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Zhao T, Wang L, Chen F. Potassium channel-related epilepsy: Pathogenesis and clinical features. Epilepsia Open 2024; 9:891-905. [PMID: 38560778 PMCID: PMC11145612 DOI: 10.1002/epi4.12934] [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: 04/25/2023] [Revised: 03/11/2024] [Accepted: 03/17/2024] [Indexed: 04/04/2024] Open
Abstract
Variants in potassium channel-related genes are one of the most important mechanisms underlying abnormal neuronal excitation and disturbances in the cellular resting membrane potential. These variants can cause different forms of epilepsy, which can seriously affect the physical and mental health of patients, especially those with refractory epilepsy or status epilepticus, which are common among pediatric patients and are potentially life-threatening. Variants in potassium ion channel-related genes have been reported in few studies; however, to our knowledge, no systematic review has been published. This study aimed to summarize the epilepsy phenotypes, functional studies, and pharmacological advances associated with different potassium channel gene variants to assist clinical practitioners and drug development teams to develop evidence-based medicine and guide research strategies. PubMed and Google Scholar were searched for relevant literature on potassium channel-related epilepsy reported in the past 5-10 years. Various common potassium ion channel gene variants can lead to heterogeneous epilepsy phenotypes, and functional effects can result from gene deletions and compound effects. Administration of select anti-seizure medications is the primary treatment for this type of epilepsy. Most patients are refractory to anti-seizure medications, and some novel anti-seizure medications have been found to improve seizures. Use of targeted drugs to correct aberrant channel function based on the type of potassium channel gene variant can be used as an evidence-based pathway to achieve precise and individualized treatment for children with epilepsy. PLAIN LANGUAGE SUMMARY: In this article, the pathogenesis and clinical characteristics of epilepsy caused by different types of potassium channel gene variants are reviewed in the light of the latest research literature at home and abroad, with the expectation of providing a certain theoretical basis for the diagnosis and treatment of children with this type of disease.
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Affiliation(s)
- Tong Zhao
- Hebei Children's HospitalShijiazhuangHebeiChina
| | - Le Wang
- Hebei Children's HospitalShijiazhuangHebeiChina
| | - Fang Chen
- Hebei Children's HospitalShijiazhuangHebeiChina
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2
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Schreurs BG, O'Dell DE, Wang D. The Role of Cerebellar Intrinsic Neuronal Excitability, Synaptic Plasticity, and Perineuronal Nets in Eyeblink Conditioning. BIOLOGY 2024; 13:200. [PMID: 38534469 DOI: 10.3390/biology13030200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 02/29/2024] [Accepted: 03/19/2024] [Indexed: 03/28/2024]
Abstract
Evidence is strong that, in addition to fine motor control, there is an important role for the cerebellum in cognition and emotion. The deep nuclei of the mammalian cerebellum also contain the highest density of perineural nets-mesh-like structures that surround neurons-in the brain, and it appears there may be a connection between these nets and cognitive processes, particularly learning and memory. Here, we review how the cerebellum is involved in eyeblink conditioning-a particularly well-understood form of learning and memory-and focus on the role of perineuronal nets in intrinsic membrane excitability and synaptic plasticity that underlie eyeblink conditioning. We explore the development and role of perineuronal nets and the in vivo and in vitro evidence that manipulations of the perineuronal net in the deep cerebellar nuclei affect eyeblink conditioning. Together, these findings provide evidence of an important role for perineuronal net in learning and memory.
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Affiliation(s)
- Bernard G Schreurs
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA
| | - Deidre E O'Dell
- Department of Biology, Earth and Environmental Sciences, Pennsylvania Western (PennWest) University, California, PA 15419, USA
| | - Desheng Wang
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA
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3
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Andreyanov M, Heinrich R, Berlin S. Design of Ultrapotent Genetically Encoded Inhibitors of Kv4.2 for Gating Neural Plasticity. J Neurosci 2024; 44:e2295222023. [PMID: 38154956 PMCID: PMC10869153 DOI: 10.1523/jneurosci.2295-22.2023] [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: 12/15/2022] [Revised: 11/05/2023] [Accepted: 11/22/2023] [Indexed: 12/30/2023] Open
Abstract
The Kv4.2 potassium channel plays established roles in neuronal excitability, while also being implicated in plasticity. Current means to study the roles of Kv4.2 are limited, motivating us to design a genetically encoded membrane tethered Heteropodatoxin-2 (MetaPoda). We find that MetaPoda is an ultrapotent and selective gating-modifier of Kv4.2. We narrow its site of contact with the channel to two adjacent residues within the voltage sensitive domain (VSD) and, with docking simulations, suggest that the toxin binds the VSD from within the membrane. We also show that MetaPoda does not require an external linker of the channel for its activity. In neurons (obtained from female and male rat neonates), MetaPoda specifically, and potently, inhibits all Kv4 currents, leaving all other A-type currents unaffected. Inhibition of Kv4 in hippocampal neurons does not promote excessive excitability, as is expected from a simple potassium channel blocker. We do find that MetaPoda's prolonged expression (1 week) increases expression levels of the immediate early gene cFos and prevents potentiation. These findings argue for a major role of Kv4.2 in facilitating plasticity of hippocampal neurons. Lastly, we show that our engineering strategy is suitable for the swift engineering of another potent Kv4.2-selective membrane-tethered toxin, Phrixotoxin-1, denoted MetaPhix. Together, we provide two uniquely potent genetic tools to study Kv4.2 in neuronal excitability and plasticity.
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Affiliation(s)
- Michael Andreyanov
- Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa 3525433, Israel
| | - Ronit Heinrich
- Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa 3525433, Israel
| | - Shai Berlin
- Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa 3525433, Israel
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4
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Ryu H, Kim M, Park H, Choi HK, Chung C. Stress-induced translation of KCNB1 contributes to the enhanced synaptic transmission of the lateral habenula. Front Cell Neurosci 2023; 17:1278847. [PMID: 38193032 PMCID: PMC10773861 DOI: 10.3389/fncel.2023.1278847] [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: 08/17/2023] [Accepted: 10/05/2023] [Indexed: 01/10/2024] Open
Abstract
The lateral habenula (LHb) is a well-established brain region involved in depressive disorders. Synaptic transmission of the LHb neurons is known to be enhanced by stress exposure; however, little is known about genetic modulators within the LHb that respond to stress. Using recently developed molecular profiling methods by phosphorylated ribosome capture, we obtained transcriptome profiles of stress responsive LHb neurons during acute physical stress. Among such genes, we found that KCNB1 (Kv2.1 channel), a delayed rectifier and voltage-gated potassium channel, exhibited increased expression following acute stress exposure. To determine the roles of KCNB1 on LHb neurons during stress, we injected short hairpin RNA (shRNA) against the kcnb1 gene to block its expression prior to stress exposure. We observed that the knockdown of KCNB1 altered the basal firing pattern of LHb neurons. Although KCNB1 blockade did not rescue despair-like behaviors in acute learned helplessness (aLH) animals, we found that KCNB1 knockdown prevented the enhancement of synaptic strength in LHb neuron after stress exposure. This study suggests that KCNB1 may contribute to shape stress responses by regulating basal firing patterns and neurotransmission intensity of LHb neurons.
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Affiliation(s)
- Hakyun Ryu
- Department of Biological Sciences, Konkuk University, Seoul, Republic of Korea
| | - Minseok Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Hoyong Park
- Department of Biological Sciences, Konkuk University, Seoul, Republic of Korea
| | - Han Kyoung Choi
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - ChiHye Chung
- Department of Biological Sciences, Konkuk University, Seoul, Republic of Korea
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5
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Ovsepian SV, Waxman SG. Gene therapy for chronic pain: emerging opportunities in target-rich peripheral nociceptors. Nat Rev Neurosci 2023; 24:252-265. [PMID: 36658346 DOI: 10.1038/s41583-022-00673-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2022] [Indexed: 01/20/2023]
Abstract
With sweeping advances in precision delivery systems and manipulation of the genomes and transcriptomes of various cell types, medical biotechnology offers unprecedented selectivity for and control of a wide variety of biological processes, forging new opportunities for therapeutic interventions. This perspective summarizes state-of-the-art gene therapies enabled by recent innovations, with an emphasis on the expanding universe of molecular targets that govern the activity and function of primary sensory neurons and which might be exploited to effectively treat chronic pain.
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Affiliation(s)
- Saak V Ovsepian
- School of Science, Faculty of Engineering and Science, University of Greenwich London, Chatham Maritime, UK.
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA.
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA.
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6
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Salpietro V, Galassi Deforie V, Efthymiou S, O'Connor E, Marcé‐Grau A, Maroofian R, Striano P, Zara F, Morrow MM, Reich A, Blevins A, Sala‐Coromina J, Accogli A, Fortuna S, Alesandrini M, Au PYB, Singhal NS, Cogne B, Isidor B, Hanna MG, Macaya A, Kullmann DM, Houlden H, Männikkö R. De novo KCNA6 variants with attenuated K V 1.6 channel deactivation in patients with epilepsy. Epilepsia 2023; 64:443-455. [PMID: 36318112 PMCID: PMC10108282 DOI: 10.1111/epi.17455] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 10/31/2022] [Accepted: 10/31/2022] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Mutations in the genes encoding neuronal ion channels are a common cause of Mendelian neurological diseases. We sought to identify novel de novo sequence variants in cases with early infantile epileptic phenotypes and neurodevelopmental anomalies. METHODS Following clinical diagnosis, we performed whole exome sequencing of the index cases and their parents. Identified channel variants were expressed in Xenopus oocytes and their functional properties assessed using two-electrode voltage clamp. RESULTS We identified novel de novo variants in KCNA6 in four unrelated individuals variably affected with neurodevelopmental disorders and seizures with onset in the first year of life. Three of the four identified mutations affect the pore-lining S6 α-helix of KV 1.6. A prominent finding of functional characterization in Xenopus oocytes was that the channel variants showed only minor effects on channel activation but slowed channel closure and shifted the voltage dependence of deactivation in a hyperpolarizing direction. Channels with a mutation affecting the S6 helix display dominant effects on channel deactivation when co-expressed with wild-type KV 1.6 or KV 1.1 subunits. SIGNIFICANCE This is the first report of de novo nonsynonymous variants in KCNA6 associated with neurological or any clinical features. Channel variants showed a consistent effect on channel deactivation, slowing the rate of channel closure following normal activation. This specific gain-of-function feature is likely to underlie the neurological phenotype in our patients. Our data highlight KCNA6 as a novel channelopathy gene associated with early infantile epileptic phenotypes and neurodevelopmental anomalies.
