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Deng Y, Li RW, Yang YL, Weiss S, Smith PN. Pharmacological prevention of renal ischemia-reperfusion injury in a rat model. ANZ J Surg 2021; 92:518-525. [PMID: 34820987 DOI: 10.1111/ans.17381] [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: 05/10/2021] [Revised: 10/10/2021] [Accepted: 11/08/2021] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Renal ischemia-reperfusion injury (IRI) can lead to significant morbidity and mortality. It remains a leading cause of acute kidney injury and is therefore an important issue in trauma and renal transplant surgery. Various pharmaceutical agents have been used in an attempt to dampen the harmful effects of IRI but few have been shown to be useful clinically. Riluzole, Lidocaine and Lamotrigine have been demonstrated to show anti-ischaemic properties in other organs; however, their use has not been tested in the kidneys. We investigated Riluzole, Lidocaine and Lamotrigine for their preventive effects of renal IRI using a rat model. METHODS Winstar rats (n = 48) were divided into four groups (n = 12 per group)-three treatment groups and one control group. Riluzole, Lidocaine and Lamotrigine were given prior to renal ischemia only (IO) or IRI. The degree of ischemia was measured by glutathione levels and a TUNEL assay was used to measure DNA fragmentation. RESULTS Riluzole, Lidocaine and Lamotrigine pre-treatment each resulted in statistically higher glutathione levels compared to controls (P = 0.002; P = 0.007 and P = 0.005, respectively). Riluzole and Lidocaine were also effective at preventing depletion of glutathione following IO (P = 0.007 and P = 0.014 respectively), while Lamotrigine was ineffective in IO (P = 0.71). The degree of DNA fragmentation seen on the TUNEL assay was markedly reduced in all three-drug groups in both IO and IRI. DISCUSSION Riluzole, Lidocaine and Lamotrigine all have anti-ischaemic effects in the rat kidney and can have potential therapeutic implications.
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Affiliation(s)
- Yi Deng
- Medical School, Australian National University, Canberra, Australian Capital Territory, Australia.,Department of Orthopaedic Surgery, Canberra Hospital, Yamba Drive, Garran, Australian Capital Territory, Australia
| | - Rachel W Li
- Medical School, Australian National University, Canberra, Australian Capital Territory, Australia.,John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Yong Liang Yang
- Department of Orthopaedics, Shandong Provincial Trauma and Orthopaedics Hospital, Jinan, China
| | - Steven Weiss
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Paul N Smith
- Medical School, Australian National University, Canberra, Australian Capital Territory, Australia.,Department of Orthopaedic Surgery, Canberra Hospital, Yamba Drive, Garran, Australian Capital Territory, Australia
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Alyu F, Olgar Y, Degirmenci S, Turan B, Ozturk Y. Interrelated In Vitro Mechanisms of Sibutramine-Induced Cardiotoxicity. Cardiovasc Toxicol 2021; 21:322-335. [PMID: 33389602 DOI: 10.1007/s12012-020-09622-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 11/24/2020] [Indexed: 11/26/2022]
Abstract
Consumption of illicit pharmaceutical products containing sibutramine has been reported to cause cardiovascular toxicity problems. This study aimed to demonstrate the toxicity profile of sibutramine, and thereby provide important implications for the development of more effective strategies in both clinical approaches and drug design studies. Action potentials (APs) were determined from freshly isolated ventricular cardiomyocytes with whole-cell configuration of current clamp as online. The maximum amplitude of APs (MAPs), the resting membrane potential (RMP), and AP duration from the repolarization phases were calculated from original records. The voltage-dependent K+-channel currents (IK) were recorded in the presence of external Cd2+ and both inward and outward parts of the current were calculated, while their expression levels were determined with qPCR. The levels of intracellular free Ca2+ and H+ (pHi) as well as reactive oxygen species (ROS) were measured using either a ratiometric micro-spectrofluorometer or confocal microscope. The mechanical activity of isolated hearts was observed with Langendorff-perfusion system. Acute sibutramine applications (10-8-10-5 M) induced significant alterations in both MAPs and RMP as well as the repolarization phases of APs and IK in a concentration-dependent manner. Sibutramine (10 μM) induced Ca2+-release from the sarcoplasmic reticulum under either electrical or caffeine stimulation, whereas it depressed left ventricular developed pressure with a marked decrease in the end-diastolic pressure. pHi inhibition by sibutramine supports the observed negative alterations in contractility. Changes in mRNA levels of different IK subunits are consistent with the acute inhibition of the repolarizing IK, affecting AP parameters, and provoke the cardiotoxicity.
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Affiliation(s)
- Feyza Alyu
- Department of Pharmacology, Faculty of Pharmacy, Anadolu University, Yunus Emre Campus, 26470, Eskisehir, Turkey
| | - Yusuf Olgar
- Department of Biophysics, Faculty of Medicine, Ankara University, 06230, Ankara, Turkey
| | - Sinan Degirmenci
- Department of Biophysics, Faculty of Medicine, Ankara University, 06230, Ankara, Turkey
| | - Belma Turan
- Department of Biophysics, Faculty of Medicine, Ankara University, 06230, Ankara, Turkey
- Department of Biophysics, Faculty of Medicine, Lokman Hekim University, 06230, Ankara, Turkey
| | - Yusuf Ozturk
- Department of Pharmacology, Faculty of Pharmacy, Anadolu University, Yunus Emre Campus, 26470, Eskisehir, Turkey.
