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Kovyazina IV, Khamidullina AA. Muscarinic Cholinoreceptors in Skeletal Muscle: Localization and Functional Role. Acta Naturae 2023; 15:44-55. [PMID: 38234599 PMCID: PMC10790362 DOI: 10.32607/actanaturae.25259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 09/24/2023] [Indexed: 01/19/2024] Open
Abstract
The review focuses on the modern concepts of the functions of muscarinic cholinoreceptors in skeletal muscles, particularly, in neuromuscular contacts, and that of the signaling pathways associated with the activation of various subtypes of muscarinic receptors in the skeletal muscles of cold-blooded and warm-blooded animals. Despite the long history of research into the involvement of muscarinic receptors in the modulation of neuromuscular transmission, many aspects of such regulation and the associated intracellular mechanisms remain unclear. Now it is obvious that the functions of muscarinic receptors in skeletal muscle are not limited to the autoregulation of neurosecretion from motor nerve endings but also extend to the development and morphological rearrangements of the synaptic apparatus, coordinating them with the degree of activity. The review discusses various approaches to the study of the functions of muscarinic receptors in motor synapses, as well as the problems arising when interpreting experimental data. The final part of the review is devoted to an analysis of some of the intracellular mechanisms and signaling pathways that mediate the effects of muscarinic agents on neuromuscular transmission.
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Affiliation(s)
- I. V. Kovyazina
- Kazan State Medical University, Kazan, 420012 Russian Federation
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, Kazan, 420111 Russian Federation
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2
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Wang X, Dupont C, Grant D, Voss AA, Rich MM. Plateau potentials contribute to myotonia in mouse models of myotonia congenita. Exp Neurol 2023; 361:114303. [PMID: 36563835 PMCID: PMC9892346 DOI: 10.1016/j.expneurol.2022.114303] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/12/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
It has long been accepted that myotonia (muscle stiffness) in patients with muscle channelopathies is due to myotonic discharges (involuntary firing of action potentials). In a previous study, we identified a novel phenomenon in myotonic muscle: development of plateau potentials, transient depolarizations to near -35 mV lasting for seconds to minutes. In the current study we examined whether plateau potentials contribute to myotonia. A recessive genetic model (ClCadr mice) with complete loss of muscle chloride channel (ClC-1) function was used to model severe myotonia congenita with complete loss of ClC-1 function and a pharmacologic model using anthracene-9-carboxylic acid (9 AC) was used to model milder myotonia congenita with incomplete loss of ClC-1 function. Simultaneous measurements of action potentials and myoplasmic Ca2+ from individual muscle fibers were compared to recordings of whole muscle force generation. In ClCadr muscle both myotonia and plateau potentials lasted 10s of seconds to minutes. During plateau potentials lasting 1-2 min, there was a gradual transition from high to low intracellular Ca2+, suggesting a transition in individual fibers from myotonia to flaccid paralysis in severe myotonia congenita. In 9 AC-treated muscles, both myotonia and plateau potentials lasted only a few seconds and Ca2+ remained elevated during the plateau potentials, suggesting plateau potentials contribute to myotonia without causing weakness. We propose, that in myotonic muscle, there is a novel state in which there is contraction in the absence of action potentials. This discovery provides a mechanism to explain reports of patients with myotonia who suffer from electrically silent muscle contraction lasting minutes.
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Affiliation(s)
- Xueyong Wang
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH 45435, USA
| | - Chris Dupont
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH 45435, USA
| | - Delaney Grant
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH 45435, USA
| | - Andrew A Voss
- Department of Biology, Wright State University, Dayton, OH 45435, USA
| | - Mark M Rich
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH 45435, USA.
