| 1. |
- Dekundy, Andrzej, et al.
(författare)
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Modulation of l-DOPA-induced abnormal involuntary movements by clinically tested compounds: Further validation of the rat dyskinesia model.
- 2007
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Ingår i: Behavioural Brain Research. - : Elsevier BV. - 0166-4328. ; 179:1, s. 76-89
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Forskningsöversikt (refereegranskat)abstract
- l-DOPA-induced dyskinesia (LID) is a major complication of the pharmacotherapy of Parkinson's Disease. A model of LID has recently been described in rats with unilateral 6-hydroxydopamine (6-OHDA) lesions. In the present study, the model was used in order to compare the efficacies of some clinically available compounds that have shown antidyskinetic effects in nonhuman primate models of LID and/or in patients, namely, amantadine (20 and 40 mg/kg), buspirone (1, 2 and 4 mg/kg), clonidine (0.01, 0.1 and 1 mg/kg), clozapine (4 and 8 mg/kg), fluoxetine (2.5 and 5 mg/kg), propranolol (5, 10 and 20 mg/kg), riluzole (2 and 4 mg/kg), and yohimbine (2 and 10 mg/kg). Rats were treated for 3 weeks with l-DOPA for an induction and monitoring of abnormal involuntary movements (AIMs) prior to the drug screening experiments. The antidyskinetic drugs or their vehicles were administered together with l-DOPA, and their effects were evaluated according to a randomized cross-over design both on the AIM rating scale and on the rotarod test. Most of the compounds under investigation attenuated the l-DOPA-induced axial, limb and orolingual AIM scores. However, the highest doses of many of these substances (but for amantadine and riluzole) had also detrimental motor effects, producing a reduction in rotarod performance and locomotor scores. Since the present results correspond well to existing clinical and experimental data, this study indicates that axial, limb and orolingual AIMs possess predictive validity for the preclinical screening of novel antidyskinetic treatments. Combining tests of general motor performance with AIMs ratings in the same experiment allows for selecting drugs that specifically reduce dyskinesia without diminishing the anti-akinetic effect of l-DOPA.
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| 2. |
- Mela, Flora, et al.
(författare)
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Antagonism of metabotropic glutamate receptor type 5 attenuates l-DOPA-induced dyskinesia and its molecular and neurochemical correlates in a rat model of Parkinson's disease.
- 2007
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 101:2, s. 483-497
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Tidskriftsartikel (refereegranskat)abstract
- Metabotropic glutamate receptor type 5 (mGluR5) modulates dopamine and glutamate neurotransmission at central synapses. In this study, we addressed the role of mGluR5 in L-DOPA-induced dyskinesia, a movement disorder that is due to abnormal activation of both dopamine and glutamate receptors in the basal ganglia. A selective and potent mGluR5 antagonist, 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl] pyridine, was tested for its ability to modulate molecular, behavioural and neurochemical correlates of dyskinesia in 6-hydroxydopamine-lesioned rats treated with L-DOPA. The compound significantly attenuated the induction of abnormal involuntary movements (AIMs) by chronic L-DOPA treatment at doses that did not interfere with the rat physiological motor activities. These effects were paralleled by an attenuation of molecular changes that are strongly associated with the dyskinesiogenic action of L-DOPA (i.e. up-regulation of prodynorphin mRNA in striatal neurons). Using in vivo microdialysis, we found a temporal correlation between the expression of L-DOPA-induced AIMs and an increased GABA outflow within the substantia nigra pars reticulata. When co-administered with L-DOPA, 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl] pyridine greatly attenuated both the increase in nigral GABA levels and the expression of AIMs. These data demonstrate that mGluR5 antagonism produces strong anti-dyskinetic effects in an animal model of Parkinson's disease through central inhibition of the molecular and neurochemical underpinnings of L-DOPA-induced dyskinesia.
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| 3. |
- Rylander, Daniella, et al.
(författare)
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A mGluR5 antagonist under clinical development improves L-DOPA-induced dyskinesia in parkinsonian rats and monkeys.
- 2010
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Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961. ; 39, s. 352-361
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Tidskriftsartikel (refereegranskat)abstract
- L-DOPA remains the gold-standard treatment for Parkinson's disease but causes motor fluctuations and dyskinesia. Metabotropic glutamate receptor type 5 (mGluR5) has been proposed as a target for antidyskinetic therapies. Here, we evaluate the effects of fenobam, a noncompetitive mGluR5 antagonist already tested in humans, using rodent and nonhuman primate models of L-DOPA-induced dyskinesia. In both animal models, acute administration of fenobam attenuated the L-DOPA-induced abnormal involuntary movements (50-70% reduction at the doses of 30mg/kg in rats and 10mg/kg in monkeys). The effect consisted in a reduction of peak-dose dyskinesia, whereas the end-dose phase was not affected. Chronic administration of fenobam to previously drug-naïve animals (de novo treatment) attenuated the development of peak-dose dyskinesia without compromising the anti-parkinsonian effect of L-DOPA. In addition, fenobam prolonged the motor stimulant effect of L-DOPA. We conclude that fenobam acts similarly in rat and primate models of L-DOPA-induced dyskinesia and that it represents a good candidate for antidyskinetic treatment in Parkinson's disease.
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| 4. |
- 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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| 5. |
- Valastro, Barbara, et al.
(författare)
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Proteomic analysis of striatal proteins in the rat model of l-DOPA-induced dyskinesia.
- 2007
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 102:4, s. 1395-1409
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Tidskriftsartikel (refereegranskat)abstract
- L-DOPA-induced dyskinesia (LID) is among the motor complications that arise in Parkinson's disease (PD) patients after a prolonged treatment with L-DOPA. To this day, transcriptome analysis has been performed in a rat model of LID [Neurobiol. Dis., 17 (2004), 219] but information regarding the proteome is still lacking. In the present study, we investigated the changes occurring at the protein level in striatal samples obtained from the unilaterally 6-hydroxydopamine-lesion rat model of PD treated with saline, L-DOPA or bromocriptine using two-dimensional difference gel electrophoresis and mass spectrometry (MS). Rats treated with L-DOPA were allocated to two groups based on the presence or absence of LID. Among the 2000 spots compared for statistical difference, 67 spots were significantly changed in abundance and identified using matrix-assisted laser desorption/ionization time-of-flight MS, atmospheric pressure matrix-assisted laser desorption/ionization and HPLC coupled tandem MS (LC/MS/ MS). Out of these 67 proteins, LID significantly changed the expression level of five proteins: alpha beta-crystalin, gamma-enolase, guanicloacetate methyltransferase, vinculin, and proteasome alpha-2 subunit. Complementary techniques such as western immunoblotting and immunohistochernistry were performed to investigate the validity of the data obtained using the proteomic approach. In conclusion, this study provides new insights into the protein changes occurring in LID.
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