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3
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Munger MA, Olğar Y, Koleske ML, Struckman HL, Mandrioli J, Lou Q, Bonila I, Kim K, Ramos Mondragon R, Priori SG, Volpe P, Valdivia HH, Biskupiak J, Carnes CA, Veeraraghavan R, Györke S, Radwański PB. Tetrodotoxin-Sensitive Neuronal-Type Na + Channels: A Novel and Druggable Target for Prevention of Atrial Fibrillation. J Am Heart Assoc 2020; 9:e015119. [PMID: 32468902 PMCID: PMC7429002 DOI: 10.1161/jaha.119.015119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Atrial fibrillation (AF) is a comorbidity associated with heart failure and catecholaminergic polymorphic ventricular tachycardia. Despite the Ca2+‐dependent nature of both of these pathologies, AF often responds to Na+ channel blockers. We investigated how targeting interdependent Na+/Ca2+ dysregulation might prevent focal activity and control AF. Methods and Results We studied AF in 2 models of Ca2+‐dependent disorders, a murine model of catecholaminergic polymorphic ventricular tachycardia and a canine model of chronic tachypacing‐induced heart failure. Imaging studies revealed close association of neuronal‐type Na+ channels (nNav) with ryanodine receptors and Na+/Ca2+ exchanger. Catecholamine stimulation induced cellular and in vivo atrial arrhythmias in wild‐type mice only during pharmacological augmentation of nNav activity. In contrast, catecholamine stimulation alone was sufficient to elicit atrial arrhythmias in catecholaminergic polymorphic ventricular tachycardia mice and failing canine atria. Importantly, these were abolished by acute nNav inhibition (tetrodotoxin or riluzole) implicating Na+/Ca2+ dysregulation in AF. These findings were then tested in 2 nonrandomized retrospective cohorts: an amyotrophic lateral sclerosis clinic and an academic medical center. Riluzole‐treated patients adjusted for baseline characteristics evidenced significantly lower incidence of arrhythmias including new‐onset AF, supporting the preclinical results. Conclusions These data suggest that nNaVs mediate Na+‐Ca2+ crosstalk within nanodomains containing Ca2+ release machinery and, thereby, contribute to AF triggers. Disruption of this mechanism by nNav inhibition can effectively prevent AF arising from diverse causes.
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Affiliation(s)
- Mark A Munger
- Departments of Pharmacotherapy and Internal Medicine University of Utah Health Sciences Center Salt Lake City UT
| | - Yusuf Olğar
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH
| | - Megan L Koleske
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH
| | - Heather L Struckman
- Department of Biomedical Engineering College of Engineering The Ohio State University Columbus OH
| | - Jessica Mandrioli
- Department of Neuroscience St. Agostino Estense Hospital Azienda Ospedaliero Universitaria di Modena Italy
| | - Qing Lou
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
| | - Ingrid Bonila
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
| | - Kibum Kim
- Department of Pharmacotherapy University of Utah Health Sciences Center Salt Lake City UT
| | - Roberto Ramos Mondragon
- Department of Internal Medicine and of Molecular & Integrative Physiology University of Michigan Ann Arbor MI
| | - Silvia G Priori
- Molecular Cardiology Istituti Clinici Scientifici Maugeri IRCCS University of Pavia Italy.,Department of Molecular Medicine University of Pavia Italy
| | - Pompeo Volpe
- Department of Biomedical Sciences University of Padova Italy
| | - Héctor H Valdivia
- Department of Internal Medicine and of Molecular & Integrative Physiology University of Michigan Ann Arbor MI
| | - Joseph Biskupiak
- Department of Pharmacotherapy University of Utah Health Sciences Center Salt Lake City UT
| | - Cynthia A Carnes
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH
| | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering College of Engineering The Ohio State University Columbus OH.,Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH
| | - Sándor Györke
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
| | - Przemysław B Radwański
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
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Rizaner N, Uzun S, Fraser SP, Djamgoz MBA, Altun S. Riluzole: Anti-invasive effects on rat prostate cancer cells under normoxic and hypoxic conditions. Basic Clin Pharmacol Toxicol 2020; 127:254-264. [PMID: 32304618 DOI: 10.1111/bcpt.13417] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 04/03/2020] [Accepted: 04/08/2020] [Indexed: 11/30/2022]
Abstract
Anti-invasive effects of riluzole and ranolazine, a neuro-protectant and an anti-anginal drug, respectively, on Mat-LyLu rat prostate cancer (PCa) cells were tested in vitro (a) at non-toxic doses and (b) under both normoxic and hypoxic conditions, the latter common to growing tumours. Tetrodotoxin (TTX) was used as a positive control. Hypoxia had no effect on cell viability but reduced growth at 48 hours. Riluzole (5 μmol/L) or ranolazine (20 μmol/L) had no effect on cell viability or growth under normoxia or hypoxia over 24 hours. Matrigel invasion was not affected by hypoxia but inhibited by TTX, ranolazine and riluzole under a range of conditions. The expression of Nav1.7 mRNA, the prevailing, pro-invasive voltage-gated sodium channel α-subunit (VGSCα), was up-regulated by hypoxia. Riluzole had no effect on Nav1.7 mRNA expression in normoxia but significantly reduced it in hypoxia. VGSCα protein expression in plasma membrane was reduced in hypoxia; riluzole increased it but only under hypoxia. It was concluded (a) that riluzole and ranolazine have anti-invasive effects on rat PCa cells and (b) that Nav1.7 mRNA and protein expression can be modulated by riluzole under hypoxia. Overall, therefore, riluzole and ranolazine may ultimately be "repurposed" as anti-metastatic drugs against PCa.
