1
|
Ribot B, Aupy J, Vidailhet M, Mazère J, Pisani A, Bezard E, Guehl D, Burbaud P. Dystonia and dopamine: From phenomenology to pathophysiology. Prog Neurobiol 2019; 182:101678. [PMID: 31404592 DOI: 10.1016/j.pneurobio.2019.101678] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/19/2019] [Accepted: 07/31/2019] [Indexed: 11/30/2022]
Abstract
A line of evidence suggests that the pathophysiology of dystonia involves the striatum, whose activity is modulated among other neurotransmitters, by the dopaminergic system. However, the link between dystonia and dopamine appears complex and remains unclear. Here, we propose a physiological approach to investigate the clinical and experimental data supporting a role of the dopaminergic system in the pathophysiology of dystonic syndromes. Because dystonia is a disorder of motor routines, we first focus on the role of dopamine and striatum in procedural learning. Second, we consider the phenomenology of dystonia from every angle in order to search for features giving food for thought regarding the pathophysiology of the disorder. Then, for each dystonic phenotype, we review, when available, the experimental and imaging data supporting a connection with the dopaminergic system. Finally, we propose a putative model in which the different phenotypes could be explained by changes in the balance between the direct and indirect striato-pallidal pathways, a process critically controlled by the level of dopamine within the striatum. Search strategy and selection criteria References for this article were identified through searches in PubMed with the search terms « dystonia », « dopamine", « striatum », « basal ganglia », « imaging data », « animal model », « procedural learning », « pathophysiology », and « plasticity » from 1998 until 2018. Articles were also identified through searches of the authors' own files. Only selected papers published in English were reviewed. The final reference list was generated on the basis of originality and relevance to the broad scope of this review.
Collapse
Affiliation(s)
- Bastien Ribot
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France
| | - Jérome Aupy
- Service de Neurophysiologie Clinique, Hôpital Pellegrin, place Amélie-Raba-Léon, 33076 Bordeaux, France; Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France
| | - Marie Vidailhet
- AP-HP, Department of Neurology, Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Sorbonne Université, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière UPMC Univ Paris 6 UMR S 1127, Inserm U 1127, CNRS UMR 7225, Paris, France
| | - Joachim Mazère
- Université de Bordeaux, INCIA, UMR 5287, F-33000 Bordeaux, France; CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France; Service de médecine nucléaire, CHU de Bordeaux, France
| | - Antonio Pisani
- Department of Neuroscience, University "Tor Vergata'', Rome, Italy; Laboratory of Neurophysiology and Plasticity, Fondazione Santa Lucia I.R.C.C.S., Rome, Italy
| | - Erwan Bezard
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France
| | - Dominique Guehl
- Service de Neurophysiologie Clinique, Hôpital Pellegrin, place Amélie-Raba-Léon, 33076 Bordeaux, France; Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France
| | - Pierre Burbaud
- Service de Neurophysiologie Clinique, Hôpital Pellegrin, place Amélie-Raba-Léon, 33076 Bordeaux, France; Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.
| |
Collapse
|
2
|
Yalcin-Cakmakli G, Rose SJ, Villalba RM, Williams L, Jinnah HA, Hess EJ, Smith Y. Striatal Cholinergic Interneurons in a Knock-in Mouse Model of L-DOPA-Responsive Dystonia. Front Syst Neurosci 2018; 12:28. [PMID: 29997483 PMCID: PMC6030733 DOI: 10.3389/fnsys.2018.00028] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 06/04/2018] [Indexed: 01/29/2023] Open
Abstract
Striatal cholinergic dysfunction is a common phenotype associated with various forms of dystonia in which anti-cholinergic drugs have some therapeutic benefits. However, the underlying substrate of striatal cholinergic defects in dystonia remain poorly understood. In this study, we used a recently developed knock-in mouse model of dopamine-responsive dystonia (DRD) with strong symptomatic responses to anti-cholinergic drugs, to assess changes in the prevalence and morphology of striatal cholinergic interneurons (ChIs) in a model of generalized dystonia. Unbiased stereological neuronal counts and Sholl analysis were used to address these issues. To determine the potential effect of aging on