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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
Author(s) -
Windels François,
Bruet Nicolas,
Poupard Annie,
Feuerstein Claude,
Bertrand Anne,
Savasta Marc
Publication year - 2003
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.10577
Subject(s) - subthalamic nucleus , globus pallidus , neurochemical , deep brain stimulation , substantia nigra , stimulation , neuroscience , microdialysis , glutamate receptor , parkinson's disease , basal ganglia , chemistry , medicine , dopamine , biology , central nervous system , dopaminergic , receptor , disease
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.