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Affiliation(s)
- Nahit Rizaner
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Imperial College London, London, UK.,Biotechnology Research Centre, Cyprus International University, Haspolat, Turkey
| | - Sercan Uzun
- Department of Biology, Faculty of Science, Istanbul University, Istanbul, Turkey
| | - Scott P Fraser
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Imperial College London, London, UK
| | - Mustafa B A Djamgoz
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Imperial College London, London, UK.,Biotechnology Research Centre, Cyprus International University, Haspolat, Turkey
| | - Seyhan Altun
- Department of Biology, Faculty of Science, Istanbul University, Istanbul, Turkey.,Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Kultur University, Istanbul, Turkey
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5
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Li RW, Deng Y, Pham HN, Weiss S, Chen M, Smith PN. Riluzole protects against skeletal muscle ischaemia-reperfusion injury in a porcine model. Injury 2020; 51:178-184. [PMID: 31882236 DOI: 10.1016/j.injury.2019.12.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/09/2019] [Accepted: 12/16/2019] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Skeletal muscle ischaemia-reperfusion injury (IRI) can be a life threatening condition. It is relevant to various aspects of the management of trauma and surgical patients. Currently there lacks a pharmacological agent that can be used to dampen the effects of IRI. Riluzole has been shown to reduce the effects of IRI on various organ systems, but there have yet to be any studies on the effects in IRI of skeletal muscle. Our aim was to investigate the effects of Riluzole on IRI in the skeletal muscle of pigs. METHODS Twenty-two pigs were randomly divided into groups. Riluzole was administered before ligation of the femoral artery to produce ischaemia in the tibialis anterior muscle in the experimental group but not the control group. The microscopic appearance of muscles were recorded, a TUNEL assay was used to identify DNA damage and glutathione levels were measured. RESULTS In the Riluzole group, muscle fibres appeared less wavy and less oedematous compared to the control group. The Riluzole group also had less evidence of DNA fragmentation on the TUNEL assay. The glutathione levels in the Riluzole group were also significantly greater than the control group. DISCUSSION Our findings suggest that Riluzole can potentially reduce the effects of IRI on skeletal muscle. This is potentially due to the ability of Riluzole to block sodium channels, decreasing action potentials and therefore glutamate release. It also acts to decrease intracellular calcium levels, which prevents apoptosis. Riluzole is a promising drug for the prevention of IRI in skeletal muscle, but further research is required.
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Affiliation(s)
- Rachel W Li
- The Medical School, the Australian National UNiversity, Canberra, ACT 2601, Australia; John Curtin School of Medical Research, The Australian National University, Garran Rd, Canberra, ACT 2601 Australia.
| | - Yi Deng
- The Medical School, the Australian National UNiversity, Canberra, ACT 2601, Australia; Canberra Hospital, Yamba Dr, Canberra, ACT 2605 Australia
| | - Hai Nam Pham
- The Medical School, the Australian National UNiversity, Canberra, ACT 2601, Australia
| | - Steven Weiss
- John Curtin School of Medical Research, The Australian National University, Garran Rd, Canberra, ACT 2601 Australia
| | - Mingming Chen
- The Medical School, the Australian National UNiversity, Canberra, ACT 2601, Australia
| | - Paul N Smith
- Canberra Hospital, Yamba Dr, Canberra, ACT 2605 Australia
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6
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Lamas JA, Fernández-Fernández D. Tandem pore TWIK-related potassium channels and neuroprotection. Neural Regen Res 2019; 14:1293-1308. [PMID: 30964046 PMCID: PMC6524494 DOI: 10.4103/1673-5374.253506] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
TWIK-related potassium channels (TREK) belong to a subfamily of the two-pore domain potassium channels family with three members, TREK1, TREK2 and TWIK-related arachidonic acid-activated potassium channels. The two-pore domain potassium channels is the last big family of channels being discovered, therefore it is not surprising that most of the information we know about TREK channels predominantly comes from the study of heterologously expressed channels. Notwithstanding, in this review we pay special attention to the limited amount of information available on native TREK-like channels and real neurons in relation to neuroprotection. Mainly we focus on the role of free fatty acids, lysophospholipids and other neuroprotective agents like riluzole in the modulation of TREK channels, emphasizing on how important this modulation may be for the development of new therapies against neuropathic pain, depression, schizophrenia, epilepsy, ischemia and cardiac complications.
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Affiliation(s)
- J Antonio Lamas
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain
| | - Diego Fernández-Fernández
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain
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7
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Farinato A, Altamura C, Desaphy JF. Effects of Benzothiazolamines on Voltage-Gated Sodium Channels. Handb Exp Pharmacol 2018; 246:233-250. [PMID: 28939972 DOI: 10.1007/164_2017_46] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Benzothiazole is a versatile fused heterocycle that aroused much interest in drug discovery as anticonvulsant, neuroprotective, analgesic, anti-inflammatory, antimicrobial, and anticancer. Two benzothiazolamines, riluzole and lubeluzole, are known blockers of voltage-gated sodium (Nav) channels. Riluzole is clinically used as a neuroprotectant in amyotrophic lateral sclerosis. Inhibition of Nav channels by riluzole is voltage-dependent due to preferential binding to inactivated sodium channels. Yet the drug exerts little use-dependent block, probably because it lacks protonable amine. One important property is riluzole ability to inhibit persistent Na+ currents, which likely contributes to its neuroprotective activity. Lubeluzole showed promising neuroprotective effects in animal stroke models, but failed to show benefits in acute ischemic stroke in humans. One important concern is its propensity to prolong the cardiac QT interval, due to hERG K+ channel block. Lubeluzole very potently inhibits Nav channels in a voltage- and use-dependent manner, due to its great preferential affinity for inactivated channels and the presence of a protonable amine group. Patch-clamp experiments suggest that the binding sites of both drugs overlap the local anesthetic receptor within the ion-conducting pathway. Riluzole and lubeluzole displayed very potent antimyotonic activity in a rat model of myotonia, a pathological skeletal muscle condition characterized by high-frequency runs of action potentials. Such results well support the repurposing of riluzole as an antimyotonic drug, allowing the launch of a pilot study in myotonic patients. Riluzole, lubeluzole, and new Nav channel blockers built on the benzothiazolamine scaffold will certainly continue to be investigated for possible clinical applications.
