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Zinchenko VP, Teplov IY, Kosenkov AM, Gaidin SG, Kairat BK, Tuleukhanov ST. Participation of calcium-permeable AMPA receptors in the regulation of epileptiform activity of hippocampal neurons. Front Synaptic Neurosci 2024; 16:1349984. [PMID: 38577639 PMCID: PMC10987725 DOI: 10.3389/fnsyn.2024.1349984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 02/20/2024] [Indexed: 04/06/2024] Open
Abstract
Introduction Epileptiform activity is the most striking result of hyperexcitation of a group of neurons that can occur in different brain regions and then spread to other sites. Later it was shown that these rhythms have a cellular correlate in vitro called paroxysmal depolarization shift (PDS). In 13-15 DIV neuron-glial cell culture, inhibition of the GABA(A) receptors induces bursts of action potential in the form of clasters PDS and oscillations of intracellular Ca2+ concentration ([Ca2+]i). We demonstrate that GABAergic neurons expressing calcium-permeable AMPA receptors (CP-AMPARs) as well as Kv7-type potassium channels regulate hippocampal glutamatergic neurons' excitability during epileptiform activity in culture. Methods A combination of whole-cell patch-clamp in current clamp mode and calcium imaging microscopy was used to simultaneously register membrane potential and [Ca2+]i level. To identify GABAergic cell cultures were fixed and stained with antibodies against glutamate decarboxylase GAD 65/67 and neuron-specific enolase (NSE) after vital [Ca2+]i imaging. Results and discussion It was shown that CP-AMPARs are involved in the regulation of the PDS clusters and [Ca2+]i pulses accompanied them. Activation of CP-AMPARs of GABAergic neurons is thought to cause the release of GABA, which activates the GABA(B) receptors of other GABAergic interneurons. It is assumed that activation of these GABA(B) receptors leads to the release of beta-gamma subunits of Gi protein, which activate potassium channels, resulting in hyperpolarization and inhibition of these interneurons. The latter causes disinhibition of glutamatergic neurons, the targets of these interneurons. In turn, the CP-AMPAR antagonist, NASPM, has the opposite effect. Measurement of membrane potential in GABAergic neurons by the patch-clamp method in whole-cell configuration demonstrated that NASPM suppresses hyperpolarization in clusters and individual PDSs. It is believed that Kv7-type potassium channels are involved in the control of hyperpolarization during epileptiform activity. The blocker of Kv7 channels, XE 991, mimicked the effect of the CP-AMPARs antagonist on PDS clusters. Both drugs increased the duration of the PDS cluster. In turn, the Kv7 activator, retigabine, decreased the duration of the PDS cluster and Ca2+ pulse. In addition, retigabine led to deep posthyperpolarization at the end of the PDS cluster. The Kv7 channel is believed to be involved in the formation of PDS, as the channel blocker reduced the rate of hyperpolarization in the PDS almost three times. Thus, GABAergic neurons expressing CP-AMPARs, regulate the membrane potential of innervated glutamatergic neurons by modulating the activity of postsynaptic potassium channels of other GABAergic neurons.
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Affiliation(s)
- Valery Petrovich Zinchenko
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Russia
| | - Ilia Yu. Teplov
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Russia
| | - Artem Mikhailovich Kosenkov
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Russia
| | - Sergei Gennadievich Gaidin
- Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Russia
| | - Bakytzhan Kairatuly Kairat
- Laboratory of Biophysics, Chronobiology and Biomedicine, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Sultan Tuleukhanovich Tuleukhanov
- Laboratory of Biophysics, Chronobiology and Biomedicine, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan
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Müller S, Kartheus M, Hendinger E, Hübner DC, Schnell E, Rackow S, Bertsche A, Köhling R, Kirschstein T. Persistent Kv7.2/7.3 downregulation in the rat pilocarpine model of mesial temporal lobe epilepsy. Epilepsy Res 2024; 200:107296. [PMID: 38219422 DOI: 10.1016/j.eplepsyres.2024.107296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/04/2023] [Accepted: 01/05/2024] [Indexed: 01/16/2024]
Abstract
Mutations within the Kv7.2 and Kv7.3 genes are well described causes for genetic childhood epilepsies. Knowledge on these channels in acquired focal epilepsy, especially in mesial temporal lobe epilepsy (mTLE), however, is scarce. Here, we used the rat pilocarpine model of drug-resistant mTLE to elucidate both expression and function by quantitative polymerase-chain reaction, immunohistochemistry, and electrophysiology, respectively. We found transcriptional downregulation of Kv7.2 and Kv7.3 as well as reduced Kv7.2 expression in epileptic CA1. Consequences were altered synaptic transmission, hyperexcitability which consisted of epileptiform afterpotentials, and increased susceptibility to acute GABAergic disinhibition. Importantly, blocking Kv7 channels with XE991 increased hyperexcitability in control tissue, but not in chronically epileptic tissue suggesting that the Kv7 deficit had precluded XE991 effects in this tissue. Conversely, XE991 resulted in comparable reduction of the paired-pulse ratio in both experimental groups implying preserved presynaptic Kv7.2 function of Schaffer collateral terminals. Consistent with Kv7.2/7.3 downregulation, the Kv7.3 channel opener β-hydroxybutyrate failed to mitigate hyperexcitability. Our findings demonstrate that compromised Kv7 function is not only relevant in genetic epilepsy, but also in acquired focal epilepsy. Moreover, they help explain reduced anti-seizure efficacy of Kv7 channel openers in drug-resistant epilepsy.
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Affiliation(s)
- Steffen Müller
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Mareike Kartheus
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Elisabeth Hendinger
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | | | - Emma Schnell
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Simone Rackow
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Astrid Bertsche
- Department Neuropaediatrics, Hospital for Children and Adolescents, University Medicine Greifswald, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany; Center of Transdisciplinary Neurosciences Rostock (CTNR), University Medicine Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany; Center of Transdisciplinary Neurosciences Rostock (CTNR), University Medicine Rostock, Germany.
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3
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Bayat A, Iavarone S, Miceli F, Jakobsen AV, Johannesen KM, Nikanorova M, Ploski R, Szymanska K, Flamini R, Cooper EC, Weckhuysen S, Taglialatela M, Møller RS. Phenotypic and functional assessment of two novel KCNQ2 gain-of-function variants Y141N and G239S and effects of amitriptyline treatment. Neurotherapeutics 2024; 21:e00296. [PMID: 38241158 PMCID: PMC10903081 DOI: 10.1016/j.neurot.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 01/21/2024] Open
Abstract
While loss-of-function (LoF) variants in KCNQ2 are associated with a spectrum of neonatal-onset epilepsies, gain-of-function (GoF) variants cause a more complex phenotype that precludes neonatal-onset epilepsy. In the present work, the clinical features of three patients carrying a de novo KCNQ2 Y141N (n = 1) or G239S variant (n = 2) respectively, are described. All three patients had a mild global developmental delay, with prominent language deficits, and strong activation of interictal epileptic activity during sleep. Epileptic seizures were not reported. The absence of neonatal seizures suggested a GoF effect and prompted functional testing of the variants. In vitro whole-cell patch-clamp electrophysiological experiments in Chinese Hamster Ovary cells transiently-transfected with the cDNAs encoding Kv7.2 subunits carrying the Y141N or G239S variants in homomeric or heteromeric configurations with Kv7.2 subunits, revealed that currents from channels incorporating mutant subunits displayed increased current densities and hyperpolarizing shifts of about 10 mV in activation gating; both these functional features are consistent with an in vitro GoF phenotype. The antidepressant drug amitriptyline induced a reversible and concentration-dependent inhibition of current carried by Kv7.2 Y141N and G239S mutant channels. Based on in vitro results, amitriptyline was prescribed in one patient (G239S), prompting a significant improvement in motor, verbal, social, sensory and adaptive behavior skillsduring the two-year-treatment period. Thus, our results suggest that KCNQ2 GoF variants Y141N and G239S cause a mild DD with prominent language deficits in the absence of neonatal seizures and that treatment with the Kv7 channel blocker amitriptyline might represent a potential targeted treatment for patients with KCNQ2 GoF variants.
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Affiliation(s)
- Allan Bayat
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark; Department for Regional Health Research, University of Southern Denmark, Odense, Denmark; Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Stefano Iavarone
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Francesco Miceli
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Anne V Jakobsen
- Department of Pediatrics, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark; Department of Genetics, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Marina Nikanorova
- Department of Pediatrics, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark
| | - Rafal Ploski
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | - Krystyna Szymanska
- Department of Pediatric Neurology, Medical University of Warsaw, Warsaw, Poland
| | | | - Edward C Cooper
- Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston TX, USA
| | - Sarah Weckhuysen
- Applied and Translational Genomics Group, VIB-Center for Molecular Neurology, VIB, University of Antwerp, Antwerp, Belgium; Neurology Department, University Hospital Antwerp, Antwerp, Belgium; Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium; μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Maurizio Taglialatela
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark; Department for Regional Health Research, University of Southern Denmark, Odense, Denmark
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Liu E, Pang K, Liu M, Tan X, Hang Z, Mu S, Han W, Yue Q, Comai S, Sun J. Activation of Kv7 channels normalizes hyperactivity of the VTA-NAcLat circuit and attenuates methamphetamine-induced conditioned place preference and sensitization in mice. Mol Psychiatry 2023; 28:5183-5194. [PMID: 37604975 DOI: 10.1038/s41380-023-02218-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/23/2023]
Abstract
The brain circuit projecting from the ventral tegmental area (VTA) to the nucleus accumbens lateral shell (NAcLat) has a key role in methamphetamine (MA) addiction. As different dopamine (DA) neuron subpopulations in the VTA participate in different neuronal circuits, it is a challenge to isolate these DA neuron subtypes. Using retrograde tracing and Patch-seq, we isolated DA neurons in the VTA-NAcLat circuit in MA-treated mice and performed gene expression profiling. Among the differentially expressed genes, KCNQ genes were dramatically downregulated. KCNQ genes encode Kv7 channel proteins, which modulate neuronal excitability. Injection of both the Kv7.2/3 agonist ICA069673 and the Kv7.4 agonist fasudil into the VTA attenuated MA-induced conditioned place preference and locomotor sensitization and decreased neuronal excitability. Increasing Kv7.2/3 activity decreased neural oscillations, synaptic plasticity and DA release in the VTA-NacLat circuit in MA-treated mice. Furthermore, overexpression of only Kv7.3 channels in the VTA-NacLat circuit was sufficient to attenuate MA-induced reward behavior and decrease VTA neuron excitability. Activation of Kv7 channels in the VTA may become a novel treatment strategy for MA abuse.
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Affiliation(s)
- E Liu
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Kunkun Pang
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
- Department of Ultrasound, The Second Hospital of Shandong University, Jinan, Shandong, China
| | - Min Liu
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Xu Tan
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Zhaofang Hang
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Shouhong Mu
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Weikai Han
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Qingwei Yue
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China
| | - Stefano Comai
- Department of Psychiatry, McGill University, Montréal, QC, Canada
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Jinhao Sun
- Department of Anatomy and Neurobiology, Shandong University School of Basic Medicine, Jinan, Shandong, China.
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Hagio H, Koyama W, Hosaka S, Song AD, Narantsatsral J, Matsuda K, Sugihara T, Shimizu T, Koyanagi M, Terakita A, Hibi M. Optogenetic manipulation of Gq- and Gi/o-coupled receptor signaling in neurons and heart muscle cells. eLife 2023; 12:e83974. [PMID: 37589544 PMCID: PMC10435233 DOI: 10.7554/elife.83974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 07/27/2023] [Indexed: 08/18/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) transmit signals into cells depending on the G protein type. To analyze the functions of GPCR signaling, we assessed the effectiveness of animal G-protein-coupled bistable rhodopsins that can be controlled into active and inactive states by light application using zebrafish. We expressed Gq- and Gi/o-coupled bistable rhodopsins in hindbrain reticulospinal V2a neurons, which are involved in locomotion, or in cardiomyocytes. Light stimulation of the reticulospinal V2a neurons expressing Gq-coupled spider Rh1 resulted in an increase in the intracellular Ca2+ level and evoked swimming behavior. Light stimulation of cardiomyocytes expressing the Gi/o-coupled mosquito Opn3, pufferfish TMT opsin, or lamprey parapinopsin induced cardiac arrest, and the effect was suppressed by treatment with pertussis toxin or barium, suggesting that Gi/o-dependent regulation of inward-rectifier K+ channels controls cardiac function. These data indicate that these rhodopsins are useful for optogenetic control of GPCR-mediated signaling in zebrafish neurons and cardiomyocytes.
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Affiliation(s)
- Hanako Hagio
- Graduate School of Science, Nagoya UniversityNagoyaJapan
- Graduate School of Bioagricultural Sciences, Nagoya UniversityNagoyaJapan
- Institute for Advanced Research, Nagoya UniversityNagoyaJapan
| | - Wataru Koyama
- Graduate School of Science, Nagoya UniversityNagoyaJapan
| | - Shiori Hosaka
- Graduate School of Science, Nagoya UniversityNagoyaJapan
| | | | | | - Koji Matsuda
- Graduate School of Science, Nagoya UniversityNagoyaJapan
| | | | | | | | - Akihisa Terakita
- Graduate School of Science, Osaka Metropolitan UniversityOsakaJapan
| | - Masahiko Hibi
- Graduate School of Science, Nagoya UniversityNagoyaJapan
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6
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Hou B, Santaniello S, Tzingounis AV. KCNQ2 channels regulate the population activity of neonatal GABAergic neurons ex vivo. Front Neurol 2023; 14:1207539. [PMID: 37409016 PMCID: PMC10318362 DOI: 10.3389/fneur.2023.1207539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 05/18/2023] [Indexed: 07/07/2023] Open
Abstract
Over the last decade KCNQ2 channels have arisen as fundamental and indispensable regulators of neonatal brain excitability, with KCNQ2 loss-of-function pathogenic variants being increasingly identified in patients with developmental and epileptic encephalopathy. However, the mechanisms by which KCNQ2 loss-of-function variants lead to network dysfunction are not fully known. An important remaining knowledge gap is whether loss of KCNQ2 function alters GABAergic interneuron activity early in development. To address this question, we applied mesoscale calcium imaging ex vivo in postnatal day 4-7 mice lacking KCNQ2 channels in interneurons (Vgat-ires-cre;Kcnq2f/f;GCamp5). In the presence of elevated extracellular potassium concentrations, ablation of KCNQ2 channels from GABAergic cells increased the interneuron population activity in the hippocampal formation and regions of the neocortex. We found that this increased population activity depends on fast synaptic transmission, with excitatory transmission promoting the activity and GABAergic transmission curtailing it. Together, our data show that loss of function of KCNQ2 channels from interneurons increases the network excitability of the immature GABAergic circuits, revealing a new function of KCNQ2 channels in interneuron physiology in the developing brain.