the number of ChIs, both young (3 months old) and aged (15 months old) mice were used. For purpose of comparisons with ChIs, the number of GABAergic parvalbumin (PV)-immunoreactive striatal interneurons was also quantified in young mice. Overall, no significant change in the prevalence of ChIs and PV-immunoreactive cells was found throughout various functional regions of the striatum in young DRD mice. Similar results were found for ChIs in aged animals. Subtle changes in the extent and complexity of the dendritic tree of ChIs were found in middle and caudal regions of the striatum in DRD mice. Additional immunohistochemical data also suggested lack of significant change in the expression of striatal cholinergic M1 and M4 muscarinic receptors immunoreactivity in DRD mice. Thus, together with our previous data from a knock-in mouse model of DYT-1 dystonia (Song et al., 2013), our data further suggest that the dysregulation of striatal cholinergic transmission in dystonia is not associated with major neuroplastic changes in the morphology or prevalence of striatal ChIs. HighlightsThere is no significant change in the number of striatal ChIs in young and aged mice model of DRD There is no significant change in the prevalence of striatal GABAergic PV-containing interneurons in the striatum of young mice models of DRD Subtle morphological changes in the dendritic arborization of striatal ChIs are found in the middle and caudal tiers of the striatum in young mice models of DRD The levels of both M1 and M4 muscarinic receptors immunoreactivity are not significantly changed in the striatum of DRD mice Major changes in the prevalence and morphology of striatal ChIs are unlikely to underlie striatal cholinergic dysfunction in DRD
Collapse
Affiliation(s)
- Gul Yalcin-Cakmakli
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States
| | - Samuel J Rose
- Department of Pharmacology, Emory University, Atlanta, GA, United States
| | - Rosa M Villalba
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States
| | - Lagena Williams
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States
| | - Hyder A Jinnah
- Department of Neurology, Emory University, Atlanta, GA, United States
| | - Ellen J Hess
- Department of Pharmacology, Emory University, Atlanta, GA, United States.,Department of Neurology, Emory University, Atlanta, GA, United States
| | - Yoland Smith
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States.,Department of Neurology, Emory University, Atlanta, GA, United States
| |
Collapse
|
3
|
Hamann M, Plank J, Richter F, Bode C, Smiljanic S, Creed M, Nobrega JN, Richter A. Alterations of M1 and M4 acetylcholine receptors in the genetically dystonic (dt sz) hamster and moderate antidystonic efficacy of M1 and M4 anticholinergics. Neuroscience 2017; 357:84-98. [PMID: 28596119 DOI: 10.1016/j.neuroscience.2017.05.051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/28/2017] [Accepted: 05/29/2017] [Indexed: 11/30/2022]
Abstract
Striatal cholinergic dysfunction has been suggested to play a critical role in the pathophysiology of dystonia. In the dtsz hamster, a phenotypic model of paroxysmal dystonia, M1 antagonists exerted moderate antidystonic efficacy after acute systemic administration. In the present study, we examined the effects of the M4 preferring antagonist tropicamid and whether long-term systemic or acute intrastriatal injections of the M1 preferring antagonist trihexyphenidyl are more effective in mutant hamsters. Furthermore, M1 and M4 receptors were analyzed by autoradiography and immunohistochemistry. Tropicamide retarded the onset of dystonic attacks, as previously observed after acute systemic administration of trihexyphenidyl. Combined systemic administration of trihexyphenidyl (30mg/kg) and tropicamide (15mg/kg) reduced the severity in acute trials and delayed the onset of dystonia during long-term treatment. In contrast, acute striatal microinjections of trihexyphenidyl, tropicamid or the positive allosteric M4 receptor modulator VU0152100 did not exert significant effects. Receptor analyses revealed changes of M1 receptors in the dorsomedial striatum, suggesting that the cholinergic system is involved in abnormal striatal plasticity in dtsz hamsters, but the pharmacological data argue against a crucial role on the phenotype in this animal model. However, antidystonic effects of tropicamide after systemic administration point to a novel therapeutic potential of M4 preferring anticholinergics for the treatment of dystonia.