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Affiliation(s)
- Alessandro Farinato
- Section of Pharmacology, Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Policlinico, Piazza G. Cesare 11, 70124, Bari, Italy
| | - Concetta Altamura
- Section of Pharmacology, Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Policlinico, Piazza G. Cesare 11, 70124, Bari, Italy
| | - Jean-François Desaphy
- Section of Pharmacology, Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Policlinico, Piazza G. Cesare 11, 70124, Bari, Italy.
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8
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Parker SL, Guerra Valero YC, Lipman J, Weiss S, Smith C, Russell L, Smith P, Roberts JA, Wallis SC. A validated UHPLC-MS/MS method for the measurement of riluzole in plasma and myocardial tissue samples. Biomed Chromatogr 2017. [PMID: 28623867 DOI: 10.1002/bmc.4030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Through blocking the cardiac persistent sodium current, riluzole has the potential to prevent myocardial damage post cardiac bypass surgery. A sensitive UHPLC-MS/MS method was developed and validated for quantitation of riluzole and 5-methoxypsoralen in human plasma and myocardial tissue homogenate using a liquid-liquid extraction with dichloromethane. The chromatographic separation was achieved using Shimadzu Shim-pack XR-ODS III, 2.0 × 50 mm, 1.6 μm column with a gradient mobile phase comprising methanol and ammonium acetate buffer pH 3.6 in purified water. The analyte and internal standard were separated within 3.5 min. Riluzole quantitation was achieved using the mass transitions of 235-138 for riluzole and 217-156 for 5-methoxypsoralen. The method was linear for riluzole plasma concentrations from 0.2 to 500 ng/mL and myocardial tissue homogenate concentrations from 0.2 to 100 ng/mL. The method developed was successfully applied to a clinical study for patients receiving riluzole while undergoing cardiac bypass surgery.
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Affiliation(s)
- Suzanne L Parker
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, UQ Centre for Clinical Research, Brisbane, Australia
| | - Yarmarly C Guerra Valero
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, UQ Centre for Clinical Research, Brisbane, Australia
| | - Jeffrey Lipman
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, UQ Centre for Clinical Research, Brisbane, Australia.,Department of Intensive Care Medicine, Royal Brisbane & Women's Hospital, Brisbane, Australia.,Faculty of Health, Queensland University of Technology, Brisbane, Australia
| | - Steven Weiss
- Medical School, College of Medicine, Biology and Environment, Australian National University, Canberra, Australia
| | - Camilla Smith
- Trauma and Orthopaedic Research Unit, Canberra Hospital, Canberra, Australia
| | - Lyndal Russell
- Trauma and Orthopaedic Research Unit, Canberra Hospital, Canberra, Australia
| | - Paul Smith
- Trauma and Orthopaedic Research Unit, Canberra Hospital, Canberra, Australia
| | - Jason A Roberts
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, UQ Centre for Clinical Research, Brisbane, Australia.,Department of Intensive Care Medicine, Royal Brisbane & Women's Hospital, Brisbane, Australia.,School of Pharmacy, The University of Queensland, Brisbane, Australia.,Department of Pharmacy, Royal Brisbane & Women's Hospital, Brisbane, Australia
| | - Steven C Wallis
- Burns, Trauma and Critical Care Research Centre, The University of Queensland, UQ Centre for Clinical Research, Brisbane, Australia
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9
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Bellanti F. Ischemia-reperfusion injury: evidences for translational research. ANNALS OF TRANSLATIONAL MEDICINE 2016; 4:S55. [PMID: 27868023 PMCID: PMC5104605 DOI: 10.21037/atm.2016.10.52] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Francesco Bellanti
- C.U.R.E. University Centre for Liver Disease Research and Treatment, Institute of Internal Medicine, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
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10
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Frolov RV, Weckström M. Harnessing the Flow of Excitation: TRP, Voltage-Gated Na(+), and Voltage-Gated Ca(2+) Channels in Contemporary Medicine. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 103:25-95. [PMID: 26920687 DOI: 10.1016/bs.apcsb.2015.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cellular signaling in both excitable and nonexcitable cells involves several classes of ion channels. Some of them are of minor importance, with very specialized roles in physiology, but here we concentrate on three major channel classes: TRP (transient receptor potential channels), voltage-gated sodium channels (Nav), and voltage-gated calcium channels (Cav). Here, we first propose a conceptual framework binding together all three classes of ion channels, a "flow-of-excitation model" that takes into account the inputs mediated by TRP and other similar channels, the outputs invariably provided by Cav channels, and the regenerative transmission of signals in the neural networks, for which Nav channels are responsible. We use this framework to examine the function, structure, and pharmacology of these channel classes both at cellular and also at whole-body physiological level. Building on that basis we go through the pathologies arising from the direct or indirect malfunction of the channels, utilizing ion channel defects, the channelopathies. The pharmacological interventions affecting these channels are numerous. Part of those are well-established treatments, like treatment of hypertension or some forms of epilepsy, but many other are deeply problematic due to poor drug specificity, ion channel diversity, and widespread expression of the channels in tissues other than those actually targeted.
