Chronic treatment with the mGlu5R antagonist MPEP reduces the functional effects of the mGlu5R agonist CHPG in the striatum of 6-hydroxydopamine-lesioned rats: Possible relevance to the effects of mGlu5R blockade in Parkinson's disease

Maria Rosaria Domenici, Rosa Luisa Potenza, Alberto Martire, Roberto Coccurello, Antonella Pèzzola, Rosaria Reggio, Maria Teresa Tebano, Patrizia Popoli

Research output: Contribution to journalArticle

Abstract

This study was designed to test whether chronic treatment with the metabotropic glutamate receptor 5 (mGlu5R) antagonist MPEP showed antiparkinsonian effects in rats unilaterally lesioned with 6-hydroxydopamine (6-OHDA) (a "classic" model of Parkinson's disease, PD), and to evaluate whether chronic MPEP influenced the functional properties and/or the expression of striatal mGlu5Rs. Wistar rats were lesioned with 6-OHDA and then treated with MPEP (3 mg/kg/day, i.p.) or its vehicle over 2 weeks. Chronic MPEP did not induce measurable antiparkinsonian effects, since no differences were found between MPEP- and vehicle-treated animals in the pattern of L-DOPA-induced contralateral rotations. In corticostriatal slices taken from animals chronically treated with MPEP, the functional effects of the mGlu5R agonist CHPG were significantly reduced in the lesioned vs. the intact side, while no changes were found in slices taken from vehicle-treated rats. The binding of [3H]MPEP to striatal membranes showed that neither the maximal number of binding sites (Bmax) nor the dissociation constant (Kd) were changed by the lesion and/or by chronic MPEP. While chronic MPEP did not potentiate L-DOPA-induced turning in a classical model of PD, its ability to reduce mGlu5R-associated signal could help to explain the neuroprotective/ antiparkinsonian effects observed in other models of PD.

Original languageEnglish
Pages (from-to)646-654
Number of pages9
JournalJournal of Neuroscience Research
Volume80
Issue number5
DOIs
Publication statusPublished - Jun 1 2005

Keywords

  • Binding
  • Electrophysiology
  • L-DOPA
  • mGlu5 receptors
  • Parkinson's disease
  • Striatum

ASJC Scopus subject areas

  • Neuroscience(all)

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