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Affiliation(s)
- Bowen Hou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Sabato Santaniello
- Department of Biomedical Engineering and CT Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, United States
| | - Anastasios V. Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
- Department of Biomedical Engineering and CT Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, United States
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7
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Urena ES, Diezel CC, Serna M, Hala'ufia G, Majuta L, Barber KR, Vanderah TW, Riegel AC. K v 7 Channel Opener Retigabine Reduces Self-Administration of Cocaine but Not Sucrose in Rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.18.541208. [PMID: 37292619 PMCID: PMC10245780 DOI: 10.1101/2023.05.18.541208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The increasing rates of drug misuse highlight the urgency of identifying improved therapeutics for treatment. Most drug-seeking behaviors that can be modeled in rodents utilize the repeated intravenous self-administration (SA) of drugs. Recent studies examining the mesolimbic pathway suggest that K v 7/KCNQ channels may contribute in the transition from recreational to chronic drug use. However, to date, all such studies used noncontingent, experimenter-delivered drug model systems, and the extent to which this effect generalizes to rats trained to self-administer drug is not known. Here, we tested the ability of retigabine (ezogabine), a K v 7 channel opener, to regulate instrumental behavior in male Sprague Dawley rats. We first validated the ability of retigabine to target experimenter-delivered cocaine in a CPP assay and found that retigabine reduced the acquisition of place preference. Next, we trained rats for cocaine-SA under a fixed-ratio or progressive-ratio reinforcement schedule and found that retigabine-pretreatment attenuated the self-administration of low to moderate doses of cocaine. This was not observed in parallel experiments, with rats self-administering sucrose, a natural reward. Compared to sucrose-SA, cocaine-SA was associated with reductions in the expression of the K v 7.5 subunit in the nucleus accumbens, without alterations in K v 7.2 and K v 7.3. Therefore, these studies reveal a reward specific reduction in SA behavior considered relevant for the study of long-term compulsive-like behavior and supports the notion that K v 7 is a potential therapeutic target for human psychiatric diseases with dysfunctional reward circuitry.
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Emerging mechanisms involving brain Kv7 channel in the pathogenesis of hypertension. Biochem Pharmacol 2022; 206:115318. [PMID: 36283445 DOI: 10.1016/j.bcp.2022.115318] [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: 08/24/2022] [Revised: 10/15/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022]
Abstract
Hypertension is a prevalent health problem inducing many organ damages. The pathogenesis of hypertension involves a complex integration of different organ systems including the brain. The elevated sympathetic nerve activity is closely related to the etiology of hypertension. Ion channels are critical regulators of neuronal excitability. Several mechanisms have been proposed to contribute to hypothalamic-driven elevated sympathetic activity, including altered ion channel function. Recent findings indicate one of the voltage-gated potassium channels, Kv7 channels (M channels), plays a vital role in regulating cardiovascular-related neurons activity, and the expression of Kv7 channels is downregulated in hypertension. This review highlights recent findings that the Kv7 channels in the brain, blood vessels, and kidneys are emerging targets involved in the pathogenesis of hypertension, suggesting new therapeutic targets for treating drug-resistant, neurogenic hypertension.
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Ying Y, Gong L, Tao X, Ding J, Chen N, Yao Y, Liu J, Chen C, Zhu T, Jiang P. Genetic Knockout of TRPM2 Increases Neuronal Excitability of Hippocampal Neurons by Inhibiting Kv7 Channel in Epilepsy. Mol Neurobiol 2022; 59:6918-6933. [PMID: 36053438 DOI: 10.1007/s12035-022-02993-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/07/2022] [Indexed: 11/30/2022]
Abstract
Epilepsy is a chronic brain disease that makes serious cognitive and motor retardation. Ion channels affect the occurrence of epilepsy in various ways, but the mechanisms have not yet been fully elucidated. Transient receptor potential melastain2 (TRPM2) ion channel is a non-selective cationic channel that can permeate Ca2+ and critical for epilepsy. Here, TRPM2 gene knockout mice were used to generate a chronic kindling epilepsy model by PTZ administration in mice. We found that TRPM2 knockout mice were more susceptible to epilepsy than WT mice. Furthermore, the neuronal excitability in the hippocampal CA1 region of TRPM2 knockout mice was significantly increased. Compared with WT group, there were no significant differences in the input resistance and after hyperpolarization of CA1 neurons in TRPM2 knockout mice. Firing adaptation rate of hippocampal CA1 pyramidal neurons of TRPM2 knockout mice was lower than that of WT mice. We also found that activation of Kv7 channel by retigabine reduced the firing frequency of action potential in the hippocampal pyramidal neurons of TRPM2 knockout mice. However, inhibiting Kv7 channel increased the firing frequency of action potential in hippocampal pyramidal neurons of WT mice. The data suggest that activation of Kv7 channel can effectively reduce epileptic seizures in TRPM2 knockout mice. We conclude that genetic knockout of TRPM2 in hippocampal CA1 pyramidal neurons may increase neuronal excitability by inhibiting Kv7 channel, affecting the susceptibility to epilepsy. These findings may provide a potential therapeutic target for epilepsy.
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Affiliation(s)
- Yingchao Ying
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Lifen Gong
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Xiaohan Tao
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Junchao Ding
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
- Department of Pediatrics, Yiwu Maternal and Child Health Care Hospital, Yiwu, China
| | - Nannan Chen
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Yinping Yao
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
- Department of Pediatrics, Shaoxing People's Hospital, Shaoxing, China
| | - Jiajing Liu
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Chen Chen
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Tao Zhu
- Department of Critical Care Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Peifang Jiang
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China.
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10
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Tsuboi D, Otsuka T, Shimomura T, Faruk MO, Yamahashi Y, Amano M, Funahashi Y, Kuroda K, Nishioka T, Kobayashi K, Sano H, Nagai T, Yamada K, Tzingounis AV, Nambu A, Kubo Y, Kawaguchi Y, Kaibuchi K. Dopamine drives neuronal excitability via KCNQ channel phosphorylation for reward behavior. Cell Rep 2022; 40:111309. [PMID: 36070693 DOI: 10.1016/j.celrep.2022.111309] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/22/2022] [Accepted: 08/12/2022] [Indexed: 11/25/2022] Open
Abstract
Dysfunctional dopamine signaling is implicated in various neuropsychological disorders. Previously, we reported that dopamine increases D1 receptor (D1R)-expressing medium spiny neuron (MSN) excitability and firing rates in the nucleus accumbens (NAc) via the PKA/Rap1/ERK pathway to promote reward behavior. Here, the results show that the D1R agonist, SKF81297, inhibits KCNQ-mediated currents and increases D1R-MSN firing rates in murine NAc slices, which is abolished by ERK inhibition. In vitro ERK phosphorylates KCNQ2 at Ser414 and Ser476; in vivo, KCNQ2 is phosphorylated downstream of dopamine signaling in NAc slices. Conditional deletion of Kcnq2 in D1R-MSNs reduces the inhibitory effect of SKF81297 on KCNQ channel activity, while enhancing neuronal excitability and cocaine-induced reward behavior. These effects are restored by wild-type, but not phospho-deficient KCNQ2. Hence, D1R-ERK signaling controls MSN excitability via KCNQ2 phosphorylation to regulate reward behavior, making KCNQ2 a potential therapeutical target for psychiatric diseases with a dysfunctional reward circuit.
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Affiliation(s)
- Daisuke Tsuboi
- Division of Cell Biology, International Center for Brain Science, Fujita Health University, 1-98 Dengakugakubo, Kusukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Takeshi Otsuka
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
| | - Takushi Shimomura
- Division of Biophysics and Neurobiology, National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Md Omar Faruk
- Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan
| | - Yukie Yamahashi
- Division of Cell Biology, International Center for Brain Science, Fujita Health University, 1-98 Dengakugakubo, Kusukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Mutsuki Amano
- Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan
| | - Yasuhiro Funahashi
- Division of Cell Biology, International Center for Brain Science, Fujita Health University, 1-98 Dengakugakubo, Kusukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Keisuke Kuroda
- Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan
| | - Tomoki Nishioka
- Division of Cell Biology, International Center for Brain Science, Fujita Health University, 1-98 Dengakugakubo, Kusukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, Center for Genetic Analysis of Behavior, National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Hiromi Sano
- Division of System Neurophysiology, National Institute for Physiological Sciences and Department of Physiological Sciences, Sokendai, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan; Division of Behavioral Neuropharmacology, International Center for Brain Science, Fujita Health University, 1-98 Dengakugakubo, Kusukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Taku Nagai
- Division of Behavioral Neuropharmacology, International Center for Brain Science, Fujita Health University, 1-98 Dengakugakubo, Kusukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Kiyofumi Yamada
- Department of Neuropsychopharmacology and Hospital Pharmacy, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, Aichi 466-8560, Japan
| | | | - Atsushi Nambu
- Division of System Neurophysiology, National Institute for Physiological Sciences and Department of Physiological Sciences, Sokendai, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Yoshihiro Kubo
- Division of Biophysics and Neurobiology, National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Yasuo Kawaguchi
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan; Brain Science Institute, Tamagawa University, Machida, Tokyo 194-8610, Japan
| | - Kozo Kaibuchi
- Division of Cell Biology, International Center for Brain Science, Fujita Health University, 1-98 Dengakugakubo, Kusukake-cho, Toyoake, Aichi 470-1192, Japan; Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan.
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11
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Antagonism of the Muscarinic Acetylcholine Type 1 Receptor Enhances Mitochondrial Membrane Potential and Expression of Respiratory Chain Components via AMPK in Human Neuroblastoma SH-SY5Y Cells and Primary Neurons. Mol Neurobiol 2022; 59:6754-6770. [PMID: 36002781 PMCID: PMC9525428 DOI: 10.1007/s12035-022-03003-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/16/2022] [Indexed: 12/05/2022]
Abstract
Impairments in mitochondrial physiology play a role in the progression of multiple neurodegenerative conditions, including peripheral neuropathy in diabetes. Blockade of muscarinic acetylcholine type 1 receptor (M1R) with specific/selective antagonists prevented mitochondrial dysfunction and reversed nerve degeneration in in vitro and in vivo models of peripheral neuropathy. Specifically, in type 1 and type 2 models of diabetes, inhibition of M1R using pirenzepine or muscarinic toxin 7 (MT7) induced AMP-activated protein kinase (AMPK) activity in dorsal root ganglia (DRG) and prevented sensory abnormalities and distal nerve fiber loss. The human neuroblastoma SH-SY5Y cell line has been extensively used as an in vitro model system to study mechanisms of neurodegeneration in DRG neurons and other neuronal sub-types. Here, we tested the hypothesis that pirenzepine or MT7 enhance AMPK activity and via this pathway augment mitochondrial function in SH-SY5Y cells. M1R expression was confirmed by utilizing a fluorescent dye, ATTO590-labeled MT7, that exhibits great specificity for this receptor. M1R antagonist treatment in SH-SY5Y culture increased AMPK phosphorylation and mitochondrial protein expression (OXPHOS). Mitochondrial membrane potential (MMP) was augmented in pirenzepine and MT7 treated cultured SH-SY5Y cells and DRG neurons. Compound C or AMPK-specific siRNA suppressed pirenzepine or MT7-induced elevation of OXPHOS expression and MMP. Moreover, muscarinic antagonists induced hyperpolarization by activating the M-current and, thus, suppressed neuronal excitability. These results reveal that negative regulation of this M1R-dependent pathway could represent a potential therapeutic target to elevate AMPK activity, enhance mitochondrial function, suppress neuropathic pain, and enhance nerve repair in peripheral neuropathy.
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12
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Baculis BC, Kesavan H, Weiss AC, Kim EH, Tracy GC, Ouyang W, Tsai NP, Chung HJ. Homeostatic regulation of extracellular signal-regulated kinase 1/2 activity and axonal Kv7.3 expression by prolonged blockade of hippocampal neuronal activity. Front Cell Neurosci 2022; 16:838419. [PMID: 35966206 PMCID: PMC9366003 DOI: 10.3389/fncel.2022.838419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/04/2022] [Indexed: 11/17/2022] Open
Abstract
Homeostatic plasticity encompasses the mechanisms by which neurons stabilize their synaptic strength and excitability in response to prolonged and destabilizing changes in their network activity. Prolonged activity blockade leads to homeostatic scaling of action potential (AP) firing rate in hippocampal neurons in part by decreased activity of N-Methyl-D-Aspartate receptors and subsequent transcriptional down-regulation of potassium channel genes including KCNQ3 which encodes Kv7.3. Neuronal Kv7 channels are mostly heterotetramers of Kv7.2 and Kv7.3 subunits and are highly enriched at the axon initial segment (AIS) where their current potently inhibits repetitive and burst firing of APs. However, whether a decrease in Kv7.3 expression occurs at the AIS during homeostatic scaling of intrinsic excitability and what signaling pathway reduces KCNQ3 transcript upon prolonged activity blockade remain unknown. Here, we report that prolonged activity blockade in cultured hippocampal neurons reduces the activity of extracellular signal-regulated kinase 1/2 (ERK1/2) followed by a decrease in the activation of brain-derived neurotrophic factor (BDNF) receptor, Tropomyosin receptor kinase B (TrkB). Furthermore, both prolonged activity blockade and prolonged pharmacological inhibition of ERK1/2 decrease KCNQ3 and BDNF transcripts as well as the density of Kv7.3 and ankyrin-G at the AIS. Collectively, our findings suggest that a reduction in the ERK1/2 activity and subsequent transcriptional down-regulation may serve as a potential signaling pathway that links prolonged activity blockade to homeostatic control of BDNF-TrkB signaling and Kv7.3 density at the AIS during homeostatic scaling of AP firing rate.