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3
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Quiñonez M, DiFranco M, Wu F, Cannon SC. Retigabine suppresses loss of force in mouse models of hypokalaemic periodic paralysis. Brain 2023; 146:1554-1560. [PMID: 36718088 PMCID: PMC10115351 DOI: 10.1093/brain/awac441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/18/2022] [Accepted: 11/12/2022] [Indexed: 02/01/2023] Open
Abstract
Recurrent episodes of weakness in periodic paralysis are caused by intermittent loss of muscle fibre excitability, as a consequence of sustained depolarization of the resting potential. Repolarization is favoured by increasing the fibre permeability to potassium. Based on this principle, we tested the efficacy of retigabine, a potassium channel opener, to suppress the loss of force induced by a low-K+ challenge in hypokalaemic periodic paralysis (HypoPP). Retigabine can prevent the episodic loss of force in HypoPP. Knock-in mutant mouse models of HypoPP (Cacna1s p.R528H and Scn4a p.R669H) were used to determine whether pre-treatment with retigabine prevented the loss of force, or post-treatment hastened recovery of force for a low-K+ challenge in an ex vivo contraction assay. Retigabine completely prevents the loss of force induced by a 2 mM K+ challenge (protection) in our mouse models of HypoPP, with 50% inhibitory concentrations of 0.8 ± 0.13 μM and 2.2 ± 0.42 μM for NaV1.4-R669H and CaV1.1-R528H, respectively. In comparison, the effective concentration for the KATP channel opener pinacidil was 10-fold higher. Application of retigabine also reversed the loss of force (rescue) for HypoPP muscle maintained in 2 mM K+. Our findings show that retigabine, a selective agonist of the KV7 family of potassium channels, is effective for the prevention of low-K+ induced attacks of weakness and to enhance recovery from an ongoing loss of force in mouse models of type 1 (Cacna1s) and type 2 (Scn4a) HypoPP. Substantial protection from the loss of force occurred in the low micromolar range, well within the therapeutic window for retigabine.
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Affiliation(s)
- Marbella Quiñonez
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Marino DiFranco
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Fenfen Wu
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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4
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Ruijs TQ, Koopmans IW, de Kam ML, Tannemaat MR, Groeneveld GJ, Heuberger JAAC. Muscle velocity recovery cycles as pharmacodynamic biomarker: Effects of mexiletine in a randomized double-blind placebo-controlled cross-over study. Clin Transl Sci 2022; 15:2971-2981. [PMID: 36281627 PMCID: PMC9747120 DOI: 10.1111/cts.13418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 08/09/2022] [Accepted: 09/04/2022] [Indexed: 01/26/2023] Open
Abstract
Measuring muscle velocity recovery cycles (MVRCs) is a method to obtain information on muscle cell excitability, independent of neuromuscular transmission. The goal was to validate MVRC as a pharmacodynamic (PD) biomarker for drugs targeting muscle excitability. As proof-of-concept, sensitivity of MVRC to detect effects of mexiletine, a voltage-gated sodium channel (Nav ) blocker, was assessed. In a randomized, double-blind, two-way crossover study, effects of a single pharmacologically active oral dose of 333 mg mexiletine was compared to placebo in 15 healthy male subjects. MVRC was performed predose, and 3- and 5-h postdose using QTrac. Effects of mexiletine versus placebo were calculated using a mixed effects model with baseline as covariate. Mexiletine had significant effects on MVRC when compared to placebo. Early supernormality after five conditioning stimuli was decreased by mexiletine (estimated difference -2.78% [95% confidence interval: -4.16, -1.40]; p value = 0.0003). Moreover, mexiletine decreased the difference in late supernormality after five versus one conditioning stimuli (5XLSN; ED -1.46% [-2.26, -0.65]; p = 0.001). These results indicate that mexiletine decreases the percentage increase in velocity of the muscle fiber action potential after five conditioning stimuli, at long and short interstimulus intervals, which corresponds to a decrease in muscle membrane excitability. This is in line with the pharmacological activity of mexiletine, which leads to use-dependent NaV 1.4 blockade affecting muscle membrane potentials. This study shows that effects of mexiletine can be detected using MVRC in healthy subjects, thereby indicating that MVRC can be used as a tool to demonstrate PD effects of drugs targeting muscle excitability in early phase drug development.