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Affiliation(s)
- Vincenzo Salpietro
- Department of Neuromuscular DiseaseUCL Institute of Neurology, University College LondonLondonUK
- Department of Biotechnological and Applied Clinical Sciences (DISCAB)University of L'AquilaL'AquilaItaly
| | | | - Stephanie Efthymiou
- Department of Neuromuscular DiseaseUCL Institute of Neurology, University College LondonLondonUK
| | - Emer O'Connor
- Department of Neuromuscular DiseaseUCL Institute of Neurology, University College LondonLondonUK
| | - Anna Marcé‐Grau
- Department of Paediatric Neurology, University Hospital Vall d'HebronUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - Reza Maroofian
- Department of Neuromuscular DiseaseUCL Institute of Neurology, University College LondonLondonUK
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DiNOGMI)University of Genoa16124 GenoaItaly
- Unit of Pediatric NeurologyIRCCS, Istituto “Giannina Gaslini”Genoa 16123Italy
| | - Federico Zara
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DiNOGMI)University of Genoa16124 GenoaItaly
- Medical Genetics UnitIRCCS, Istituto “Giannina Gaslini”Genoa 16123Italy
| | | | | | | | | | - Júlia Sala‐Coromina
- Department of Paediatric Neurology, University Hospital Vall d'HebronUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - Andrea Accogli
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DiNOGMI)University of Genoa16124 GenoaItaly
- Medical Genetics UnitIRCCS, Istituto “Giannina Gaslini”Genoa 16123Italy
| | | | - Marie Alesandrini
- Neuropediatrics UnitCentre Hospitalier Universitaire NantesNantesFrance
| | - P. Y. Billie Au
- Department of Medical Genetics, Alberta Children's Hospital Research Institute, Cumming School of MedicineUniversity of CalgaryAlbertaCalgaryCanada
| | - Nilika Shah Singhal
- Departments of Neurology and Pediatrics, UCSF Benioff Children's HospitalUniversity of CaliforniaCaliforniaSan FranciscoUSA
| | - Benjamin Cogne
- Centre Hospitalier Universitaire NantesService de Génétique MédicaleNantesFrance
- Université de Nantes, CNRS, INSERML'Institut du ThoraxNantesFrance
| | - Bertrand Isidor
- Centre Hospitalier Universitaire NantesService de Génétique MédicaleNantesFrance
- Université de Nantes, CNRS, INSERML'Institut du ThoraxNantesFrance
| | - Michael G. Hanna
- Department of Neuromuscular DiseaseUCL Institute of Neurology, University College LondonLondonUK
- Queen Square Centre for Neuromuscular DiseasesNational Hospital for Neurology and NeurosurgeryLondonUK
| | - Alfons Macaya
- Department of Paediatric Neurology, University Hospital Vall d'HebronUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - Dimitri M. Kullmann
- Department of Clinical and Experimental EpilepsyUCL Institute of Neurology, University College LondonLondonUK
| | - Henry Houlden
- Department of Neuromuscular DiseaseUCL Institute of Neurology, University College LondonLondonUK
| | - Roope Männikkö
- Department of Neuromuscular DiseaseUCL Institute of Neurology, University College LondonLondonUK
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7
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Diochot S. Pain-related toxins in scorpion and spider venoms: a face to face with ion channels. J Venom Anim Toxins Incl Trop Dis 2021; 27:e20210026. [PMID: 34925480 PMCID: PMC8667759 DOI: 10.1590/1678-9199-jvatitd-2021-0026] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/10/2021] [Indexed: 12/12/2022] Open
Abstract
Pain is a common symptom induced during envenomation by spiders and scorpions.
Toxins isolated from their venom have become essential tools for studying the
functioning and physiopathological role of ion channels, as they modulate their
activity. In particular, toxins that induce pain relief effects can serve as a
molecular basis for the development of future analgesics in humans. This review
provides a summary of the different scorpion and spider toxins that directly
interact with pain-related ion channels, with inhibitory or stimulatory effects.
Some of these toxins were shown to affect pain modalities in different animal
models providing information on the role played by these channels in the pain
process. The close interaction of certain gating-modifier toxins with membrane
phospholipids close to ion channels is examined along with molecular approaches
to improve selectivity, affinity or bioavailability in vivo for
therapeutic purposes.
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Affiliation(s)
- Sylvie Diochot
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS) UMR 7275 et Université Côte d'Azur (UCA), 06560 Valbonne, France. Institut de Pharmacologie Moléculaire et Cellulaire Centre National de la Recherche Scientifique Université Côte d'Azur Valbonne France
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8
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Hedrich UBS, Lauxmann S, Wolff M, Synofzik M, Bast T, Binelli A, Serratosa JM, Martínez-Ulloa P, Allen NM, King MD, Gorman KM, Zeev BB, Tzadok M, Wong-Kisiel L, Marjanovic D, Rubboli G, Sisodiya SM, Lutz F, Ashraf HP, Torge K, Yan P, Bosselmann C, Schwarz N, Fudali M, Lerche H. 4-Aminopyridine is a promising treatment option for patients with gain-of-function KCNA2-encephalopathy. Sci Transl Med 2021; 13:eaaz4957. [PMID: 34516822 DOI: 10.1126/scitranslmed.aaz4957] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Markus Wolff
- Department of Pediatric Neurology and Developmental Medicine, University Children's Hospital, 72076 Tuebingen, Germany.,Department of Pediatric Neurology, Vivantes-Klinikum Neukölln, 12351 Berlin, Germany
| | - Matthis Synofzik
- Department of Neurology and Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - Thomas Bast
- Epilepsy Center Kork, 77694 Kehl-Kork, Germany.,Medical Faculty of the University of Freiburg, 79110 Freiburg, Germany
| | - Adrian Binelli
- Department of Pediatric Neurology, Elizalde Children's Hospital, C1270 Buenos Aires, Argentina
| | - José M Serratosa
- Neurology Laboratory and Epilepsy Unit, Department of Neurology, IIS- Fundacio'n Jime'nez Dı'az, UAM, 28040 Madrid, Spain.,Centro de Investigacio'n Biome'dica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain
| | - Pedro Martínez-Ulloa
- Neurology Laboratory and Epilepsy Unit, Department of Neurology, IIS- Fundacio'n Jime'nez Dı'az, UAM, 28040 Madrid, Spain
| | - Nicholas M Allen
- Department of Paediatrics, Clinical Sciences Institute, National University of Ireland Galway, Galway H91 TK33, Ireland
| | - Mary D King
- Department of Neurology and Neurophysiology, Children's Health Ireland at Temple Street, Dublin DO1 YC67, Ireland.,School of Medicine and Medical Science, University College Dublin, Dublin DO4 V1W8, Ireland
| | - Kathleen M Gorman
- Department of Neurology and Neurophysiology, Children's Health Ireland at Temple Street, Dublin DO1 YC67, Ireland.,School of Medicine and Medical Science, University College Dublin, Dublin DO4 V1W8, Ireland
| | - Bruria Ben Zeev
- Sackler School of Medicine Tel Aviv University, Tel Aviv 6997801, Israel.,Pediatric Neurology Unit, Edmond and Lilly Safra Pediatric Hospital, Sheba Medical Center, 5265601 Ramat Gan, Israel
| | - Michal Tzadok
- Sackler School of Medicine Tel Aviv University, Tel Aviv 6997801, Israel.,Pediatric Neurology Unit, Edmond and Lilly Safra Pediatric Hospital, Sheba Medical Center, 5265601 Ramat Gan, Israel
| | - Lily Wong-Kisiel
- Divisions of Child Neurology & Division of Epilepsy, Department of Neurology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | | | - Guido Rubboli
- Danish Epilepsy Center, Filadelfia, 4293 Dianalund, Denmark.,University of Copenhagen, 1165 Copenhagen, Denmark
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.,Chalfont Centre for Epilepsy, Bucks SL9 0RJ, UK
| | - Florian Lutz
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Harshad Pannikkaveettil Ashraf
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Kirsten Torge
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Pu Yan
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Christian Bosselmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Niklas Schwarz
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Monika Fudali
- Department of Neurosurgery, University of Tuebingen, 72076 Tuebingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
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9
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Xu W, Wang Y, Qi X, Li K, Zhou L, Sha S, Wang X, Wu C, Du Y, Chen L. Involvement of TRPV4 in changes in rapidly inactivating potassium channels in the early stage of pilocarpine-induced status epilepticus in mice. J Cell Physiol 2021; 237:856-867. [PMID: 34415059 DOI: 10.1002/jcp.30558] [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] [Received: 03/31/2021] [Revised: 08/06/2021] [Accepted: 08/11/2021] [Indexed: 11/11/2022]
Abstract
The rapidly inactivating potassium current (IA ) is important in controlling neuronal action potentials. Altered IA function and K+ channel expression have been found in epilepsy, and activation of the transient receptor potential vanilloid 4 (TRPV4) channel is involved in epilepsy pathogenesis. This study examined whether TRPV4 affects Kv4.2 and K+ channel interacting protein (KCHIP) expression and IA changes following pilocarpine-induced status epilepticus (PISE) in mice. Herein, hippocampal protein levels of Kv4.2 and KCHIP2 increased 3 h-3 d and decreased 7-30 d; that of KCHIP1 increased 3-24 h and decreased 3-30 d post-PISE. The TRPV4 antagonist HC-067047 attenuated the increased protein levels of Kv4.2 and KCHIP2 but not that of KCHIP1 post-PISE. The TRPV4 agonist GSK1016790A increased hippocampal protein levels of Kv4.2 and KCHIP2 but had no effect on KCHIP1 expression. HC-067047 attenuated the increased IA in hippocampal pyramidal neurons 24 h and 3 d post-PISE. GSK1016790A increased IA in hippocampal pyramidal neurons, shifting the voltage-dependent inactivation curve toward depolarization. The GSK1016790A-induced increase of IA was blocked by protein kinase A and calcium/calmodulin-dependent kinase II antagonists but was unaffected by protein kinase C antagonists. We conclude that TRPV4 activation may be responsible for the increases of Kv4.2 and KCHIP2 expression in hippocampi and IA in hippocampal pyramidal neurons in PISE mice, which are likely compensatory measures for hyperexcitability at the early stage of epilepsy.
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Affiliation(s)
- Weixing Xu
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Yue Wang
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Xiuting Qi
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Kunpeng Li
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Li Zhou
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Sha Sha
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Xiaoli Wang
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Chunfeng Wu
- Department of Neurology, Children's Hospital of Nanjing Medical University, Nanjing, P.R. China
| | - Yimei Du
- Department of cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Lei Chen
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
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10
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Yang Y, Okada S, Sakurai M. Adenosine-to-inosine RNA editing in neurological development and disease. RNA Biol 2021; 18:999-1013. [PMID: 33393416 DOI: 10.1080/15476286.2020.1867797] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Adenosine-to-inosine (A-to-I) editing is one of the most prevalent post-transcriptional RNA modifications in metazoan. This reaction is catalysed by enzymes called adenosine deaminases acting on RNA (ADARs). RNA editing is involved in the regulation of protein function and gene expression. The numerous A-to-I editing sites have been identified in both coding and non-coding RNA transcripts. These editing sites are also found in various genes expressed in the central nervous system (CNS) and play an important role in neurological development and brain function. Aberrant regulation of RNA editing has been associated with the pathogenesis of neurological and psychiatric disorders, suggesting the physiological significance of RNA editing in the CNS. In this review, we discuss the current knowledge of editing on neurological disease and development.
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Affiliation(s)
- Yuxi Yang
- Research Institute for Biomedical Sciences, Tokyo University of Science, Noda-shi, Chiba, Japan
| | - Shunpei Okada
- Research Institute for Biomedical Sciences, Tokyo University of Science, Noda-shi, Chiba, Japan
| | - Masayuki Sakurai
- Research Institute for Biomedical Sciences, Tokyo University of Science, Noda-shi, Chiba, Japan
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11
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Piccialli I, Tedeschi V, Boscia F, Ciccone R, Casamassa A, de Rosa V, Grieco P, Secondo A, Pannaccione A. The Anemonia sulcata Toxin BDS-I Protects Astrocytes Exposed to Aβ 1-42 Oligomers by Restoring [Ca 2+] i Transients and ER Ca 2+ Signaling. Toxins (Basel) 2020; 13:20. [PMID: 33396295 PMCID: PMC7823622 DOI: 10.3390/toxins13010020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/22/2020] [Accepted: 12/24/2020] [Indexed: 12/28/2022] Open
Abstract
Intracellular calcium concentration ([Ca2+]i) transients in astrocytes represent a highly plastic signaling pathway underlying the communication between neurons and glial cells. However, how this important phenomenon may be compromised in Alzheimer's disease (AD) remains unexplored. Moreover, the involvement of several K+ channels, including KV3.4 underlying the fast-inactivating currents, has been demonstrated in several AD models. Here, the effect of KV3.4 modulation by the marine toxin blood depressing substance-I (BDS-I) extracted from Anemonia sulcata has been studied on [Ca2+]i transients in rat primary cortical astrocytes exposed to Aβ1-42 oligomers. We showed that: (1) primary cortical astrocytes expressing KV3.4 channels displayed [Ca2+]i transients depending on the occurrence of membrane potential spikes, (2) BDS-I restored, in a dose-dependent way, [Ca2+]i transients in astrocytes exposed to Aβ1-42 oligomers (5 µM/48 h) by inhibiting hyperfunctional KV3.4 channels, (3) BDS-I counteracted Ca2+ overload into the endoplasmic reticulum (ER) induced by Aβ1-42 oligomers, (4) BDS-I prevented the expression of the ER stress markers including active caspase 12 and GRP78/BiP in astrocytes treated with Aβ1-42 oligomers, and (5) BDS-I prevented Aβ1-42-induced reactive oxygen species (ROS) production and cell suffering measured as mitochondrial activity and lactate dehydrogenase (LDH) release. Collectively, we proposed that the marine toxin BDS-I, by inhibiting the hyperfunctional KV3.4 channels and restoring [Ca2+]i oscillation frequency, prevented Aβ1-42-induced ER stress and cell suffering in astrocytes.
