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Bloms-Funke P, Bankstahl M, Bankstahl J, Kneip C, Schröder W, Löscher W. The novel dual-mechanism Kv7 potassium channel/TSPO receptor activator GRT-X is more effective than the Kv7 channel opener retigabine in the 6-Hz refractory seizure mouse model. Neuropharmacology 2022; 203:108884. [PMID: 34785163 DOI: 10.1016/j.neuropharm.2021.108884] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/16/2022]
Abstract
Epilepsy, one of the most common and most disabling neurological disorders, is characterized by spontaneous recurrent seizures, often associated with structural brain alterations and cognitive and psychiatric comorbidities. In about 30% of patients, the seizures are resistant to current treatments; so more effective treatments are urgently needed. Among the ∼30 clinically approved antiseizure drugs, retigabine (ezogabine) is the only drug that acts as a positive allosteric modulator (or opener) of voltage-gated Kv7 potassium channels, which is particularly interesting for some genetic forms of epilepsy. Here we describe a novel dual-mode-of-action compound, GRT-X (N-[(3-fluorophenyl)-methyl]-1-(2-methoxyethyl)-4-methyl-2-oxo-(7-trifluoromethyl)-1H-quinoline-3-carboxylic acid amide) that activates both Kv7 potassium channels and the mitochondrial translocator protein 18 kDa (TSPO), leading to increased synthesis of brain neurosteroids. TSPO activators are known to exert anti-inflammatory, neuroprotective, anxiolytic, and antidepressive effects, which, together with an antiseizure effect (mediated by Kv7 channels), would be highly relevant for the treatment of epilepsy. This prompted us to compare the antiseizure efficacy of retigabine and GRT-X in six mouse and rat models of epileptic seizures, including the 6-Hz model of difficult-to-treat focal seizures. Furthermore, the tolerability of the two compounds was compared in mice and rats. Potency comparisons were based on both doses and peak plasma concentrations. Overall, GRT-X was more effective than retigabine in three of the six seizure models used here, the most important difference being the high efficacy in the 6-Hz (32 mA) seizure model in mice. Based on drug plasma levels, GRT-X was at least 30 times more potent than retigabine in the latter model. These data indicate that GRT-X is a highly interesting novel anti-seizure drug with a unique (first-in-class) dual-mode mechanism of action.
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Affiliation(s)
| | - Marion Bankstahl
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Jens Bankstahl
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | | | | | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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Guo Y, Du P, Guo L, Lin X, He B, Yu L. Alcohol use among patients with epilepsy in western China. A hospital-based study. Epilepsy Behav 2021; 124:108302. [PMID: 34509040 DOI: 10.1016/j.yebeh.2021.108302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/20/2021] [Accepted: 08/22/2021] [Indexed: 11/25/2022]
Abstract
AMIS: Alcohol consumption has multiple negative consequences for people with epilepsy, including precipitation of seizure or status epilepticus, worsening of seizure control, increased adverse effects of anti-seizure medications, increased sudden unexpected death in epilepsy, and premature mortality. The aim of this study was to investigate alcohol use and explore the sociodemographic and clinical factors associated with alcohol use among patients with epilepsy in western China. METHODS A face-to-face questionnaire on alcohol use was conducted at Sichuan Provincial People's Hospital from December 2020 to June 2021. All adult patients who came to our epilepsy center (inpatient and outpatient) were invited to participate in this study. Logistic regression was used to evaluate the possible risk factors associated with alcohol use within the last 12 months. RESULTS A total of 425 patients completed this study, 24.2% of patients with epilepsy had used alcohol within the last 12 months, being male and having a history of alcohol use were independently associated factors. Among patients who had used alcohol within the last 12 months, 52.4% complained of worsening of seizure control, heavy alcohol use, and frequent alcohol use were independently associated with worsening of seizure control after alcohol use in patients with epilepsy. CONCLUSION This study revealed that the rate of alcohol use among patients with epilepsy was high. Male patients with a history of alcohol use were more prone to alcohol use after a diagnosis of epilepsy. Heavy alcohol use and frequent alcohol use were independently associated with worsening of seizure control after alcohol use in patients with epilepsy. Patient education on the destructive effects of alcohol use is needed for patients with epilepsy.