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Affiliation(s)
- Roman V Frolov
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland.
| | - Matti Weckström
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland
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11
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Radwański PB, Brunello L, Veeraraghavan R, Ho HT, Lou Q, Makara MA, Belevych AE, Anghelescu M, Priori SG, Volpe P, Hund TJ, Janssen PML, Mohler PJ, Bridge JHB, Poelzing S, Györke S. Neuronal Na+ channel blockade suppresses arrhythmogenic diastolic Ca2+ release. Cardiovasc Res 2014; 106:143-52. [PMID: 25538156 DOI: 10.1093/cvr/cvu262] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
AIMS Sudden death resulting from cardiac arrhythmias is the most common consequence of cardiac disease. Certain arrhythmias caused by abnormal impulse formation including catecholaminergic polymorphic ventricular tachycardia (CPVT) are associated with delayed afterdepolarizations resulting from diastolic Ca2+ release (DCR) from the sarcoplasmic reticulum (SR). Despite high response of CPVT to agents directly affecting Ca2+ cycling, the incidence of refractory cases is still significant. Surprisingly, these patients often respond to treatment with Na+ channel blockers. However, the relationship between Na+ influx and disturbances in Ca2+ handling immediately preceding arrhythmias in CPVT remains poorly understood and is the object of this study. METHODS AND RESULTS We performed optical Ca2+ and membrane potential imaging in ventricular myocytes and intact cardiac muscles as well as surface ECGs on a CPVT mouse model with a mutation in cardiac calsequestrin. We demonstrate that a subpopulation of Na+ channels (neuronal Na+ channels; nNav) colocalize with ryanodine receptor Ca2+ release channels (RyR2). Disruption of the crosstalk between nNav and RyR2 by nNav blockade with riluzole reduced and also desynchronized DCR in isolated cardiomyocytes and in intact cardiac tissue. Such desynchronization of DCR on cellular and tissue level translated into decreased arrhythmias in CPVT mice. CONCLUSIONS Thus, our study offers the first evidence that nNav contribute to arrhythmogenic DCR, thereby providing a conceptual basis for mechanism-based antiarrhythmic therapy.
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Affiliation(s)
- Przemysław B Radwański
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA Division of Pharmacy Practice and Administration, College of Pharmacy, The Ohio State University, Columbus, OH, USA
| | - Lucia Brunello
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Rengasayee Veeraraghavan
- VTC Research Institute, School of Biomedical Engineering and Sciences, Virginia Tech, Roanoke, VA, USA
| | - Hsiang-Ting Ho
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Qing Lou
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Michael A Makara
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Andriy E Belevych
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Mircea Anghelescu
- Department of Biological and Allied Health Sciences, Ohio Northern University, Ada, OH, USA
| | - Silvia G Priori
- Division of Cardiology and Molecular Cardiology, Maugeri Foundation-University of Pavia, Pavia, Italy
| | - Pompeo Volpe
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Thomas J Hund
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA
| | - Paul M L Janssen
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Peter J Mohler
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - John H B Bridge
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, USA
| | - Steven Poelzing
- VTC Research Institute, School of Biomedical Engineering and Sciences, Virginia Tech, Roanoke, VA, USA
| | - Sándor Györke
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Room 507, Columbus, OH 43210, USA Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
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Partial block by riluzole of muscle sodium channels in myotubes from amyotrophic lateral sclerosis patients. Neurol Res Int 2014; 2014:946073. [PMID: 25548669 PMCID: PMC4273590 DOI: 10.1155/2014/946073] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/18/2014] [Indexed: 12/13/2022] Open
Abstract
Denervated muscles undergo fibrillations due to spontaneous activation of voltage-gated sodium (Na(+)) channels generating action potentials. Fibrillations also occur in patients with amyotrophic lateral sclerosis (ALS). Riluzole, the only approved drug for ALS treatment, blocks voltage-gated Na(+) channels, but its effects on muscle Na(+) channels and fibrillations are yet poorly characterized. Using patch-clamp technique, we studied riluzole effect on Na(+) channels in cultured myotubes from ALS patients. Needle electromyography was used to study fibrillation potentials (Fibs) in ALS patients during riluzole treatment and after one week of suspension. Patients were clinically characterized in all recording sessions. In myotubes, riluzole (1 μM, a therapeutic concentration) reduced Na(+) current by 20%. The rate of rise and amplitude of spikes evoked by depolarizing stimuli were also reduced. Fibs were detected in all patients tested during riluzole treatment and riluzole washout had no univocal effect. Our study indicates that, in human myotubes, riluzole partially blocks Na(+) currents and affects action potentials but does not prevent firing. In line with this in vitro finding, muscle Fibs in ALS patients appear to be largely unaffected by riluzole.
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Abstract
Late I Na is an integral part of the sodium current, which persists long after the fast-inactivating component. The magnitude of the late I Na is relatively small in all species and in all types of cardiomyocytes as compared with the amplitude of the fast sodium current, but it contributes significantly to the shape and duration of the action potential. This late component had been shown to increase in several acquired or congenital conditions, including hypoxia, oxidative stress, and heart failure, or due to mutations in SCN5A, which encodes the α-subunit of the sodium channel, as well as in channel-interacting proteins, including multiple β subunits and anchoring proteins. Patients with enhanced late I Na exhibit the type-3 long QT syndrome (LQT3) characterized by high propensity for the life-threatening ventricular arrhythmias, such as Torsade de Pointes (TdP), as well as for atrial fibrillation. There are several distinct mechanisms of arrhythmogenesis due to abnormal late I Na, including abnormal automaticity, early and delayed after depolarization-induced triggered activity, and dramatic increase of ventricular dispersion of repolarization. Many local anesthetic and antiarrhythmic agents have a higher potency to block late I Na as compared with fast I Na. Several novel compounds, including ranolazine, GS-458967, and F15845, appear to be the most selective inhibitors of cardiac late I Na reported to date. Selective inhibition of late I Na is expected to be an effective strategy for correcting these acquired and congenital channelopathies.