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Affiliation(s)
- Ilaria Piccialli
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Valentina Tedeschi
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Roselia Ciccone
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Antonella Casamassa
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Valeria de Rosa
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Paolo Grieco
- Department of Pharmacy, School of Medicine, Federico II Universityof Naples, 80131 Napoli, Italy;
| | - Agnese Secondo
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
| | - Anna Pannaccione
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, 80131 Napoli, Italy; (I.P.); (V.T.); (F.B.); (R.C.); (A.C.); (V.d.R.)
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12
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Zhou L, Xu W, An D, Sha S, Men C, Li Y, Wang X, Du Y, Chen L. Transient receptor potential vanilloid 4 activation inhibits the delayed rectifier potassium channels in hippocampal pyramidal neurons: An implication in pathological changes following pilocarpine-induced status epilepticus. J Neurosci Res 2020; 99:914-926. [PMID: 33393091 DOI: 10.1002/jnr.24749] [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: 08/17/2020] [Revised: 10/10/2020] [Accepted: 10/18/2020] [Indexed: 11/06/2022]
Abstract
Activation of transient receptor potential vanilloid 4 (TRPV4) can increase hippocampal neuronal excitability. TRPV4 has been reported to be involved in the pathogenesis of epilepsy. Voltage-gated potassium channels (VGPCs) play an important role in regulating neuronal excitability and abnormal VGPCs expression or function is related to epilepsy. Here, we examined the effect of TRPV4 activation on the delayed rectifier potassium current (IK ) in hippocampal pyramidal neurons and on the Kv subunits expression in male mice. We also explored the role of TRPV4 in changes in Kv subunits expression in male mice following pilocarpine-induced status epilepticus (PISE). Application of TRPV4 agonists, GSK1016790A and 5,6-EET, markedly reduced IK in hippocampal pyramidal neurons and shifted the voltage-dependent inactivation curve to the hyperpolarizing direction. GSK1016790A- and 5,6-EET-induced inhibition of IK was blocked by TRPV4 specific antagonists, HC-067047 and RN1734. GSK1016790A-induced inhibition of IK was markedly attenuated by calcium/calmodulin-dependent kinase II (CaMKII) antagonist. Application of GSK1016790A for up to 1 hr did not change the hippocampal protein levels of Kv1.1, Kv1.2, or Kv2.1. Intracerebroventricular injection of GSK1016790A for 3 d reduced the hippocampal protein levels of Kv1.2 and Kv2.1, leaving that of Kv1.1 unchanged. Kv1.2 and Kv2.1 protein levels as well as IK reduced markedly in hippocampi on day 3 post PISE, which was significantly reversed by HC-067047. We conclude that activation of TRPV4 inhibits IK in hippocampal pyramidal neurons, possibly by activating CaMKII. TRPV4-induced decrease in Kv1.2 and Kv2.1 expression and IK may be involved in the pathological changes following PISE.
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Affiliation(s)
- Li Zhou
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Weixing Xu
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Dong An
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Sha Sha
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Chen Men
- Department of Geriatrics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, P.R. China
| | - Yingchun Li
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Xiaoli Wang
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China
| | - Yimei Du
- Research Center of Ion Channelopathy, Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Lei Chen
- Department of Physiology, Nanjing Medical University, Nanjing, P.R. China.,Neuroprotective Drug Discovery Key Laboratory of Nanjing Medical University, Nanjing, P.R. China
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13
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Exaggerated potassium current reduction by oxytocin in visceral sensory neurons following chronic intermittent hypoxia. Auton Neurosci 2020; 229:102735. [PMID: 33032244 DOI: 10.1016/j.autneu.2020.102735] [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] [Received: 05/15/2020] [Revised: 08/18/2020] [Accepted: 09/21/2020] [Indexed: 11/22/2022]
Abstract
Oxytocin (OT) from the hypothalamus is increased in several cardiorespiratory nuclei and systemically in response to a variety of stimuli and stressors, including hypoxia. Within the nucleus tractus solitarii (nTS), the first integration site for cardiorespiratory reflexes, OT enhances synaptic transmission, action potential (AP) discharge, and cardiac baroreflex gain. The hypoxic stressor obstructive sleep apnea, and its CIH animal model, elevates blood pressure and alters heart rate variability. The nTS receives sensory input from baroafferent neurons that originate in the nodose ganglia. Nodose neurons express the OT receptor (OTR) whose activation elevates intracellular calcium. However, the influence of OT on other ion channels, especially potassium channels important for neuronal activity during CIH, is less known. This study sought to determine the mechanism (s) by which OT modulates sensory afferent-nTS mediated reflexes normally and after CIH. Nodose ganglia neurons from male Sprague-Dawley rats were examined after 10d CIH (6% O2 every 3 min) or their normoxic (21% O2) control. OTR mRNA and protein were identified in Norm and CIH ganglia and was similar between groups. To examine OTR function, APs and potassium currents (IK) were recorded in dissociated neurons. Compared to Norm, after CIH OT depolarized neurons and reduced current-induced AP discharge. After CIH OT also produced a greater reduction in IK that where tetraethylammonium-sensitive. These data demonstrate after CIH OT alters ionic currents in nodose ganglia cells to likely influence cardiorespiratory reflexes and overall function.
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14
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Jiang Z, Wang D, Shang H, Chen Y. Effect of potassium channel noise on nerve discharge based on the Chay model. Technol Health Care 2020; 28:371-381. [PMID: 32364170 PMCID: PMC7369062 DOI: 10.3233/thc-209038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND: The nervous system senses and transmits information through the firing behavior of neurons, and this process is affected by various noises. However, in the previous study of the influence of noise on nerve discharge, the channel of some noise effects is not clear, and the difference from other noises was not examined. OBJECTIVE: To construct ion channel noise which is more biologically significant, and to clarify the basic characteristics of the random firing rhythm of neurons generated by different types of noise acting on ion channels. Method: Based on the dynamics of the ion channel, we constructed ion channel noise. We simulated the nerve discharge based on the Chay model of potassium ion channel noise, and used the nonlinear time series analysis method to measure the certainty and randomness of nerve discharge. RESULTS: In the Chay model with potassium ion noise, the chaotic rhythm defined by the original model could be effectively unified with the random rhythm simulated by the previous random Chay model into a periodic bifurcation process. CONCLUSION: This method clarified the influence of ion channel noise on nerve discharge, better understood the randomness of nerve discharge and provided a more reasonable explanation for the mechanism of nerve discharge.
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Affiliation(s)
- Zhongting Jiang
- School of Information Science and Engineering, University of Jinan, Jinan, Shandong, China
| | - Dong Wang
- School of Information Science and Engineering, University of Jinan, Jinan, Shandong, China.,Shandong Provincial Key Laboratory of Network Based Intelligent Computing, Jinan, Shandong, China.,Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau in Qinghai Province, Qinghai Normal University, Xining, Qinghai, China
| | - Huijie Shang
- School of Information Science and Engineering, University of Jinan, Jinan, Shandong, China
| | - Yuehui Chen
- School of Information Science and Engineering, University of Jinan, Jinan, Shandong, China
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15
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Manduca JD, Thériault RK, Perreault ML. Glycogen synthase kinase-3: The missing link to aberrant circuit function in disorders of cognitive dysfunction? Pharmacol Res 2020; 157:104819. [PMID: 32305493 DOI: 10.1016/j.phrs.2020.104819] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/10/2020] [Accepted: 04/07/2020] [Indexed: 12/15/2022]
Abstract
Elevated GSK-3 activity has been implicated in cognitive dysfunction associated with various disorders including Alzheimer's disease, schizophrenia, type 2 diabetes, traumatic brain injury, major depressive disorder and bipolar disorder. Further, aberrant neural oscillatory activity in, and between, cortical regions and the hippocampus is consistently present within these same cognitive disorders. In this review, we will put forth the idea that increased GSK-3 activity serves as a pathological convergence point across cognitive disorders, inducing similar consequent impacts on downstream signaling mechanisms implicated in the maintenance of processes critical to brain systems communication and normal cognitive functioning. In this regard we suggest that increased activation of GSK-3 and neuronal oscillatory dysfunction are early pathological changes that may be functionally linked. Mechanistic commonalities between these disorders of cognitive dysfunction will be discussed and potential downstream targets of GSK-3 that may contribute to neuronal oscillatory dysfunction identified.
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Affiliation(s)
- Joshua D Manduca
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
| | | | - Melissa L Perreault
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada.
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16
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Antiepileptic therapy approaches in KCNQ2 related epilepsy: A systematic review. Eur J Med Genet 2020; 63:103628. [DOI: 10.1016/j.ejmg.2019.02.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 02/04/2019] [Accepted: 02/10/2019] [Indexed: 12/12/2022]
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17
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Shinoda M, Fukuoka T, Takeda M, Iwata K, Noguchi K. Spinal glial cell line-derived neurotrophic factor infusion reverses reduction of Kv4.1-mediated A-type potassium currents of injured myelinated primary afferent neurons in a neuropathic pain model. Mol Pain 2019; 15:1744806919841196. [PMID: 30868936 PMCID: PMC6463340 DOI: 10.1177/1744806919841196] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
High frequency spontaneous activity in injured primary afferents has been proposed as a pathological mechanism of neuropathic pain following nerve injury. Although spinal infusion of glial cell line-derived neurotrophic factor reduces the activity of injured myelinated A-fiber neurons after fifth lumbar (L5) spinal nerve ligation in rats, the implicated molecular mechanism remains undetermined. The fast-inactivating transient A-type potassium current (IA) is an important determinant of neuronal excitability, and five voltage-gated potassium channel (Kv) alpha-subunits, Kv1.4, Kv3.4, Kv4.1, Kv4.2, and Kv4.3, display IA in heterologous expression systems. Here, we examined the effect of spinal glial cell line-derived neurotrophic factor infusion on IA and the expression of these five Kv mRNAs in injured A-fiber neurons using the in vitro patch clamp technique and in situ hybridization histochemistry. Glial cell line-derived neurotrophic factor infusion reversed axotomy-induced reduction of the rheobase, elongation of first spike duration, and depolarization of the resting membrane potential. L5 spinal nerve ligation significantly reduced the current density of IA and glial cell line-derived neurotrophic factor treatment reversed the reduction. Among the examined Kv mRNAs, only the change in Kv4.1-expression was parallel with the change in IA after spinal nerve ligation and glial cell line-derived neurotrophic factor treatment. These findings suggest that glial cell line-derived neurotrophic factor should reduce the hyperexcitability of injured A-fiber primary afferents by IA recurrence. Among the five IA-related Kv channels, Kv4.1 should be a key channel, which account for this IA recurrence.