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Affiliation(s)
- Yi Guo
- Department of Neurology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China; Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China
| | - Peishan Du
- Department of Neurology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China; Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China
| | - Lixia Guo
- Department of Neurology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China; Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China
| | - Xu Lin
- Department of Neurology, Chengdu 363 Hospital, Daosangshu Street, Chengdu, Sichuan 610072, People's Republic of China
| | - Baoming He
- Department of Neurology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China; Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China.
| | - Liang Yu
- Department of Neurology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China; Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, 32# W. Sec 2, 1st Ring Rd, Chengdu, Sichuan 610072, People's Republic of China.
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Steinhoff BJ. Cenobamate tablets as a treatment for focal-onset seizures in adults. Expert Rev Clin Pharmacol 2021; 14:161-172. [PMID: 33470139 DOI: 10.1080/17512433.2021.1879637] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Introduction: Despite the introduction of numerous new antiseizure medications (ASMs) still about one-third of epilepsies remain drug-resistant. Therefore, new compounds with advanced efficacy are urgently needed. Cenobamate (CNB) is a new ASM that has been recently introduced in the United States for the treatment of adults with focal-onset seizures. The approval in Europe is under way.Areas covered: This review covers the pharmacological profile of CNB, the proof-of-concept trial, the two double-blind, placebo-controlled phase 2 trials investigating adjunct CNB in adults with focal-onset seizures, one open-label safety trial, and a variety of published abstract material that provided additional post hoc data.Expert opinion: In two placebo-controlled randomized multicenter phase 2 trials adjunct CNB showed unusually high efficacy with rates of seizure-free people with epilepsy (PWE) partially beyond 20%. However, during the clinical program cases of drug-related reactions with eosinophilia and systemic symptoms (DRESS syndrome) occurred. Therefore, an open-label safety study was performed in more than 1300 PWE with particularly slower titration schedules which did not add more cases with similar reactions. Taking into consideration the promising efficacy and the safety experience from the open-label trial, CNB applied according to the meanwhile recommended titration strategy, might offer a new prospect.
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Affiliation(s)
- Bernhard J Steinhoff
- Kork Epilepsy Center, Kehl-Kork, Germany.,Department of Neurology, Albert-Ludwigs University of Freiburg, Freiburg, Germany
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4
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Hu TY, Wang HQ, Zhang WP, Tian RF, Lei GS, Deng YC, Xing JL. Network meta-analysis of antiepileptic drugs in focal drug-resistant epilepsy. Epilepsy Res 2020; 167:106433. [DOI: 10.1016/j.eplepsyres.2020.106433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 06/29/2020] [Accepted: 07/17/2020] [Indexed: 12/11/2022]
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Steinhoff BJ. [Cenobamate-a new perspective for epilepsy treatment]. DER NERVENARZT 2020; 92:150-160. [PMID: 32990790 DOI: 10.1007/s00115-020-01000-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/07/2020] [Indexed: 10/23/2022]
Abstract
In spite of the introduction of numerous new antiseizure drugs (ASD) over the last decades, the percentage of drug-resistant epilepsies has remained almost stable. To achieve seizure freedom in such patients with any modified ASD regimen is an exception. Cenobamate (CNB) is a new ASD that showed unusually high efficacy in the pivotal placebo controlled, randomized trials. In both studies (C013 and C017), the rate of seizure-free patients was sometimes more than 20% and thus in a range never reached over the last decades in comparable trials with other new ASDs. This suggests that CNB which is already approved in the USA might actually offer a new and encouraging perspective for epilepsy treatment concerning efficacy. In this review the pharmacological profile, the currently known mode of action, and the results of the clinical trials are summarized.
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Affiliation(s)
- Bernhard J Steinhoff
- Epilepsiezentrum Kork, Landstraße 1, 77694, Kehl-Kork, Deutschland. .,Klinik für Neurologie, Albert-Ludwigs Universität Freiburg, Freiburg, Deutschland.