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Affiliation(s)
- Brian C. Baculis
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Harish Kesavan
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Amanda C. Weiss
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Edward H. Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Gregory C. Tracy
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Wenhao Ouyang
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Nien-Pei Tsai
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Hee Jung Chung
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- *Correspondence: Hee Jung Chung,
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13
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Gorlewicz A, Barthet G, Zucca S, Vincent P, Griguoli M, Grosjean N, Wilczynski G, Mulle C. The Deletion of GluK2 Alters Cholinergic Control of Neuronal Excitability. Cereb Cortex 2022; 32:2907-2923. [PMID: 34730179 DOI: 10.1093/cercor/bhab390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/14/2022] Open
Abstract
Kainate receptors (KARs) are key regulators of synaptic circuits by acting at pre- and postsynaptic sites through either ionotropic or metabotropic actions. KARs can be activated by kainate, a potent neurotoxin, which induces acute convulsions. Here, we report that the acute convulsive effect of kainate mostly depends on GluK2/GluK5 containing KARs. By contrast, the acute convulsive activity of pilocarpine and pentylenetetrazol is not alleviated in the absence of KARs. Unexpectedly, the genetic inactivation of GluK2 rather confers increased susceptibility to acute pilocarpine-induced seizures. The mechanism involves an enhanced excitability of GluK2-/- CA3 pyramidal cells compared with controls upon pilocarpine application. Finally, we uncover that the absence of GluK2 increases pilocarpine modulation of Kv7/M currents. Taken together, our findings reveal that GluK2-containing KARs can control the excitability of hippocampal circuits through interaction with the neuromodulatory cholinergic system.
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Affiliation(s)
- Adam Gorlewicz
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Gael Barthet
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Stefano Zucca
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Peggy Vincent
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Marilena Griguoli
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Noëlle Grosjean
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Grzegorz Wilczynski
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Christophe Mulle
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
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14
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Evidence for Dual Activation of IK(M) and IK(Ca) Caused by QO-58 (5-(2,6-Dichloro-5-fluoropyridin-3-yl)-3-phenyl-2-(trifluoromethyl)-1H-pyrazolol[1,5-a]pyrimidin-7-one). Int J Mol Sci 2022; 23:ijms23137042. [PMID: 35806047 PMCID: PMC9266432 DOI: 10.3390/ijms23137042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/20/2022] [Accepted: 06/22/2022] [Indexed: 02/06/2023] Open
Abstract
QO-58 (5-(2,6-dichloro-5-fluoropyridin-3-yl)-3-phenyl-2-(trifluoromethyl)-1H-pyrazolol[1,5-a]pyrimidin-7-one) has been regarded to be an activator of KV7 channels with analgesic properties. However, whether and how the presence of this compound can result in any modifications of other types of membrane ion channels in native cells are not thoroughly investigated. In this study, we investigated its perturbations on M-type K+ current (IK(M)), Ca2+-activated K+ current (IK(Ca)), large-conductance Ca2+-activated K+ (BKCa) channels, and erg-mediated K+ current (IK(erg)) identified from pituitary tumor (GH3) cells. Addition of QO-58 can increase the amplitude of IK(M) and IK(Ca) in a concentration-dependent fashion, with effective EC50 of 3.1 and 4.2 μM, respectively. This compound could shift the activation curve of IK(M) toward a leftward direction with being void of changes in the gating charge. The strength in voltage-dependent hysteresis (Vhys) of IK(M) evoked by upright triangular ramp pulse (Vramp) was enhanced by adding QO-58. The probabilities of M-type K+ (KM) channels that will be open increased upon the exposure to QO-58, although no modification in single-channel conductance was seen. Furthermore, GH3-cell exposure to QO-58 effectively increased the amplitude of IK(Ca) as well as enhanced the activity of BKCa channels. Under inside-out configuration, QO-58, applied at the cytosolic leaflet of the channel, activated BKCa-channel activity, and its increase could be attenuated by further addition of verruculogen, but not by linopirdine (10 μM). The application of QO-58 could lead to a leftward shift in the activation curve of BKCa channels with neither change in the gating charge nor in single-channel conductance. Moreover, cell exposure of QO-58 (10 μM) resulted in a minor suppression of IK(erg) amplitude in response to membrane hyperpolarization. The docking results also revealed that there are possible interactions of the QO-58 molecule with the KCNQ or KCa1.1 channel. Overall, dual activation of IK(M) and IK(Ca) caused by the presence of QO-58 eventually may have high impacts on the functional activity (e.g., anti-nociceptive effect) residing in electrically excitable cells. Care must be exercised when interpreting data generated with QO-58 as it is not entirely KCNQ/KV7 selective.
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15
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Medina C, Krawczyk MC, Millan J, Blake MG, Boccia MM. Oxytocin-Cholinergic Central Interaction: Implications for Non-Social Memory Formation. Neuroscience 2022; 497:73-85. [PMID: 35752429 DOI: 10.1016/j.neuroscience.2022.06.028] [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: 01/17/2022] [Revised: 06/09/2022] [Accepted: 06/16/2022] [Indexed: 10/17/2022]
Abstract
Oxytocin (OT) and vasopressin (AVP) are two closely related neuropeptides implicated in learning and memory processes, anxiety, nociception, addiction, feeding behavior and social information processing. Regarding learning and memory, OT has induced long-lasting impairment in different behaviors, while the opposite was observed with AVP. We have previously evaluated the effect of peripheral administration of OT or its antagonist (AOT) on the inhibitory avoidance response of mice and on the modulation of cholinergic mechanisms. Here, we replicate and validate those results, but this time through central administration of neuropeptides, considering their poor passage through the blood-brain barrier (BBB). When we delivered OT (0.10 ng/mouse) and its antagonist (0.10 ng/mouse) through intracerebroventricular (ICV) injections, the neuropeptide impaired and AOT enhanced the behavioral performance on an inhibitory avoidance response evaluated 48 h after training in a dose-dependent manner. On top of that, we investigated a possible central interaction between OT and the cholinergic system. Administration of anticholinesterases inhibitors with access to the central nervous system (CNS), the activation of muscarinic acetylcholine (Ach) receptors and the increase of evoked ACh release using linopirdine (Lino) (3-10 µg/kg, IP), reversed the impairment of retention performance induced by OT. Besides, either muscarinic or nicotinic antagonists with unrestricted access to the CNS reduced the magnitude of the performance-facilitating effect of AOT's central infusion. We suggest that OT might induce a cholinergic hypofunction state, resulting in an impairment of IA memory formation, a process for which the cholinergic system is crucially necessary.
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Affiliation(s)
- C Medina
- Laboratorio de Neurofarmacología de los Procesos de Memoria, Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - M C Krawczyk
- Laboratorio de Neurofarmacología de los Procesos de Memoria, Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - J Millan
- Laboratorio de Neurofarmacología de los Procesos de Memoria, Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - M G Blake
- Instituto de Fisiología y Biofísica (IFIBIO UBA-CONICET), Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - M M Boccia
- Laboratorio de Neurofarmacología de los Procesos de Memoria, Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.
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16
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Glycogen Synthase Kinase 3: Ion Channels, Plasticity, and Diseases. Int J Mol Sci 2022; 23:ijms23084413. [PMID: 35457230 PMCID: PMC9028019 DOI: 10.3390/ijms23084413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/13/2022] [Accepted: 04/14/2022] [Indexed: 12/15/2022] Open
Abstract
Glycogen synthase kinase 3β (GSK3) is a multifaceted serine/threonine (S/T) kinase expressed in all eukaryotic cells. GSK3β is highly enriched in neurons in the central nervous system where it acts as a central hub for intracellular signaling downstream of receptors critical for neuronal function. Unlike other kinases, GSK3β is constitutively active, and its modulation mainly involves inhibition via upstream regulatory pathways rather than increased activation. Through an intricate converging signaling system, a fine-tuned balance of active and inactive GSK3β acts as a central point for the phosphorylation of numerous primed and unprimed substrates. Although the full range of molecular targets is still unknown, recent results show that voltage-gated ion channels are among the downstream targets of GSK3β. Here, we discuss the direct and indirect mechanisms by which GSK3β phosphorylates voltage-gated Na+ channels (Nav1.2 and Nav1.6) and voltage-gated K+ channels (Kv4 and Kv7) and their physiological effects on intrinsic excitability, neuronal plasticity, and behavior. We also present evidence for how unbalanced GSK3β activity can lead to maladaptive plasticity that ultimately renders neuronal circuitry more vulnerable, increasing the risk for developing neuropsychiatric disorders. In conclusion, GSK3β-dependent modulation of voltage-gated ion channels may serve as an important pharmacological target for neurotherapeutic development.
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17
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Dai G. Neuronal KCNQ2/3 channels are recruited to lipid raft microdomains by palmitoylation of BACE1. J Gen Physiol 2022; 154:213033. [PMID: 35201266 PMCID: PMC8876601 DOI: 10.1085/jgp.202112888] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 02/04/2022] [Indexed: 12/14/2022] Open
Abstract
β-Secretase 1 (β-site amyloid precursor protein [APP]-cleaving enzyme 1, BACE1) plays a crucial role in the amyloidogenesis of Alzheimer’s disease (AD). BACE1 was also discovered to act like an auxiliary subunit to modulate neuronal KCNQ2/3 channels independently of its proteolytic function. BACE1 is palmitoylated at its carboxyl-terminal region, which brings BACE1 to ordered, cholesterol-rich membrane microdomains (lipid rafts). However, the physiological consequences of this specific localization of BACE1 remain elusive. Using spectral Förster resonance energy transfer (FRET), BACE1 and KCNQ2/3 channels were confirmed to form a signaling complex, a phenomenon that was relatively independent of the palmitoylation of BACE1. Nevertheless, palmitoylation of BACE1 was required for recruitment of KCNQ2/3 channels to lipid-raft domains. Two fluorescent probes, designated L10 and S15, were used to label lipid-raft and non-raft domains of the plasma membrane, respectively. Coexpressing BACE1 substantially elevated FRET between L10 and KCNQ2/3, whereas the BACE1-4C/A quadruple mutation failed to produce this effect. In contrast, BACE1 had no significant effect on FRET between S15 probes and KCNQ2/3 channels. A reduction of BACE1-dependent FRET between raft-targeting L10 probes and KCNQ2/3 channels by applying the cholesterol-extracting reagent methyl-β-cyclodextrin (MβCD), raft-disrupting general anesthetics, or pharmacological inhibitors of palmitoylation, all supported the hypothesis of the palmitoylation-dependent and raft-specific localization of KCNQ2/3 channels. Furthermore, mutating the four carboxyl-terminal cysteines (4C/A) of BACE1 abolished the BACE1-dependent increase of FRET between KCNQ2/3 and the lipid raft–specific protein caveolin 1. Taking these data collectively, we propose that the AD-related protein BACE1 underlies the localization of a neuronal potassium channel.
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Affiliation(s)
- Gucan Dai
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
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18
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Ye H, Liu ZX, He YJ, Wang X. Effects of M currents on the persistent activity of pyramidal neurons in mouse primary auditory cortex. J Neurophysiol 2022; 127:1269-1278. [PMID: 35294269 DOI: 10.1152/jn.00332.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neuronal persistent activity (PA) is a common phenomenon observed in many types of neurons. PA can be induced in neurons in the mouse auditory nucleus by activating cholinergic receptors with carbachol (CCh), a dual muscarinic and nicotinic receptor agonist. PA is presumed to be associated with learning-related auditory plasticity at the cellular level. However, the mechanism is not clearly understood. Many studies have reported that muscarinic cholinergic receptor agonists inhibit muscarinic-sensitive potassium channels (M channels). Potassium influx through M channels produces potassium currents, called M currents, which play an essential role in regulating neural excitability and synaptic plasticity. Further study is needed to determine whether M currents affect the PA of auditory central neurons and provide additional analysis of the variations in electrophysiological properties. We used in vitro whole-cell patch-clamp recordings in isolated mouse brain slices to investigate the effects of M currents on the PA in pyramidal neurons in layer V of the primary auditory cortex (AI-L5). We found that blocking M currents with XE991 depolarized the AI-L5 pyramidal neurons, which significantly increased the input resistance. The active threshold and threshold intensity were significantly reduced, indicating that the intrinsic excitability was enhanced. Our results also showed that blocking M currents with XE991 switched the neuronal firing patterns in the AI-L5 pyramidal neurons from regular-spiking to intrinsic-bursting. Blocking M currents facilitated PA by increasing the plateau potential and enhancing intrinsic excitability. Our results suggested that blocking M currents might facilitate the PA in AI-L5 pyramidal neurons, which underlies auditory plasticity.