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Affiliation(s)
- Titia Q. Ruijs
- Centre for Human Drug ResearchLeidenThe Netherlands,Leiden University Medical CentreLeidenThe Netherlands
| | - Ingrid W. Koopmans
- Centre for Human Drug ResearchLeidenThe Netherlands,Leiden University Medical CentreLeidenThe Netherlands
| | | | | | - Geert Jan Groeneveld
- Centre for Human Drug ResearchLeidenThe Netherlands,Leiden University Medical CentreLeidenThe Netherlands
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5
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Woelfel C, Meurs K, Friedenberg S, DeBruyne N, Olby NJ. A novel mutation of the CLCN1 gene in a cat with myotonia congenita: Diagnosis and treatment. Vet Med (Auckl) 2022; 36:1454-1459. [PMID: 35815860 PMCID: PMC9308434 DOI: 10.1111/jvim.16471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 05/27/2022] [Indexed: 11/29/2022]
Abstract
Case Description A 10‐month‐old castrated male domestic longhair cat was evaluated for increasing frequency of episodic limb rigidity. Clinical Findings The cat presented for falling over and lying recumbent with its limbs in extension for several seconds when startled or excited. Upon examination, the cat had hypertrophied musculature, episodes of facial spasm, and a short‐strided, stiff gait. Diagnostics Electromyography (EMG) identified spontaneous discharges that waxed and waned in amplitude and frequency, consistent with myotonic discharges. A high impact 8‐base pair (bp) deletion across the end of exon 3 and intron 3 of the chloride voltage‐gated channel 1 (CLCN1) gene was identified using whole genome sequencing. Treatment and Outcome Phenytoin treatment was initiated at 3 mg/kg po q24 h and resulted in long‐term improvement. Clinical Relevance This novel mutation within the CLCN1 gene is a cause of myotonia congenita in cats and we report for the first time its successful treatment.
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Affiliation(s)
- Christian Woelfel
- College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Kathryn Meurs
- College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Steven Friedenberg
- Veterinary Medical Center, University of Minnesota, Saint Paul, Minnesota, USA
| | - Nicole DeBruyne
- College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Natasha J Olby
- College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
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6
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Wrzosek A, Gałecka S, Żochowska M, Olszewska A, Kulawiak B. Alternative Targets for Modulators of Mitochondrial Potassium Channels. Molecules 2022; 27:299. [PMID: 35011530 PMCID: PMC8746388 DOI: 10.3390/molecules27010299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/30/2021] [Accepted: 12/31/2021] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial potassium channels control potassium influx into the mitochondrial matrix and thus regulate mitochondrial membrane potential, volume, respiration, and synthesis of reactive oxygen species (ROS). It has been found that pharmacological activation of mitochondrial potassium channels during ischemia/reperfusion (I/R) injury activates cytoprotective mechanisms resulting in increased cell survival. In cancer cells, the inhibition of these channels leads to increased cell death. Therefore, mitochondrial potassium channels are intriguing targets for the development of new pharmacological strategies. In most cases, however, the substances that modulate the mitochondrial potassium channels have a few alternative targets in the cell. This may result in unexpected or unwanted effects induced by these compounds. In our review, we briefly present the various classes of mitochondrial potassium (mitoK) channels and describe the chemical compounds that modulate their activity. We also describe examples of the multidirectional activity of the activators and inhibitors of mitochondrial potassium channels.
