Shaw. The War Against the Intellect. Iowa City: The University of Iowa Press, 1989. 181 pp. $10.95 paperback. Robert Alter. The Pleasures of Reading in an Ideological Age. New York: Simon &; Schuster, 1989. 250 pp. $18.95 hardcover. Ian Crofton. A Dictionary of Art Quotations. New York: Macmillan Publishing Company, 1989. $19.95 hardcover. 相似文献
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Ethanol-Induced Cell Death by Lipid Peroxidation in PC12 Cells 总被引:8,自引:0,他引:8
Sun Albert Y. Chen Yong-mei James-Kracke Marilyn Wixom Patricia Cheng Yu 《Neurochemical research》1997,22(10):1187-1192
Free radical generation is hypothesized to be the cause of alcohol-induced tissue injury. Using fluorescent cis-parinaric acid and TBARS, lipid peroxidation was shown to be increased in the presence of trace amounts of free ferrous ion in PC12 cells. This increase in lipid peroxidation was enhanced by ethanol in a dose dependent manner and also correlated with loss of cell viability, as measured by increased release of lactate dehydrogenase (LDH). Resveratrol, a potent antioxidant, had a protective effect against lipid peroxidation and cell death. These findings strongly suggest that ethanol-induced tissue injury and cell death is a free radical mediated process, and may be important in alcohol-related premature aging and other degenerative diseases. 相似文献
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Acetolactate metabolism and the presence of a dehydroxy acid dehydratase in micro-organisms 下载免费PDF全文
R. L. Wixom 《The Biochemical journal》1965,94(2):427-435
1. The growth characteristics of nine micro-organisms on complex broth and defined media, usually with a single nitrogen source (other than vitamins), were examined as a necessary step before growth of cells for enzyme assays. Six of these bacteria gave a positive colour test with a creatine–potassium hydroxide reagent, indicating the presence of acetoin, which other investigators have shown is formed via the intermediate, α-acetolactate. 2. Cell-free extracts of exponential-phase cells of Bacillus subtilis, Staphylococcus aureus, Proteus morganii, Acetobacter rancens (two strains), A. kuetzingianus, A. acetosus, Acetomonas (Acetobacter) melanogenus and Acetomonas (Acetobacter) suboxydans (A.T.C.C. no. 621) were found to contain the enzyme, dihydroxy acid dehydratase (2,3-dihydroxy acid hydro-lyase). 3. The specific activity of the dehydratase from organisms grown on valine- and isoleucine-deficient media was greater than those grown on a complex broth or media containing complete amino acid mixtures. The omission of valine plus isoleucine from a medium containing 19 amino acids caused an increase in the dehydratase specific activity of Staphylococcus aureus and Proteus morganii. 4. The rate of keto acid formation from αβ-dihydroxyisovalerate by extracts of six of the above-named organisms was faster than, but somewhat proportional to, the similar rate from αβ-dihydroxy-β-methyl-n-valerate as substrate. 5. These findings may be related to acetolactate synthesis, acetoin formation and valine–isoleucine biosynthesis in the above-mentioned micro-organisms. 相似文献