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Malysz J, Petkov GV. Detrusor Smooth Muscle K V7 Channels: Emerging New Regulators of Urinary Bladder Function. Front Physiol 2020; 11:1004. [PMID: 33041840 PMCID: PMC7526500 DOI: 10.3389/fphys.2020.01004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/23/2020] [Indexed: 01/21/2023] Open
Abstract
Relaxation and contraction of the urinary bladder smooth muscle, also known as the detrusor smooth muscle (DSM), facilitate the micturition cycle. DSM contractility depends on cell excitability, which is established by the synchronized activity of multiple diverse ion channels. K+ channels, the largest family of channels, control DSM excitability by maintaining the resting membrane potential and shaping the action potentials that cause the phasic contractions. Among the members of the voltage-gated K+ (KV) channel superfamily, KV type 7 (KV7) channels - KV7.1-KV7.5 members encoded by KCNQ1-KCNQ5 genes - have been recently identified as functional regulators in various cell types including vascular, cardiac, and neuronal cells. Their regulatory roles in DSM, however, are just now emerging and remain to be elucidated. To address this gap, our research group has initiated the systematic investigation of human DSM KV7 channels in collaboration with clinical urologists. In this comprehensive review, we summarize the current understanding of DSM Kv7 channels and highlight recent discoveries in the field. We describe KV7 channel expression profiles at the mRNA and protein levels, and further elaborate on functional effects of KV7 channel selective modulators on DSM excitability, contractility, and intracellular Ca2+ dynamics in animal species along with in vivo studies and the limited data on human DSM. Within each topic, we highlight the main observations, current gaps in knowledge, and most pressing questions and concepts in need of resolution. We emphasize the lack of systematic studies on human DSM KV7 channels that are now actively ongoing in our laboratory.
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Affiliation(s)
- John Malysz
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Georgi V. Petkov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, United States
- Department of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, United States
- Department of Urology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, United States
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Vigil FA, Carver CM, Shapiro MS. Pharmacological Manipulation of K v 7 Channels as a New Therapeutic Tool for Multiple Brain Disorders. Front Physiol 2020; 11:688. [PMID: 32636759 PMCID: PMC7317068 DOI: 10.3389/fphys.2020.00688] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 05/27/2020] [Indexed: 12/12/2022] Open
Abstract
K v 7 ("M-type," KCNQ) K+ currents, play dominant roles in controlling neuronal excitability. They act as a "brake" against hyperexcitable states in the central and peripheral nervous systems. Pharmacological augmentation of M current has been developed for controlling epileptic seizures, although current pharmacological tools are uneven in practical usefulness. Lately, however, M-current "opener" compounds have been suggested to be efficacious in preventing brain damage after multiple types of insults/diseases, such as stroke, traumatic brain injury, drug addiction and mood disorders. In this review, we will discuss what is known to date on these efforts and identify gaps in our knowledge regarding the link between M current and therapeutic potential for these disorders. We will outline the preclinical experiments that are yet to be performed to demonstrate the likelihood of success of this approach in human trials. Finally, we also address multiple pharmacological tools available to manipulate different K v 7 subunits and the relevant evidence for translational application in the clinical use for disorders of the central nervous system and multiple types of brain insults. We feel there to be great potential for manipulation of K v 7 channels as a novel therapeutic mode of intervention in the clinic, and that the paucity of existing therapies obligates us to perform further research, so that patients can soon benefit from such therapeutic approaches.