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Affiliation(s)
- Masamichi Shinoda
- 1 Department of Physiology, Nihon University School of Dentistry, Surugadai, Chiyoda-ku, Tokyo, Japan
| | - Tetsuo Fukuoka
- 2 Department of Anatomy and Neuroscience, Hyogo College of Medicine, Mukogawa-cho, Nishinomiya, Hyogo, Japan.,3 Fukuoka Clinic, Kasuga, Suita, Osaka, Japan
| | - Mamoru Takeda
- 4 Laboratory of Food and Physiological Sciences, Department of Life and Food Sciences, School of Life and Environmental Sciences, Azabu University, Fuchinobe, Chuo-ku, Sagamihara, Japan
| | - Koichi Iwata
- 1 Department of Physiology, Nihon University School of Dentistry, Surugadai, Chiyoda-ku, Tokyo, Japan
| | - Koichi Noguchi
- 2 Department of Anatomy and Neuroscience, Hyogo College of Medicine, Mukogawa-cho, Nishinomiya, Hyogo, Japan
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18
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Hill AS, Jain P, Folan NE, Ben-Shahar Y. The Drosophila ERG channel seizure plays a role in the neuronal homeostatic stress response. PLoS Genet 2019; 15:e1008288. [PMID: 31393878 PMCID: PMC6687100 DOI: 10.1371/journal.pgen.1008288] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 07/04/2019] [Indexed: 11/24/2022] Open
Abstract
Neuronal physiology is particularly sensitive to acute stressors that affect excitability, many of which can trigger seizures and epilepsies. Although intrinsic neuronal homeostasis plays an important role in maintaining overall nervous system robustness and its resistance to stressors, the specific genetic and molecular mechanisms that underlie these processes are not well understood. Here we used a reverse genetic approach in Drosophila to test the hypothesis that specific voltage-gated ion channels contribute to neuronal homeostasis, robustness, and stress resistance. We found that the activity of the voltage-gated potassium channel seizure (sei), an ortholog of the mammalian ERG channel family, is essential for protecting flies from acute heat-induced seizures. Although sei is broadly expressed in the nervous system, our data indicate that its impact on the organismal robustness to acute environmental stress is primarily mediated via its action in excitatory neurons, the octopaminergic system, as well as neuropile ensheathing and perineurial glia. Furthermore, our studies suggest that human mutations in the human ERG channel (hERG), which have been primarily implicated in the cardiac Long QT Syndrome (LQTS), may also contribute to the high incidence of seizures in LQTS patients via a cardiovascular-independent neurogenic pathway.
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Affiliation(s)
- Alexis S. Hill
- Department of Biology, College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Poorva Jain
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Nicole E. Folan
- Department of Biology, College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Yehuda Ben-Shahar
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, United States of America
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19
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Diverse Role of Biological Plasticity in Low Back Pain and Its Impact on Sensorimotor Control of the Spine. J Orthop Sports Phys Ther 2019; 49:389-401. [PMID: 31151376 DOI: 10.2519/jospt.2019.8716] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pain is complex. It is no longer acceptable to consider pain solely as a peripheral phenomenon involving activation of nociceptive neurons. The contemporary understanding of pain involves consideration of different underlying pain mechanisms and an increasing awareness of plasticity in all of the biological systems. Of note, recent advances in technology and understanding have highlighted the critical importance of neuroimmune interactions, both in the peripheral and central nervous systems, and the interaction between the nervous system and body tissues in the development and maintenance of pain, including low back pain (LBP). Further, the biology of many tissues changes when challenged by pain and injury, as reported in a growing body of literature on the biology of muscle, fat, and connective tissue. These advances in understanding of the complexity of LBP have implications for our understanding of pain and its interaction with the motor system, and may change how we consider motor control in the rehabilitation of LBP. This commentary provides a state-of-the-art overview of plasticity of biology in LBP. The paper is divided into 4 parts that address (1) biology of pain mechanisms, (2) neuroimmune interaction in the central nervous system, (3) neuroimmune interaction in the periphery, and (4) brain and peripheral tissue interaction. Each section considers the implications for clinical management of LBP. J Orthop Sports Phys Ther 2019;49(6):389-401. doi:10.2519/jospt.2019.8716.
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20
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Lin Z, Huang X, Zhou W, Zhang W, Liu Y, Bian T, Niu L, Meng L, Guo Y. Ultrasound Stimulation Modulates Voltage-Gated Potassium Currents Associated With Action Potential Shape in Hippocampal CA1 Pyramidal Neurons. Front Pharmacol 2019; 10:544. [PMID: 31178727 PMCID: PMC6538798 DOI: 10.3389/fphar.2019.00544] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/30/2019] [Indexed: 11/28/2022] Open
Abstract
Potassium channels (K+) play an important role in the regulation of cellular signaling. Dysfunction of potassium channels is associated with several severe ion channels diseases, such as long QT syndrome, episodic ataxia and epilepsy. Ultrasound stimulation has proven to be an effective non-invasive tool for the modulation of ion channels and neural activity. In this study, we demonstrate that ultrasound stimulation enables to modulate the potassium currents and has an impact on the shape modulation of action potentials (AP) in the hippocampal pyramidal neurons using whole-cell patch-clamp recordings in vitro. The results show that outward potassium currents in neurons increase significantly, approximately 13%, in response to 30 s ultrasound stimulation. Simultaneously, the increasing outward potassium currents directly decrease the resting membrane potential (RMP) from −64.67 ± 1.10 mV to −67.51 ± 1.35 mV. Moreover, the threshold current and AP fall rate increase while the reduction of AP half-width and after-hyperpolarization peak time is detected. During ultrasound stimulation, reduction of the membrane input resistance of pyramidal neurons can be found and shorter membrane time constant is achieved. Additionally, we verify that the regulation of potassium currents and shape of action potential is mainly due to the mechanical effects induced by ultrasound. Therefore, ultrasound stimulation may offer an alternative tool to treat some ion channels diseases related to potassium channels.
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Affiliation(s)
- Zhengrong Lin
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Xiaowei Huang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Wei Zhou
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Wenjun Zhang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Key Laboratory of E&M, Ministry of Education and Zhejiang Province, Zhejiang University of Technology, Hangzhou, China
| | - Yingzhe Liu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China
| | - Tianyuan Bian
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China
| | - Lili Niu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Long Meng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering - Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yanwu Guo
- The National Key Clinic Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
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21
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Sheng A, Zhang Y, Li G, Zhang G. Inhibitory Effects of Honokiol on the Voltage-Gated Potassium Channels in Freshly Isolated Mouse Dorsal Root Ganglion Neurons. Neurochem Res 2017; 43:450-457. [PMID: 29177805 DOI: 10.1007/s11064-017-2440-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/17/2017] [Accepted: 11/22/2017] [Indexed: 01/06/2023]
Abstract
Voltage-gated potassium (KV) currents, subdivided into rapidly inactivating A-type currents (I A) and slowly inactivating delayed rectifier currents (I K), play a fundamental role in modulating pain by controlling neuronal excitability. The effects of Honokiol (Hon), a natural biphenolic compound derived from Magnolia officinalis, on KV currents were investigated in freshly isolated mouse dorsal root ganglion neurons using the whole-cell patch clamp technique. Results showed that Hon inhibited I A and I K in concentration-dependent manner. The IC50 values for block of I A and I K were 30.5 and 25.7 µM, respectively. Hon (30 µM) shifted the steady-state activation curves of I A and I K to positive potentials by 17.6 and 16.7 mV, whereas inactivation and recovery from the inactivated state of I A were unaffected. These results suggest that Hon preferentially interacts with the active states of the I A and I K channels, and has no effect on the resting state and inactivated state of the I A channel. Blockade on K+ channels by Hon may contribute to its antinociceptive effect, especially anti-inflammatory pain.
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Affiliation(s)
- Anqi Sheng
- Department of Clinical Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Yan Zhang
- Department of Clinical Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Guang Li
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, 646000, China
| | - Guangqin Zhang
- Department of Clinical Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
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22
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Zhang F, Bian Y, Huang L, Fan W. Association between connexin 40 and potassium voltage-gated channel subfamily A member 5 expression in the atrial myocytes of patients with atrial fibrillation. Exp Ther Med 2017; 14:5170-5176. [PMID: 29201233 DOI: 10.3892/etm.2017.5129] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 03/17/2017] [Indexed: 12/24/2022] Open
Abstract
Structural and electrical remodeling within the atrium mediate the pathogenesis of atrial fibrillation (AF). Two key genes that sever a role in this remodeling are connexin 40 (Cx40) and potassium voltage-gated channel subfamily A member 5 (KCNA5), respectively. Electrical remodeling is considered to induce structural remodeling during AF. In the present study, the left atrial appendage section and atrial myocytes of patients with AF were evaluated. It was observed that Cx40 and KCNA5 mRNA (P<0.05) and protein (P<0.01) expression was significantly downregulated in AF compared with rheumatic heart disease. In addition, a positive correlation between the mRNA expression Cx40 and KCNA5 was observed in the atrial myocytes of patients with AF (P<0.05; r=0.42). The association between Cx40 and KCNA5 expression was subsequently investigated in primary cultured atrial myocytes using siRNA transfection. In atrial myocytes, downregulation of Cx40 inhibited the expression of KCNA5. Similarly, silencing of KCNA5 suppressed the expression of Cx40. These results indicate that synergistic regulation may occur between Cx40 and KCNA5 expression. Furthermore, the combined effects of electrical and structural remodeling in the atrial myocytes of patients with AF may contribute to the pathogenesis of AF.
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Affiliation(s)
- Fei Zhang
- Department of Cardiothoracic Surgery, Nanshan People's Hospital, Shenzhen, Guangdong 518052, P.R. China
| | - Yuhao Bian
- Department of Cardiothoracic Surgery, Nanshan People's Hospital, Shenzhen, Guangdong 518052, P.R. China.,Graduate School, Guangzhou Medical University, Guangzhou, Guangdong 510182, P.R. China
| | - Lei Huang
- Department of Cardiothoracic Surgery, Nanshan People's Hospital, Shenzhen, Guangdong 518052, P.R. China
| | - Wenbin Fan
- Department of Cardiothoracic Surgery, Nanshan People's Hospital, Shenzhen, Guangdong 518052, P.R. China
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Adongo DW, Mante PK, Kukuia KKE, Biney RP, Boakye-Gyasi E, Benneh CK, Ameyaw EO, Woode E. Anticonvulsant activity of Pseudospondias microcarpa (A. Rich) Engl. hydroethanolic leaf extract in mice: The role of excitatory/inhibitory neurotransmission and nitric oxide pathway. JOURNAL OF ETHNOPHARMACOLOGY 2017; 206:78-91. [PMID: 28528187 DOI: 10.1016/j.jep.2017.05.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 06/07/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Pseudospondias microcarpa (A. Rich) Engl. is a plant used for managing various diseases including central nervous system disorders. AIM OF THE STUDY This study explored the anticonvulsant activity of P. microcarpa hydroethanolic leaf extract (PME) as well as possible mechanism(s) of action in animal models. METHODS Effects of PME was assessed in electroconvulsive (the maximal electroshock and 6-Hz seizures) and chemoconvulsive (pentylenetetrazole-, picrotoxin-, isoniazid-, 4-aminopyridine-, and strychnine-induced seizures) models of epilepsy. In addition, effect of the extract on the nitric oxide pathway and GABAA receptor complex was evaluated. RESULTS The extract (30, 100 and 300mgkg-1, p.o.) significantly delayed the onset as well as decreased the duration and frequency of pentylenetetrazole-, picrotoxin- and strychnine-induced seizures. In addition, PME pre-treatment significantly improved survival in the 4-aminopyridine- and isoniazid-induced seizure tests. Furthermore, the extract protected against 6-Hz psychomotor seizures but had no effect in the maximal electroshock test. The anticonvulsant effect of PME (100mgkg-1, p.o.) was also reversed by pre-treatment with flumazenil, L-arginine or sildenafil. However, L-NAME or methylene blue (MB) augmented its effect. CONCLUSION Results show that PME has anticonvulsant activity and may probably be affecting GABAergic, glycinergic, NMDA, K+ channels and nitric oxide-cGMP pathways to exert its effect.