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Affiliation(s)
- Huan Ye
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Zhen-Xu Liu
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Ya-Jie He
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Xin Wang
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
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19
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Szlaga A, Sambak P, Trenk A, Gugula A, Singleton CE, Drwiega G, Blasiak T, Ma S, Gundlach AL, Blasiak A. Functional Neuroanatomy of the Rat Nucleus Incertus–Medial Septum Tract: Implications for the Cell-Specific Control of the Septohippocampal Pathway. Front Cell Neurosci 2022; 16:836116. [PMID: 35281300 PMCID: PMC8913896 DOI: 10.3389/fncel.2022.836116] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
The medial septum (MS) is critically involved in theta rhythmogenesis and control of the hippocampal network, with which it is reciprocally connected. MS activity is influenced by brainstem structures, including the stress-sensitive, nucleus incertus (NI), the main source of the neuropeptide relaxin-3 (RLN3). In the current study, we conducted a comprehensive neurochemical and electrophysiological characterization of NI neurons innervating the MS in the rat, by employing classical and viral-based neural tract-tracing and electrophysiological approaches, and multiplex fluorescent in situ hybridization. We confirmed earlier reports that the MS is innervated by RLN3 NI neurons and documented putative glutamatergic (vGlut2 mRNA-expressing) neurons as a relevant NI neuronal population within the NI–MS tract. Moreover, we observed that NI neurons innervating MS can display a dual phenotype for GABAergic and glutamatergic neurotransmission, and that 40% of MS-projecting NI neurons express the corticotropin-releasing hormone-1 receptor. We demonstrated that an identified cholecystokinin (CCK)-positive NI neuronal population is part of the NI–MS tract, and that RLN3 and CCK NI neurons belong to a neuronal pool expressing the calcium-binding proteins, calbindin and calretinin. Finally, our electrophysiological studies revealed that MS is innervated by A-type potassium current-expressing, type I NI neurons, and that type I and II NI neurons differ markedly in their neurophysiological properties. Together these findings indicate that the MS is controlled by a discrete NI neuronal network with specific electrophysiological and neurochemical features; and these data are of particular importance for understanding neuronal mechanisms underlying the control of the septohippocampal system and related behaviors.
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Affiliation(s)
- Agata Szlaga
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Patryk Sambak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Aleksandra Trenk
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Anna Gugula
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Caitlin E. Singleton
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Gniewosz Drwiega
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Tomasz Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Andrew L. Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
- *Correspondence: Anna Blasiak,
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20
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Patel AV, Codeluppi SA, Ervin KSJ, St-Denis MB, Choleris E, Bailey CDC. Developmental Age and Biological Sex Influence Muscarinic Receptor Function and Neuron Morphology within Layer VI of the Medial Prefrontal Cortex. Cereb Cortex 2021; 32:3137-3158. [PMID: 34864929 DOI: 10.1093/cercor/bhab406] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 01/15/2023] Open
Abstract
Acetylcholine (ACh) neurotransmission within the medial prefrontal cortex (mPFC) plays an important modulatory role to support mPFC-dependent cognitive functions. This role is mediated by ACh activation of its nicotinic (nAChR) and muscarinic (mAChR) classes of receptors, which are both present on mPFC layer VI pyramidal neurons. While the expression and function of nAChRs have been characterized thoroughly for rodent mPFC layer VI neurons during postnatal development, mAChRs have not been characterized in detail. We employed whole-cell electrophysiology with biocytin filling to demonstrate that mAChR function is greater during the juvenile period of development than in adulthood for both sexes. Pharmacological experiments suggest that each of the M1, M2, and M3 mAChR subtypes contributes to ACh responses in these neurons in a sex-dependent manner. Analysis of dendrite morphology identified effects of age more often in males, as the amount of dendrite matter was greatest during the juvenile period. Interestingly, a number of positive correlations were identified between the magnitude of ACh/mAChR responses and dendrite morphology in juvenile mice that were not present in adulthood. To our knowledge, this work describes the first detailed characterization of mAChR function and its correlation with neuron morphology within layer VI of the mPFC.
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Affiliation(s)
- Ashutosh V Patel
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Sierra A Codeluppi
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Kelsy S J Ervin
- Department of Psychology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Myles B St-Denis
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Elena Choleris
- Department of Psychology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Craig D C Bailey
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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21
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Posttranscriptional modulation of KCNQ2 gene expression by the miR-106b microRNA family. Proc Natl Acad Sci U S A 2021; 118:2110200118. [PMID: 34785595 DOI: 10.1073/pnas.2110200118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
MicroRNAs (miRNAs) have recently emerged as important regulators of ion channel expression. We show here that select miR-106b family members repress the expression of the KCNQ2 K+ channel protein by binding to the 3'-untranslated region of KCNQ2 messenger RNA. During the first few weeks after birth, the expression of miR-106b family members rapidly decreases, whereas KCNQ2 protein level inversely increases. Overexpression of miR-106b mimics resulted in a reduction in KCNQ2 protein levels. Conversely, KCNQ2 levels were up-regulated in neurons transfected with antisense miRNA inhibitors. By constructing more specific and stable forms of miR-106b controlling systems, we further confirmed that overexpression of precursor-miR-106b-5p led to a decrease in KCNQ current density and an increase in firing frequency of hippocampal neurons, while tough decoy miR-106b-5p dramatically increased current density and decreased neuronal excitability. These results unmask a regulatory mechanism of KCNQ2 channel expression in early postnatal development and hint at a role for miR-106b up-regulation in the pathophysiology of epilepsy.
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22
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Gasior K, Korshunov K, Trombley PQ, Bertram R. Fast-slow analysis as a technique for understanding the neuronal response to current ramps. J Comput Neurosci 2021; 50:145-159. [PMID: 34665376 DOI: 10.1007/s10827-021-00799-0] [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: 03/18/2021] [Revised: 08/19/2021] [Accepted: 09/22/2021] [Indexed: 11/28/2022]
Abstract
The standard protocol for studying the spiking properties of single neurons is the application of current steps while monitoring the voltage response. Although this is informative, the jump in applied current is artificial. A more physiological input is where the applied current is ramped up, reflecting chemosensory input. Unsurprisingly, neurons can respond differently to the two protocols, since ion channel activation and inactivation are affected differently. Understanding the effects of current ramps, and changes in their slopes, is facilitated by mathematical models. However, techniques for analyzing current ramps are under-developed. In this article, we demonstrate how current ramps can be analyzed in single neuron models. The primary issue is the presence of gating variables that activate on slow time scales and are therefore far from equilibrium throughout the ramp. The use of an appropriate fast-slow analysis technique allows one to fully understand the neural response to ramps of different slopes. This study is motivated by data from olfactory bulb dopamine neurons, where both fast ramp (tens of milliseconds) and slow ramp (tens of seconds) protocols are used to understand the spiking profiles of the cells. The slow ramps generate experimental bifurcation diagrams with the applied current as a bifurcation parameter, thereby establishing asymptotic spiking activity patterns. The faster ramps elicit purely transient behavior that is of relevance to most physiological inputs, which are short in duration. The two protocols together provide a broader understanding of the neuron's spiking profile and the role that slowly activating ion channels can play.
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Affiliation(s)
- Kelsey Gasior
- Department of Mathematics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Kirill Korshunov
- Department of Biological Science and Program in Neuroscience, Florida State University, Tallahassee, FL, 32306, USA
| | - Paul Q Trombley
- Department of Biological Science and Program in Neuroscience, Florida State University, Tallahassee, FL, 32306, USA
| | - Richard Bertram
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, FL, 32306, USA.
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23
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Prieto ML, Firouzi K, Khuri-Yakub BT, Madison DV, Maduke M. Spike frequency-dependent inhibition and excitation of neural activity by high-frequency ultrasound. J Gen Physiol 2021; 152:182190. [PMID: 33074301 PMCID: PMC7534904 DOI: 10.1085/jgp.202012672] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/14/2020] [Indexed: 01/09/2023] Open
Abstract
Ultrasound can modulate action potential firing in vivo and in vitro, but the mechanistic basis of this phenomenon is not well understood. To address this problem, we used patch-clamp recording to quantify the effects of focused, high-frequency (43 MHz) ultrasound on evoked action potential firing in CA1 pyramidal neurons in acute rodent hippocampal brain slices. We find that ultrasound can either inhibit or potentiate firing in a spike frequency–dependent manner: at low (near-threshold) input currents and low firing frequencies, ultrasound inhibits firing, while at higher input currents and higher firing frequencies, ultrasound potentiates firing. The net result of these two competing effects is that ultrasound increases the threshold current for action potential firing, the slope of frequency-input curves, and the maximum firing frequency. In addition, ultrasound slightly hyperpolarizes the resting membrane potential, decreases action potential width, and increases the depth of the after-hyperpolarization. All of these results can be explained by the hypothesis that ultrasound activates a sustained potassium conductance. According to this hypothesis, increased outward potassium currents hyperpolarize the resting membrane potential and inhibit firing at near-threshold input currents but potentiate firing in response to higher-input currents by limiting inactivation of voltage-dependent sodium channels during the action potential. This latter effect is a consequence of faster action potential repolarization, which limits inactivation of voltage-dependent sodium channels, and deeper (more negative) after-hyperpolarization, which increases the rate of recovery from inactivation. Based on these results, we propose that ultrasound activates thermosensitive and mechanosensitive two-pore-domain potassium (K2P) channels through heating or mechanical effects of acoustic radiation force. Finite-element modeling of the effects of ultrasound on brain tissue suggests that the effects of ultrasound on firing frequency are caused by a small (<2°C) increase in temperature, with possible additional contributions from mechanical effects.
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Affiliation(s)
- Martin Loynaz Prieto
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Kamyar Firouzi
- E.L. Ginzton Laboratory, Stanford University, Stanford, CA
| | | | - Daniel V Madison
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Merritt Maduke
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
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24
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Mohan S, Tiwari MN, Stanojević M, Biala Y, Yaari Y. Muscarinic regulation of the neuronal Na + /K + -ATPase in rat hippocampus. J Physiol 2021; 599:3735-3754. [PMID: 34148230 DOI: 10.1113/jp281460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 06/16/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Stimulation of postsynaptic muscarinic receptors was shown to excite principal hippocampal neurons by modulating several membrane ion conductances. We show here that activation of postsynaptic muscarinic receptors also causes neuronal excitation by inhibiting Na+ /K+ -ATPase activity. Muscarinic Na+ /K+ -ATPase inhibition is mediated by two separate signalling pathways that lead downstream to enhanced Na+ /K+ -ATPase phosphorylation by activating protein kinase C and protein kinase G. Muscarinic excitation through Na+ /K+ -ATPase inhibition is probably involved in cholinergic modulation of hippocampal activity and may turn out to be a widespread mechanism of neuronal excitation in the brain. ABSTRACT Stimulation of muscarinic cholinergic receptors on principal hippocampal neurons enhances intrinsic neuronal excitability by modulating several membrane ion conductances. The electrogenic Na+ /K+ -ATPase (NKA; the 'Na+ pump') is a ubiquitous regulator of intrinsic neuronal excitability, generating a hyperpolarizing current to thwart excessive neuronal firing. Using electrophysiological and pharmacological methodologies in rat hippocampal slices, we show that neuronal NKA pumping activity is also subjected to cholinergic regulation. Stimulation of postsynaptic muscarinic, but not nicotinic, cholinergic receptors activates membrane-bound phospholipase C and hydrolysis of membrane-integral phosphatidylinositol 4,5-bisphosphate into diacylglycerol (DAG) and inositol 1,4,5-triphosphate (IP3 ). Along one signalling pathway, DAG activates protein kinase C (PKC). Along a second signalling pathway, IP3 causes Ca2+ release from the endoplasmic reticulum, facilitating nitric oxide (NO) production. The rise in NO levels stimulates cGMP synthesis by guanylate-cyclase, activating protein kinase G (PKG). The two pathways converge to cause partial NKA inhibition through enzyme phosphorylation by PKC and PKG, leading to a marked increase in intrinsic neuronal excitability. This novel mechanism of neuronal NKA regulation probably contributes to the cholinergic modulation of hippocampal activity in spatial navigation, learning and memory.
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Affiliation(s)
- Sandesh Mohan
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel
| | - Manindra Nath Tiwari
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel
| | - Marija Stanojević
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel
| | - Yoav Biala
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel
| | - Yoel Yaari
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah School of Medicine, Jerusalem, 91120, Israel
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25
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Karadenizli S, Şahin D, Ateş N. Age dependent effects of Retigabine on absence seizure in WAG/Rij rats; an experimental study. Clin Exp Pharmacol Physiol 2021; 48:1251-1260. [PMID: 34133772 DOI: 10.1111/1440-1681.13537] [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: 10/28/2020] [Revised: 10/24/2019] [Accepted: 06/07/2021] [Indexed: 12/01/2022]
Abstract
Retigabine (RTG, Ezogabine, DC23129) is the first neuronal potassium channel opener in the treatment of epilepsy and exerts its effects through the activation of neuronal KCNQ2/3 potassium channels; in higher doses, it acts also on sodium and voltage-gated calcium channels. The aim of this study was to investigate possible age-dependent therapeutic effects of RTG on spike-and-wave discharges (SWD) in an animal model of absence epilepsy using WAG/Rij rats. In this study, 6- and 12-month-old WAG/Rij rats were used. For both age categories, three sub-groups that consisted of one control group (n=7) by the administration of 20% DMSO (control) and two study groups by the administration of 5 mg/kg (n=7) and 15 mg/kg RTG (n=7) were designed. EEG electrodes were placed onto the skull of anaesthetized animals; and baseline EEG was recorded for one hour after a recovery period from surgery. Then, the pre-determined two distinct doses of RTG and 20% DMSO were administered as a solvent via intraperitoneal injections, and EEG was recorded for 3 hours. After injection, both doses of RTG increased the total SWD number and duration of SWD in the first and second hours in 12-month-old rats. These parameters were elevated compared to 6-month-old rats. Age-dependent effects of RTG were observed in SWD activity. Pro-epileptic effects in middle-aged WAG/Rij rats were demonstrated in both RTG doses. Differences in the distribution of KCNQ2/3 channels and switch of GABAergic system from inhibitory to excitatory with age might contribute to increased SWD activity in middle-aged rats.