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Affiliation(s)
- Fabio A Vigil
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Chase M Carver
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Mark S Shapiro
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
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Abd-Elsayed A, Jackson M, Gu SL, Fiala K, Gu J. Neuropathic pain and Kv7 voltage-gated potassium channels: The potential role of Kv7 activators in the treatment of neuropathic pain. Mol Pain 2020; 15:1744806919864256. [PMID: 31342847 PMCID: PMC6659175 DOI: 10.1177/1744806919864256] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Neuropathic pain conditions severely and chronically affect the quality of life
in a large human population, but the pain conditions are not adequately managed
due to poor understanding of their underlying mechanisms. There is a pressing
need for further research into this field to help develop effective and
nonaddictive medications to treat neuropathic pain. This article first describes
general clinical classification of pain, types and symptoms of neuropathic pain,
and current practices of clinical management for neuropathic pain. This is
followed by a discussion of various cellular and molecular mechanisms
responsible for the development and maintenance of neuropathic pain. In this
review, we highlight the loss of function of Kv7 voltage-gated potassium as a
mechanism of neuropathic pain and the potential use of Kv7 channel activator as
subsequent treatment.
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Affiliation(s)
- Alaa Abd-Elsayed
- 1 Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA.,2 Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Markus Jackson
- 1 Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Steven L Gu
- 3 Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kenneth Fiala
- 2 Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Jianguo Gu
- 1 Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA.,3 Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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9
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Gore A, Neufeld-Cohen A, Egoz I, Baranes S, Gez R, Grauer E, Chapman S, Lazar S. Efficacy of retigabine in ameliorating the brain insult following sarin exposure in the rat. Toxicol Appl Pharmacol 2020; 395:114963. [PMID: 32209366 DOI: 10.1016/j.taap.2020.114963] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Sarin is an irreversible organophosphate cholinesterase inhibitor. Following toxic signs, an extensive long-term brain damage is often reported. Thus, we evaluated the efficacy of a novel anticonvulsant drug retigabine, a modulator of neuronal voltage gated K+ channels, as a neuroprotective agent following sarin exposure. METHODS Rats were exposed to 1 LD50 or 1.2 LD50 sarin and treated at onset of convulsions with retigabine (5 mg/kg, i.p.) alone or in combination with 5 mg/kg atropine and 7.5 mg/kg TMB-4 (TA) respectively. Brain biochemical and immunohistopathological analyses were processed 24 h and 1 week following 1 LD50 sarin exposure and at 4 weeks following exposure to 1.2 LD50 sarin. EEG activity in freely moving rats was also monitored by telemetry during the first week following exposure to 1.2 LD50 and behavior in the Open Field was evaluated 3 weeks post exposure. RESULTS Treatment with retigabine following 1 LD50 sarin exposure or in combination with TA following 1.2 LD50 exposure significantly reduced mortality rate compared to the non-treated groups. In both experiments, the retigabine treatment significantly reduced gliosis, astrocytosis and brain damage as measured by translocator protein (TSPO). Following sarin exposure the combined treatment (retigabine+ TA) significantly minimized epileptiform seizure activity. Finally, in the Open Field behavioral test the non-treated sarin group showed an increased mobility which was reversed by the combined treatment. CONCLUSIONS The M current modulator retigabine has been shown to be an effective adjunct therapy following OP induced convulsion, minimizing epileptiform seizure activity and attenuating the ensuing brain damage.
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Affiliation(s)
- Ariel Gore
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
| | - Adi Neufeld-Cohen
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Inbal Egoz
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shlomi Baranes
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Rellie Gez
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Ettie Grauer
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shira Chapman
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shlomi Lazar
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
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10
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Manville RW, Abbott GW. Potassium channels act as chemosensors for solute transporters. Commun Biol 2020; 3:90. [PMID: 32111967 PMCID: PMC7048750 DOI: 10.1038/s42003-020-0820-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/06/2020] [Indexed: 01/27/2023] Open
Abstract
Potassium channels form physical complexes with solute transporters in vivo, yet little is known about their range of possible signaling modalities and the underlying mechanisms. The KCNQ2/3 potassium channel, which generates neuronal M-current, is voltage-gated and its activity is also stimulated by binding of various small molecules. KCNQ2/3 forms reciprocally regulating complexes with sodium-coupled myo-inositol transporters (SMITs) in mammalian neurons. Here, we report that the neurotransmitter γ-aminobutyric acid (GABA) and other small molecules directly regulate myo-inositol transport in rat dorsal root ganglia, and by human SMIT1-KCNQ2/3 complexes in vitro, by inducing a distinct KCNQ2/3 pore conformation. Reciprocally, SMIT1 tunes KCNQ2/3 sensing of GABA and related metabolites. Ion permeation and mutagenesis studies suggest that SMIT1 and GABA similarly alter KCNQ2/3 pore conformation but via different KCNQ subunits and molecular mechanisms. KCNQ channels therefore act as chemosensors to enable co-assembled myo-inositol transporters to respond to diverse stimuli including neurotransmitters, metabolites and drugs.