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Affiliation(s)
- Antoni Wrzosek
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Shur Gałecka
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Monika Żochowska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Anna Olszewska
- Department of Histology, Medical University of Gdansk, 1a Debinki, 80-211 Gdansk, Poland;
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
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7
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Wang X, Burke SRA, Talmadge RJ, Voss AA, Rich MM. Depressed neuromuscular transmission causes weakness in mice lacking BK potassium channels. J Gen Physiol 2021; 152:151617. [PMID: 32243496 PMCID: PMC7201880 DOI: 10.1085/jgp.201912526] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 01/27/2020] [Accepted: 03/02/2020] [Indexed: 12/20/2022] Open
Abstract
Mice lacking functional large-conductance voltage- and Ca2+-activated K+ channels (BK channels) are viable but have motor deficits including ataxia and weakness. The cause of weakness is unknown. In this study, we discovered, in vivo, that skeletal muscle in mice lacking BK channels (BK−/−) was weak in response to nerve stimulation but not to direct muscle stimulation, suggesting a failure of neuromuscular transmission. Voltage-clamp studies of the BK−/− neuromuscular junction (NMJ) revealed a reduction in evoked endplate current amplitude and the frequency of spontaneous vesicle release compared with WT littermates. Responses to 50-Hz stimulation indicated a reduced probability of vesicle release in BK−/− mice, suggestive of lower presynaptic Ca2+ entry. Pharmacological block of BK channels in WT NMJs did not affect NMJ function, surprisingly suggesting that the reduced vesicle release in BK−/− NMJs was not due to loss of BK channel–mediated K+ current. Possible explanations for our data include an effect of BK channels on development of the NMJ, a role for BK channels in regulating presynaptic Ca2+ current or the effectiveness of Ca2+ in triggering release. Consistent with reduced Ca2+ entry or effectiveness of Ca2+ in triggering release, use of 3,4-diaminopyridine to widen action potentials normalized evoked release in BK−/− mice to WT levels. Intraperitoneal application of 3,4-diaminopyridine fully restored in vivo nerve-stimulated muscle force in BK−/− mice. Our work demonstrates that mice lacking BK channels have weakness due to a defect in vesicle release at the NMJ.
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Affiliation(s)
- Xueyong Wang
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH
| | - Steven R A Burke
- Department of Biological Sciences, Wright State University, Dayton, OH
| | - Robert J Talmadge
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA
| | - Andrew A Voss
- Department of Biological Sciences, Wright State University, Dayton, OH
| | - Mark M Rich
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH
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8
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Borgini M, Mondal P, Liu R, Wipf P. Chemical modulation of Kv7 potassium channels. RSC Med Chem 2021; 12:483-537. [PMID: 34046626 PMCID: PMC8128042 DOI: 10.1039/d0md00328j] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/01/2020] [Indexed: 01/10/2023] Open
Abstract
The rising interest in Kv7 modulators originates from their ability to evoke fundamental electrophysiological perturbations in a tissue-specific manner. A large number of therapeutic applications are, in part, based on the clinical experience with two broad-spectrum Kv7 agonists, flupirtine and retigabine. Since precise molecular structures of human Kv7 channel subtypes in closed and open states have only very recently started to emerge, computational studies have traditionally been used to analyze binding modes and direct the development of more potent and selective Kv7 modulators with improved safety profiles. Herein, the synthetic and medicinal chemistry of small molecule modulators and the representative biological properties are summarized. Furthermore, new therapeutic applications supported by in vitro and in vivo assay data are suggested.
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Affiliation(s)
- Matteo Borgini
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Pravat Mondal
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Ruiting Liu
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
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9
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Myers JH, Denman K, DuPont C, Hawash AA, Novak KR, Koesters A, Grabner M, Dayal A, Voss AA, Rich MM. The mechanism underlying transient weakness in myotonia congenita. eLife 2021; 10:e65691. [PMID: 33904400 PMCID: PMC8079152 DOI: 10.7554/elife.65691] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 03/24/2021] [Indexed: 12/23/2022] Open
Abstract
In addition to the hallmark muscle stiffness, patients with recessive myotonia congenita (Becker disease) experience debilitating bouts of transient weakness that remain poorly understood despite years of study. We performed intracellular recordings from muscle of both genetic and pharmacologic mouse models of Becker disease to identify the mechanism underlying transient weakness. Our recordings reveal transient depolarizations (plateau potentials) of the membrane potential to -25 to -35 mV in the genetic and pharmacologic models of Becker disease. Both Na+ and Ca2+ currents contribute to plateau potentials. Na+ persistent inward current (NaPIC) through NaV1.4 channels is the key trigger of plateau potentials and current through CaV1.1 Ca2+ channels contributes to the duration of the plateau. Inhibiting NaPIC with ranolazine prevents the development of plateau potentials and eliminates transient weakness in vivo. These data suggest that targeting NaPIC may be an effective treatment to prevent transient weakness in myotonia congenita.
