Long-term treatment of Parkinson's disease with l-DOPA almost always leads to the development of involuntary movements termed l-DOPA-induced dyskinesia. Whereas hyperdopaminergic signaling in the basal ganglia is thought to cause dyskinesia, alterations in primary motor cortex (M1) activity are also prominent during dyskinesia, suggesting that the cortex may represent a therapeutic target. The present study used the rat unilateral 6-hydroxydopamine lesion model of Parkinson's disease to characterize in vivo changes in GABA and glutamate neurotransmission within M1 and determine their contribution to behavioral output. 6-Hydroxydopamine lesion led to parkinsonian motor impairment that was partially reversed by l-DOPA. Among sham-lesioned rats, l-DOPA did not change glutamate or GABA efflux. Likewise, 6-hydroxydopamine lesion did not impact GABA or glutamate among rats chronically treated with saline. However, we observed an interaction of lesion and treatment whereby, among lesioned rats, l-DOPA given acutely (1 d) or chronically (14-16 d) reduced glutamate efflux and enhanced GABA efflux. Site-specific microinjections into M1 demonstrated that l-DOPA-induced dyskinesia was reduced by M1 infusion of a D1 antagonist, an AMPA antagonist, or a GABAA agonist. Overall, the present study demonstrates that l-DOPA-induced dyskinesia is associated with increased M1 inhibition and that exogenously enhancing M1 inhibition may attenuate dyskinesia, findings that are in agreement with functional imaging and transcranial magnetic stimulation studies in human Parkinson's disease patients. Together, our study suggests that increasing M1 inhibitory tone is an endogenous compensatory response designed to limit dyskinesia severity and that potentiating this response is a viable therapeutic strategy.
Pubmed ID: 27656025 RIS Download
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Software package used for interactive, or batched, statistical analysis in social science, health sciences and marketing. Software platform offers advanced statistical analysis, a library of machine-learning algorithms, text analysis, open-source extensibility, integration with big data and deployment into applications.Versions that were produced by SPSS Inc. before the IBM acquisition (Versions 18 and earlier) would be given origin or publisher of SPSS Inc. in Chicago.
View all literature mentionsRattus norvegicus with name HotHsd:SD from RGD.
View all literature mentionsSoftware package used for interactive, or batched, statistical analysis in social science, health sciences and marketing. Software platform offers advanced statistical analysis, a library of machine-learning algorithms, text analysis, open-source extensibility, integration with big data and deployment into applications.Versions that were produced by SPSS Inc. before the IBM acquisition (Versions 18 and earlier) would be given origin or publisher of SPSS Inc. in Chicago.
View all literature mentionsRattus norvegicus with name HotHsd:SD from RGD.
View all literature mentionsSoftware package used for interactive, or batched, statistical analysis in social science, health sciences and marketing. Software platform offers advanced statistical analysis, a library of machine-learning algorithms, text analysis, open-source extensibility, integration with big data and deployment into applications.Versions that were produced by SPSS Inc. before the IBM acquisition (Versions 18 and earlier) would be given origin or publisher of SPSS Inc. in Chicago.
View all literature mentionsRattus norvegicus with name HotHsd:SD from RGD.
View all literature mentionsRattus norvegicus with name HotHsd:SD from RGD.
View all literature mentionsSoftware package used for interactive, or batched, statistical analysis in social science, health sciences and marketing. Software platform offers advanced statistical analysis, a library of machine-learning algorithms, text analysis, open-source extensibility, integration with big data and deployment into applications.Versions that were produced by SPSS Inc. before the IBM acquisition (Versions 18 and earlier) would be given origin or publisher of SPSS Inc. in Chicago.
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