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Affiliation(s)
- Rίan W Manville
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA.
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Rubi L, Kovar M, Zebedin-Brandl E, Koenig X, Dominguez-Rodriguez M, Todt H, Kubista H, Boehm S, Hilber K. Modulation of the heart's electrical properties by the anticonvulsant drug retigabine. Toxicol Appl Pharmacol 2017. [PMID: 28641963 DOI: 10.1016/j.taap.2017.06.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Retigabine, currently used as antiepileptic drug, has a wide range of potential medical uses. Administration of the drug in patients can lead to QT interval prolongation in the electrocardiogram and to cardiac arrhythmias in rare cases. This suggests that the drug may perturb the electrical properties of the heart, and the underlying mechanisms were investigated here. Effects of retigabine on currents through human cardiac ion channels, heterologously expressed in tsA-201 cells, were studied in whole-cell patch-clamp experiments. In addition, the drug's impact on the cardiac action potential was tested. This was done using ventricular cardiomyocytes isolated from Langendorff-perfused guinea pig hearts and cardiomyocytes derived from human induced pluripotent stem cells. Further, to unravel potential indirect effects of retigabine on the heart which might involve the autonomic nervous system, membrane potential and noradrenaline release from sympathetic ganglionic neurons were measured in the absence and presence of the drug. Retigabine significantly inhibited currents through hKv11.1 potassium, hNav1.5 sodium, as well as hCav1.2 calcium channels, but only in supra-therapeutic concentrations. In a similar concentration range, the drug shortened the action potential in both guinea pig and human cardiomyocytes. Therapeutic concentrations of retigabine, on the other hand, were sufficient to inhibit the activity of sympathetic ganglionic neurons. We conclude that retigabine- induced QT interval prolongation, and the reported cases of cardiac arrhythmias after application of the drug in a typical daily dose range, cannot be explained by a direct modulatory effect on cardiac ion channels. They are rather mediated by indirect actions at the level of the autonomic nervous system.
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Affiliation(s)
- Lena Rubi
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Michael Kovar
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Eva Zebedin-Brandl
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Xaver Koenig
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Manuel Dominguez-Rodriguez
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Hannes Todt
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Helmut Kubista
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Stefan Boehm
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria.
| | - Karlheinz Hilber
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria.
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McGuier NS, Griffin WC, Gass JT, Padula AE, Chesler EJ, Mulholland PJ. Kv7 channels in the nucleus accumbens are altered by chronic drinking and are targets for reducing alcohol consumption. Addict Biol 2016; 21:1097-1112. [PMID: 26104325 DOI: 10.1111/adb.12279] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Alcohol use disorders (AUDs) are a major public health issue and produce enormous societal and economic burdens. Current Food and Drug Administration (FDA)-approved pharmacotherapies for treating AUDs suffer from deleterious side effects and are only effective in a subset of individuals. It is therefore essential to find improved medications for the management of AUDs. Emerging evidence suggests that anticonvulsants are a promising class of drugs for treating individuals with AUDs. In these studies, we used integrative functional genomics to demonstrate that genes that encode Kv7 channels (i.e. Kcnq2/3) are related to alcohol (ethanol) consumption, preference and acceptance in rodents. We then tested the ability of the FDA-approved anticonvulsant retigabine, a Kv7 channel opener, to reduce voluntary ethanol consumption of Wistar rats in a two-bottle choice intermittent alcohol access paradigm. Systemic administration and microinjections of retigabine into the nucleus accumbens significantly reduced alcohol drinking, and retigabine was more effective at reducing intake in high- versus low-drinking populations of Wistar rats. Prolonged voluntary drinking increased the sensitivity to the proconvulsant effects of pharmacological blockade of Kv7 channels and altered surface trafficking and SUMOylation patterns of Kv7.2 channels in the nucleus accumbens. These data implicate Kcnq2/3 in the regulation of ethanol drinking and demonstrate that long-term drinking produces neuroadaptations in Kv7 channels. In addition, these results have identified retigabine as a potential pharmacotherapy for treating AUDs and Kv7 channels as a novel therapeutic target for reducing heavy drinking.