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Affiliation(s)
- Donatus W Adongo
- Department of Pharmacology, School of Medicine, University of Health and Allied Sciences, Ho, Ghana.
| | - Priscilla K Mante
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Kennedy K E Kukuia
- Department of Pharmacology and Toxicology, University of Ghana School of Pharmacy, University of Ghana, Accra, Ghana.
| | - Robert P Biney
- Department of Pharmacology, School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana.
| | - Eric Boakye-Gyasi
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Charles K Benneh
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Elvis O Ameyaw
- Department of Biomedical and Forensic Sciences, School of Biological Science, University of Cape Coast, Cape Coast, Ghana.
| | - Eric Woode
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
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Acute Knockdown of Kv4.1 Regulates Repetitive Firing Rates and Clock Gene Expression in the Suprachiasmatic Nucleus and Daily Rhythms in Locomotor Behavior. eNeuro 2017; 4:eN-NWR-0377-16. [PMID: 28560311 PMCID: PMC5440767 DOI: 10.1523/eneuro.0377-16.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 04/14/2017] [Accepted: 05/07/2017] [Indexed: 11/23/2022] Open
Abstract
Rapidly activating and inactivating A-type K+ currents (IA) encoded by Kv4.2 and Kv4.3 pore-forming (α) subunits of the Kv4 subfamily are key regulators of neuronal excitability. Previous studies have suggested a role for Kv4.1 α-subunits in regulating the firing properties of mouse suprachiasmatic nucleus (SCN) neurons. To test this, we utilized an RNA-interference strategy to knockdown Kv4.1, acutely and selectively, in the SCN. Current-clamp recordings revealed that the in vivo knockdown of Kv4.1 significantly (p < 0.0001) increased mean ± SEM repetitive firing rates in SCN neurons during the day (6.4 ± 0.5 Hz) and at night (4.3 ± 0.6 Hz), compared with nontargeted shRNA-expressing SCN neurons (day: 3.1 ± 0.5 Hz; night: 1.6 ± 0.3 Hz). IA was also significantly (p < 0.05) reduced in Kv4.1-targeted shRNA-expressing SCN neurons (day: 80.3 ± 11.8 pA/pF; night: 55.3 ± 7.7 pA/pF), compared with nontargeted shRNA-expressing (day: 121.7 ± 10.2 pA/pF; night: 120.6 ± 16.5 pA/pF) SCN neurons. The magnitude of the effect of Kv4.1-targeted shRNA expression on firing rates and IA was larger at night. In addition, Kv4.1-targeted shRNA expression significantly (p < 0.001) increased mean ± SEM nighttime input resistance (Rin; 2256 ± 166 MΩ), compared to nontargeted shRNA-expressing SCN neurons (1143 ± 93 MΩ). Additional experiments revealed that acute knockdown of Kv4.1 significantly (p < 0.01) shortened, by ∼0.5 h, the circadian period of spontaneous electrical activity, clock gene expression and locomotor activity demonstrating a physiological role for Kv4.1-encoded IA channels in regulating circadian rhythms in neuronal excitability and behavior.
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Song MS, Ryu PD, Lee SY. Kv3.4 is modulated by HIF-1α to protect SH-SY5Y cells against oxidative stress-induced neural cell death. Sci Rep 2017; 7:2075. [PMID: 28522852 PMCID: PMC5437029 DOI: 10.1038/s41598-017-02129-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 04/06/2017] [Indexed: 12/14/2022] Open
Abstract
The Kv3.4 channel is characterized by fast inactivation and sensitivity to oxidation. However, the physiological role of Kv3.4 as an oxidation-sensitive channel has yet to be investigated. Here, we demonstrate that Kv3.4 plays a pivotal role in oxidative stress-related neural cell damage as an oxidation-sensitive channel and that HIF-1α down-regulates Kv3.4 function, providing neuroprotection. MPP+ and CoCl2 are reactive oxygen species (ROS)-generating reagents that induce oxidative stress. However, only CoCl2 decreases the expression and function of Kv3.4. HIF-1α, which accumulates in response to CoCl2 treatment, is a key factor in Kv3.4 regulation. In particular, mitochondrial Kv3.4 was more sensitive to CoCl2. Blocking Kv3.4 function using BDS-II, a Kv3.4-specific inhibitor, protected SH-SY5Y cells against MPP+-induced neural cell death. Kv3.4 inhibition blocked MPP+-induced cytochrome c release from the mitochondrial intermembrane space to the cytosol and mitochondrial membrane potential depolarization, which are characteristic features of apoptosis. Our results highlight Kv3.4 as a possible new therapeutic paradigm for oxidative stress-related diseases, including Parkinson’s disease.
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Affiliation(s)
- Min Seok Song
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea.
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Wen RJ, Huang D, Zhang Y, Liu YW. Bis(3)-tacrine inhibits the sustained potassium current in cultured rat hippocampal neurons. Physiol Res 2017; 66:539-544. [PMID: 28248535 DOI: 10.33549/physiolres.933354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Bis(3)-tacrine is a dimeric AChE inhibitor derived from tacrine with a potential to treat Alzheimer's disease. It was recently been reported to act as a fast off-rate antagonist of NMDA receptors with moderate affinity. In the present study, we aimed to explore whether bis(3)-tacrine could modulate the function of native sustained potassium current in cultured rat hippocampal neurons using whole-cell patch-clamp technique. We found that bis(3)-tacrine inhibited the amplitude of sustained potassium current in a reversible and concentration-dependent manner, with a potency two orders of magnitude higher than that of tacrine. The inhibition was voltage-independent between 0 to +60 mV. The IC(50) values for bis(3)-tacrine and tacrine inhibition of sustained potassium current were 0.45+/-0.07 and 50.5+/-4.8 microM, respectively. I-V curves showed a more potent inhibition of sustained potassium current by bis(3)-tacrine (1 microM) compared to tacrine at the same concentration. Bis(3)-tacrine hyperpolarized the activation curve of the current by 11.2 mV, albeit leaving the steady-state inactivation of the current unaffected.
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Affiliation(s)
- R-J Wen
- Department of Physiology, School of Medicine, Jianghan University, Wuhan, People's Republic of China; Department of Anatomy, School of Medicine, Jianghan University, Wuhan, People's Republic of China.
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Serotonin type-1D receptor stimulation of A-type K(+) channel decreases membrane excitability through the protein kinase A- and B-Raf-dependent p38 MAPK pathways in mouse trigeminal ganglion neurons. Cell Signal 2016; 28:979-88. [PMID: 27156838 DOI: 10.1016/j.cellsig.2016.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 01/09/2023]
Abstract
Although recent studies have implicated serotonin 5-HT1B/D receptors in the nociceptive sensitivity of primary afferent neurons, the underlying molecular and cellular mechanisms remain unclear. In this study, we identified a novel functional role of the 5-HT1D receptor subtype in regulating A-type potassium (K(+)) currents (IA) as well as membrane excitability in small trigeminal ganglion (TG) neurons. We found that the selective activation of 5-HT1D, rather than 5-HT1B, receptors reversibly increased IA, while the sustained delayed rectifier K(+) current was unaffected. The 5-HT1D-mediated IA increase was associated with a depolarizing shift in the voltage dependence of inactivation. Blocking G-protein signaling with pertussis toxin or by intracellular application of a selective antibody raised against Gαo or Gβ abolished the 5-HT1D effect on IA. Inhibition of protein kinase A (PKA), but not of phosphatidylinositol 3-kinase or protein kinase C, abolished the 5-HT1D-mediated IA increase. Analysis of phospho-p38 (p-p38) revealed that activation of 5-HT1D, but not 5-HT1B, receptors significantly activated p38, while p-ERK and p-JNK were unaffected. The p38 MAPK inhibitor SB203580, but not its inactive analogue SB202474, and inhibition of B-Raf blocked the 5-HT1D-mediated IA response. Functionally, we observed a significantly decreased action potential firing rate induced by the 5-HT1D receptors; pretreatment with 4-aminopyridine abolished this effect. Taken together, these results suggest that the activation of 5-HT1D receptors selectively enhanced IA via the Gβγ of the Go-protein, PKA, and the sequential B-Raf-dependent p38 MAPK signaling cascade. This 5-HT1D receptor effect may contribute to neuronal hypoexcitability in small TG neurons.
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Shafeghat N, Heidarinejad M, Murata N, Nakamura H, Inoue T. Optical detection of neuron connectivity by random access two-photon microscopy. J Neurosci Methods 2016; 263:48-56. [PMID: 26851307 DOI: 10.1016/j.jneumeth.2016.01.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 12/24/2015] [Accepted: 01/26/2016] [Indexed: 01/28/2023]
Abstract
BACKGROUND Knowledge about the distribution, strength, and direction of synaptic connections within neuronal networks are crucial for understanding brain function. Electrophysiology using multiple electrodes provides a very high temporal resolution, but does not yield sufficient spatial information for resolving neuronal connection topology. Optical recording techniques using single-cell resolution have provided promise for providing spatial information. Although calcium imaging from hundreds of neurons has provided a novel view of the neural connections within the network, the kinetics of calcium responses are not fast enough to resolve each action potential event with high fidelity. Therefore, it is not possible to detect the direction of neuronal connections. NEW METHOD We took advantage of the fast kinetics and large dynamic range of the DiO/DPA combination of voltage sensitive dye and the fast scan speed of a custom-made random-access two-photon microscope to resolve each action potential event from multiple neurons in culture. RESULTS Long-duration recording up to 100min from cultured hippocampal neurons yielded sufficient numbers of spike events for analyzing synaptic connections. Cross-correlation analysis of neuron pairs clearly distinguished synaptically connected neuron pairs with the connection direction. COMPARISON WITH EXISTING METHOD The long duration recording of action potentials with voltage-sensitive dye utilized in the present study is much longer than in previous studies. Simultaneous optical voltage and calcium measurements revealed that voltage-sensitive dye is able to detect firing events more reliably than calcium indicators. CONCLUSIONS This novel method reveals a new view of the functional structure of neuronal networks.
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Affiliation(s)
- Nasrin Shafeghat
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Morteza Heidarinejad
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Noboru Murata
- Department of Electrical Engineering and Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Hideki Nakamura
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Takafumi Inoue
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
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29
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Delgado-Ramírez M, Morán-Zendejas R, Aréchiga-Figueroa IA, Toro-Castillo C, Ramírez-Martínez JF, Rodríguez-Menchaca AA. Modulation of the voltage-gated potassium channel Kv2.1 by the anti-tumor alkylphospholipid perifosine. Pharmacol Rep 2015; 68:457-61. [PMID: 26922553 DOI: 10.1016/j.pharep.2015.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 11/10/2015] [Accepted: 11/13/2015] [Indexed: 12/28/2022]
Abstract
BACKGROUND The aim of the present study was to assess the effects of perifosine-a third generation alkylphospholipid analog with anti-tumor properties-on the activity of Kv2.1 channels. METHODS The whole-cell patch clamp technique was applied to follow the modulatory effect of perifosine on Kv2.1 channels expressed in HEK293 cells. RESULTS Obtained data provide evidence that perifosine application decreases the whole cell Kv2.1 currents in a concentration-independent manner. Perifosine induces a hyperpolarizing shift in the voltage dependence of Kv2.1 channels inactivation without altering the voltage dependence of channels activation. The kinetics of Kv2.1 closed-state inactivation was accelerated by perifosine, with no significant effects on the recovery rate from inactivation. CONCLUSIONS Taken together, these results show that perifosine modified the Kv2.1 inactivation gating resulting in a decrease of the current amplitude. These data will help to elucidate the mechanism of action of this promising anti-cancer drug on ion channels and their possible implications.