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Affiliation(s)
- Sabriye Karadenizli
- Department of Physiology, Medical Faculty of Kocaeli University, Kocaeli, Turkey
| | - Deniz Şahin
- Department of Physiology, Medical Faculty of Kocaeli University, Kocaeli, Turkey
| | - Nurbay Ateş
- Department of Physiology, Medical Faculty of Kocaeli University, Kocaeli, Turkey
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26
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Stincic TL, Bosch MA, Hunker AC, Juarez B, Connors AM, Zweifel LS, Rønnekleiv OK, Kelly MJ. CRISPR knockdown of Kcnq3 attenuates the M-current and increases excitability of NPY/AgRP neurons to alter energy balance. Mol Metab 2021; 49:101218. [PMID: 33766732 PMCID: PMC8093934 DOI: 10.1016/j.molmet.2021.101218] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/12/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE Arcuate nucleus neuropeptide Y/agouti-related peptide (NPY/AgRP) neurons drive ingestive behavior. The M-current, a subthreshold non-inactivating potassium current, plays a critical role in regulating NPY/AgRP neuronal excitability. Fasting decreases while 17β-estradiol increases the M-current by regulating the mRNA expression of Kcnq2, 3, and 5 (Kv7.2, 3, and 5) channel subunits. Incorporating KCNQ3 into heteromeric channels has been considered essential to generate a robust M-current. Therefore, we investigated the behavioral and physiological effects of selective Kcnq3 deletion from NPY/AgRP neurons. METHODS We used a single adeno-associated viral vector containing a recombinase-dependent Staphylococcus aureus Cas9 with a single-guide RNA to selectively delete Kcnq3 in NPY/AgRP neurons. Single-cell quantitative measurements of mRNA expression and whole-cell patch clamp experiments were conducted to validate the selective knockdown. Body weight, food intake, and locomotor activity were measured in male mice to assess disruptions in energy balance. RESULTS The virus reduced the expression of Kcnq3 mRNA without affecting Kcnq2 or Kcnq5. The M-current was attenuated, causing NPY/AgRP neurons to be more depolarized, exhibit a higher input resistance, and require less depolarizing current to fire action potentials, indicative of increased excitability. Although the resulting decrease in the M-current did not overtly alter ingestive behavior, it significantly reduced the locomotor activity as measured by open-field testing. Control mice on a high-fat diet exhibited an enhanced M-current and increased Kcnq2 and Kcnq3 expression, but the M-current remained significantly attenuated in KCNQ3 knockdown animals. CONCLUSIONS The M-current plays a critical role in modulating the intrinsic excitability of NPY/AgRP neurons that is essential for maintaining energy homeostasis.
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Affiliation(s)
- Todd L Stincic
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA.
| | - Martha A Bosch
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Avery C Hunker
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, 98195, USA
| | - Barbara Juarez
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - Ashley M Connors
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Larry S Zweifel
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, 98195, USA; Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - Oline K Rønnekleiv
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA; Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Martin J Kelly
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA; Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, 97006, USA.
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27
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Wu B, Su X, Zhang W, Zhang YH, Feng X, Ji YH, Tan ZY. Oxaliplatin Depolarizes the IB4 - Dorsal Root Ganglion Neurons to Drive the Development of Neuropathic Pain Through TRPM8 in Mice. Front Mol Neurosci 2021; 14:690858. [PMID: 34149356 PMCID: PMC8211750 DOI: 10.3389/fnmol.2021.690858] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 05/10/2021] [Indexed: 01/13/2023] Open
Abstract
Use of chemotherapy drug oxaliplatin is associated with painful peripheral neuropathy that is exacerbated by cold. Remodeling of ion channels including TRP channels in dorsal root ganglion (DRG) neurons contribute to the sensory hypersensitivity following oxaliplatin treatment in animal models. However, it has not been studied if TRP channels and membrane depolarization of DRG neurons serve as the initial ionic/membrane drives (such as within an hour) that contribute to the development of oxaliplatin-induced neuropathic pain. In the current study, we studied in mice (1) in vitro acute effects of oxaliplatin on the membrane excitability of IB4+ and IB4- subpopulations of DRG neurons using a perforated patch clamping, (2) the preventative effects of a membrane-hyperpolarizing drug retigabine on oxaliplatin-induced sensory hypersensitivity, and (3) the preventative effects of TRP channel antagonists on the oxaliplatin-induced membrane hyperexcitability and sensory hypersensitivity. We found (1) IB4+ and IB4- subpopulations of small DRG neurons displayed previously undiscovered, substantially different membrane excitability, (2) oxaliplatin selectively depolarized IB4- DRG neurons, (3) pretreatment of retigabine largely prevented oxaliplatin-induced sensory hypersensitivity, (4) antagonists of TRPA1 and TRPM8 channels prevented oxaliplatin-induced membrane depolarization, and (5) the antagonist of TRPM8 largely prevented oxaliplatin-induced sensory hypersensitivity. These results suggest that oxaliplatin depolarizes IB4- neurons through TRPM8 channels to drive the development of neuropathic pain and targeting the initial drives of TRPM8 and/or membrane depolarization may prevent oxaliplatin-induce neuropathic pain.
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Affiliation(s)
- Bin Wu
- Institute of Special Environment Medicine, Nantong University, Nantong, China.,Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Xiaolin Su
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States.,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Wentong Zhang
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Yi-Hong Zhang
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Xinghua Feng
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China
| | - Yong-Hua Ji
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, China
| | - Zhi-Yong Tan
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
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28
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Müller L, Kirschstein T, Köhling R, Kuhla A, Teipel S. Neuronal Hyperexcitability in APPSWE/PS1dE9 Mouse Models of Alzheimer's Disease. J Alzheimers Dis 2021; 81:855-869. [PMID: 33843674 DOI: 10.3233/jad-201540] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Transgenic mouse models serve a better understanding of Alzheimer's disease (AD) pathogenesis and its consequences on neuronal function. Well-known and broadly used AD models are APPswe/PS1dE9 mice, which are able to reproduce features of amyloid-β (Aβ) plaque formations as well as neuronal dysfunction as reflected in electrophysiological recordings of neuronal hyperexcitability. The most prominent findings include abnormal synaptic function and synaptic reorganization as well as changes in membrane threshold and spontaneous neuronal firing activities leading to generalized excitation-inhibition imbalances in larger neuronal circuits and networks. Importantly, these findings in APPswe/PS1dE9 mice are at least partly consistent with results of electrophysiological studies in humans with sporadic AD. This underscores the potential to transfer mechanistic insights into amyloid related neuronal dysfunction from animal models to humans. This is of high relevance for targeted downstream interventions into neuronal hyperexcitability, for example based on repurposing of existing antiepileptic drugs, as well as the use of combinations of imaging and electrophysiological readouts to monitor effects of upstream interventions into amyloid build-up and processing on neuronal function in animal models and human studies. This article gives an overview on the pathogenic and methodological basis for recording of neuronal hyperexcitability in AD mouse models and on key findings in APPswe/PS1dE9 mice. We point at several instances to the translational perspective into clinical intervention and observation studies in humans. We particularly focus on bi-directional relations between hyperexcitability and cerebral amyloidosis, including build-up as well as clearance of amyloid, possibly related to sleep and so called glymphatic system function.
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Affiliation(s)
- Luisa Müller
- Department of Psychosomatic Medicine and Psychotherapy, University of Rostock, Rostock, Germany.,Rudolf Zenker Institute for Experimental Surgery, University of Rostock, Rostock, Germany.,Centre for Transdisciplinary Neurosciences Rostock (CTNR), University of Rostock, Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany.,Centre for Transdisciplinary Neurosciences Rostock (CTNR), University of Rostock, Rostock, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany.,Centre for Transdisciplinary Neurosciences Rostock (CTNR), University of Rostock, Rostock, Germany
| | - Angela Kuhla
- Rudolf Zenker Institute for Experimental Surgery, University of Rostock, Rostock, Germany.,Centre for Transdisciplinary Neurosciences Rostock (CTNR), University of Rostock, Rostock, Germany
| | - Stefan Teipel
- Department of Psychosomatic Medicine and Psychotherapy, University of Rostock, Rostock, Germany.,German Center for Neurodegenerative Diseases (DZNE), Rostock and Greifswald, Germany.,Centre for Transdisciplinary Neurosciences Rostock (CTNR), University of Rostock, Rostock, Germany
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29
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Revill AL, Katzell A, Del Negro CA, Milsom WK, Funk GD. KCNQ Current Contributes to Inspiratory Burst Termination in the Pre-Bötzinger Complex of Neonatal Rats in vitro. Front Physiol 2021; 12:626470. [PMID: 33927636 PMCID: PMC8078421 DOI: 10.3389/fphys.2021.626470] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 02/23/2021] [Indexed: 12/23/2022] Open
Abstract
The pre-Bötzinger complex (preBötC) of the ventral medulla generates the mammalian inspiratory breathing rhythm. When isolated in explants and deprived of synaptic inhibition, the preBötC continues to generate inspiratory-related rhythm. Mechanisms underlying burst generation have been investigated for decades, but cellular and synaptic mechanisms responsible for burst termination have received less attention. KCNQ-mediated K+ currents contribute to burst termination in other systems, and their transcripts are expressed in preBötC neurons. Therefore, we tested the hypothesis that KCNQ channels also contribute to burst termination in the preBötC. We recorded KCNQ-like currents in preBötC inspiratory neurons in neonatal rat slices that retain respiratory rhythmicity. Blocking KCNQ channels with XE991 or linopirdine (applied via superfusion or locally) increased inspiratory burst duration by 2- to 3-fold. By contrast, activation of KCNQ with retigabine decreased inspiratory burst duration by ~35%. These data from reduced preparations suggest that the KCNQ current in preBötC neurons contributes to inspiratory burst termination.
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Affiliation(s)
- Ann L. Revill
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
- Women and Children’s Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Alexis Katzell
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
- Women and Children’s Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | | | - William K. Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Gregory D. Funk
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
- Women and Children’s Health Research Institute, University of Alberta, Edmonton, AB, Canada
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30
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Simkin D, Marshall KA, Vanoye CG, Desai RR, Bustos BI, Piyevsky BN, Ortega JA, Forrest M, Robertson GL, Penzes P, Laux LC, Lubbe SJ, Millichap JJ, George AL, Kiskinis E. Dyshomeostatic modulation of Ca 2+-activated K + channels in a human neuronal model of KCNQ2 encephalopathy. eLife 2021; 10:64434. [PMID: 33544076 PMCID: PMC7864629 DOI: 10.7554/elife.64434] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/20/2021] [Indexed: 12/22/2022] Open
Abstract
Mutations in KCNQ2, which encodes a pore-forming K+ channel subunit responsible for neuronal M-current, cause neonatal epileptic encephalopathy, a complex disorder presenting with severe early-onset seizures and impaired neurodevelopment. The condition is exceptionally difficult to treat, partially because the effects of KCNQ2 mutations on the development and function of human neurons are unknown. Here, we used induced pluripotent stem cells (iPSCs) and gene editing to establish a disease model and measured the functional properties of differentiated excitatory neurons. We find that patient iPSC-derived neurons exhibit faster action potential repolarization, larger post-burst afterhyperpolarization and a functional enhancement of Ca2+-activated K+ channels. These properties, which can be recapitulated by chronic inhibition of M-current in control neurons, facilitate a burst-suppression firing pattern that is reminiscent of the interictal electroencephalography pattern in patients. Our findings suggest that dyshomeostatic mechanisms compound KCNQ2 loss-of-function leading to alterations in the neurodevelopmental trajectory of patient iPSC-derived neurons.
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Affiliation(s)
- Dina Simkin
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Kelly A Marshall
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Carlos G Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Reshma R Desai
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Bernabe I Bustos
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Brandon N Piyevsky
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Juan A Ortega
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Marc Forrest
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Center for Autism and Neurodevelopment, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Gabriella L Robertson
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Peter Penzes
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Center for Autism and Neurodevelopment, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Linda C Laux
- Epilepsy Center and Division of Neurology, Departments of Pediatrics and Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Steven J Lubbe
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - John J Millichap
- Epilepsy Center and Division of Neurology, Departments of Pediatrics and Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States
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31
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Liu Y, Bian X, Wang K. Pharmacological Activation of Neuronal Voltage-Gated Kv7/KCNQ/M-Channels for Potential Therapy of Epilepsy and Pain. Handb Exp Pharmacol 2021; 267:231-251. [PMID: 33837465 DOI: 10.1007/164_2021_458] [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: 01/10/2023]
Abstract
Native M-current is a low-threshold, slowly activating potassium current that exerts an inhibitory control over neuronal excitability. The M-channel is primarily co-assembled by heterotetrameric Kv7.2/KCNQ2 and Kv7.3/KCNQ3 subunits that are specifically expressed in the brain and peripheral nociceptive and visceral sensory neurons in the spinal cord. Reduction of M-channel function leads to neuronal hyperexcitability that defines the fundamental mechanism of neurological disorders such as epilepsy and pain, indicating that pharmacological activation of Kv7/KCNQ/M-channels may serve the basis for the therapy. The well-known KCNQ opener retigabine (ezogabine or Potiga) was approved by FDA in 2011 as an anticonvulsant used for an adjunctive treatment of partial epilepsies. Unfortunately, retigabine was discontinued in 2017 due to its side effects of blue-colored appearance of the skin and eyes after prolonged intake. In addition, flupirtine, a structural derivative of retigabine and a centrally acting non-opioid analgesic, was also withdrawn in 2018 for liver toxicity. Fortunately, these side effects are compound-structures related and can be avoided. Thus, further identification and development of novel potent and selective Kv7 channel openers may lead to an effective therapy with improved safety window for anti-epilepsy and anti-nociception.