Collapse
Affiliation(s)
- Melanie Hamann
- Institute of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Schubertstrasse 81, BFS, 35392 Giessen, Germany.
| | - Jagoda Plank
- Institute of Pharmacology and Toxicology, Department of Veterinary Medicine, Freie Universität Berlin, Koserstrasse 20, 14195 Berlin, Germany
| | - Franziska Richter
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 15, Leipzig, Germany
| | - Christoph Bode
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 15, Leipzig, Germany
| | - Sinisa Smiljanic
- Institute of Pharmacology and Toxicology, Department of Veterinary Medicine, Freie Universität Berlin, Koserstrasse 20, 14195 Berlin, Germany
| | - Meaghan Creed
- Neuroimaging Research Section, Centre for Addiction and Mental Health, Toronto, Canada
| | - José N Nobrega
- Institute of Pharmacology and Toxicology, Department of Veterinary Medicine, Freie Universität Berlin, Koserstrasse 20, 14195 Berlin, Germany
| | - Angelika Richter
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 15, Leipzig, Germany.
| |
Collapse
|
4
|
Bode C, Richter F, Spröte C, Brigadski T, Bauer A, Fietz S, Fritschy JM, Richter A. Altered postnatal maturation of striatal GABAergic interneurons in a phenotypic animal model of dystonia. Exp Neurol 2017; 287:44-53. [PMID: 27780732 DOI: 10.1016/j.expneurol.2016.10.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 09/30/2016] [Accepted: 10/21/2016] [Indexed: 01/05/2023]
Abstract
GABAergic disinhibition has been suggested to play a critical role in the pathophysiology of several basal ganglia disorders, including dystonia, a common movement disorder. Previous studies have shown a deficit of striatal GABAergic interneurons (IN) in the dtsz mutant hamster, one of the few phenotypic animal models of dystonia. However, mechanisms underlying this deficit are largely unknown. In the present study, we investigated the migration and maturation of striatal IN during postnatal development (18days of age) and at age of highest severity of dystonia (33days of age) in this hamster model. In line with previous findings, the density of GAD67-positive IN and the level of parvalbumin mRNA, a marker for fast spiking GABAergic IN, were lower in the dtsz mutant than in control hamsters. However, an unaltered density of Nkx2.1 labeled cells and Nkx2.1 mRNA level suggested that the migration of GABAergic IN into the striatum was not retarded. Therefore, different factors that indicate maturation of GABAergic IN were determined. While mRNA of the KCC2 cation/chloride transporters and the cytosolic carboanhydrase VII, used as markers for the so called GABA switch, as well as BDNF were unaltered, we found a reduced number of IN expressing the alpha1 subunit of the GABAA-receptor (37.5%) in dtsz hamsters at an age of 33days, but not after spontaneous remission of dystonia at an age of 90days. Since IN shift expression from alpha2 to alpha1 subunits during postnatal maturation, this result together with a decreased parvalbumin mRNA expression suggest a delayed maturation of striatal GABAergic IN in this animal model, which might underlie abnormal neuronal activity and striatal plasticity.
Collapse
Affiliation(s)
- Christoph Bode
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Franziska Richter
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany.
| | - Christine Spröte
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Tanja Brigadski
- Institute for Physiology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; Center of Behavioral Brain Sciences (CBBS), 39120 Magdeburg, Germany
| | - Anne Bauer
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Simone Fietz
- Institute of Veterinary Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich 8057, Switzerland
| | - Angelika Richter
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany.
| |
Collapse
|
5
|
Striatal cholinergic dysfunction as a unifying theme in the pathophysiology of dystonia. Prog Neurobiol 2015; 127-128:91-107. [PMID: 25697043 DOI: 10.1016/j.pneurobio.2015.02.002] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/05/2015] [Accepted: 02/07/2015] [Indexed: 01/06/2023]
Abstract
Dystonia is a movement disorder of both genetic and non-genetic causes, which typically results in twisted posturing due to abnormal muscle contraction. Evidence from dystonia patients and animal models of dystonia indicate a crucial role for the striatal cholinergic system in the pathophysiology of dystonia. In this review, we focus on striatal circuitry and the centrality of the acetylcholine system in the function of the basal ganglia in the control of voluntary movement and ultimately clinical manifestation of movement disorders. We consider the impact of cholinergic interneurons (ChIs) on dopamine-acetylcholine interactions and examine new evidence for impairment of ChIs in dysfunction of the motor systems producing dystonic movements, particularly in animal models. We have observed paradoxical excitation of ChIs in the presence of dopamine D2 receptor agonists and impairment of striatal synaptic plasticity in a mouse model of DYT1 dystonia, which are improved by administration of recently developed M1 receptor antagonists. These findings have been confirmed across multiple animal models of DYT1 dystonia and may represent a common endophenotype by which to investigate dystonia induced by other types of genetic and non-genetic causes and to investigate the potential effectiveness of pharmacotherapeutics and other strategies to improve dystonia.
