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Influence of the frequency parameter on extracellular glutamate and γ-aminobutyric acid in substantia nigra and globus pallidus during electrical stimulation of subthalamic nucleus in rats

Authors

  • François Windels,

    1. Equipe Neurochimie et Neuroplasticité Fonctionnelles, INSERM U.318—Neurosciences Précliniques, Université Joseph Fourier, Pavillon de Neurologie, CHU de Grenoble, Grenoble, France
    Current affiliation:
    1. NIDA/IRP, 5500 Nathan Shock Drive, Baltimore, MD 21224
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  • Nicolas Bruet,

    1. Equipe Neurochimie et Neuroplasticité Fonctionnelles, INSERM U.318—Neurosciences Précliniques, Université Joseph Fourier, Pavillon de Neurologie, CHU de Grenoble, Grenoble, France
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  • Annie Poupard,

    1. Equipe Neurochimie et Neuroplasticité Fonctionnelles, INSERM U.318—Neurosciences Précliniques, Université Joseph Fourier, Pavillon de Neurologie, CHU de Grenoble, Grenoble, France
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  • Claude Feuerstein,

    1. Equipe Neurochimie et Neuroplasticité Fonctionnelles, INSERM U.318—Neurosciences Précliniques, Université Joseph Fourier, Pavillon de Neurologie, CHU de Grenoble, Grenoble, France
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  • Anne Bertrand,

    1. Equipe Neurochimie et Neuroplasticité Fonctionnelles, INSERM U.318—Neurosciences Précliniques, Université Joseph Fourier, Pavillon de Neurologie, CHU de Grenoble, Grenoble, France
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  • Marc Savasta

    Corresponding author
    1. Equipe Neurochimie et Neuroplasticité Fonctionnelles, INSERM U.318—Neurosciences Précliniques, Université Joseph Fourier, Pavillon de Neurologie, CHU de Grenoble, Grenoble, France
    • Equipe Neurochimie et Neuroplasticité Fonctionnelles, INSERM U.318—Neurosciences Précliniques, Université Joseph Fourier, Pavillon de Neurologie, CHU de Grenoble, 38043 Grenoble Cedex 09, France
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Abstract

High-frequency stimulation (HFS) of the subthalamic nucleus (STN) proves to be an efficient treatment for alleviating motor symptoms in Parkinson's disease (PD). However, the mechanisms of HFS underlying these clinical effects remain unknown. Using intracerebral microdialysis, we previously reported that HFS induces, in normal rats, a significant increase of extracellular glutamate (Glu) in the globus pallidus (GP in rats or GPe in primates) and the substantia nigra pars reticulata (SNr), whereas γ-aminobutyric acid (GABA) was increased only in the SNr. Bradykinesia can be improved by STN stimulation in a frequency-dependent manner, a plateau being reached around 130 Hz. The aim of the present study was to determine whether neurochemical changes are also frequency dependent. Electrical STN stimulation was applied at various frequencies (10, 60, 130, and 350 Hz) in normal rats. The results show that, for Glu, the amplitude of increase detected in GP and SNr is maximal at 130 Hz and is maintained at 350 Hz. No modifications of GABA were observed in GP whatever the frequency applied, whereas, in SNr, GABA increased from 60 to 350 Hz. Our results provide new neurochemical data implicating STN target structures in deep-brain-stimulation mechanisms. © 2003 Wiley-Liss, Inc.

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