title: High-frequency stimulation of the subthalamic nucleus potentiates L-DOPA-induced neurochemical changes in the striatum in a rat model of Parkinson's disease.
abstract: This study examined the cellular changes produced in the striatum by chronic L-DOPA treatment and prolonged subthalamic nucleus high-frequency stimulation (STN-HFS) applied separately, successively, or in association, in the 6-hydroxydopamine-lesioned rat model of Parkinson's disease (PD). Only animals showing severe L-DOPA-induced dyskinesias (LIDs) were included, and STN-HFS was applied for 5 d at an intensity efficient for alleviating akinesia without inducing dyskinesias. L-DOPA treatment alone induced FosB/deltaFosB immunoreactivity, exacerbated the postlesional increase in preproenkephalin, reversed the decrease in preprotachykinin, and markedly increased mRNA levels of preprodynorphin and of the glial glutamate transporter GLT1, which were respectively decreased and unaffected by the dopamine lesion. STN-HFS did not affect per se the postlesion changes in any of these markers. However, when applied in association with L-DOPA treatment, it potentiated the positive modulation exerted by L-DOPA on all of the markers examined and tended to exacerbate LIDs. After 5 d of L-DOPA withdrawal, the only persisting drug-induced responses were an elevation in preprodynorphin mRNA levels and in the number of FosB/deltaFosB-immunoreactive neurons. Selective additional increases in these two markers were measured when STN-HFS was applied subsequently to L-DOPA treatment. These data provide the first evidence that STN-HFS exacerbates the responsiveness of striatal cells to L-DOPA medication and suggest that STN-HFS acts specifically through an L-DOPA-modulated signal transduction pathway associated with LIDs in the striatum. They point to striatal cells as a primary site for the complex interactions between these two therapeutic approaches in PD and argue against a direct anti-dyskinetic action of STN-HFS.
authors.affiliation: Developmental Biology Institute of Marseille Luminy, Unité Mixte de Recherche 6216, Centre National de la Recherche Scientifique-Université de la Méditerranée, 13402 Marseille cedex 20, France.
authors.forename: Abid
authors.initials: A
authors.lastname: Oueslati
authors.forename: Véronique
authors.initials: V
authors.lastname: Sgambato-Faure
authors.forename: Christophe
authors.initials: C
authors.lastname: Melon
authors.forename: Philippe
authors.initials: P
authors.lastname: Kachidian
authors.forename: Paolo
authors.initials: P
authors.lastname: Gubellini
authors.forename: Mohammed
authors.initials: M
authors.lastname: Amri
authors.forename: Lydia
authors.initials: L
authors.lastname: Kerkerian-Le Goff
authors.forename: Pascal
authors.initials: P
authors.lastname: Salin
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D046690:Deep Brain Stimulation; D003714:Denervation; D004195:Disease Models, Animal; D004357:Drug Synergism; D020820:Dyskinesias / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D003576:Electron Transport Complex IV / Q000378:metabolism; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D009044:Motor Cortex / Q000503:physiopathology*; D009479:Neuropeptides / Q000378:metabolism; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020531:Subthalamic Nucleus / Q000503:physiopathology*
chemical_list: D015415:Biomarkers; C483820:Fosb protein, rat; D009479:Neuropeptides; D016760:Proto-Oncogene Proteins c-fos; D007980:Levodopa; D003576:Electron Transport Complex IV