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Weiss SM, Dahlstrom JE, Saint DA. Riluzole reduces arrhythmias and myocardial damage induced by coronary occlusion in anaesthetized pigs. Clin Exp Pharmacol Physiol 2013; 40:856-63. [DOI: 10.1111/1440-1681.12175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 08/02/2013] [Accepted: 09/11/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Steven M Weiss
- Australian National University Medical School; The Canberra Hospital; Canberra ACT Australia
| | - Jane E Dahlstrom
- Australian National University Medical School; The Canberra Hospital; Canberra ACT Australia
- Department of Anatomical Pathology; ACT Pathology; The Canberra Hospital; Canberra ACT Australia
| | - David A Saint
- School of Medical Sciences; University of Adelaide; Adelaide SA Australia
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Eijkelkamp N, Linley JE, Baker MD, Minett MS, Cregg R, Werdehausen R, Rugiero F, Wood JN. Neurological perspectives on voltage-gated sodium channels. Brain 2012; 135:2585-612. [PMID: 22961543 PMCID: PMC3437034 DOI: 10.1093/brain/aws225] [Citation(s) in RCA: 248] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The activity of voltage-gated sodium channels has long been linked to disorders of neuronal excitability such as epilepsy and chronic pain. Recent genetic studies have now expanded the role of sodium channels in health and disease, to include autism, migraine, multiple sclerosis, cancer as well as muscle and immune system disorders. Transgenic mouse models have proved useful in understanding the physiological role of individual sodium channels, and there has been significant progress in the development of subtype selective inhibitors of sodium channels. This review will outline the functions and roles of specific sodium channels in electrical signalling and disease, focusing on neurological aspects. We also discuss recent advances in the development of selective sodium channel inhibitors.
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Affiliation(s)
- Niels Eijkelkamp
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK.
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Morris CE, Juranka PF, Joós B. Perturbed voltage-gated channel activity in perturbed bilayers: implications for ectopic arrhythmias arising from damaged membrane. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:245-56. [PMID: 22846437 DOI: 10.1016/j.pbiomolbio.2012.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 07/11/2012] [Indexed: 12/31/2022]
Abstract
The ceaseless opening and closing of the voltage-gated channels (VGCs) underlying cardiac rhythmicity is controlled, in each VGC, by four mobile voltage sensors embedded in bilayer. Every action potential necessitates extensive packing/repacking of voltage sensor domains with adjacent interacting lipid molecules. This renders VGC activity mechanosensitive (MS), i.e., energetically sensitive to the bilayer's mechanical state. Irreversible perturbations of sarcolemmal bilayer such as those associated with ischemia, reperfusion, inflammation, cortical-cytoskeleton abnormalities, bilayer-disrupting toxins, diet aberrations, etc, should therefore perturb VGC activity. Disordered/fluidized bilayer states that facilitate voltage sensor repacking, and thus make VGC opening too easy could, therefore, explain VGC-leakiness in these conditions. To study this in membrane patches we impose mechanical blebbing injury during pipette aspiration-induced membrane stretch, a process that modulates VGC activity irreversibly (plastic regime) and then, eventually, reversibly (elastic regime). Because of differences in sensor-to-gate coupling among different VGCs, their responses to stretch fall into two major categories, MS-Speed, MS-Number, exemplified by Nav and Cav channels. For particular VGCs in perturbed bilayers, leak mechanisms depend on whether or not the rate-limiting voltage-dependent step is MS. Mode-switch transitions might also be mechanosensitive and thus play a role. Incorporated mathematically in axon models, plastic-regime Nav responses elicit ectopic firing behaviors typical of peripheral neuropathies. In cardiomyocytes with mild bleb damage, Nav and/or Cav leaks from irreversible MS modulation (MS-Speed, MS-Number, respectively) could, similarly, foster ectopic arrhythmias. Where pathologically leaky VGCs reside in damaged bilayer, peri-channel bilayer disorder/fluidity conditions could be an important "target feature" for anti-arrhythmic VGC drugs.
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Boucher PA, Joós B, Morris CE. Coupled left-shift of Nav channels: modeling the Na⁺-loading and dysfunctional excitability of damaged axons. J Comput Neurosci 2012; 33:301-19. [PMID: 22476614 DOI: 10.1007/s10827-012-0387-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 01/25/2012] [Accepted: 02/12/2012] [Indexed: 11/29/2022]
Abstract
Injury to neural tissue renders voltage-gated Na⁺ (Nav) channels leaky. Even mild axonal trauma initiates Na⁺-loading, leading to secondary Ca²⁺-loading and white matter degeneration. The nodal isoform is Nav1.6 and for Nav1.6-expressing HEK-cells, traumatic whole cell stretch causes an immediate tetrodotoxin-sensitive Na⁺-leak. In stretch-damaged oocyte patches, Nav1.6 current undergoes damage-intensity dependent hyperpolarizing- (left-) shifts, but whether left-shift underlies injured-axon Nav-leak is uncertain. Nav1.6 inactivation (availability) is kinetically limited by (coupled to) Nav activation, yielding coupled left-shift (CLS) of the two processes: CLS should move the steady-state Nav1.6 "window conductance" closer to typical firing thresholds. Here we simulated excitability and ion homeostasis in free-running nodes of Ranvier to assess if hallmark injured-axon behaviors--Na⁺-loading, ectopic excitation, propagation block--would occur with Nav-CLS. Intact/traumatized axolemma ratios were varied, and for some simulations Na/K pumps were included, with varied in/outside volumes. We simulated saltatory propagation with one mid-axon node variously traumatized. While dissipating the [Na⁺] gradient and hyperactivating the Na/K pump, Nav-CLS generated neuropathic pain-like ectopic bursts. Depending on CLS magnitude, fraction of Nav channels affected, and pump intensity, tonic or burst firing or nodal inexcitability occurred, with [Na⁺] and [K⁺] fluctuating. Severe CLS-induced inexcitability did not preclude Na⁺-loading; in fact, the steady-state Na⁺-leaks elicited large pump currents. At a mid-axon node, mild CLS perturbed normal anterograde propagation, and severe CLS blocked saltatory propagation. These results suggest that in damaged excitable cells, Nav-CLS could initiate cellular deterioration with attendant hyper- or hypo-excitability. Healthy-cell versions of Nav-CLS, however, could contribute to physiological rhythmic firing.
