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- Francardo, Veronica, et al.
(författare)
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Impact of the lesion procedure on the profiles of motor impairment and molecular responsiveness to L-DOPA in the 6-hydroxydopamine mouse model of Parkinson's disease.
- 2011
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Ingår i: Neurobiology of disease. - : Elsevier BV. - 1095-953X .- 0969-9961. ; 42:3, s. 327-40
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Tidskriftsartikel (refereegranskat)abstract
- 6-Hydroxydopamine (6-OHDA) lesions are being used in the mouse for basic research on Parkinson's disease and L-DOPA-induced dyskinesia. We set out to compare unilateral lesion models produced by intrastriatal or intramesencephalic injections of a fixed 6-OHDA concentration (3.2 μg/μl) in C57BL/6 mice. In the first experiment, toxin injections were performed either at two striatal coordinates (1 or 2 μl per site, termed "striatum(2 × 1 μl)" and "striatum(2 × 2 μl)" models), in the medial forebrain bundle (MFB), or in the substantia nigra pars compacta (SN) (1 μl per site). All the four lesion models produced significant forelimb use asymmetry, but spontaneous turning asymmetry only occurred in the MFB and striatum(2 × 2 μl) models. After the behavioral studies, the induction of phosphorylated extracellular signal-regulated kinases 1 and 2 (pERK1/2) by acute L-DOPA (30 mg/kg) was used as a marker of post-synaptic supersensitivity. Striatal pERK1/2 expression was sparse in the SN and striatum(2 × 1 μl) groups, but pronounced in the striatum(2 × 2 μl) and MFB-lesioned mice. In further experiments, mice with MFB and striatal(2 × 2 μl) lesions were used to compare behavioral and molecular responses to chronic L-DOPA treatment (12 days at 3 and 6 mg/kg/day). Maximally severe abnormal involuntary movements (AIMs) occurred in all MFB-lesioned mice, whereas only 35% of the mice with striatal lesions developed dyskinesia. Striatal tissue levels of dopamine were significantly lower in the dyskinetic animals (both MFB and striatum(2 × 2 μl) groups) in comparison with the non-dyskinetic ones. Noradrenaline levels were significantly reduced only in MFB lesioned animals and did not differ among the dyskinetic and non-dyskinetic cases with striatal lesions. In all groups, the L-DOPA-induced AIM scores correlated closely with the number of cells immunoreactive for tyrosine hydroxylase or FosB/∆FosB in the striatum. In conclusion, among the four lesion procedures examined here, only the MFB and striatum(2 × 2 μl) models yielded a degree of dopamine denervation sufficient to produce spontaneous postural asymmetry and molecular supersensitivity to L-DOPA. Both lesion models are suitable to reproduce L-DOPA-induced dyskinesia, although only MFB lesions yield a pronounced and widespread expression of post-synaptic supersensitivity markers in the striatum.
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- Rylander, Daniella, et al.
(författare)
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Pharmacological modulation of glutamate transmission in a rat model of L-DOPA-induced dyskinesia: effects on motor behavior and striatal nuclear signalling.
- 2009
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Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103 .- 0022-3565. ; 330:1, s. 227-235
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Tidskriftsartikel (refereegranskat)abstract
- L-DOPA-induced dyskinesia (LID) in Parkinson's disease has been linked to altered dopamine and glutamate transmission within the basal ganglia. In the present study, we compared compounds targeting specific subtypes of glutamate receptors or calcium channels for their ability to attenuate LID and the associated activation of striatal nuclear signalling and gene expression in the rat. Rats with 6-hydroxydopamine lesions were treated acutely or chronically with L-DOPA in combination with the following selective compounds: antagonists of group I metabotropic glutamate receptors (MTEP for mGluR5, and EMQMCM for mGluR1), agonist of group II mGluR (LY379268), NR2B-selective NMDA receptor antagonists (Ro631908 and Ro256981), and antagonist of L-type calcium channels (isradipine). Dyskinesia and rotarod performance were monitored during chronic drug treatment. The striatal expression of phospho-ERK1/2 and MSK-1, or prodynorphin mRNA were examined following acute or chronic treatment, respectively. In the acute treatment studies, only MTEP and EMQMCM significantly attenuated L-DOPA-induced phospho-ERK 1/2 and/or phospho-MSK-1 expression, MTEP being the most effective (70-80% reduction). In the chronic experiment, only MTEP significantly attenuated dyskinesia without adverse motor effects, whereas EMQMCM and LY379268 inhibited the L-DOPA-induced improvement in rotarod performance. The NR2B antagonist had positive anti-akinetic effects but did not reduce dyskinesia. Only MTEP blocked the upregulation of prodynorphin mRNA induced by L-DOPA. Among the pharmacological treatments here examined, MTEP was most effective in inhibiting LID and the associated molecular alterations. Antagonism of mGluR5 seems to be a promising strategy to reduce dyskinesia in Parkinson's disease.
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