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Affiliation(s)
- Mayra Delgado-Ramírez
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Rita Morán-Zendejas
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Ivan A Aréchiga-Figueroa
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Carmen Toro-Castillo
- Departamento de Ciencias Computacionales, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Jalisco, México
| | - Juan F Ramírez-Martínez
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Aldo A Rodríguez-Menchaca
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México.
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Enhanced Firing in NTS Induced by Short-Term Sustained Hypoxia Is Modulated by Glia-Neuron Interaction. J Neurosci 2015; 35:6903-17. [PMID: 25926465 DOI: 10.1523/jneurosci.4598-14.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Humans ascending to high altitudes are submitted to sustained hypoxia (SH), activating peripheral chemoreflex with several autonomic and respiratory responses. Here we analyzed the effect of short-term SH (24 h, FIO210%) on the processing of cardiovascular and respiratory reflexes using an in situ preparation of rats. SH increased both the sympatho-inhibitory and bradycardiac components of baroreflex and the sympathetic and respiratory responses of peripheral chemoreflex. Electrophysiological properties and synaptic transmission in the nucleus tractus solitarius (NTS) neurons, the first synaptic station of afferents of baroreflexes and chemoreflexes, were evaluated using brainstem slices and whole-cell patch-clamp. The second-order NTS neurons were identified by previous application of fluorescent tracer onto carotid body for chemoreceptor afferents or onto aortic depressor nerve for baroreceptor afferents. SH increased the intrinsic excitability of NTS neurons. Delayed excitation, caused by A-type potassium current (IKA), was observed in most of NTS neurons from control rats. The IKA amplitude was higher in identified second-order NTS neurons from control than in SH rats. SH also blunted the astrocytic inhibition of IKA in NTS neurons and increased the synaptic transmission in response to afferent fibers stimulation. The frequency of spontaneous excitatory currents was also increased in neurons from SH rats, indicating that SH increased the neurotransmission by presynaptic mechanisms. Therefore, short-term SH changed the glia-neuron interaction, increasing the excitability and excitatory transmission of NTS neurons, which may contribute to the observed increase in the reflex sensitivity of baroreflex and chemoreflex in in situ preparation.
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Meneses D, Mateos V, Islas G, Barral J. G-protein-coupled inward rectifier potassium channels involved in corticostriatal presynaptic modulation. Synapse 2015; 69:446-52. [DOI: 10.1002/syn.21833] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 06/01/2015] [Accepted: 06/16/2015] [Indexed: 01/13/2023]
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Sforna L, D'Adamo MC, Servettini I, Guglielmi L, Pessia M, Franciolini F, Catacuzzeno L. Expression and function of a CP339,818-sensitive K⁺ current in a subpopulation of putative nociceptive neurons from adult mouse trigeminal ganglia. J Neurophysiol 2015; 113:2653-65. [PMID: 25652918 PMCID: PMC4416569 DOI: 10.1152/jn.00379.2014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 02/02/2015] [Indexed: 01/15/2023] Open
Abstract
Trigeminal ganglion (TG) neurons are functionally and morphologically heterogeneous, and the molecular basis of this heterogeneity is still not fully understood. Here we describe experiments showing that a subpopulation of neurons expresses a delayed-rectifying K(+) current (IDRK) with a characteristically high (nanomolar) sensitivity to the dihydroquinoline CP339,818 (CP). Although submicromolar CP has previously been shown to selectively block Kv1.3 and Kv1.4 channels, the CP-sensitive IDRK found in TG neurons could not be associated with either of these two K(+) channels. It could neither be associated with Kv2.1 channels homomeric or heteromerically associated with the Kv9.2, Kv9.3, or Kv6.4 subunits, whose block by CP, tested using two-electrode voltage-clamp recordings from Xenopus oocytes, resulted in the low micromolar range, nor to the Kv7 subfamily, given the lack of blocking efficacy of 3 μM XE991. Within the group of multiple-firing neurons considered in this study, the CP-sensitive IDRK was preferentially expressed in a subpopulation showing several nociceptive markers, such as small membrane capacitance, sensitivity to capsaicin, and slow afterhyperpolarization (AHP); in these neurons the CP-sensitive IDRK controls the membrane resting potential, the firing frequency, and the AHP duration. A biophysical study of the CP-sensitive IDRK indicated the presence of two kinetically distinct components: a fast deactivating component having a relatively depolarized steady-state inactivation (IDRKf) and a slow deactivating component with a more hyperpolarized V1/2 for steady-state inactivation (IDRKs).
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Affiliation(s)
- Luigi Sforna
- Dipartimento di Chimica, Biologia e Biotecnologie, Universitá di Perugia, Perugia, Italy; and
| | - Maria Cristina D'Adamo
- Dipartimento di Medicina Sperimentale, Facoltá di Medicina e Chirurgia, Universitá di Perugia, Perugia, Italy
| | - Ilenio Servettini
- Dipartimento di Medicina Sperimentale, Facoltá di Medicina e Chirurgia, Universitá di Perugia, Perugia, Italy
| | - Luca Guglielmi
- Dipartimento di Medicina Sperimentale, Facoltá di Medicina e Chirurgia, Universitá di Perugia, Perugia, Italy
| | - Mauro Pessia
- Dipartimento di Medicina Sperimentale, Facoltá di Medicina e Chirurgia, Universitá di Perugia, Perugia, Italy
| | - Fabio Franciolini
- Dipartimento di Chimica, Biologia e Biotecnologie, Universitá di Perugia, Perugia, Italy; and
| | - Luigi Catacuzzeno
- Dipartimento di Chimica, Biologia e Biotecnologie, Universitá di Perugia, Perugia, Italy; and
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Kim JM, Park SW, Lin HY, Shin KC, Sung DJ, Kim JG, Cho H, Kim B, Bae YM. Blockade of voltage-gated K+ currents in rat mesenteric arterial smooth muscle cells by MK801. J Pharmacol Sci 2015; 127:92-102. [DOI: 10.1016/j.jphs.2014.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/28/2014] [Accepted: 11/04/2014] [Indexed: 02/08/2023] Open
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Aslanidis A, Karlstetter M, Walczak Y, Jägle H, Langmann T. RETINA-specific expression of Kcnv2 is controlled by cone-rod homeobox (Crx) and neural retina leucine zipper (Nrl). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:31-41. [PMID: 24664678 DOI: 10.1007/978-1-4614-3209-8_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Cone dystrophy with supernormal rod response (CDSRR) is an autosomal recessive disorder that leads to progressive retinal degeneration with a distinct electroretinogram (ERG) phenotype. CDSRR patients show reduced sensitivity to dim light, augmented response to suprathreshold light and reduced response to flicker. The disorder is caused by mutations in the KCNV2 gene, which encodes the Kv11.1 subunit of a voltage-gated potassium channel. Here, we studied the retina-specific expression and cis-regulatory activity of the murine Kcnv2 gene using electroporation of explanted retinas. Using qRT-PCR profiling of early postnatal retinas, we showed that Kcnv2 expression increased towards P14, which marks the beginning of visual activity in mice. In vivo electroporation of GFP-Kcnv2 expressing plasmids revealed that Kv11.1 localizes to the inner segment membranes of adult P21 photoreceptors. Using bioinformatic prediction and chromatin immunoprecipitation (ChIP), we identified two Crx binding sites (CBS) and one Nrl binding site (NBS) in the Kcnv2 promoter. Reporter electroporation of the wild type promoter region induced strong DsRed expression, indicating high regulatory activity, whereas shRNA-mediated knockdown of Crx and Nrl resulted in reduced Kcnv2 promoter activity and low endogenous Kcnv2 mRNA expression in the retina. Site-directed mutagenesis of the CBS and NBS demonstrated that CBS2 is crucial for Kcnv2 promoter activity. We conclude that nucleotide changes in evolutionary conserved CBS could impact retina-specific expression levels of Kcnv2.
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Affiliation(s)
- Alexander Aslanidis
- Department of Ophthalmology, University of Cologne, Joseph-Stelzmann-Str. 9, 50931, Cologne, Germany
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McCord MC, Kullmann PH, He K, Hartnett KA, Horn JP, Lotan I, Aizenman E. Syntaxin-binding domain of Kv2.1 is essential for the expression of apoptotic K+ currents. J Physiol 2014; 592:3511-21. [PMID: 24928958 DOI: 10.1113/jphysiol.2014.276964] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Intracellular signalling cascades triggered by oxidative injury can lead to upregulation of Kv2.1 K(+) channels at the plasma membrane of dying neurons. Membrane incorporation of new channels is necessary for enhanced K(+) efflux and a consequent reduction of intracellular K(+) that facilitates apoptosis. We showed previously that the observed increase in K(+) currents is a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated process, and that the SNARE protein syntaxin binds directly to Kv2.1 channels. In the present study, we tested whether disrupting the interaction of Kv2.1 and syntaxin promoted the survival of cortical neurons following injury. Syntaxin is known to bind to Kv2.1 in a domain comprising amino acids 411-522 of the channel's cytoplasmic C terminus (C1a). Here we show that this domain is required for the apoptotic K(+) current enhancement. Moreover, expression of an isolated, Kv2.1-derived C1a peptide is sufficient to suppress the injury-induced increase in currents by interfering with Kv2.1/syntaxin binding. By subdividing the C1a peptide, we were able to localize the syntaxin binding site on Kv2.1 to the most plasma membrane-distal residues of C1a. Importantly, expression of this peptide segment in neurons prevented the apoptotic K(+) current enhancement and cell death following an oxidative insult, without greatly impairing baseline K(+) currents or normal electrical profiles of neurons. These results establish that binding of syntaxin to Kv2.1 is crucial for the manifestation of oxidant-induced apoptosis, and thereby reveal a potential new direction for therapeutic intervention in the treatment of neurodegenerative disorders.
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Affiliation(s)
- Meghan C McCord
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Paul H Kullmann
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Kai He
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Karen A Hartnett
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - John P Horn
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Ilana Lotan
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Ramat Aviv, 69978, Israel
| | - Elias Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
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Kv4 channels underlie A-currents with highly variable inactivation time courses but homogeneous other gating properties in the nucleus tractus solitarii. Pflugers Arch 2014; 467:789-803. [PMID: 24872163 DOI: 10.1007/s00424-014-1533-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 04/18/2014] [Accepted: 05/08/2014] [Indexed: 10/25/2022]
Abstract
In the nucleus of the tractus solitarii (NTS), a large proportion of neurones express transient A-type potassium currents (I KA) having deep influence on the fidelity of the synaptic transmission of the visceral primary afferent inputs to second-order neurones. Up to now, the strong impact of I KA within the NTS was considered to result exclusively from its variation in amplitude, and its molecular correlate(s) remained unknown. In order to identify which Kv channels underlie I KA in NTS neurones, the gating properties and the pharmacology of this current were determined using whole cell patch clamp recordings in slices. Complementary information was brought by immunohistochemistry. Strikingly, two neurone subpopulations characterized by fast or slow inactivation time courses (respectively about 50 and 200 ms) were discriminated. Both characteristics matched those of the Kv4 channel subfamily. The other gating properties, also matching the Kv4 channel ones, were homogeneous through the NTS. The activation and inactivation occurred at membrane potentials around the threshold for generating action potentials, and the time course of recovery from inactivation was rapid. Pharmacologically, I KA in NTS neurones was found to be resistant to tetraethylammonium (TEA), sea anemone toxin blood-depressing substance (BDS) and dendrotoxin (DTX), whereas Androctonus mauretanicus mauretanicus toxin 3 (AmmTX3), a scorpion toxin of the α-KTX 15 family that has been shown to block all the members of the Kv4 family, inhibited 80 % of I KA irrespectively of its inactivation time course. Finally, immunohistochemistry data suggested that, among the Kv4 channel subfamily, Kv4.3 is the prevalent subunit expressed in the NTS.