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Morris CE, Boucher PA, Joós B. Left-shifted nav channels in injured bilayer: primary targets for neuroprotective nav antagonists? Front Pharmacol 2012; 3:19. [PMID: 22375118 PMCID: PMC3284691 DOI: 10.3389/fphar.2012.00019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 02/06/2012] [Indexed: 12/26/2022] Open
Abstract
Mechanical, ischemic, and inflammatory injuries to voltage-gated sodium channel (Nav)-rich membranes of axon initial segments and nodes of Ranvier render Nav channels dangerously leaky. By what means? The behavior of recombinant Nav1.6 (Wang et al., 2009) leads us to postulate that, in neuropathologic conditions, structural degradation of axolemmal bilayer fosters chronically left-shifted Nav channel operation, resulting in E(Na) rundown. This "sick excitable cell Nav-leak" would encompass left-shifted fast- and slow-mode based persistent I(Na) (i.e., I(window) and slow-inactivating I(Na)). Bilayer-damage-induced electrophysiological dysfunctions of native-Nav channels, and effects on inhibitors on those channels, should, we suggest, be studied in myelinated axons, exploiting I(Na)(V,t) hysteresis data from sawtooth ramp clamp. We hypothesize that (like dihydropyridines for Ca channels), protective lipophilic Nav antagonists would partition more avidly into disorderly bilayers than into the well-packed bilayers characteristic of undamaged, healthy plasma membrane. Whereas inhibitors using aqueous routes would access all Navs equally, differential partitioning into "sick bilayer" would co-localize lipophilic antagonists with "sick-Nav channels," allowing for more specific targeting of impaired cells. Molecular fine-tuning of Nav antagonists to favor more avid partitioning into damaged than into intact bilayers could reduce side effects. In potentially salvageable neurons of traumatic and/or ischemic penumbras, in inflammatory neuropathies, in muscular dystrophy, in myocytes of cardiac infarct borders, Nav-leak driven excitotoxicity overwhelms cellular repair mechanisms. Precision-tuning of a lipophilic Nav antagonist for greatest efficacy in mildly damaged membranes could render it suitable for the prolonged continuous administration needed to allow for the remodeling of the excitable membranes, and thus functional recovery.
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Theile JW, Cummins TR. Recent developments regarding voltage-gated sodium channel blockers for the treatment of inherited and acquired neuropathic pain syndromes. Front Pharmacol 2011; 2:54. [PMID: 22007172 PMCID: PMC3185237 DOI: 10.3389/fphar.2011.00054] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 09/12/2011] [Indexed: 12/19/2022] Open
Abstract
Chronic and neuropathic pain constitute significant health problems affecting millions of individuals each year. Pain sensations typically originate in sensory neurons of the peripheral nervous system which relay information to the central nervous system (CNS). Pathological pain sensations can arise as result of changes in excitability of these peripheral sensory neurons. Voltage-gated sodium channels are key determinants regulating action potential generation and propagation; thus, changes in sodium channel function can have profound effects on neuronal excitability and pain signaling. At present, most of the clinically available sodium channel blockers used to treat pain are non-selective across sodium channel isoforms and can contribute to cardio-toxicity, motor impairments, and CNS side effects. Numerous strides have been made over the last decade in an effort to develop more selective and efficacious sodium channel blockers to treat pain. The purpose of this review is to highlight some of the more recent developments put forth by research universities and pharmaceutical companies alike in the pursuit of developing more targeted sodium channel therapies for the treatment of a variety of neuropathic pain conditions.
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Affiliation(s)
- Jonathan W Theile
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine Indianapolis, IN, USA
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Schwingshackl A, Teng B, Ghosh M, West AN, Makena P, Gorantla V, Sinclair SE, Waters CM. Regulation and function of the two-pore-domain (K2P) potassium channel Trek-1 in alveolar epithelial cells. Am J Physiol Lung Cell Mol Physiol 2011; 302:L93-L102. [PMID: 21949155 DOI: 10.1152/ajplung.00078.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Hyperoxia can lead to a myriad of deleterious effects in the lung including epithelial damage and diffuse inflammation. The specific mechanisms by which hyperoxia promotes these pathological changes are not completely understood. Activation of ion channels has been proposed as one of the mechanisms required for cell activation and mediator secretion. The two-pore-domain K(+) channel (K2P) Trek-1 has recently been described in lung epithelial cells, but its function remains elusive. In this study we hypothesized that hyperoxia affects expression of Trek-1 in alveolar epithelial cells and that Trek-1 is involved in regulation of cell proliferation and cytokine secretion. We found gene expression of several K2P channels in mouse alveolar epithelial cells (MLE-12), and expression of Trek-1 was significantly downregulated in cultured cells and lungs of mice exposed to hyperoxia. Similarly, proliferation cell nuclear antigen (PCNA) and Cyclin D1 expression were downregulated by exposure to hyperoxia. We developed an MLE-12 cell line deficient in Trek-1 expression using shRNA and found that Trek-1 deficiency resulted in increased cell proliferation and upregulation of PCNA but not Cyclin D1. Furthermore, IL-6 and regulated on activation normal T-expressed and presumably secreted (RANTES) secretion was decreased in Trek-1-deficient cells, whereas release of monocyte chemoattractant protein-1 was increased. Release of KC/IL-8 was not affected by Trek-1 deficiency. Overall, deficiency of Trek-1 had a more pronounced effect on mediator secretion than exposure to hyperoxia. This is the first report suggesting that the K(+) channel Trek-1 could be involved in regulation of alveolar epithelial cell proliferation and cytokine secretion, but a direct association with hyperoxia-induced changes in Trek-1 levels remains elusive.