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Affiliation(s)
- Yani Liu
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Xiling Bian
- Department of Pharmacology, Peking University School of Pharmaceutical Sciences, Beijing, China
| | - KeWei Wang
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China. .,Institute of Innovative Drugs Qingdao University, Qingdao, China.
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32
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The M-current works in tandem with the persistent sodium current to set the speed of locomotion. PLoS Biol 2020; 18:e3000738. [PMID: 33186352 PMCID: PMC7688130 DOI: 10.1371/journal.pbio.3000738] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 11/25/2020] [Accepted: 10/13/2020] [Indexed: 01/20/2023] Open
Abstract
The central pattern generator (CPG) for locomotion is a set of pacemaker neurons endowed with inherent bursting driven by the persistent sodium current (INaP). How they proceed to regulate the locomotor rhythm remained unknown. Here, in neonatal rodents, we identified a persistent potassium current critical in regulating pacemakers and locomotion speed. This current recapitulates features of the M-current (IM): a subthreshold noninactivating outward current blocked by 10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone dihydrochloride (XE991) and enhanced by N-(2-chloro-5-pyrimidinyl)-3,4-difluorobenzamide (ICA73). Immunostaining and mutant mice highlight an important role of Kv7.2-containing channels in mediating IM. Pharmacological modulation of IM regulates the emergence and the frequency regime of both pacemaker and CPG activities and controls the speed of locomotion. Computational models captured these results and showed how an interplay between IM and INaP endows the locomotor CPG with rhythmogenic properties. Overall, this study provides fundamental insights into how IM and INaP work in tandem to set the speed of locomotion.
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33
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Ramakrishna Y, Manca M, Glowatzki E, Sadeghi SG. Cholinergic Modulation of Membrane Properties of Calyx Terminals in the Vestibular Periphery. Neuroscience 2020; 452:98-110. [PMID: 33197502 DOI: 10.1016/j.neuroscience.2020.10.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 01/10/2023]
Abstract
Vestibular nerve afferents are divided into regular and irregular groups based on the variability of interspike intervals in their resting discharge. Most afferents receive inputs from bouton terminals that contact type II hair cells as well as from calyx terminals that cover the basolateral walls of type I hair cells. Calyces have an abundance of different subtypes of KCNQ (Kv7) potassium channels and muscarinic acetylcholine receptors (mAChRs) and receive cholinergic efferent inputs from neurons in the brainstem. We investigated whether mAChRs affected membrane properties and firing patterns of calyx terminals through modulation of KCNQ channel activity. Patch clamp recordings were performed from calyx terminals in central regions of the cristae of the horizontal and anterior canals in 13-26 day old Sprague-Dawley rats. KCNQ mediated currents were observed as voltage sensitive currents with slow kinetics (activation and deactivation), resulting in spike frequency adaptation so that calyces at best fired a single action potential at the beginning of a depolarizing step. Activation of mAChRs by application of oxotremorine methiodide or inhibition of KCNQ channels by linopirdine dihydrochloride decreased voltage activated currents by ∼30%, decreased first spike latencies by ∼40%, resulted in action potential generation in response to smaller current injections and at lower (i.e., more hyperpolarized) membrane potentials, and increased the number of spikes fired during depolarizing steps. Interestingly, some of the calyces showed spontaneous discharge in the presence of these drugs. Together, these findings suggest that cholinergic efferents can modulate the response properties and encoding of head movements by afferents.
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Affiliation(s)
- Yugandhar Ramakrishna
- Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, State University of New York at Buffalo, Buffalo, NY, United States; Department of Communication Disorders and Sciences, California State University, Northridge, CA, United States
| | - Marco Manca
- Department of Otolaryngology - Head and Neck Surgery, The Center for Hearing and Balance, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Elisabeth Glowatzki
- Department of Otolaryngology - Head and Neck Surgery, The Center for Hearing and Balance, Johns Hopkins University School of Medicine, Baltimore, MD, United States; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Soroush G Sadeghi
- Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, State University of New York at Buffalo, Buffalo, NY, United States; Neuroscience Program, State University of New York at Buffalo, Buffalo, NY, United States.
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34
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Hu P, Maita I, Phan ML, Gu E, Kwok C, Dieterich A, Gergues MM, Yohn CN, Wang Y, Zhou JN, Qi XR, Swaab DF, Pang ZP, Lucassen PJ, Roepke TA, Samuels BA. Early-life stress alters affective behaviors in adult mice through persistent activation of CRH-BDNF signaling in the oval bed nucleus of the stria terminalis. Transl Psychiatry 2020; 10:396. [PMID: 33177511 PMCID: PMC7658214 DOI: 10.1038/s41398-020-01070-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/15/2020] [Accepted: 10/07/2020] [Indexed: 01/06/2023] Open
Abstract
Early-life stress (ELS) leads to stress-related psychopathology in adulthood. Although dysfunction of corticotropin-releasing hormone (CRH) signaling in the bed nucleus of the stria terminalis (BNST) mediates chronic stress-induced maladaptive affective behaviors that are historically associated with mood disorders such as anxiety and depression, it remains unknown whether ELS affects CRH function in the adult BNST. Here we applied a well-established ELS paradigm (24 h maternal separation (MS) at postnatal day 3) and assessed the effects on CRH signaling and electrophysiology in the oval nucleus of BNST (ovBNST) of adult male mouse offspring. ELS increased maladaptive affective behaviors, and amplified mEPSCs and decreased M-currents (a voltage-gated K+ current critical for stabilizing membrane potential) in ovBNST CRH neurons, suggesting enhanced cellular excitability. Furthermore, ELS increased the numbers of CRH+ and PACAP+ (the pituitary adenylate cyclase-activating polypeptide, an upstream CRH regulator) cells and decreased STEP+ (striatal-enriched protein tyrosine phosphatase, a CRH inhibitor) cells in BNST. Interestingly, ELS also increased BNST brain-derived neurotrophic factor (BDNF) expression, indicating enhanced neuronal plasticity. These electrophysiological and behavioral effects of ELS were reversed by chronic application of the CRHR1-selective antagonist R121919 into ovBNST, but not when BDNF was co-administered. In addition, the neurophysiological effects of BDNF on M-currents and mEPSCs in BNST CRH neurons mimic effects and were abolished by PKC antagonism. Together, our findings indicate that ELS results in a long-lasting activation of CRH signaling in the mouse ovBNST. These data highlight a regulatory role of CRHR1 in the BNST and for BDNF signaling in mediating ELS-induced long-term behavioral changes.
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Affiliation(s)
- Pu Hu
- grid.430387.b0000 0004 1936 8796Department of Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA
| | - Isabella Maita
- grid.430387.b0000 0004 1936 8796Department of Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA
| | - Mimi L. Phan
- grid.430387.b0000 0004 1936 8796Department of Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA
| | - Edward Gu
- grid.430387.b0000 0004 1936 8796Department of Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA
| | - Christopher Kwok
- grid.430387.b0000 0004 1936 8796Department of Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA
| | - Andrew Dieterich
- grid.430387.b0000 0004 1936 8796Department of Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA
| | - Mark M. Gergues
- grid.430387.b0000 0004 1936 8796Department of Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA ,grid.266102.10000 0001 2297 6811Present Address: Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158 USA
| | - Christine N. Yohn
- grid.430387.b0000 0004 1936 8796Department of Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA
| | - Yu Wang
- grid.59053.3a0000000121679639CAS Key Laboratory of Brain Function and Diseases, Life Science School, University of Science and Technology of China, Hefei, 230027 China
| | - Jiang-Ning Zhou
- grid.59053.3a0000000121679639CAS Key Laboratory of Brain Function and Diseases, Life Science School, University of Science and Technology of China, Hefei, 230027 China
| | - Xin-Rui Qi
- grid.412538.90000 0004 0527 0050Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People’s Hospital Affiliated to Tongji University School of Medicine, Shanghai, 200072 China
| | - Dick F. Swaab
- grid.418101.d0000 0001 2153 6865Department of Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef, Amsterdam 1105 BA The Netherlands
| | - Zhiping P. Pang
- grid.430387.b0000 0004 1936 8796Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901 USA
| | - Paul J. Lucassen
- grid.7177.60000000084992262Brain Plasticity Group, Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Troy A. Roepke
- grid.430387.b0000 0004 1936 8796Department of Animal Sciences, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA
| | - Benjamin A. Samuels
- grid.430387.b0000 0004 1936 8796Department of Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 USA
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35
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Baculis BC, Zhang J, Chung HJ. The Role of K v7 Channels in Neural Plasticity and Behavior. Front Physiol 2020; 11:568667. [PMID: 33071824 PMCID: PMC7530275 DOI: 10.3389/fphys.2020.568667] [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: 06/01/2020] [Accepted: 08/28/2020] [Indexed: 12/12/2022] Open
Abstract
Activity-dependent persistent changes in neuronal intrinsic excitability and synaptic strength are widely thought to underlie learning and memory. Voltage-gated KCNQ/Kv7 potassium channels have been of great interest as the potential targets for memory disorders due to the beneficial effects of their antagonists in cognition. Importantly, de novo dominant mutations in their neuronal subunits KCNQ2/Kv7.2 and KCNQ3/Kv7.3 are associated with epilepsy and neurodevelopmental disorder characterized by developmental delay and intellectual disability. The role of Kv7 channels in neuronal excitability and epilepsy has been extensively studied. However, their functional significance in neural plasticity, learning, and memory remains largely unknown. Here, we review recent studies that support the emerging roles of Kv7 channels in intrinsic and synaptic plasticity, and their contributions to cognition and behavior.
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Affiliation(s)
- Brian C Baculis
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Jiaren Zhang
- Department of Molecular Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Hee Jung Chung
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Department of Molecular Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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36
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Grupe M, Bentzen BH, Benned-Jensen T, Nielsen V, Frederiksen K, Jensen HS, Jacobsen AM, Skibsbye L, Sams AG, Grunnet M, Rottländer M, Bastlund JF. In vitro and in vivo characterization of Lu AA41178: A novel, brain penetrant, pan-selective Kv7 potassium channel opener with efficacy in preclinical models of epileptic seizures and psychiatric disorders. Eur J Pharmacol 2020; 887:173440. [PMID: 32745603 DOI: 10.1016/j.ejphar.2020.173440] [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: 05/07/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/29/2022]
Abstract
Activation of the voltage-gated Kv7 channels holds therapeutic promise in several neurological and psychiatric disorders, including epilepsy, schizophrenia, and depression. Here, we present a pharmacological characterization of Lu AA41178, a novel, pan-selective Kv7.2-7.5 opener, using both in vitro assays and a broad range of in vivo assays with relevance to epilepsy, schizophrenia, and depression. Electrophysiological characterization in Xenopus oocytes expressing human Kv7.2-Kv7.5 confirmed Lu AA41178 as a pan-selective opener of Kv7 channels by significantly left-shifting the activation threshold. Additionally, Lu AA41178 was tested in vitro for off-target effects, demonstrating a clean Kv7-selective profile, with no impact on common cardiac ion channels, and no potentiating activity on GABAA channels. Lu AA41178 was evaluated across preclinical in vivo assays with relevance to neurological and psychiatric disorders. In the maximum electroshock seizure threshold test and PTZ seizure threshold test, Lu AA41178 significantly increased the seizure thresholds in mice, demonstrating anticonvulsant efficacy. Lu AA41178 demonstrated antipsychotic-like activity by reducing amphetamine-induced hyperlocomotion in mice as well as lowering conditioned avoidance responses in rats. In the mouse forced swim test, a model with antidepressant predictivity, Lu AA41178 significantly reduced immobility. Additionally, behavioral effects typically observed with Kv7 openers was also characterized. In vivo assays were accompanied by plasma and brain exposures, revealing minimum effective plasma levels <1000 ng/ml. Lu AA41178, a potent opener of neuronal Kv7 channels demonstrate efficacy in assays of epilepsy, schizophrenia and depression and might serve as a valuable tool for exploring the role of Kv7 channels in both neurological and psychiatric disorders.
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Affiliation(s)
- Morten Grupe
- H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark.
| | - Bo Hjorth Bentzen
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
| | | | | | | | | | | | | | | | | | - Mario Rottländer
- CMC Outsourcing, Novo Nordisk A/S, Smoermosevej 17-19, 2880 Bagsvaerd, Denmark
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37
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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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38
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Zhu C, Lin R, Liu C, Huang M, Lin F, Zhang G, Zhang Y, Miao J, Lin W, Huang H. The Antagonism of 5-HT6 Receptor Attenuates Current-Induced Spikes and Improves Long-Term Potentiation via the Regulation of M-Currents in a Pilocarpine-Induced Epilepsy Model. Front Pharmacol 2020; 11:475. [PMID: 32425770 PMCID: PMC7212420 DOI: 10.3389/fphar.2020.00475] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/26/2020] [Indexed: 12/02/2022] Open
Abstract
Recent studies have documented that reduced M-current promotes epileptogenesis and attenuates synaptic remodeling. Neurite growth is closely related to the level of 5-HT6 receptor (5-HT6R) in the central nervous system. However, little research is available regarding the relation between 5-HT6R and M-current and the role of 5-HT6R in M-current regulation. Herein, we found that the expression of 5-HT6R was notably increased and the expression of KNCQ2/3, the main components of the M channel, was decreased in a time-dependent manner in pilocarpine-induced chronic epileptic hippocampus. Interestingly, antagonism of 5-HT6R by SB271046 upregulated the expression of KCNQ2 but not KCNQ3. SB271046 greatly alleviated excitatory/inhibitory imbalance and improved the impaired LTP in the chronic epileptic hippocampus. Further mechanism exploration revealed that the above effects of SB271046 can be reversed by the M-channel inhibitor XE991, which also confirmed that SB271046 can indeed improve abnormal M current. These data indicate that the antagonism of 5-HT6R may decrease the excitability of hippocampal pyramidal neurons in chronic epileptic rats and improve the impaired long-term potentiation by upregulating the expression of KCNQ2 in the M-channel.
