| 1. |
- Ohlin, Elisabet, et al.
(författare)
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Vascular endothelial growth factor is upregulated by L-dopa in the parkinsonian brain: implications for the development of dyskinesia.
- 2011
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Ingår i: Brain. - : Oxford University Press (OUP). - 1460-2156 .- 0006-8950. ; 134, s. 2339-2357
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenesis and increased permeability of the blood-brain barrier have been reported to occur in animal models of Parkinson's disease and l-dopa-induced dyskinesia, but the significance of these phenomena has remained unclear. Using a validated rat model of l-dopa-induced dyskinesia, this study demonstrates that chronic treatment with l-dopa dose dependently induces the expression of vascular endothelial growth factor in the basal ganglia nuclei. Vascular endothelial growth factor was abundantly expressed in astrocytes and astrocytic processes in the proximity of blood vessels. When co-administered with l-dopa, a small molecule inhibitor of vascular endothelial growth factor signalling significantly attenuated the development of dyskinesia and completely blocked the angiogenic response and associated increase in blood-brain barrier permeability induced by the treatment. The occurrence of angiogenesis and vascular endothelial growth factor upregulation was verified in post-mortem basal ganglia tissue from patients with Parkinson's disease with a history of dyskinesia, who exhibited increased microvascular density, microvascular nestin expression and an upregulation of vascular endothelial growth factor messenger ribonucleic acid. These congruent findings in the rat model and human patients indicate that vascular endothelial growth factor is implicated in the pathophysiology of l-dopa-induced dyskinesia and emphasize an involvement of the microvascular compartment in the adverse effects of l-dopa pharmacotherapy in Parkinson's disease.
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| 2. |
- Lundblad, Martin, et al.
(författare)
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Pharmacological validation of behavioural measures of akinesia and dyskinesia in a rat model of Parkinson's disease.
- 2002
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Ingår i: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 15:1, s. 120-132
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Tidskriftsartikel (refereegranskat)abstract
- In an attempt to define clinically relevant models of akinesia and dyskinesia in 6-hydroxydopamine (6-OHDA)-lesioned rats, we have examined the effects of drugs with high (L-DOPA) vs. low (bromocriptine) dyskinesiogenic potential in Parkinson's disease on three types of motor performance, namely: (i) abnormal involuntary movements (AIMs) (ii) rotational behaviour, and (iii) spontaneous forelimb use (cylinder test). Rats with unilateral 6-OHDA lesions received single daily i.p. injections of L-DOPA or bromocriptine at therapeutic doses. During 3 weeks of treatment, L-DOPA but not bromocriptine induced increasingly severe AIMs affecting the limb, trunk and orofacial region. Rotational behaviour was induced to a much higher extent by bromocriptine than L-DOPA. In the cylinder test, the two drugs initially improved the performance of the parkinsonian limb to a similar extent. However, L-DOPA-treated animals showed declining levels of performance in this test because the drug-induced AIMs interfered with physiological limb use, and gradually replaced all normal motor activities. L-DOPA-induced axial, limb and orolingual AIM scores were significantly reduced by the acute administration of compounds that have antidyskinetic efficacy in parkinsonian patients and/or nonhuman primates (-91%, yohimbine 10 mg/kg; -19%, naloxone 4-8 mg/kg; -37%, 5-methoxy 5-N,N-dimethyl-tryptamine 2 mg/kg; -30%, clozapine 8 mg/kg; -50%, amantadine 40 mg/kg). L-DOPA-induced rotation was, however, not affected. The present results demonstrate that 6-OHDA-lesioned rats do exhibit motor deficits that share essential functional similarities with parkinsonian akinesia or dyskinesia. Such deficits can be quantified using novel and relatively simple testing procedures, whereas rotometry cannot discriminate between dyskinetic and antiakinetic effects of antiparkinsonian treatments.
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| 3. |
- Westin, J. E., et al.
(författare)
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Persistent changes in striatal gene expression induced by long-term L-DOPA treatment in a rat model of Parkinson's disease
- 2001
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Ingår i: European Journal of Neuroscience. - 0953-816X .- 1460-9568. ; 14:7, s. 1171-1176
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Tidskriftsartikel (refereegranskat)abstract
- Current knowledge of the molecular changes induced by dopamine denervation and subsequent treatment with L-DOPA is based on studies performed on relatively acute and young animal models of parkinsonism. It is highly warranted to ask how well these models simulate the state of chronic denervation and sustained L-DOPA pharmacotherapy which are typical of advanced Parkinson's disease. This study investigates the effects of time postdenervation and L-dopa treatment duration on the striatal expression of opioid precursor mRNAs and FosB/DFosB-related proteins. Unilaterally 6-hydroxydopamine-lesioned rats were treated with therapeutical doses of L-DOPA for one year (long-term group) or a few weeks (short-term group). Age-matched lesioned rats received injections of vehicle or bromocriptine, an antiparkinsonian compound which does not produce dyskinesia when administered de novo. The lesion-induced up-regulation of preproenkephalin mRNA expression persisted at more than one year postlesion, and was unaffected by the pharmacological treatments applied. L-DOPA, but not bromocriptine, induced high striatal levels of FosB/DFosB immunoreactivity and prodynorphin mRNA, and these did not differ between short-term and long-term L-DOPA-treated rats. The present data provide the first demonstration that L-DOPA maintains high striatal levels of fosB and prodynorphin gene expression during a prolonged course of treatment, which simulates the clinical practice in Parkinson's disease more closely than the short-treatment paradigms studied thus far.
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| 4. |
- Andersson, M, et al.