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Wehrspaun CC, Ponting CP, Marques AC. Brain-expressed 3'UTR extensions strengthen miRNA cross-talk between ion channel/transporter encoding mRNAs. Front Genet 2014; 5:41. [PMID: 24616735 PMCID: PMC3935148 DOI: 10.3389/fgene.2014.00041] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 02/03/2014] [Indexed: 01/28/2023] Open
Abstract
Why protein-coding genes express transcripts with longer 3′untranslated regions (3′UTRs) in the brain rather than in other tissues remains poorly understood. Given the established role of 3′UTRs in post-transcriptional regulation of transcript abundance and their recently highlighted contributions to miRNA-mediated cross-talk between mRNAs, we hypothesized that 3′UTR lengthening enhances coordinated expression between functionally-related genes in the brain. To test this hypothesis, we annotated 3′UTRs of human brain-expressed genes and found that transcripts encoding ion channels or transporters are specifically enriched among those genes expressing their longest 3′UTR extension in this tissue. These 3′UTR extensions have high density of response elements predicted for those miRNAs that are specifically expressed in the human frontal cortex (FC). Importantly, these miRNA response elements are more frequently shared among ion channel/transporter-encoding mRNAs than expected by chance. This indicates that miRNA-mediated cross-talk accounts, at least in part, for the observed coordinated expression of ion channel/transporter genes in the adult human brain. We conclude that extension of these genes' 3′UTRs enhances the miRNA-mediated cross-talk among their transcripts which post-transcriptionally regulates their mRNAs' relative levels.
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Affiliation(s)
- Claudia C Wehrspaun
- Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK ; Section on Neuropathology, Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, IRP, NIMH, National Institutes of Health Bethesda, MD, USA
| | - Chris P Ponting
- Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK ; MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
| | - Ana C Marques
- Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK ; MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
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Xie C, Su H, Guo T, Yan Y, Peng X, Cao R, Wang Y, Chen P, Wang X, Liang S. Synaptotagmin I delays the fast inactivation of Kv1.4 channel through interaction with its N-terminus. Mol Brain 2014; 7:4. [PMID: 24423395 PMCID: PMC3896893 DOI: 10.1186/1756-6606-7-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 01/11/2014] [Indexed: 12/01/2022] Open
Abstract
Background The voltage-gated potassium channel Kv1.4 is an important A-type potassium channel and modulates the excitability of neurons in central nervous system. Analysis of the interaction between Kv1.4 and its interacting proteins is helpful to elucidate the function and mechanism of the channel. Results In the present research, synaptotagmin I was for the first time demonstrated to be an interacting protein of Kv1.4 and its interaction with Kv1.4 channel did not require the mediation of other synaptic proteins. Using patch-clamp technique, synaptotagmin I was found to delay the inactivation of Kv1.4 in HEK293T cells in a Ca2+-dependent manner, and this interaction was proven to have specificity. Mutagenesis experiments indicated that synaptotagmin I interacted with the N-terminus of Kv1.4 and thus delayed its N-type fast inactivation. Conclusion These data suggest that synaptotagmin I is an interacting protein of Kv1.4 channel and, as a negative modulator, may play an important role in regulating neuronal excitability and synaptic efficacy.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Xianchun Wang
- Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, P, R, China.
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Amaya F, Izumi Y, Matsuda M, Sasaki M. Tissue injury and related mediators of pain exacerbation. Curr Neuropharmacol 2014; 11:592-7. [PMID: 24396335 PMCID: PMC3849785 DOI: 10.2174/1570159x11311060003] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 06/13/2013] [Accepted: 07/12/2013] [Indexed: 01/03/2023] Open
Abstract
Tissue injury and inflammation result in release of various mediators that promote ongoing pain or pain hypersensitivity against mechanical, thermal and chemical stimuli. Pro-nociceptive mediators activate primary afferent neurons directly or indirectly to enhance nociceptive signal transmission to the central nervous system. Excitation of primary afferents by peripherally originating mediators, so-called “peripheral sensitization”, is a hallmark of tissue injury-related pain. Many kinds of pro-nociceptive mediators, including ATP, glutamate, kinins, cytokines and tropic factors, synthesized at the damaged tissue, contribute to the development of peripheral sensitization. In the present review we will discuss the molecular mechanisms of peripheral sensitization following tissue injury.
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Affiliation(s)
- Fumimasa Amaya
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kajiicho 465, Kamigyo-Ku, Kyoto 602-8566, Japan
| | - Yuta Izumi
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kajiicho 465, Kamigyo-Ku, Kyoto 602-8566, Japan
| | - Megumi Matsuda
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kajiicho 465, Kamigyo-Ku, Kyoto 602-8566, Japan
| | - Mika Sasaki
- Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kajiicho 465, Kamigyo-Ku, Kyoto 602-8566, Japan
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Wang W, Kim HJ, Lv P, Tempel B, Yamoah EN. Association of the Kv1 family of K+ channels and their functional blueprint in the properties of auditory neurons as revealed by genetic and functional analyses. J Neurophysiol 2013; 110:1751-64. [PMID: 23864368 DOI: 10.1152/jn.00290.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Developmental plasticity in spiral ganglion neurons (SGNs) ensues from profound alterations in the functional properties of the developing hair cell (HC). For example, prehearing HCs are spontaneously active. However, at the posthearing stage, HC membrane properties transition to graded receptor potentials. The dendrotoxin (DTX)-sensitive Kv1 channel subunits (Kv1.1, 1.2, and 1.6) shape the firing properties and membrane potential of SGNs, and the expression of the channel undergoes developmental changes. Because of the stochastic nature of Kv subunit heteromultimerization, it has been difficult to determine physiologically relevant subunit-specific interactions and their functions in the underlying mechanisms of Kv1 channel plasticity in SGNs. Using Kcna2 null mutant mice, we demonstrate a surprising paradox in changes in the membrane properties of SGNs. The resting membrane potential of Kcna2(-/-) SGNs was significantly hyperpolarized compared with that of age-matched wild-type (WT) SGNs. Analyses of outward currents in the mutant SGNs suggest an apparent approximately twofold increase in outward K(+) currents. We show that in vivo and in vitro heteromultimerization of Kv1.2 and Kv1.4 α-subunits underlies the striking and unexpected alterations in the properties of SGNs. The results suggest that heteromeric interactions of Kv1.2 and Kv1.4 dominate the defining features of Kv1 channels in SGNs.
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Affiliation(s)
- Wenying Wang
- Program in Communication Science, Center for Neuroscience, University of California, Davis, School of Medicine, Davis, California
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Guo Q, Jiang YJ, Jin H, Jiang XH, Gu B, Zhang YM, Wang JG, Qin ZH, Tao J. Modulation of A-type K+ channels by the short-chain cobrotoxin through the protein kinase C-delta isoform decreases membrane excitability in dorsal root ganglion neurons. Biochem Pharmacol 2013; 85:1352-62. [DOI: 10.1016/j.bcp.2013.02.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/12/2013] [Accepted: 02/12/2013] [Indexed: 12/15/2022]
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Peng BW, Justice JA, He XH, Sanchez RM. Decreased A-currents in hippocampal dentate granule cells after seizure-inducing hypoxia in the immature rat. Epilepsia 2013; 54:1223-31. [PMID: 23815572 DOI: 10.1111/epi.12150] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2013] [Indexed: 11/29/2022]
Abstract
PURPOSE Cerebral hypoxia is a major cause of neonatal seizures, and can lead to epilepsy. Pathologic anatomic and physiologic changes in the dentate gyrus have been associated with epileptogenesis in many experimental models, as this region is widely believed to gate the propagation of limbic seizures. However, the consequences of hypoxia-induced seizures for the immature dentate gyrus have not been extensively examined. METHODS Seizures were induced by global hypoxia (5-7% O2 for 15 min) in rat pups on postnatal day 10. Whole-cell voltage-clamp recordings were used to examine A-type potassium currents (IA ) in dentate granule cells in hippocampal slices obtained 1-17 days after hypoxia treatment. KEY FINDINGS Seizure-inducing hypoxia resulted in decreased maximum IA amplitude in dentate granule cells recorded within the first week but not at later times after hypoxia treatment. The decreased IA amplitude was not associated with changes in the voltage-dependence of activation or inactivation removal, or in sensitivity to inhibition by 4-aminopyridine (4-AP). However, consistent with the role of IA in shaping firing patterns, we observed in the hypoxia group a significantly decreased latency to first spike with depolarizing current injection from hyperpolarized potentials. These differences were not associated with changes in resting membrane potential or input resistance, and were eliminated by application of 10 m 4-AP. SIGNIFICANCE Given the role of IA to slow action potential firing, decreased IA could contribute to long-term hippocampal pathology after neonatal seizure-inducing hypoxia by increasing dentate granule cell excitability during a critical window of activity-dependent hippocampal maturation.
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Affiliation(s)
- Bi-Wen Peng
- Department of Physiology, Wuhan University School of Basic Medical Sciences, Wuhan, Hubei, China
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Winston JH, Sarna SK. Developmental origins of functional dyspepsia-like gastric hypersensitivity in rats. Gastroenterology 2013; 144:570-579.e3. [PMID: 23142231 PMCID: PMC3578170 DOI: 10.1053/j.gastro.2012.11.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 10/10/2012] [Accepted: 11/06/2012] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Gastric hypersensitivity (GHS) contributes to epigastric pain in patients with functional dyspepsia (FD); the etiology and cellular mechanisms of this dysfunction remain unknown. We investigated whether inflammatory insult to the colons of neonatal rats induced GHS in adult life. METHODS We used cellular, molecular, and in vivo approaches to investigate the mechanisms of GHS in adult rats subjected to neonatal colonic insult by intraluminal administration of trinitrobenzene sulfonic acid; controls received saline. Six to 8 weeks later, rats were evaluated for GHS and tissue was collected for molecular experiments. RESULTS Inflammatory insult to the colon on post-natal day 10 caused an aberrant increase of corticosterone on post-natal day 15 and induced GHS in adult life. We called these FD-like rats. Inhibition of glucocorticoid receptors after neonatal insult blocked the induction of GHS in adult rats. The aberrant increase of plasma corticosterone in neonates increased the plasma concentration of norepinephrine, nerve growth factor in the gastric fundus muscularis externae, brain-derived neurotrophic factor in the thoracic dorsal root ganglia and spinal cord, and down-regulated K(v)1.1 messenger RNA in thoracic dorsal root ganglia without affecting the expression of K(v)1.4, Na(v)1.8, TrpA1, TrpV1, or P2X3 in FD-like rats. Inhibition of glucocorticoid receptors during neonatal insult or the inhibition of adrenergic receptors, nerve growth factor, or brain-derived neurotrophic factor in FD-like rats suppressed GHS. The intrathecal administration of small interfering RNAs against K(v)1.1 increased GHS in naive rats. CONCLUSIONS Inflammatory insult to the colons of rat pups leads to GHS in adult life. GHS is caused by altered expression of genes encoding neurotrophins and ion channels, and altered activity of the sympathetic nervous system.
