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Khan W, Chopra S, Zheng X, Liu S, Paszkowski P, Valcarce-Aspegren M, Sieu LA, Mcgill S, Mccafferty C, Blumenfeld H. Neuronal rhythmicity and cortical arousal in a mouse model of absence epilepsy. Exp Neurol 2024; 381:114925. [PMID: 39151596 DOI: 10.1016/j.expneurol.2024.114925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 07/15/2024] [Accepted: 08/13/2024] [Indexed: 08/19/2024]
Abstract
OBJECTIVES Absence seizures impair psychosocial function, yet their detailed neuronal basis remains unknown. Recent work in a rat model suggests that cortical arousal state changes prior to seizures and that single neurons show diverse firing patterns during seizures. Our aim was to extend these investigations to a mouse model with studies of neuronal activity and arousal state to facilitate future fundamental investigations of absence epilepsy. METHODS We performed in vivo extracellular single unit recordings on awake head-fixed C3H/HeJ mice. Mice were implanted with tripolar electrodes for cortical electroencephalography (EEG). Extracellular single unit recordings were obtained with glass micropipettes in the somatosensory barrel cortex, while animals ambulated freely on a running wheel. Signals were digitized and analyzed during seizures and at baseline. RESULTS Neuronal activity was recorded from 36 cortical neurons in 19 mice while EEG showed characteristic 7-8 Hz spike-wave discharges. Different single neurons showed distinct firing patterns during seizures, but the overall mean population neuronal firing rate during seizures was no different from pre-seizure baseline. However, the rhythmicity of neuronal firing during seizures was significantly increased (p < 0.001). In addition, beginning 10s prior to seizure initiation, we observed a progressive decrease in cortical high frequency (>40 Hz) EEG and an increase in lower frequency (1-39 Hz) activity suggesting decreased arousal state. SIGNIFICANCE We found that the awake head-fixed C3H/HeJ mouse model demonstrated rhythmic neuronal firing during seizures, and a decreased cortical arousal state prior to seizure onset. Unlike the rat model we did not observe an overall decrease in neuronal firing during seizures. Similarities and differences across species strengthen the ability to investigate fundamental key mechanisms. Future work in the mouse model will identify the molecular basis of neurons with different firing patterns, their role in seizure initiation and behavioral deficits, with ultimate translation to human absence epilepsy.
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Affiliation(s)
- Waleed Khan
- Department of Neurology, Yale University, School of Medicine, New Haven, CT, United States
| | - Samiksha Chopra
- Department of Neurology, Yale University, School of Medicine, New Haven, CT, United States
| | - Xinyuan Zheng
- Department of Neurology, Yale University, School of Medicine, New Haven, CT, United States; Department of Biomedical Engineering, Yale University, School of Medicine, New Haven, CT, United States
| | - Shixin Liu
- Department of Neurology, Yale University, School of Medicine, New Haven, CT, United States
| | - Patrick Paszkowski
- Department of Neurology, Yale University, School of Medicine, New Haven, CT, United States
| | | | - Lim-Anna Sieu
- Department of Neurology, Yale University, School of Medicine, New Haven, CT, United States
| | - Sarah Mcgill
- Department of Neurology, Yale University, School of Medicine, New Haven, CT, United States; Interdepartmental Neuroscience Program, Yale University, School of Medicine, New Haven, CT, United States
| | - Cian Mccafferty
- Department of Neurology, Yale University, School of Medicine, New Haven, CT, United States; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Hal Blumenfeld
- Department of Neurology, Yale University, School of Medicine, New Haven, CT, United States; Interdepartmental Neuroscience Program, Yale University, School of Medicine, New Haven, CT, United States; Department of Neuroscience, Yale University, School of Medicine, New Haven, CT, United States; Department of Neurosurgery, Yale University, School of Medicine, New Haven, CT, United States.