(författare)
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cAMP response element-binding protein is required for dopamine-dependent gene expression in the intact but not the dopamine-denervated striatum
- 2001
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Ingår i: The Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 21:24, s. 9930-9943
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Tidskriftsartikel (refereegranskat)abstract
- The cAMP response element-binding protein (CREB) is believed to play a pivotal role in dopamine (DA) receptor-mediated nuclear signaling and neuroplasticity. Here we demonstrate that the significance of CREB for gene expression depends on the experimental paradigm. We compared the role of CREB in two different but related models: L-DOPA administration to unilaterally 6-hydroxydopamine lesioned rats, and cocaine administration to neurologically intact animals. Antisense technology was used to produce a local knockdown of CREB in the lateral caudate-putamen, a region that mediates the dyskinetic or stereotypic manifestations associated with L-DOPA or cocaine treatment, respectively. In intact rats, CREB antisense reduced both basal and cocaine-induced expression of c-Fos, FosB/ΔFosB, and prodynorphin mRNA. In the DA-denervated striatum, CREB was not required for L-DOPA to induce these gene products, nor did CREB contribute considerably to DNA binding activity at cAMP responsive elements (CREs) and CRE-like enhancers. ΔFosB-related proteins and JunD were the main contributors to both CRE and AP-1 DNA-protein complexes in L-DOPA-treated animals. In behavioral studies, intrastriatal CREB knockdown caused enhanced activity scores in intact control animals and exacerbated the dyskinetic effects of acute L-DOPA treatment in 6-OHDA-lesioned animals. These data demonstrate that CREB is not required for the development of L-DOPA-induced dyskinesia in hemiparkinsonian rats. Moreover, our results reveal an unexpected alteration of nuclear signaling mechanisms in the parkinsonian striatum treated with L-DOPA, where AP-1 transcription factors appear to supersede CREB in the activation of CRE-containing genes.
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| 5. |
- Andersson, M, et al.
(författare)
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Time course of striatal DeltaFosB-like immunoreactivity and prodynorphin mRNA levels after discontinuation of chronic dopaminomimetic treatment.
- 2003
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Ingår i: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 17:3, s. 661-666
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Tidskriftsartikel (refereegranskat)abstract
- DFosB-like proteins are particularly stable transcription factors that accumulate in the brain in response to chronic perturbations. In this study we have compared the time-course of striatal FosB/DFosB-like immunoreactivity and prodynorphin mRNA expression after discontinuation of chronic cocaine treatment to intact rats and chronic L-DOPA treatment to unilaterally 6-hydroxydopamine (6-OHDA) lesioned rats. The animals were killed between 3 h and 16 days after the last drug injection. In both treatment paradigms, the druginduced FosB/DFosB immunoreactivity remained significantly elevated in the caudate putamen even at the longest withdrawal period examined. The concomitant upregulation of prodynorphin mRNA, a target of DFosB, paralleled the time-course of DFosB-like immunoreactivity in the 6-OHDA-lesion/L-DOPA model, but was more transient in animals treated with cocaine. These results suggest that DFosB-like proteins have exceptional in vivo stability. In the dopamine-denervated striatum, these proteins may exert sustained effects on the expression of their target genes long after discontinuation of L-DOPA pharmacotherapy.
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| 6. |
- Cenci, M. Angela, et al.
(författare)
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Dyskinesia matters
- 2020
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Ingår i: Movement Disorders. - : Wiley. - 0885-3185 .- 1531-8257. ; 35:3, s. 392-396
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Tidskriftsartikel (refereegranskat)abstract
- Levodopa-induced dyskinesia (LID) represents a significant source of discomfort for people with Parkinson's disease (PD). It negatively affects quality of life, it is associated with both motor and nonmotor fluctuations, and it brings an increased risk of disability, balance problems, and falls. Although the prevalence of severe LID appears to be lower than in previous eras (likely owing to a more conservative use of oral levodopa), we have not yet found a way to prevent the development of this complication. Advanced surgical therapies, such as deep brain stimulation, ameliorate LID, but only a minority of PD patients qualify for these interventions. Although some have argued that PD patients would rather be ON with dyskinesia than OFF, the deeper truth is that patients would very much prefer to be ON without dyskinesia. As researchers and clinicians, we should aspire to make that goal a reality. To this end, translational research on LID is to be encouraged and persistently pursued.
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| 7. |
- Valastro, Barbara, et al.
(författare)
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Expression pattern of JunD after acute or chronic l-DOPA treatment: Comparison with DeltaFosB.
- 2007
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Ingår i: Neuroscience. - : Elsevier BV. - 1873-7544 .- 0306-4522. ; 144:Oct 19, s. 198-207
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we have used 6-hydroxydopamine-lesioned rats to examine changes in striatal junD and fosB/Delta fosB expression induced by acute and chronic treatment with (L)-DOPA (5 and 15 days). Changes at the protein levels were studied using Western immunoblotting while mRNA changes were compared using in situ hybridization histochemistry. We observed a significant increase in the level of Delta FosB proteins after chronic treatment with L-DOPA, an effect that was not observed for JunD proteins. In addition, the upregulation of Delta FosB was already present after an acute treatment but increased upon chronic treatment. By contrast, junD and Delta fosB mRNA were both upregulated significantly above control levels after an acute injection of L-DOPA. In conclusion, this study suggests a differential expression pattern of junD and Delta fosB in a rat model of L-DOPA-induced dyskinesia. The upregulation of Delta FosB protein, but not JunD, is likely to reflect an increased stability of the Delta FosB proteins without ongoing enhanced transcription of the encoding genes. (c) 2006 IBRO. Published by Elsevier Ltd. All rights reserved.
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