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Affiliation(s)
- Natalie S. McGuier
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
| | - William C. Griffin
- Department of Psychiatry and Behavioral Sciences; Medical University of South Carolina; Charleston SC USA
| | - Justin T. Gass
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
| | - Audrey E. Padula
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
| | | | - Patrick J. Mulholland
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
- Department of Psychiatry and Behavioral Sciences; Medical University of South Carolina; Charleston SC USA
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13
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Efficacy and safety of retigabine/ezogabine as adjunctive therapy in adult Asian patients with drug-resistant partial-onset seizures: A randomized, placebo-controlled Phase III study. Epilepsy Behav 2016; 61:224-230. [PMID: 27376872 DOI: 10.1016/j.yebeh.2016.05.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/12/2016] [Accepted: 05/14/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE The purpose of this study was to evaluate the efficacy and safety of adjunctive retigabine/ezogabine (RTG/EZG) therapy in Asian adults with partial-onset seizures. METHODS A Phase III, randomized, double-blind, placebo-controlled, parallel-group study was conducted at 26 centers in Asia. Eligible patients were randomized in a 1:1:1 ratio to receive RTG/EZG 600mg/day (200mg 3 times daily), RTG/EZG 900mg/day (300mg 3 times daily), or placebo. The study consisted of an 8-week screening/baseline phase, followed by a 16-week treatment phase (4-week titration phase and 12-week maintenance phase). RESULTS The study was terminated early because of emerging safety information on RTG/EZG (i.e., retinal pigmentation and skin/mucosal discoloration) from long-term trials. Of 132 patients screened and 76 randomized, 75 (placebo, n=25; RTG/EZG 600mg/day, n=26; RTG/EZG 900mg/day, n=24) received at least 1 dose of the study drug and were included in the safety and intent-to-treat populations. The responder rate (≥50% reduction in 28-day total partial-onset seizure frequency) was 31% with RTG/EZG 600mg/day and 17% with RTG/EZG 900mg/day versus 0% with placebo. Median percent change from baseline in 28-day total partial-onset seizure frequency during the maintenance phase was -33.90% and -22.46% with RTG/EZG 600 and 900mg/day, respectively, versus -22.21% with placebo. No new safety concerns were identified. CONCLUSIONS Insufficient data were obtained to permit definitive conclusions. However, the results appear to be broadly in line with those from previous studies that included primarily Caucasian patients.
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Abstract
This review attempts to give a concise and up-to-date overview on the role of potassium channels in epilepsies. Their role can be defined from a genetic perspective, focusing on variants and de novo mutations identified in genetic studies or animal models with targeted, specific mutations in genes coding for a member of the large potassium channel family. In these genetic studies, a demonstrated functional link to hyperexcitability often remains elusive. However, their role can also be defined from a functional perspective, based on dynamic, aggravating, or adaptive transcriptional and posttranslational alterations. In these cases, it often remains elusive whether the alteration is causal or merely incidental. With ∼80 potassium channel types, of which ∼10% are known to be associated with epilepsies (in humans) or a seizure phenotype (in animals), if genetically mutated, a comprehensive review is a challenging endeavor. This goal may seem all the more ambitious once the data on posttranslational alterations, found both in human tissue from epilepsy patients and in chronic or acute animal models, are included. We therefore summarize the literature, and expand only on key findings, particularly regarding functional alterations found in patient brain tissue and chronic animal models.