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Affiliation(s)
- Jessica H Myers
- Department of Neuroscience, Cell Biology and Physiology, Wright State UniversityDaytonUnited States
| | - Kirsten Denman
- Department of Neuroscience, Cell Biology and Physiology, Wright State UniversityDaytonUnited States
| | - Chris DuPont
- Department of Neuroscience, Cell Biology and Physiology, Wright State UniversityDaytonUnited States
| | - Ahmed A Hawash
- Department of Dermatology & Cutaneous Surgery, University of MiamiMiamiUnited States
| | | | - Andrew Koesters
- Naval Medical Research Unit, Wright Patterson Air Force BaseDaytonUnited States
| | - Manfred Grabner
- Department of Pharmacology, Medical University of InnsbruckInnsbruckAustria
| | - Anamika Dayal
- Department of Pharmacology, Medical University of InnsbruckInnsbruckAustria
| | - Andrew A Voss
- Department of Biology, Wright State UniversityDaytonUnited States
| | - Mark M Rich
- Department of Neuroscience, Cell Biology and Physiology, Wright State UniversityDaytonUnited States
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10
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Desaphy JF, Altamura C, Vicart S, Fontaine B. Targeted Therapies for Skeletal Muscle Ion Channelopathies: Systematic Review and Steps Towards Precision Medicine. J Neuromuscul Dis 2021; 8:357-381. [PMID: 33325393 PMCID: PMC8203248 DOI: 10.3233/jnd-200582] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Skeletal muscle ion channelopathies include non-dystrophic myotonias (NDM), periodic paralyses (PP), congenital myasthenic syndrome, and recently identified congenital myopathies. The treatment of these diseases is mainly symptomatic, aimed at reducing muscle excitability in NDM or modifying triggers of attacks in PP. OBJECTIVE This systematic review collected the evidences regarding effects of pharmacological treatment on muscle ion channelopathies, focusing on the possible link between treatments and genetic background. METHODS We searched databases for randomized clinical trials (RCT) and other human studies reporting pharmacological treatments. Preclinical studies were considered to gain further information regarding mutation-dependent drug effects. All steps were performed by two independent investigators, while two others critically reviewed the entire process. RESULTS For NMD, RCT showed therapeutic benefits of mexiletine and lamotrigine, while other human studies suggest some efficacy of various sodium channel blockers and of the carbonic anhydrase inhibitor (CAI) acetazolamide. Preclinical studies suggest that mutations may alter sensitivity of the channel to sodium channel blockers in vitro, which has been translated to humans in some cases. For hyperkalemic and hypokalemic PP, RCT showed efficacy of the CAI dichlorphenamide in preventing paralysis. However, hypokalemic PP patients carrying sodium channel mutations may have fewer benefits from CAI compared to those carrying calcium channel mutations. Few data are available for treatment of congenital myopathies. CONCLUSIONS These studies provided limited information about the response to treatments of individual mutations or groups of mutations. A major effort is needed to perform human studies for designing a mutation-driven precision medicine in muscle ion channelopathies.
