A Selective Increase in Particulate Superoxide Dismutase Activity in Parkinsonian Substantia Nigra

Authors

  • H. Saggu,

    1. MRC Movement Disorders Research Group, University Department of Neurology and Parkinson's Disease Society Research Centre, Institute of Psychiatry and King's College Hospital Medical School
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  • J. Cooksey,

    1. MRC Movement Disorders Research Group, University Department of Neurology and Parkinson's Disease Society Research Centre, Institute of Psychiatry and King's College Hospital Medical School
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  • D. Dexter,

    1. MRC Movement Disorders Research Group, University Department of Neurology and Parkinson's Disease Society Research Centre, Institute of Psychiatry and King's College Hospital Medical School
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  • F. R. Wells,

    1. The National Hospital, Queen Square, London, England
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  • A. Lees,

    1. MRC Movement Disorders Research Group, University Department of Neurology and Parkinson's Disease Society Research Centre, Institute of Psychiatry and King's College Hospital Medical School
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  • P. Jenner,

    Corresponding author
    1. MRC Movement Disorders Research Group, University Department of Neurology and Parkinson's Disease Society Research Centre, Institute of Psychiatry and King's College Hospital Medical School
      Address correspondence and reprint requests to Dr. P. Jenner at University Department of Neurology, Institute of Psychiatry, London SE5, U.K.
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  • C. D. Marsden

    1. Department of Clinical Neurology, Institute of Neurology, The National Hospital, Queen Square
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Address correspondence and reprint requests to Dr. P. Jenner at University Department of Neurology, Institute of Psychiatry, London SE5, U.K.

Abstract

The total activity of superoxide dismutase (SOD) and cytosolic and particulate activity of SOD in human substantia nigra and cerebellum were measured by a spectrophotometric method based on the ability of SOD to inhibit the autoxidation of adrenaline. The cystosolic and particulate isoenzymes of SOD were differentiated by the inclusion of potassium cyanide which selectively inhibits cytosolic copper/zinc-dependent SOD activity. In autopsied human brains, there was no difference in total SOD) activity, or the activity of SOD in cytosol in substantia nigra jof patients dying with Parkinson's disease compared to age-matched controls. However, the activity of the particulate form of SOD was higher in the parkinsonian substantia nigra compared to control tissue. In the cerebellum there was no difference in the total, cytosolic, or particulate activity of SOD between parkinsonian patients and age-matched controls. Increased activity of SOD in particulate fraction may be a protective response to elevated levels of toxic free radicals in the parkinsonian substantia nigra. Alternatively, increased SOD activity may induce cell death through the accumulation of hydrogen peroxide.

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