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Affiliation(s)
- John H. Winston
- Enteric Neuromuscular Disorders and Visceral Pain Center, Division of Gastroenterology, Department of Internal Medicine, The University of Texas Medical Branch at Galveston, Galveston, TX 77555-1064
| | - Sushil K. Sarna
- Enteric Neuromuscular Disorders and Visceral Pain Center, Division of Gastroenterology, Department of Internal Medicine, The University of Texas Medical Branch at Galveston, Galveston, TX 77555-1064,Department of Neuroscience and Cell Biology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555-1064
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Ovsepian SV, Steuber V, Le Berre M, O'Hara L, O'Leary VB, Dolly JO. A defined heteromeric KV1 channel stabilizes the intrinsic pacemaking and regulates the output of deep cerebellar nuclear neurons to thalamic targets. J Physiol 2013; 591:1771-91. [PMID: 23318870 DOI: 10.1113/jphysiol.2012.249706] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The output of the cerebellum to the motor axis of the central nervous system is orchestrated mainly by synaptic inputs and intrinsic pacemaker activity of deep cerebellar nuclear (DCN) projection neurons. Herein, we demonstrate that the soma of these cells is enriched with K(V)1 channels produced by mandatory multi-merization of K(V)1.1, 1.2 α and KV β2 subunits. Being constitutively active, the K(+) current (IK(V)1) mediated by these channels stabilizes the rate and regulates the temporal precision of self-sustained firing of these neurons. Placed strategically, IK(V)1 provides a powerful counter-balance to prolonged depolarizing inputs, attenuates the rebound excitation, and dampens the membrane potential bi-stability. Somatic location with low activation threshold render IK(V)1 instrumental in voltage-dependent de-coupling of the axon initial segment from the cell body of projection neurons, impeding invasion of back-propagating action potentials into the somato-dendritic compartment. The latter is also demonstrated to secure the dominance of clock-like somatic pacemaking in driving the regenerative firing activity of these neurons, to encode time variant inputs with high fidelity. Through the use of multi-compartmental modelling and retro-axonal labelling, the physiological significance of the described functions for processing and communication of information from the lateral DCN to thalamic relay nuclei is established.
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Affiliation(s)
- Saak V Ovsepian
- International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
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Wildburger NC, Laezza F. Control of neuronal ion channel function by glycogen synthase kinase-3: new prospective for an old kinase. Front Mol Neurosci 2012; 5:80. [PMID: 22811658 PMCID: PMC3397315 DOI: 10.3389/fnmol.2012.00080] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 06/20/2012] [Indexed: 12/19/2022] Open
Abstract
Glycogen synthase kinase 3 (GSK-3) is an evolutionarily conserved multifaceted ubiquitous enzyme. In the central nervous system (CNS), GSK-3 acts through an intricate network of intracellular signaling pathways culminating in a highly divergent cascade of phosphorylations that control neuronal function during development and adulthood. Accumulated evidence indicates that altered levels of GSK-3 correlate with maladaptive plasticity of neuronal circuitries in psychiatric disorders, addictive behaviors, and neurodegenerative diseases, and pharmacological interventions known to limit GSK-3 can counteract some of these deficits. Thus, targeting the GSK-3 cascade for therapeutic interventions against this broad spectrum of brain diseases has raised a tremendous interest. Yet, the multitude of GSK-3 downstream effectors poses a substantial challenge in the development of selective and potent medications that could efficiently block or modulate the activity of this enzyme. Although the full range of GSK-3 molecular targets are far from resolved, exciting new evidence indicates that ion channels regulating excitability, neurotransmitter release, and synaptic transmission, which ultimately contribute to the mechanisms underling brain plasticity and higher level cognitive and emotional processing, are new promising targets of this enzyme. Here, we will revise this new emerging role of GSK-3 in controling the activity of voltage-gated Na(+), K(+), Ca(2+) channels and ligand-gated glutamate receptors with the goal of highlighting new relevant endpoints of the neuronal GSK-3 cascade that could provide a platform for a better understanding of the mechanisms underlying the dysfunction of this kinase in the CNS and serve as a guidance for medication development against the broad range of GSK-3-linked human diseases.
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Affiliation(s)
- Norelle C. Wildburger
- Department of Pharmacology and Toxicology, University of Texas Medical BranchGalveston, TX, USA
- Neuroscience Graduate Program, University of Texas Medical BranchGalveston, TX, USA
- Sealy Center for Cancer Cell Biology, University of Texas Medical BranchGalveston, TX, USA
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical BranchGalveston, TX, USA
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical BranchGalveston, TX, USA
- Center for Addiction Research, University of Texas Medical BranchGalveston, TX, USA
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Sun W, Miao B, Wang XC, Duan JH, Ye X, Han WJ, Wang WT, Luo C, Hu SJ. Gastrodin inhibits allodynia and hyperalgesia in painful diabetic neuropathy rats by decreasing excitability of nociceptive primary sensory neurons. PLoS One 2012; 7:e39647. [PMID: 22761855 PMCID: PMC3382466 DOI: 10.1371/journal.pone.0039647] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 05/24/2012] [Indexed: 01/29/2023] Open
Abstract
Painful diabetic neuropathy (PDN) is a common complication of diabetes mellitus and adversely affects the patients' quality of life. Evidence has accumulated that PDN is associated with hyperexcitability of peripheral nociceptive primary sensory neurons. However, the precise cellular mechanism underlying PDN remains elusive. This may result in the lacking of effective therapies for the treatment of PDN. The phenolic glucoside, gastrodin, which is a main constituent of the Chinese herbal medicine Gastrodia elata Blume, has been widely used as an anticonvulsant, sedative, and analgesic since ancient times. However, the cellular mechanisms underlying its analgesic actions are not well understood. By utilizing a combination of behavioral surveys and electrophysiological recordings, the present study investigated the role of gastrodin in an experimental rat model of STZ-induced PDN and to further explore the underlying cellular mechanisms. Intraperitoneal administration of gastrodin effectively attenuated both the mechanical allodynia and thermal hyperalgesia induced by STZ injection. Whole-cell patch clamp recordings were obtained from nociceptive, capsaicin-sensitive small diameter neurons of the intact dorsal root ganglion (DRG). Recordings from diabetic rats revealed that the abnormal hyperexcitability of neurons was greatly abolished by application of GAS. To determine which currents were involved in the antinociceptive action of gastrodin, we examined the effects of gastrodin on transient sodium currents (I(NaT)) and potassium currents in diabetic small DRG neurons. Diabetes caused a prominent enhancement of I(NaT) and a decrease of potassium currents, especially slowly inactivating potassium currents (I(AS)); these effects were completely reversed by GAS in a dose-dependent manner. Furthermore, changes in activation and inactivation kinetics of I(NaT) and total potassium current as well as I(AS) currents induced by STZ were normalized by GAS. This study provides a clear cellular basis for the peripheral analgesic action of gastrodin for the treatment of chronic pain, including PDN.
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Affiliation(s)
- Wei Sun
- Institute of Neuroscience, The Fourth Military Medical University, Xi’an, People’s Republic of China
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, the Fourth Military Medical University, Xi’an, People’s Republic of China
| | - Bei Miao
- Institute of Neuroscience, The Fourth Military Medical University, Xi’an, People’s Republic of China
- Jiangsu Province Key Laboratory of Anesthesiology and Center for Pain Research and Treatment, Xuzhou Medical College, Xuzhou, People’s Republic of China
| | - Xiu-Chao Wang
- Institute of Neuroscience, The Fourth Military Medical University, Xi’an, People’s Republic of China
| | - Jian-Hong Duan
- Institute of Neuroscience, The Fourth Military Medical University, Xi’an, People’s Republic of China
| | - Xin Ye
- Department of Endocrinology, The 451th Hospital of People’s Liberation Army, Xi’an, People’s Republic of China
| | - Wen-Juan Han
- Institute of Neuroscience, The Fourth Military Medical University, Xi’an, People’s Republic of China
| | - Wen-Ting Wang
- Institute of Neuroscience, The Fourth Military Medical University, Xi’an, People’s Republic of China
| | - Ceng Luo
- Institute of Neuroscience, The Fourth Military Medical University, Xi’an, People’s Republic of China
| | - San-Jue Hu
- Institute of Neuroscience, The Fourth Military Medical University, Xi’an, People’s Republic of China
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Zhang Y, Jiang D, Zhang Y, Jiang X, Wang F, Tao J. Neuromedin U type 1 receptor stimulation of A-type K+ current requires the βγ subunits of Go protein, protein kinase A, and extracellular signal-regulated kinase 1/2 (ERK1/2) in sensory neurons. J Biol Chem 2012; 287:18562-72. [PMID: 22493291 DOI: 10.1074/jbc.m111.322271] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Although neuromedin U (NMU) has been implicated in analgesia, the detailed mechanisms still remain unclear. In this study, we identify a novel functional role of NMU type 1 receptor (NMUR1) in regulating the transient outward K(+) currents (I(A)) in small dorsal root ganglion (DRG) neurons. We found that NMU reversibly increased I(A) in a dose-dependent manner, instead the sustained delayed rectifier K(+) current (I(DR)) was not affected. This NMU-induced I(A) increase was pertussis toxin-sensitive and was totally reversed by NMUR1 knockdown. Intracellular application of GDPβS (guanosine 5'-O-(2-thiodiphosphate)), QEHA peptide, or a selective antibody raised against the Gα(o) or Gβ blocked the stimulatory effects of NMU. Pretreatment of the cells with the protein kinase A (PKA) inhibitor or ERK inhibitor abolished the NMU-induced I(A) response, whereas inhibition of phosphatidylinositol 3-kinase or PKC had no such effects. Exposure of DRG neurons to NMU markedly induced the phosphorylation of ERK (p-ERK), whereas p-JNK or p-p38 was not affected. Moreover, the NMU-induced p-ERK increase was attenuated by PKA inhibition and activation of PKA by foskolin would mimic the NMU-induced I(A) increase. Functionally, we observed a significant decrease of the firing rate of neuronal action potential induced by NMU and pretreatment of DRG neurons with 4-AP could abolish this effect. In summary, these results suggested that NMU increases I(A) via activation of NMUR1 that couples sequentially to the downstream activities of Gβγ of the G(o) protein, PKA, and ERK, which could contribute to its physiological functions including neuronal hypoexcitability in DRG neurons.
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Affiliation(s)
- Yiming Zhang
- Department of Neurobiology, Key Laboratory of Pain Research & Therapy, Medical College of Soochow University, Suzhou 215123, China
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Abstract
Adaptation to cold temperature is mediated by RNA editing of a potassium channel in octopus neurons.
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Affiliation(s)
- Marie Ohman
- Department of Molecular Biology and Functional Genomics, Stockholm University, Stockholm, Sweden. [corrected]
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Identification of voltage-gated potassium channel subfamilies from sequence information using support vector machine. Comput Biol Med 2012; 42:504-7. [PMID: 22297432 DOI: 10.1016/j.compbiomed.2012.01.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 10/16/2011] [Accepted: 01/12/2012] [Indexed: 02/05/2023]
Abstract
Proteins belonging to different subfamilies of Voltage-gated K(+) channels (VKC) are functionally divergent. The traditional method to classify ion channels is more time consuming. Thus, it is highly desirable to develop novel computational methods for VKC subfamily classification. In this study, a support vector machine based method was proposed to predict VKC subfamilies using amino acid and dipeptide compositions. In order to remove redundant information, a novel feature selection technique was employed to single out optimized features. In the jackknife cross-validation, the proposed method (VKCPred) achieved an overall accuracy of 93.09% with 93.22% average sensitivity and 98.34% average specificity, which are superior to that of other two state-of-the-art classifiers. These results indicate that VKCPred can be efficiently used to identify and annotate voltage-gated K(+) channels' subfamilies. The VKCPred software and dataset are freely available at http://cobi.uestc.edu.cn/people/hlin/tools/VKCPred/.
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50
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Hao S, Bao YM, An LJ, Cheng W, Zhao RG, Bi J, Wang HS, Sun CS, Liu JW, Jiang B. Effects of Resibufogenin and Cinobufagin on voltage-gated potassium channels in primary cultures of rat hippocampal neurons. Toxicol In Vitro 2011; 25:1644-53. [DOI: 10.1016/j.tiv.2011.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 05/29/2011] [Accepted: 07/04/2011] [Indexed: 10/17/2022]
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