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Affiliation(s)
- Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Concetta Altamura
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Savine Vicart
- Sorbonne Université, INSERM, Assistance Publique Hôpitaux de Paris, Centre de Recherche en Myologie-UMR 974, Reference center in neuro-muscular channelopathies, Institute of Myology, Hôpital Universitaire Pitié-Salpêtrière, Paris, France
| | - Bertrand Fontaine
- Sorbonne Université, INSERM, Assistance Publique Hôpitaux de Paris, Centre de Recherche en Myologie-UMR 974, Reference center in neuro-muscular channelopathies, Institute of Myology, Hôpital Universitaire Pitié-Salpêtrière, Paris, France
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11
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Hoppe K, Sartorius T, Chaiklieng S, Wietzorrek G, Ruth P, Jurkat-Rott K, Wearing S, Lehmann-Horn F, Klingler W. Paxilline Prevents the Onset of Myotonic Stiffness in Pharmacologically Induced Myotonia: A Preclinical Investigation. Front Physiol 2020; 11:533946. [PMID: 33329012 PMCID: PMC7719791 DOI: 10.3389/fphys.2020.533946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 10/12/2020] [Indexed: 11/13/2022] Open
Abstract
Reduced Cl− conductance causes inhibited muscle relaxation after forceful voluntary contraction due to muscle membrane hyperexcitability. This represents the pathomechanism of myotonia congenita. Due to the prevailing data suggesting that an increased potassium level is a main contributor, we studied the effect of a modulator of a big conductance Ca2+- and voltage-activated K+ channels (BK) modulator on contraction and relaxation of slow- and high-twitch muscle specimen before and after the pharmacological induction of myotonia. Human and murine muscle specimens (wild-type and BK−/−) were exposed to anthracene-9-carboxylic acid (9-AC) to inhibit CLC-1 chloride channels and to induce myotonia in-vitro. Functional effects of BK-channel activation and blockade were investigated by exposing slow-twitch (soleus) and fast-twitch (extensor digitorum longus) murine muscle specimens or human musculus vastus lateralis to an activator (NS1608) and a blocker (Paxilline), respectively. Muscle-twitch force and relaxation times (T90/10) were monitored. Compared to wild type, fast-twitch muscle specimen of BK−/− mice resulted in a significantly decreased T90/10 in presence of 9-AC. Paxilline significantly shortened T90/10 of murine slow- and fast-twitch muscles as well as human vastus lateralis muscle. Moreover, twitch force was significantly reduced after application of Paxilline in myotonic muscle. NS1608 had opposite effects to Paxilline and aggravated the onset of myotonic activity by prolongation of T90/10. The currently used standard therapy for myotonia is, in some individuals, not very effective. This in vitro study demonstrated that a BK channel blocker lowers myotonic stiffness and thus highlights its potential therapeutic option in myotonia congenital (MC).
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Affiliation(s)
- Kerstin Hoppe
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, Goethe University, Frankfurt University Hospital, Frankfurt, Germany.,Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, Wuerzburg University Hospital, Wuerzburg, Germany
| | - Tina Sartorius
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Tuebingen, Germany
| | - Sunisa Chaiklieng
- Division of Neurophysiology in the Center of Rare Diseases, Ulm University, Ulm, Germany.,Faculty of Public Health, Khon Kaen University, Muang Khon Kaen, Thailand
| | - Georg Wietzorrek
- Institute for Molecular and Cellular Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Tuebingen, Germany
| | - Karin Jurkat-Rott
- Division of Experimental Anesthesiology, University Medical Center Ulm, Ulm, Germany
| | - Scott Wearing
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.,Department of Conservative and Rehabilitation Orthopedics, Faculty of Sport and Health Science, Technical University of Munich, Munich, Germany
| | - Frank Lehmann-Horn
- Division of Neurophysiology in the Center of Rare Diseases, Ulm University, Ulm, Germany
| | - Werner Klingler
- Division of Neurophysiology in the Center of Rare Diseases, Ulm University, Ulm, Germany.,Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.,Department of Conservative and Rehabilitation Orthopedics, Faculty of Sport and Health Science, Technical University of Munich, Munich, Germany.,Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, SRH Clinincs, Sigmaringen, Germany
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12
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Hoppe K, Chaiklieng S, Lehmann-Horn F, Jurkat-Rott K, Wearing S, Klingler W. Preclinical pharmacological in vitro investigations on low chloride conductance myotonia: effects of potassium regulation. Pflugers Arch 2020; 472:1481-1494. [PMID: 32748018 DOI: 10.1007/s00424-020-02410-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 05/24/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022]
Abstract