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Affiliation(s)
- Chaofeng Zhu
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Rong Lin
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Changyun Liu
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Mingzhu Huang
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Feng Lin
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Gan Zhang
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Yuying Zhang
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Junjie Miao
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Wanhui Lin
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Huapin Huang
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, China.,Department of Electrophysiology, Fujian Key Laboratory of Molecular Neurology, Fuzhou, China.,Department of Geriatrics, Fujian Medical University Union Hospital, Fuzhou, China
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39
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Tubert C, Murer MG. What’s wrong with the striatal cholinergic interneurons in Parkinson’s disease? Focus on intrinsic excitability. Eur J Neurosci 2020; 53:2100-2116. [DOI: 10.1111/ejn.14742] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/04/2020] [Accepted: 04/05/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Cecilia Tubert
- Instituto de Fisiología y Biofísica “Bernardo Houssay”, (IFIBIO‐Houssay) Grupo de Neurociencia de Sistemas Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Buenos Aires Argentina
| | - Mario Gustavo Murer
- Instituto de Fisiología y Biofísica “Bernardo Houssay”, (IFIBIO‐Houssay) Grupo de Neurociencia de Sistemas Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Buenos Aires Argentina
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40
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M-Current Inhibition in Hippocampal Excitatory Neurons Triggers Intrinsic and Synaptic Homeostatic Responses at Different Temporal Scales. J Neurosci 2020; 40:3694-3706. [PMID: 32277041 DOI: 10.1523/jneurosci.1914-19.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 11/21/2022] Open
Abstract
Persistent alterations in neuronal activity elicit homeostatic plastic changes in synaptic transmission and/or intrinsic excitability. However, it is unknown whether these homeostatic processes operate in concert or at different temporal scales to maintain network activity around a set-point value. Here we show that chronic neuronal hyperactivity, induced by M-channel inhibition, triggered intrinsic and synaptic homeostatic plasticity at different timescales in cultured hippocampal pyramidal neurons from mice of either sex. Homeostatic changes of intrinsic excitability occurred at a fast timescale (1-4 h) and depended on ongoing spiking activity. This fast intrinsic adaptation included plastic changes in the threshold current and a distal relocation of FGF14, a protein physically bridging Nav1.6 and Kv7.2 channels along the axon initial segment. In contrast, synaptic adaptations occurred at a slower timescale (∼2 d) and involved decreases in miniature EPSC amplitude. To examine how these temporally distinct homeostatic responses influenced hippocampal network activity, we quantified the rate of spontaneous spiking measured by multielectrode arrays at extended timescales. M-Channel blockade triggered slow homeostatic renormalization of the mean firing rate (MFR), concomitantly accompanied by a slow synaptic adaptation. Thus, the fast intrinsic adaptation of excitatory neurons is not sufficient to account for the homeostatic normalization of the MFR. In striking contrast, homeostatic adaptations of intrinsic excitability and spontaneous MFR failed in hippocampal GABAergic inhibitory neurons, which remained hyperexcitable following chronic M-channel blockage. Our results indicate that a single perturbation such as M-channel inhibition triggers multiple homeostatic mechanisms that operate at different timescales to maintain network mean firing rate.SIGNIFICANCE STATEMENT Persistent alterations in synaptic input elicit homeostatic plastic changes in neuronal activity. Here we show that chronic neuronal hyperexcitability, induced by M-type potassium channel inhibition, triggered intrinsic and synaptic homeostatic plasticity at different timescales in hippocampal excitatory neurons. The data indicate that the fast adaptation of intrinsic excitability depends on ongoing spiking activity but is not sufficient to provide homeostasis of the mean firing rate. Our results show that a single perturbation such as M-channel inhibition can trigger multiple homeostatic processes that operate at different timescales to maintain network mean firing rate.
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41
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Yousuf H, Nye AN, Moyer JR. Heterogeneity of neuronal firing type and morphology in retrosplenial cortex of male F344 rats. J Neurophysiol 2020; 123:1849-1863. [PMID: 32267193 DOI: 10.1152/jn.00577.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The rodent granular retrosplenial cortex (gRSC) has reciprocal connections to the hippocampus to support fear memories. Although activity-dependent plasticity occurs within the RSC during memory formation, the intrinsic and morphological properties of RSC neurons are poorly understood. The present study used whole-cell recordings to examine intrinsic neuronal firing and morphology of neurons in layer 2/3 (L2/3) and layer 5 (L5) of the gRSC in adult male rats. Five different classifications were observed: regular-spiking (RS), regular-spiking afterdepolarization (RSADP), late-spiking (LS), burst-spiking (BS), and fast-spiking (FS) neurons. RSADP neurons were the most commonly observed neuronal class, identified by their robust spike frequency adaptation and pronounced afterdepolarization (ADP) following an action potential (AP). They also had the most extensive dendritic branching compared with other cell types. LS neurons were predominantly found in L2/3 and exhibited a long delay before onset of their initial AP. They also had reduced dendritic branching compared with other cell types. BS neurons were limited to L5 and generated an initial burst of two or more APs. FS neurons demonstrated sustained firing and little frequency adaptation and were the only nonpyramidal firing type. Relative to adults, RS neurons from juvenile rats (PND 14-30) lacked an ADP and were less excitable. Bath application of group 1 mGluR blockers attenuated the ADP in adult neurons. In other fear-related brain structures, the ADP has been shown to enhance excitability and synaptic plasticity. Thus, understanding cellular mechanisms of the gRSC will provide insight regarding its precise role in memory-related processes across the lifespan.NEW & NOTEWORTHY This is the first study to demonstrate that granular retrosplenial cortical (gRSC) neurons exhibit five distinctive firing types: regular spiking (RS), regular spiking with an afterdepolarization (RSADP), late spiking (LS), burst spiking (BS), and fast spiking (FS). RSADP neurons were the most frequently observed cell type in adult gRSC neurons. Interestingly, RS neurons without an ADP were most common in gRSC neurons of juvenile rats (PND 14-30). Thus, the ADP property, which was previously shown to enhance neuronal excitability, emerges during development.
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Affiliation(s)
- Hanna Yousuf
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin
| | - Andrew N Nye
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin
| | - James R Moyer
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin.,Department of Biological Sciences University of Wisconsin-Milwaukee, Milwaukee, Wisconsin
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Schulze F, Müller S, Guli X, Schumann L, Brehme H, Riffert T, Rohde M, Goerss D, Rackow S, Einsle A, Kirschstein T, Köhling R. CK2 Inhibition Prior to Status Epilepticus Persistently Enhances K Ca2 Function in CA1 Which Slows Down Disease Progression. Front Cell Neurosci 2020; 14:33. [PMID: 32174814 PMCID: PMC7054465 DOI: 10.3389/fncel.2020.00033] [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] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/04/2020] [Indexed: 12/19/2022] Open
Abstract
Purpose Epilepsy therapy is currently based on anti-seizure drugs that do not modify the course of the disease, i.e., they are not anti-epileptogenic in nature. Previously, we observed that in vivo casein kinase 2 (CK2) inhibition with 4,5,6,7-tetrabromotriazole (TBB) had anti-epileptogenic effects in the acute epilepsy slice model. Methods Here, we pretreated rats with TBB in vivo prior to the establishment of a pilocarpine-induced status epilepticus (SE) in order to analyze the long-term sequelae of such a preventive TBB administration. Results We found that TBB pretreatment delayed onset of seizures after pilocarpine and slowed down disease progression during epileptogenesis. This was accompanied with a reduced proportion of burst firing neurons in the CA1 area. Western blot analyses demonstrated that CA1 tissue from TBB-pretreated epileptic animals contained significantly less CK2 than TBB-pretreated controls. On the transcriptional level, TBB pretreatment led to differential gene expression changes of KCa2.2, but also of HCN1 and HCN3 channels. Thus, in the presence of the HCN channel blocker ZD7288, pretreatment with TBB rescued the afterhyperpolarizing potential (AHP) as well as spike frequency adaptation in epileptic animals, both of which are prominent functions of KCa2 channels. Conclusion These data indicate that TBB pretreatment prior to SE slows down disease progression during epileptogenesis involving increased KCa2 function, probably due to a persistently decreased CK2 protein expression.
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Affiliation(s)
- Felix Schulze
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Steffen Müller
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Xiati Guli
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Lukas Schumann
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Hannes Brehme
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Till Riffert
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Marco Rohde
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Doreen Goerss
- Department of Psychosomatic Medicine, Rostock University Medical Center, Rostock, Germany.,German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Simone Rackow
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Anne Einsle
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany.,Center of Transdisciplinary Neurosciences Rostock, University of Rostock, Rostock, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany.,Center of Transdisciplinary Neurosciences Rostock, University of Rostock, Rostock, Germany
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Zhang J, Kim EC, Chen C, Procko E, Pant S, Lam K, Patel J, Choi R, Hong M, Joshi D, Bolton E, Tajkhorshid E, Chung HJ. Identifying mutation hotspots reveals pathogenetic mechanisms of KCNQ2 epileptic encephalopathy. Sci Rep 2020; 10:4756. [PMID: 32179837 PMCID: PMC7075958 DOI: 10.1038/s41598-020-61697-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 03/02/2020] [Indexed: 11/08/2022] Open
Abstract
Kv7 channels are enriched at the axonal plasma membrane where their voltage-dependent potassium currents suppress neuronal excitability. Mutations in Kv7.2 and Kv7.3 subunits cause epileptic encephalopathy (EE), yet the underlying pathogenetic mechanism is unclear. Here, we used novel statistical algorithms and structural modeling to identify EE mutation hotspots in key functional domains of Kv7.2 including voltage sensing S4, the pore loop and S6 in the pore domain, and intracellular calmodulin-binding helix B and helix B-C linker. Characterization of selected EE mutations from these hotspots revealed that L203P at S4 induces a large depolarizing shift in voltage dependence of Kv7.2 channels and L268F at the pore decreases their current densities. While L268F severely reduces expression of heteromeric channels in hippocampal neurons without affecting internalization, K552T and R553L mutations at distal helix B decrease calmodulin-binding and axonal enrichment. Importantly, L268F, K552T, and R553L mutations disrupt current potentiation by increasing phosphatidylinositol 4,5-bisphosphate (PIP2), and our molecular dynamics simulation suggests PIP2 interaction with these residues. Together, these findings demonstrate that each EE variant causes a unique combination of defects in Kv7 channel function and neuronal expression, and suggest a critical need for both prediction algorithms and experimental interrogations to understand pathophysiology of Kv7-associated EE.
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Affiliation(s)
- Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Congcong Chen
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Department of Statistics, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Shashank Pant
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Kin Lam
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Jaimin Patel
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Rebecca Choi
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Mary Hong
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Dhruv Joshi
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Eric Bolton
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Emad Tajkhorshid
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA.
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA.
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Chronic Stress Induces Maladaptive Behaviors by Activating Corticotropin-Releasing Hormone Signaling in the Mouse Oval Bed Nucleus of the Stria Terminalis. J Neurosci 2020; 40:2519-2537. [PMID: 32054675 DOI: 10.1523/jneurosci.2410-19.2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/16/2020] [Accepted: 01/16/2020] [Indexed: 12/21/2022] Open
Abstract
The bed nucleus of the stria terminalis (BNST) is a forebrain region highly responsive to stress that expresses corticotropin-releasing hormone (CRH) and is implicated in mood disorders, such as anxiety. However, the exact mechanism by which chronic stress induces CRH-mediated dysfunction in BNST and maladaptive behaviors remains unclear. Here, we first confirmed that selective acute optogenetic activation of the oval nucleus BNST (ovBNST) increases maladaptive avoidance behaviors in male mice. Next, we found that a 6 week chronic variable mild stress (CVMS) paradigm resulted in maladaptive behaviors and increased cellular excitability of ovBNST CRH neurons by potentiating mEPSC amplitude, altering the resting membrane potential, and diminishing M-currents (a voltage-gated K+ current that stabilizes membrane potential) in ex vivo slices. CVMS also increased c-fos+ cells in ovBNST following handling. We next investigated potential molecular mechanism underlying the electrophysiological effects and observed that CVMS increased CRH+ and pituitary adenylate cyclase-activating polypeptide+ (PACAP; a CRH upstream regulator) cells but decreased striatal-enriched protein tyrosine phosphatase+ (a STEP CRH inhibitor) cells in ovBNST. Interestingly, the electrophysiological effects of CVMS were reversed by CRHR1-selective antagonist R121919 application. CVMS also activated protein kinase A (PKA) in BNST, and chronic infusion of the PKA-selective antagonist H89 into ovBNST reversed the effects of CVMS. Coadministration of the PKA agonist forskolin prevented the beneficial effects of R121919. Finally, CVMS induced an increase in surface expression of phosphorylated GluR1 (S845) in BNST. Collectively, these findings highlight a novel and indispensable stress-induced role for PKA-dependent CRHR1 signaling in activating BNST CRH neurons and mediating maladaptive behaviors.SIGNIFICANCE STATEMENT Chronic stress and acute activation of oval bed nucleus of the stria terminalis (ovBNST) induces maladaptive behaviors in rodents. However, the precise molecular and electrophysiological mechanisms underlying these effects remain unclear. Here, we demonstrate that chronic variable mild stress activates corticotropin-releasing hormone (CRH)-associated stress signaling and CRH neurons in ovBNST by potentiating mEPSC amplitude and decreasing M-current in male mice. These electrophysiological alterations and maladaptive behaviors were mediated by BNST protein kinase A-dependent CRHR1 signaling. Our results thus highlight the importance of BNST CRH dysfunction in chronic stress-induced disorders.