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Affiliation(s)
- Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock 18057, Germany
| | - Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock 18057, Germany
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Humphries ESA, Dart C. Neuronal and Cardiovascular Potassium Channels as Therapeutic Drug Targets: Promise and Pitfalls. JOURNAL OF BIOMOLECULAR SCREENING 2015; 20:1055-73. [PMID: 26303307 PMCID: PMC4576507 DOI: 10.1177/1087057115601677] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 07/26/2015] [Accepted: 07/28/2015] [Indexed: 12/21/2022]
Abstract
Potassium (K(+)) channels, with their diversity, often tissue-defined distribution, and critical role in controlling cellular excitability, have long held promise of being important drug targets for the treatment of dysrhythmias in the heart and abnormal neuronal activity within the brain. With the exception of drugs that target one particular class, ATP-sensitive K(+) (KATP) channels, very few selective K(+) channel activators or inhibitors are currently licensed for clinical use in cardiovascular and neurological disease. Here we review what a range of human genetic disorders have told us about the role of specific K(+) channel subunits, explore the potential of activators and inhibitors of specific channel populations as a therapeutic strategy, and discuss possible reasons for the difficulty in designing clinically relevant K(+) channel modulators.
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Affiliation(s)
| | - Caroline Dart
- Institute of Integrative Biology, University of Liverpool, UK
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16
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Wolfart J, Laker D. Homeostasis or channelopathy? Acquired cell type-specific ion channel changes in temporal lobe epilepsy and their antiepileptic potential. Front Physiol 2015; 6:168. [PMID: 26124723 PMCID: PMC4467176 DOI: 10.3389/fphys.2015.00168] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/19/2015] [Indexed: 01/16/2023] Open
Abstract
Neurons continuously adapt the expression and functionality of their ion channels. For example, exposed to chronic excitotoxicity, neurons homeostatically downscale their intrinsic excitability. In contrast, the “acquired channelopathy” hypothesis suggests that proepileptic channel characteristics develop during epilepsy. We review cell type-specific channel alterations under different epileptic conditions and discuss the potential of channels that undergo homeostatic adaptations, as targets for antiepileptic drugs (AEDs). Most of the relevant studies have been performed on temporal lobe epilepsy (TLE), a widespread AED-refractory, focal epilepsy. The TLE patients, who undergo epilepsy surgery, frequently display hippocampal sclerosis (HS), which is associated with degeneration of cornu ammonis subfield 1 pyramidal cells (CA1 PCs). Although the resected human tissue offers insights, controlled data largely stem from animal models simulating different aspects of TLE and other epilepsies. Most of the cell type-specific information is available for CA1 PCs and dentate gyrus granule cells (DG GCs). Between these two cell types, a dichotomy can be observed: while DG GCs acquire properties decreasing the intrinsic excitability (in TLE models and patients with HS), CA1 PCs develop channel characteristics increasing intrinsic excitability (in TLE models without HS only). However, thorough examination of data on these and other cell types reveals the coexistence of protective and permissive intrinsic plasticity within neurons. These mechanisms appear differentially regulated, depending on the cell type and seizure condition. Interestingly, the same channel molecules that are upregulated in DG GCs during HS-related TLE, appear as promising targets for future AEDs and gene therapies. Hence, GCs provide an example of homeostatic ion channel adaptation which can serve as a primer when designing novel anti-epileptic strategies.
