The pathophysiological basis of dystonias.

Department of Neurology and Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
Nature Reviews Neuroscience (Impact Factor: 31.38). 04/2008; 9(3):222-34. DOI: 10.1038/nrn2337
Source: PubMed

ABSTRACT Dystonias comprise a group of movement disorders that are characterized by involuntary movements and postures. Insight into the nature of neuronal dysfunction has been provided by the identification of genes responsible for primary dystonias, the characterization of animal models and functional evaluations and in vivo brain imaging of patients with dystonia. The data suggest that alterations in neuronal development and communication within the brain create a susceptible substratum for dystonia. Although there is no overt neurodegeneration in most forms of dystonia, there are functional and microstructural brain alterations. Dystonia offers a window into the mechanisms whereby subtle changes in neuronal function, particularly in sensorimotor circuits that are associated with motor learning and memory, can corrupt normal coordination and lead to a disabling motor disorder.

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    PLoS ONE 04/2015; 10(4):e0124937. DOI:10.1371/journal.pone.0124937 · 3.53 Impact Factor
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    ABSTRACT: DYT1 dystonia is a movement disorder caused by a trinucleotide deletion (ΔGAG) in DYT1 (TOR1A), corresponding to a glutamic acid loss in the C-terminal region of torsinA. Functional alterations in the basal ganglia circuits have been reported in both DYT1 dystonia patients and rodent models. Dyt1 ΔGAG heterozygous knock-in (KI) mice exhibit motor deficits and decreased striatal dopamine receptor 2 (D2R) binding activity, suggesting a malfunction of the indirect pathway. However, the role of the direct pathway in pathogenesis of dystonia is not yet clear. Here, we report that Dyt1 KI mice exhibit significantly decreased striatal dopamine receptor 1 (D1R) binding activity and D1R protein levels, suggesting the alteration of the direct pathway. The decreased D1R may be caused by translational or post-translational processes since Dyt1 KI mice had normal levels of striatal D1R mRNA and a normal number of striatal neurons expressing D1R. Levels of striatal ionotropic glutamate receptor subunits, dopamine transporter, acetylcholine muscarinic M4 receptor and adenosine A2A receptor were not altered suggesting a specificity of affected polytopic membrane-associated proteins. Contribution of the direct pathway to motor-skill learning has been suggested in another pharmacological rat model injected with a D1R antagonist. In the present study, we developed a novel motor skill transfer test for mice and found deficits in Dyt1 KI mice. Further characterization of both the direct and the indirect pathways in Dyt1 KI mice will aid the development of novel therapeutic drugs. Copyright © 2014 Elsevier B.V. All rights reserved.
    Behavioural Brain Research 11/2014; 279. DOI:10.1016/j.bbr.2014.11.037 · 3.39 Impact Factor
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    ABSTRACT: Dystonia is a neurological disorder with involuntary and simultaneous contractions of agonist and antagonist muscles. Rapid-onset dystonia parkinsonism (RDP), one of the heredity forms of dystonia, is caused by mutations of Na,K-ATPase α3 subunit gene (ATP1A3). The abrupt onset of bulbar and limb symptoms of RDP are often triggered by physical and/or emotional stress. We reported previously that Atp1a3-deficient heterozygous mice showed higher locomotor activity and developed enhanced dystonia symptoms after kainate injection into the cerebellum, but not spontaneous movement disorder like RDP patients. Here we show that Atp1a3-deficient heterozygous mice exhibited shorter stride length at 4 weeks of age without stress and at later stages under chronic restraint stress loading. Shorter hanging time in the hanging box test was also observed after stress loading. Shorter stride length and hanging time may be relevant to certain phenotypes, such as gait abnormality, observed in RDP patients. Atp1a3 was widely expressed in the brain, including basal ganglia and cerebellum, and spinal cord of young mice, and the expression pattern was compatible with movement abnormalities under lack of one of alleles. Our results demonstrated the usefulness of Atp1a3-deficient heterozygous mice as an animal model of RDP and its potential use to explore the pathophysiology of movement abnormality in this disorder.
    Behavioural Brain Research 06/2014; 272. DOI:10.1016/j.bbr.2014.06.048 · 3.39 Impact Factor


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