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Affiliation(s)
- Andreas Schwingshackl
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee 38111, USA.
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Theile JW, Cummins TR. Inhibition of Navβ4 peptide-mediated resurgent sodium currents in Nav1.7 channels by carbamazepine, riluzole, and anandamide. Mol Pharmacol 2011; 80:724-34. [PMID: 21788423 DOI: 10.1124/mol.111.072751] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Paroxysmal extreme pain disorder (PEPD) and inherited erythromelalgia (IEM) are inherited pain syndromes arising from different sets of gain-of-function mutations in the sensory neuronal sodium channel isoform Nav1.7. Mutations associated with PEPD, but not IEM, result in destabilized inactivation of Nav1.7 and enhanced resurgent sodium currents. Resurgent currents arise after relief of ultra-fast open-channel block mediated by an endogenous blocking particle and are thought to influence neuronal excitability. As such, enhancement of resurgent currents may constitute a pathological mechanism contributing to sensory neuron hyperexcitability and pain hypersensitivity associated with PEPD. Furthermore, pain associated with PEPD, but not IEM, is alleviated by the sodium channel inhibitor carbamazepine. We speculated that selective attenuation of PEPD-enhanced resurgent currents might contribute to this therapeutic effect. Here we examined whether carbamazepine and two other sodium channel inhibitors, riluzole and anandamide, exhibit differential inhibition of resurgent currents. To gain further insight into the potential mechanism(s) of resurgent currents, we examined whether these inhibitors produced correlative changes in other properties of sodium channel inactivation. Using stably transfected human embryonic kidney 293 cells expressing wild-type Nav1.7 and the PEPD mutants T1464I and M1627K, we examined the effects of the three drugs on Navβ4 peptide-mediated resurgent currents. We observed a correlation between resurgent current inhibition and a drug-mediated increase in the rate of inactivation and inhibition of persistent sodium currents. Furthermore, although carbamazepine did not selectively target resurgent currents, anandamide strongly inhibited resurgent currents with minimal effects on the peak transient current amplitude, demonstrating that resurgent currents can be selectively targeted.
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Affiliation(s)
- Jonathan W Theile
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Weiss SM, Saint DA. The persistent sodium current blocker riluzole is antiarrhythmic and anti-ischaemic in a pig model of acute myocardial infarction. PLoS One 2010; 5:e14103. [PMID: 21124787 PMCID: PMC2991348 DOI: 10.1371/journal.pone.0014103] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 11/03/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The potential of the cardiac persistent sodium current as a target for protection of the myocardium from ischaemia and reperfusion injury is gaining increasing interest. We have investigated the anti-ischaemic and antiarrhythmic effects of riluzole, a selective INaP blocker, in an open chest pig model of infarction. METHODS AND PRINCIPAL FINDINGS The left anterior descending coronary artery (LAD) was ligated in 27 anesthetised pigs (landrace or large white, either sex, 20-35 kg) which had received riluzole (8 mg/kg IP; n = 6), lidocaine (2.5-12 mg/kg bolus plus 0.05-0.24 mg/kg/min; n = 11) or vehicle (n = 10) 50 min prior. Arrhythmias could be delineated into phase 1a (0 to 20 min), phase 1b (20 to 50 min) and phase 2 (from 50 min to termination at 180 min) and were classified as premature ventricular contractions (PVCs), non-sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) (spontaneously reverting within 15 s) or sustained VT or VF (ie. requiring cardioversion at 15 s). Riluzole reduced the average number of all arrhythmias in Phase 2 (PVCs from 484+/-119 to 32+/-13; non sustained arrhythmias from 8.9+/-4.4 to 0.7+/-0.5; sustained arrhythmias from 3.9+/-2.2 to 0.5+/-0.4); lidocaine reduced the average number of non-sustained and sustained arrhythmias (to 0.4+/-0.3 and 0.4+/-0.3 respectively) but not PVCs (to 390+/-234). Riluzole and lidocaine reduced the average number of sustained arrhythmias in phase 1b (from 1.8+/-0.4 to 0.17+/-0.13 (p<0.02) and to 0.55+/-0.26 (p = ns) respectively). Neither lidocaine or riluzole changed the ECG intervals: there was no statistical significance between groups at time zero (just before ligation) for any ECG measure. During the course of the 3 hour period of the ischaemia R-R, and P-R intervals shortened slightly in control and riluzole groups (not significantly different from each other) but not in the lidocaine group (significantly different from control). QRS and QTc did not change appreciably in any group Riluzole reduced the degree of histopathological tissue damage across the infarct zone considerably more than did lidocaine. CONCLUSIONS At the doses used, riluzole was at least as effective as lidocaine at reducing the number of episodes of ischaemic VT or VF in pigs, and much more effective at reducing the number of PVCs. We propose that this is related to the ability of riluzole to block cardiac persistent sodium current.
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