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Biol Psychiatry. 2006 Jan 1;59(1):64-74. Epub 2005 Sep 1.

ERK phosphorylation and FosB expression are associated with L-DOPA-induced dyskinesia in hemiparkinsonian mice.

Author information

1
Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain.

Abstract

BACKGROUND:

The dopamine precursor 3,4-dihydroxyphenyl-L-alanine (L-DOPA) is currently the most efficacious noninvasive therapy for Parkinson's disease. A major complication of this therapy, however, is the appearance of the abnormal involuntary movements known as dyskinesias. We have developed a model of L-DOPA-induced dyskinesias in mice that reproduces the main clinical features of dyskinesia in humans.

METHODS:

Dyskinetic symptoms were triggered by repetitive administration of a constant dose of L-DOPA (25 mg/kg, twice a day, for 25 days) in unilaterally 6-hydroxydopamine (6-OHDA) lesioned mice. Mice were examined for behavior, expression of FosB, neuropeptides, and externally regulated kinase (ERK) phosphorylation.

RESULTS:

Dyskinetic symptoms appear toward the end of the first week of treatment and are associated with L-DOPA-induced changes in DeltaFosB and prodynorphin expression. L-DOPA also induces activation of ERK1/2 in the dopamine-depleted striatum. Interestingly, elevated FosB/DeltaFosB expression occurs exclusively within completely lesioned regions of the striatum, displaying an inverse correlation with remaining dopaminergic terminals. Following acute L-DOPA treatment, FosB expression occurs in direct striatal output neurons, whereas chronic L-DOPA also induces FosB expression in nitric oxide synthase-positive striatal interneurons.

CONCLUSIONS:

This model provides a system in which genetic manipulation of individual genes can be used to elucidate the molecular mechanisms responsible for the development and expression of dyskinesia.

PMID:
16139809
DOI:
10.1016/j.biopsych.2005.05.044
[Indexed for MEDLINE]

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