In myotonia, reduced Cl- conductance of the mutated ClC-1 channels causes hindered muscle relaxation after forceful voluntary contraction due to muscle membrane hyperexcitability. Repetitive contraction temporarily decreases myotonia, a phenomena called "warm up." The underlying mechanism for the reduction of hyperexcitability in warm-up is currently unknown. Since potassium displacement is known to reduce excitability in, for example, muscle fatigue, we characterized the role of potassium in native myotonia congenita (MC) muscle. Muscle specimens of ADR mice (an animal model for low gCl- conductance myotonia) were exposed to increasing K+ concentrations. To characterize functional effects of potassium ion current, the muscle of ADR mice was exposed to agonists and antagonists of the big conductance Ca2+-activated K+ channel (BK) and the voltage-gated Kv7 channel. Effects were monitored by functional force and membrane potential measurements. By increasing [K+]0 to 5 mM, the warm-up phenomena started earlier and at [K+]0 7 mM only weak myotonia was detected. The increase of [K+]0 caused a sustained membrane depolarization accompanied with a reduction of myotonic bursts in ADR mice. Retigabine, a Kv7.2-Kv7.5 activator, dose-dependently reduced relaxation deficit of ADR myotonic muscle contraction and promoted the warm-up phenomena. In vitro results of this study suggest that increasing potassium conductivity via activation of voltage-gated potassium channels enhanced the warm-up phenomena, thereby offering a potential therapeutic treatment option for myotonia congenita.
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Affiliation(s)
- Kerstin Hoppe
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital of Wuerzburg, Oberduerrbacher Str. 6, 97080, Wuerzburg, Germany.
| | - Sunisa Chaiklieng
- Division of Neurophysiology in the Center of Rare Diseases, Ulm University, Albert Einstein Allee 23, 89081, Ulm, Germany
- Faculty of Public Health, Khon Kaen University, Muang Khon Kaen, Thailand
| | - Frank Lehmann-Horn
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital of Wuerzburg, Oberduerrbacher Str. 6, 97080, Wuerzburg, Germany
| | - Karin Jurkat-Rott
- Universtiy Medical Center Ulm, Division of Experimental Anesthesiology, Albert-Einstein-Allee 23, 89081, Ullm, Germany
| | - Scott Wearing
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, 4059, Australia
- Department of Conservative and Rehabilitation Orthopedics, Faculty of Sport and Health Science, Technical University of Munich, Gerog-Brauchle-Ring 60/62, Munich, Germany
| | - Werner Klingler
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, 4059, Australia
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, SRH Clinincs, Hohenzollernstraße 40, 72488, Sigmaringen, Germany
- Department of Conservative and Rehabilitation Orthopedics, Faculty of Sport and Health Science, Technical University of Munich, Gerog-Brauchle-Ring 60/62, Munich, Germany
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13
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Dupont C, Novak K, Denman K, Myers JH, Sullivan JM, Walker PV, Brown NL, Ladle DR, Bogdanik L, Lutz CM, A Voss A, Sumner CJ, Rich MM. TRPV4 Antagonism Prevents Mechanically Induced Myotonia. Ann Neurol 2020; 88:297-308. [PMID: 32418267 PMCID: PMC7657963 DOI: 10.1002/ana.25780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/27/2020] [Accepted: 05/07/2020] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Myotonia is caused by involuntary firing of skeletal muscle action potentials and causes debilitating stiffness. Current treatments are insufficiently efficacious and associated with side effects. Myotonia can be triggered by voluntary movement (electrically induced myotonia) or percussion (mechanically induced myotonia). Whether distinct molecular mechanisms underlie these triggers is unknown. Our goal was to identify ion channels involved in mechanically induced myotonia and to evaluate block of the channels involved as a novel approach to therapy. METHODS We developed a novel system to enable study of mechanically induced myotonia using both genetic and pharmacologic mouse models of myotonia congenita. We extended ex vivo studies of excitability to in vivo studies of muscle stiffness. RESULTS As previous work suggests activation of transient receptor potential vanilloid 4 (TRPV4) channels by mechanical stimuli in muscle, we examined the role of this cation channel. Mechanically induced myotonia was markedly suppressed in TRPV4-null muscles and in muscles treated with TRPV4 small molecule antagonists. The suppression of mechanically induced myotonia occurred without altering intrinsic muscle excitability, such that myotonia triggered by firing of action potentials (electrically induced myotonia) was unaffected. When injected intraperitoneally, TRPV4 antagonists lessened the severity of myotonia in vivo by approximately 80%. INTERPRETATION These data demonstrate that there are distinct molecular mechanisms triggering electrically induced and mechanically induced myotonia. Our data indicates that activation of TRPV4 during muscle contraction plays an important role in triggering myotonia in vivo. Elimination of mechanically induced myotonia by TRPV4 inhibition offers a new approach to treating myotonia. ANN NEUROL 2020;88:297-308.