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Affiliation(s)
- Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
| | - Debora Laker
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
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Pisano T, Numis AL, Heavin SB, Weckhuysen S, Angriman M, Suls A, Podesta B, Thibert RL, Shapiro KA, Guerrini R, Scheffer IE, Marini C, Cilio MR. Early and effective treatment ofKCNQ2encephalopathy. Epilepsia 2015; 56:685-91. [DOI: 10.1111/epi.12984] [Citation(s) in RCA: 186] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Tiziana Pisano
- Neurology Unit and Laboratories; A. Meyer Children's Hospital; Florence Italy
| | - Adam L. Numis
- Department of Neurology; University of California, San Francisco; San Francisco California U.S.A
| | - Sinéad B. Heavin
- Departments of Medicine and Paediatrics; Florey Institute; Austin Health and Royal Children's Hospital; University of Melbourne; Melbourne Victoria Australia
| | - Sarah Weckhuysen
- Neurogenetics Group; Department of Molecular Genetics; VIB; Antwerp Belgium
- Laboratory of Neurogenetics; Institute Born-Bunge; University of Antwerp; Antwerp Belgium
| | | | - Arvid Suls
- Neurogenetics Group; Department of Molecular Genetics; VIB; Antwerp Belgium
- Laboratory of Neurogenetics; Institute Born-Bunge; University of Antwerp; Antwerp Belgium
| | - Barbara Podesta
- Child Neurology and Psychiatry Unit; S. Croce and S. Carlo Hospital; Cuneo Italy
| | - Ronald L. Thibert
- Pediatric Epilepsy Program; Massachusetts General Hospital; Harvard Medical School; Boston Massachusetts U.S.A
| | - Kevin A. Shapiro
- Department of Neurology; University of California, San Francisco; San Francisco California U.S.A
| | - Renzo Guerrini
- Neurology Unit and Laboratories; A. Meyer Children's Hospital; Florence Italy
- University of Florence; Florence Italy
| | - Ingrid E. Scheffer
- Departments of Medicine and Paediatrics; Florey Institute; Austin Health and Royal Children's Hospital; University of Melbourne; Melbourne Victoria Australia
| | - Carla Marini
- Neurology Unit and Laboratories; A. Meyer Children's Hospital; Florence Italy
| | - Maria Roberta Cilio
- Department of Neurology; University of California, San Francisco; San Francisco California U.S.A
- Department of Pediatrics; University of California San Francisco; San Francisco California U.S.A
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Zwierzyńska E, Krupa A, Pietrzak B. A pharmaco-EEG study of the interaction between ethanol and retigabine in rabbits. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2015; 41:153-60. [DOI: 10.3109/00952990.2014.987349] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Ewa Zwierzyńska
- Department of Pharmacodynamics, Medical University of Łódź, Łódź, Poland
| | - Agata Krupa
- Department of Pharmacodynamics, Medical University of Łódź, Łódź, Poland
| | - Bogusława Pietrzak
- Department of Pharmacodynamics, Medical University of Łódź, Łódź, Poland
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Abstract
Most children with new-onset epilepsy achieve seizure freedom with appropriate antiepileptic drugs (AEDs). However, nearly 20 % will continue to have seizures despite AEDs, as either monotherapy or in combination. Despite the growing market of new molecules over the last 20 years, the proportion of drug-resistant epilepsies has not changed. In this review, we report the evidence of efficacy and safety based on phase III randomized controlled clinical trials (RCTs) of AEDs currently used in the paediatric population. We conducted a literature search using the PubMed database and the Cochrane Database of Systematic Reviews. We also analysed the RCTs of newer AEDs whose efficacy in adolescents and adults might suggest possible use in children. Most of the phase III trials on AEDs in children have major methodological limitations that considerably limit meaningful conclusions about comparative efficacy between old and new molecules. Since the efficacy of new drugs has only been reported versus placebo, the commonly held opinion that new and newer AEDs have a better safety profile than old ones does not appear to be supported by evidence. Despite limited solid evidence, pharmacological management has improved over the years as a consequence of increased awareness of some degree of specificity of treatment in relation to different epilepsy syndromes and attention to adverse events. Future research should be directed taking these factors, as well as the diversity of epilepsy, into consideration.
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Affiliation(s)
- Anna Rosati
- Paediatric Neurology Unit, Children's Hospital A. Meyer, University of Firenze, Viale Pieraccini 24, 50139, Florence, Italy
| | - Salvatore De Masi
- Clinical Trial Office, Children's Hospital A. Meyer, Viale Pieraccini 24, 50139, Florence, Italy
| | - Renzo Guerrini
- Paediatric Neurology Unit, Children's Hospital A. Meyer, University of Firenze, Viale Pieraccini 24, 50139, Florence, Italy.
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