Collapse
|
6
|
Genetic animal models of dystonia: common features and diversities. Prog Neurobiol 2014; 121:91-113. [PMID: 25034123 DOI: 10.1016/j.pneurobio.2014.07.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 06/06/2014] [Accepted: 07/03/2014] [Indexed: 01/13/2023]
Abstract
Animal models are pivotal for studies of pathogenesis and treatment of disorders of the central nervous system which in its complexity cannot yet be modeled in vitro or using computer simulations. The choice of a specific model to test novel therapeutic strategies for a human disease should be based on validity of the model for the approach: does the model reflect symptoms, pathogenesis and treatment response present in human patients? In the movement disorder dystonia, prior to the availability of genetically engineered mice, spontaneous mutants were chosen based on expression of dystonic features, including abnormal muscle contraction, movements and postures. Recent discovery of a number of genes and gene products involved in dystonia initiated research on pathogenesis of the disorder, and the creation of novel models based on gene mutations. Here we present a review of current models of dystonia, with a focus on genetic rodent models, which will likely be first choice in the future either for pathophysiological or for preclinical drug testing or both. In order to help selection of a model depending on expression of a specific feature of dystonia, this review is organized by symptoms and current knowledge of pathogenesis of dystonia. We conclude that albeit there is increasing need for research on pathogenesis of the disease and development of improved models, current models do replicate features of dystonia and are useful tools to develop urgently demanded treatment for this debilitating disorder.
Collapse
|
7
|
Kreil A, Hamann M, Sander SE, Richter A. Changes in dynorphin immunoreactivity but unaltered density of enkephalin immunoreactive neurons in basal ganglia nuclei of genetically dystonic hamsters. Synapse 2011; 65:1196-203. [PMID: 21638337 DOI: 10.1002/syn.20959] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 05/21/2011] [Accepted: 05/24/2011] [Indexed: 12/12/2022]
Abstract
Dystonia is regarded as a basal ganglia disorder. In the dt(sz) hamster, a genetic animal model of paroxysmal dystonia, previous studies demonstrated a reduced density of striatal GABAergic interneurons which inhibit striatal GABAergic projection neurons. Although the disinhibition of striatal GABAergic projection neurons was evidenced in the dt(sz) hamster, alterations in their density have not been elucidated so far. Therefore, in the present study, the density of striatal methionin-(met-) enkephalin (ENK) immunoreactive GABAergic neurons, which project to the globus pallidus (indirect pathway), was determined in dt(sz) and control hamsters to clarify a possible role of an altered ratio between striatal interneurons and projection neurons. Furthermore, the immunoreactivity of dynorphin A (DYN), which is expressed in entopeduncular fibers of striatal neurons of the direct pathway, was verified by gray level measurements to illuminate the functional relevance of an enhanced striato-entopeduncular neuronal activity previously found in dt(sz) hamsters. While the density of striatal ENK immunoreactive (ENK(+) ) neurons did not significantly differ between mutant and control hamsters, there was a significantly enhanced ratio between the DYN immunoreactive area and the whole area of the EPN in dt(sz) hamsters compared to controls. These results support the hypothesis that a disbalance between a reduced density of striatal interneurons and an unchanged density of striatal projection neurons causes imbalances in the basal ganglia network. The consequentially enhanced striato-entopeduncular inhibition leads to an already evidenced reduced activity and an altered firing pattern of entopeduncular neurons in the dt(sz) hamster.