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45
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Arnsten AF, Jin LE, Gamo NJ, Ramos B, Paspalas CD, Morozov YM, Kata A, Bamford NS, Yeckel MF, Kaczmarek LK, El-Hassar L. Role of KCNQ potassium channels in stress-induced deficit of working memory. Neurobiol Stress 2019; 11:100187. [PMID: 31832507 PMCID: PMC6889760 DOI: 10.1016/j.ynstr.2019.100187] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 06/21/2019] [Accepted: 07/23/2019] [Indexed: 12/25/2022] Open
Abstract
The prefrontal cortex (PFC) mediates higher cognition but is impaired by stress exposure when high levels of catecholamines activate calcium-cAMP-protein kinase A (PKA) signaling. The current study examined whether stress and increased cAMP-PKA signaling in rat medial PFC (mPFC) reduce pyramidal cell firing and impair working memory by activating KCNQ potassium channels. KCNQ2 channels were found in mPFC layers II/III and V pyramidal cells, and patch-clamp recordings demonstrated KCNQ currents that were increased by forskolin or by chronic stress exposure, and which were associated with reduced neuronal firing. Low dose of KCNQ blockers infused into rat mPFC improved cognitive performance and prevented acute pharmacological stress-induced deficits. Systemic administration of low doses of KCNQ blocker also improved performance in young and aged rats, but higher doses impaired performance and occasionally induced seizures. Taken together, these data demonstrate that KCNQ channels have powerful influences on mPFC neuronal firing and cognitive function, contributing to stress-induced PFC dysfunction.
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Affiliation(s)
- Amy F.T. Arnsten
- Departments of Neuroscience, Yale University School of Medicine, USA
| | - Lu E. Jin
- Departments of Neuroscience, Yale University School of Medicine, USA
| | - Nao J. Gamo
- Departments of Neuroscience, Yale University School of Medicine, USA
| | - Brian Ramos
- Departments of Neuroscience, Yale University School of Medicine, USA
| | | | - Yury M. Morozov
- Departments of Neuroscience, Yale University School of Medicine, USA
| | - Anna Kata
- Departments of Neuroscience, Yale University School of Medicine, USA
| | - Nigel S. Bamford
- Pediatric Neurology, Cellular and Molecular Physiology, Yale University School of Medicine, USA
| | - Mark F. Yeckel
- Departments of Neuroscience, Yale University School of Medicine, USA
| | | | - Lynda El-Hassar
- Departments of Neuroscience, Yale University School of Medicine, USA
- Pharmacology, Yale University School of Medicine, USA
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Kamiya H. Excitability Tuning of Axons by Afterdepolarization. Front Cell Neurosci 2019; 13:407. [PMID: 31555100 PMCID: PMC6742905 DOI: 10.3389/fncel.2019.00407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/26/2019] [Indexed: 11/13/2022] Open
Abstract
The axon provides a sole output of the neuron which propagates action potentials reliably to the axon terminal and transmits neuronal information to the postsynaptic neuron across the synapse. A classical view of neuronal signaling is based on these two processes, namely binary (all or none) signaling along the axon and graded (tunable) signaling at the synapse. Recent studies, however, have revealed that the excitability of the axon is subject to dynamic tuning for a short period after axonal action potentials. This was first described as post-spike hyperexcitability, as measured by the changes in stimulus threshold for a short period after an action potential. Later on, direct recordings from central nervous system (CNS) axons or axon terminals using subcellular patch-clamp recording showed that axonal spikes are often followed by afterdepolarization (ADP) lasting for several tens of milliseconds and has been suggested to mediate post-spike hyperexcitability. In this review article, I focused on the mechanisms as well as the functional significance of ADP in fine-scale modulation of axonal spike signaling in the CNS, with special reference to hippocampal mossy fibers, one of the best-studied CNS axons. As a common basic mechanism underlying axonal ADP, passive propagation by the capacitive discharge of the axonal membrane as well as voltage-dependent K+ conductance underlies the generation of ADP. Small but prolonged axonal ADP lasting for several tens of milliseconds may influence the subsequent action potential and transmitter release from the axon terminals. Both duration and amplitude of axonal spike are subject to such modulation by preceding action potential-ADP sequence, deviating from the conventional assumption of digital nature of axonal spike signaling. Impact on the transmitter release is also discussed in the context of axonal spike plasticity. Axonal spike is subject to dynamic control on a fine-scale and thereby contributes to the short-term plasticity at the synapse.
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Affiliation(s)
- Haruyuki Kamiya
- Department of Neurobiology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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47
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Kim EC, Patel J, Zhang J, Soh H, Rhodes JS, Tzingounis AV, Chung HJ. Heterozygous loss of epilepsy gene KCNQ2 alters social, repetitive and exploratory behaviors. GENES BRAIN AND BEHAVIOR 2019; 19:e12599. [PMID: 31283873 PMCID: PMC7050516 DOI: 10.1111/gbb.12599] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/28/2019] [Accepted: 07/06/2019] [Indexed: 12/28/2022]
Abstract
KCNQ/Kv7 channels conduct voltage‐dependent outward potassium currents that potently decrease neuronal excitability. Heterozygous inherited mutations in their principle subunits Kv7.2/KCNQ2 and Kv7.3/KCNQ3 cause benign familial neonatal epilepsy whereas patients with de novo heterozygous Kv7.2 mutations are associated with early‐onset epileptic encephalopathy and neurodevelopmental disorders characterized by intellectual disability, developmental delay and autism. However, the role of Kv7.2‐containing Kv7 channels in behaviors especially autism‐associated behaviors has not been described. Because pathogenic Kv7.2 mutations in patients are typically heterozygous loss‐of‐function mutations, we investigated the contributions of Kv7.2 to exploratory, social, repetitive and compulsive‐like behaviors by behavioral phenotyping of both male and female KCNQ2+/− mice that were heterozygous null for the KCNQ2 gene. Compared with their wild‐type littermates, male and female KCNQ2+/− mice displayed increased locomotor activity in their home cage during the light phase but not the dark phase and showed no difference in motor coordination, suggesting hyperactivity during the inactive light phase. In the dark phase, KCNQ2+/− group showed enhanced exploratory behaviors, and repetitive grooming but decreased sociability with sex differences in the degree of these behaviors. While male KCNQ2+/− mice displayed enhanced compulsive‐like behavior and social dominance, female KCNQ2+/− mice did not. In addition to elevated seizure susceptibility, our findings together indicate that heterozygous loss of Kv7.2 induces behavioral abnormalities including autism‐associated behaviors such as reduced sociability and enhanced repetitive behaviors. Therefore, our study is the first to provide a tangible link between loss‐of‐function Kv7.2 mutations and the behavioral comorbidities of Kv7.2‐associated epilepsy.
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Affiliation(s)
- Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Jaimin Patel
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Justin S Rhodes
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Psychology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | | | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
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48
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Kamiya H. Modeling Analysis of Axonal After Potential at Hippocampal Mossy Fibers. Front Cell Neurosci 2019; 13:210. [PMID: 31139051 PMCID: PMC6527874 DOI: 10.3389/fncel.2019.00210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/25/2019] [Indexed: 11/13/2022] Open
Abstract
Action potentials reliably propagate along the axons, and after potential often follows the axonal action potentials. After potential lasts for several tens of millisecond and plays a crucial role in regulating excitability during repetitive firings of the axon. Several mechanisms underlying the generation of after potential have been suggested, including activation of ionotropic autoreceptors, accumulation of K+ ions in the surrounding extracellular space, the opening of slow voltage-dependent currents, and capacitive discharge of upstream action potentials passively propagated through axon cable. Among them, capacitive discharge is difficult to examine experimentally, since the quantitative evaluation of a capacitive component requires simultaneous recordings from at least two different sites on the connecting axon. In this study, a series of numerical simulation of the axonal action potential was performed using a proposed model of the hippocampal mossy fiber where morphological as well as electrophysiological data are accumulated. To evaluate the relative contribution of the capacitive discharge in axonal after potential, voltage-dependent Na+ current as well as voltage-dependent K+ current was omitted from a distal part of mossy fiber axons. Slow depolarization with a similar time course with the recorded after potential in the previous study was left after blockade of Na+ and K+ currents, suggesting that a capacitive component contributes substantially in axonal after potential following propagating action potentials. On the other hand, it has been shown that experimentally recorded after potential often showed clear voltage-dependency upon changes in the initial membrane potential, obviously deviating from voltage-independent nature of the capacitive component. The simulation revealed that activation of voltage-dependent K+ current also contributes to shape a characteristic waveform of axonal after potential and reconstitute similar voltage-dependency with that reported for the after potential recorded from mossy fiber terminals. These findings suggest that the capacitive component reflecting passive propagation of upstream action potential substantially contributes to the slow time course of axonal after potential, although voltage-dependent K+ current provided a characteristic voltage dependency of after potential waveform.
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Affiliation(s)
- Haruyuki Kamiya
- Department of Neurobiology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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Regulation of Neuronal Na +/K +-ATPase by Specific Protein Kinases and Protein Phosphatases. J Neurosci 2019; 39:5440-5451. [PMID: 31085608 DOI: 10.1523/jneurosci.0265-19.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/27/2019] [Accepted: 04/16/2019] [Indexed: 01/13/2023] Open
Abstract
The Na+/K+-ATPase (NKA) is a ubiquitous membrane-bound enzyme responsible for generating and maintaining the Na+ and K+ electrochemical gradients across the plasmalemma of living cells. Numerous studies in non-neuronal tissues have shown that this transport mechanism is reversibly regulated by phosphorylation/dephosphorylation of the catalytic α subunit and/or associated proteins. In neurons, Na+/K+ transport by NKA is essential for almost all neuronal operations, consuming up to two-thirds of the neuron's energy expenditure. However, little is known about its cellular regulatory mechanisms. Here we have used an electrophysiological approach to monitor NKA transport activity in male rat hippocampal neurons in situ We report that this activity is regulated by a balance between serine/threonine phosphorylation and dephosphorylation. Phosphorylation by the protein kinases PKG and PKC inhibits NKA activity, whereas dephosphorylation by the protein phosphatases PP-1 and PP-2B (calcineurin) reverses this effect. Given that these kinases and phosphatases serve as downstream effectors in key neuronal signaling pathways, they may mediate the coupling of primary messengers, such as neurotransmitters, hormones, and growth factors, to the NKAs, through which multiple brain functions can be regulated or dysregulated.SIGNIFICANCE STATEMENT The Na+/K+-ATPase (NKA), known as the "Na+ pump," is a ubiquitous membrane-bound enzyme responsible for generating and maintaining the Na+ and K+ electrochemical gradients across the plasma membrane of living cells. In neurons, as in most types of cells, the NKA generates the negative resting membrane potential, which is the basis for almost all aspects of cellular function. Here we used an electrophysiological approach to monitor physiological NKA transport activity in single hippocampal pyramidal cells in situ We have found that neuronal NKA activity is oppositely regulated by phosphorylation and dephosphorylation, and we have identified the main protein kinases and phosphatases mediating this regulation. This fundamental form of NKA regulation likely plays a role in multiple brain functions.
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50
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Ghotbeddin Z, Heysieattalab S, Borjkhani M, Mirnajafi-Zadeh J, Semnanian S, Hosseinmardi N, Janahmadi M. Ca 2+ Channels Involvement in Low-Frequency Stimulation-Mediated Suppression of Intrinsic Excitability of Hippocampal CA1 Pyramidal Cells in a Rat Amygdala Kindling Model. Neuroscience 2019; 406:234-248. [PMID: 30885638 DOI: 10.1016/j.neuroscience.2019.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 12/26/2022]
Abstract
Low-frequency stimulation has demonstrated promising seizure suppression in animal models of epilepsy, while the mechanism of the effect is still debated. Changes in intrinsic properties have been recognized as a prominent pathophysiologically relevant feature of numerous neurological disorders including epilepsy. Here, it was evaluated whether LFS can preserve the intrinsic neuronal electrophysiological properties in a rat model of epilepsy, focusing on the possible involvement of voltage-gated Ca2+ channels. The amygdala kindling model was induced by 3 s monophasic square wave pulses (50 Hz, 1 ms duration, 12times/day at 5 min intervals). Both LFS alone and kindled plus LFS (KLFS) groups received four packages of LFS (each consisting of 200 monophasic square pulses, 0.1 ms pulse duration at 1 Hz with the after discharge threshold intensity), which in KLFS rats was applied immediately after kindling induction. Whole-cell patch-clamp recordings were made in the presence of fast synaptic blockers 24 h after the last kindling stimulations or following kindling stimulations plus LFS application. In the KLFS group, both the rebound excitation and kindling-induced intrinsic hyperexcitability were decreased, associated with a regular intrinsic firing as indicated by a lower coefficient of variation. The amplitude of afterdepolarization (ADP) and its area under the curve were both decreased in the KLFS group compared to the kindled group. LFS prevented the increasing effect of kindling on Ca2+ currents in the KLFS group. Findings provided evidence for a novel form of epileptiform activity suppression by LFS in the presence of synaptic blockade possibly by decreasing Ca2+ currents.
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Affiliation(s)
- Zohreh Ghotbeddin
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Department of Physiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran; Stem Cell and Transgenic Technology Research Center, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | | | - Mehdi Borjkhani
- Department of Electrical Engineering, Urmia University of Technology, Urmia, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saeed Semnanian
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Narges Hosseinmardi
- Neuroscience Research Center and Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahyar Janahmadi
- Neuroscience Research Center and Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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