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Affiliation(s)
- Chris Dupont
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Kevin Novak
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Kirsten Denman
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Jessica H Myers
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Jeremy M Sullivan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Phillip V Walker
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Nicklaus L Brown
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - David R Ladle
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | | | | | - Andrew A Voss
- Department of Biology, Wright State University, Dayton, OH, USA
| | - Charlotte J Sumner
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mark M Rich
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
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14
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Altamura C, Desaphy JF, Conte D, De Luca A, Imbrici P. Skeletal muscle ClC-1 chloride channels in health and diseases. Pflugers Arch 2020; 472:961-975. [PMID: 32361781 DOI: 10.1007/s00424-020-02376-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/18/2020] [Accepted: 03/31/2020] [Indexed: 12/14/2022]
Abstract
In 1970, the study of the pathomechanisms underlying myotonia in muscle fibers isolated from myotonic goats highlighted the importance of chloride conductance for skeletal muscle function; 20 years later, the human ClC-1 chloride channel has been cloned; last year, the crystal structure of human protein has been solved. Over the years, the efforts of many researchers led to significant advances in acknowledging the role of ClC-1 in skeletal muscle physiology and the mechanisms through which ClC-1 dysfunctions lead to impaired muscle function. The wide spectrum of pathophysiological conditions associated with modification of ClC-1 activity, either as the primary cause, such as in myotonia congenita, or as a secondary adaptive mechanism in other neuromuscular diseases, supports the idea that ClC-1 is relevant to preserve not only for skeletal muscle excitability, but also for skeletal muscle adaptation to physiological or harmful events. Improving this understanding could open promising avenues toward the development of selective and safe drugs targeting ClC-1, with the aim to restore normal muscle function. This review summarizes the most relevant research on ClC-1 channel physiology, associated diseases, and pharmacology.
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Affiliation(s)
- Concetta Altamura
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari "Aldo Moro", Bari, Italy
| | - Jean-Francois Desaphy
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari "Aldo Moro", Bari, Italy
| | - Diana Conte
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Annamaria De Luca
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Paola Imbrici
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Bari, Italy.
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15
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Metzger S, Dupont C, Voss AA, Rich MM. Central Role of Subthreshold Currents in Myotonia. Ann Neurol 2019; 87:175-183. [PMID: 31725924 DOI: 10.1002/ana.25646] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/12/2019] [Accepted: 11/12/2019] [Indexed: 01/11/2023]
Abstract
It is generally thought that muscle excitability is almost exclusively controlled by currents responsible for generation of action potentials. We propose that smaller ion channel currents that contribute to setting the resting potential and to subthreshold fluctuations in membrane potential can also modulate excitability in important ways. These channels open at voltages more negative than the action potential threshold and are thus termed subthreshold currents. As subthreshold currents are orders of magnitude smaller than the currents responsible for the action potential, they are hard to identify and easily overlooked. Discovery of their importance in regulation of excitability opens new avenues for improved therapy for muscle channelopathies and diseases of the neuromuscular junction. ANN NEUROL 2020;87:175-183.
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Affiliation(s)
- Sabrina Metzger
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Dayton, OH
| | - Chris Dupont
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Dayton, OH
| | - Andrew A Voss
- Department of Biology, Wright State University, Dayton, OH
| | - Mark M Rich
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Dayton, OH
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