Collapse
Affiliation(s)
- Annette Kreil
- Institute of Pharmacology and Toxicology, Department of Veterinary Medicine, Freie Universität Berlin, Koserstrasse 20, 14195 Berlin, Germany
| | | | | | | |
Collapse
|
8
|
Araujo JA, Nobrega JN, Raymond R, Milgram NW. Aged dogs demonstrate both increased sensitivity to scopolamine impairment and decreased muscarinic receptor density. Pharmacol Biochem Behav 2011; 98:203-9. [DOI: 10.1016/j.pbb.2011.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 12/22/2010] [Accepted: 01/07/2011] [Indexed: 11/29/2022]
|
9
|
Sander S, Richter F, Raymond R, Diwan M, Lange N, Nobrega J, Richter A. Pharmacological and autoradiographic studies on the pathophysiological role of GABAB receptors in the dystonic hamster: pronounced antidystonic effects of baclofen after striatal injections. Neuroscience 2009; 162:423-30. [DOI: 10.1016/j.neuroscience.2009.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 05/04/2009] [Accepted: 05/04/2009] [Indexed: 12/18/2022]
|
10
|
Hamann M, Richter A, Meillasson FV, Nitsch C, Ebert U. Age-related changes in parvalbumin-positive interneurons in the striatum, but not in the sensorimotor cortex in dystonic brains of the dt mutant hamster. Brain Res 2007; 1150:190-9. [PMID: 17391652 DOI: 10.1016/j.brainres.2007.02.074] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 02/26/2007] [Accepted: 02/27/2007] [Indexed: 10/23/2022]
Abstract
In the dt(sz) hamster, a model of paroxysmal dystonia, an age-dependent increase in the activity of striatal projection neurons has been hypothesized to be based on a deficit of striatal parvalbumin-immunoreactive (PV(+)) interneurons at an age of most marked expression of dystonia (30-40 days of life). In the present study, the spontaneous age-dependent remission of paroxysmal dystonia in older dt(sz) hamsters (age>90 days) was found to coincide with a normalization of the density of striatal PV(+) interneurons. Furthermore, the arborization of these interneurons was lower in 31 day old dt(sz) hamsters, but was even higher in dt(sz) mutant at an age of >90 days than in control animals. Double-labeling with bromodeoxyuridine failed to show a retarded proliferation, while the number of interneurons with strong expression of PV mRNA was lower in young mutant hamsters. As shown by unaltered density of PV(+) interneurons in sensorimotor cortex of 31 day old dt(sz) hamsters, PV containing interneurons are not reduced throughout the whole brain at the sensitive age. The present data suggest that a retarded postnatal maturation of striatal PV(+) interneurons plays a critical role in paroxysmal dystonia.
Collapse
Affiliation(s)
- Melanie Hamann
- Institute of Pharmacology and Toxicology, Department of Veterinary Medicine, Freie Universität Berlin (FU), Koserstr. 20, 14195 Berlin, Germany
| | | | | | | | | |
Collapse
|
11
|
Richter A, Sander SE, Rundfeldt C. Antidystonic effects of Kv7 (KCNQ) channel openers in the dt sz mutant, an animal model of primary paroxysmal dystonia. Br J Pharmacol 2006; 149:747-53. [PMID: 17016514 PMCID: PMC2014660 DOI: 10.1038/sj.bjp.0706878] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Mutations in neuronal Kv7 (KCNQ) potassium channels can cause episodic neurological disorders. Paroxysmal dyskinesias with dystonia are a group of movement disorders which are regarded as ion channelopathies, but the role of Kv7 channels in the pathogenesis and as targets for the treatment have so far not been examined. EXPERIMENTAL APPROACH In the present study, we therefore examined the effects of the activators of neuronal Kv7.2/7.3 channels retigabine (5, 7.5, 10 mg kg(-1) i.p. and 10, 20 mg kg(-1) p.o.) and flupirtine (10, 20 mg kg(-1) i.p.) and of the channel blocker 10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone (XE-991, 3 and 6 mg kg(-1) i.p.) in the dt sz mutant hamster, a model of paroxysmal dyskinesia in which dystonic episodes occur in response to stress. KEY RESULTS Retigabine (10 mg kg(-1) i.p., 20 mg kg(-1) p.o.) and flupirtine (20 mg kg(-1) i.p.) significantly improved dystonia, while XE-991 caused a significant aggravation in the dt sz mutant. The antidystonic effect of retigabine (10 mg kg(-1) i.p.) was counteracted by XE-991 (3 mg kg(-1) i.p.). CONCLUSIONS AND IMPLICATIONS These data indicate that dysfunctions of neuronal Kv7 channels deserve attention in dyskinesias. Since retigabine and flupirtine are well tolerated in humans, the present finding of pronounced antidystonic efficacy in the dt sz mutant suggests that neuronal Kv7 channel activators are interesting candidates for the treatment of dystonia-associated dyskinesias and probably of other types of dystonias. The established analgesic effects of Kv7 channel openers might contribute to improvement of these disorders which are often accompanied by painful muscle spasms.
Collapse
Affiliation(s)
- A Richter
- Institute of Pharmacology and Toxicology, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
| | | | | |
Collapse
|