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Plutino S, Laghouati E, Jarre G, Depaulis A, Guillemain I, Bureau I. Barrel cortex development lacks a key stage of hyperconnectivity from deep to superficial layers in a rat model of Absence Epilepsy. Prog Neurobiol 2024; 234:102564. [PMID: 38244975 DOI: 10.1016/j.pneurobio.2023.102564] [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: 07/21/2023] [Revised: 12/04/2023] [Accepted: 12/30/2023] [Indexed: 01/22/2024]
Abstract
During development of the sensory cortex, the ascending innervation from deep to upper layers provides a temporary scaffold for the construction of other circuits that remain at adulthood. Whether an alteration in this sequence leads to brain dysfunction in neuro-developmental diseases remains unknown. Using functional approaches in a genetic model of Absence Epilepsy (GAERS), we investigated in barrel cortex, the site of seizure initiation, the maturation of excitatory and inhibitory innervations onto layer 2/3 pyramidal neurons and cell organization into neuronal assemblies. We found that cortical development in GAERS lacks the early surge of connections originating from deep layers observed at the end of the second postnatal week in normal rats and the concomitant structuring into multiple assemblies. Later on, at seizure onset (1 month old), excitatory neurons are hyper-excitable in GAERS when compared to Wistar rats. These findings suggest that early defects in the development of connectivity could promote this typical epileptic feature and/or its comorbidities.
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Affiliation(s)
| | - Emel Laghouati
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Guillaume Jarre
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Antoine Depaulis
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Isabelle Guillemain
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000 Grenoble, France
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Fontes-Dutra M, Righes Marafiga J, Santos-Terra J, Deckmann I, Brum Schwingel G, Rabelo B, Kazmierzak de Moraes R, Rockenbach M, Vendramin Pasquetti M, Gottfried C, Calcagnotto ME. GABAergic synaptic transmission and cortical oscillation patterns in the primary somatosensory area of a valproic acid rat model of autism spectrum disorder. Eur J Neurosci 2023; 57:527-546. [PMID: 36504470 DOI: 10.1111/ejn.15893] [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: 02/08/2022] [Revised: 11/20/2022] [Accepted: 11/30/2022] [Indexed: 12/14/2022]
Abstract
Autism spectrum disorder (ASD) is characterized by impaired social communication and interaction associated with repetitive or stereotyped behaviour. Prenatal valproic acid (VPA) exposure in rodents is a commonly used model of ASD. Resveratrol (RSV) has been shown to prevent interneuronal and behavioural impairments in the VPA model. We investigated the effects of prenatal VPA exposure and RSV on the GABAergic synaptic transmission, brain oscillations and on the genic expression of interneuron-associated transcription factor LHX6 in the primary somatosensory area (PSSA). Prenatal VPA exposure decreased the sIPSC and mIPSC frequencies and the sIPSC decay kinetics onto layers 4/5 pyramidal cells of PSSA. About 40% of VPA animals exhibited absence-like spike-wave discharge (SWD) events associated with behaviour arrest and increased power spectrum density of delta, beta and gamma cortical oscillations. VPA animals had reduced LHX6 expression in PSSA, but VPA animals treated with RSV had no changes on synaptic inhibition or LHX6 expression in the PSSA. SWD events associated with behaviour arrest and the abnormal increment of cortical oscillations were also absent in VPA animals treated with RSV. These findings provide new venues to investigate the role of both RSV and VPA in the pathophysiology of ASD and highlight the VPA animal model as an interesting tool to investigate pathways related to the aetiology and possible future therapies to this neuropsychiatric disorder.
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Affiliation(s)
- Mellanie Fontes-Dutra
- Translational Research Group in Autism Spectrum Disorders (GETTEA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation (INCT-NIM), Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Joseane Righes Marafiga
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Graduate Program in Biological Science: Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Júlio Santos-Terra
- Translational Research Group in Autism Spectrum Disorders (GETTEA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation (INCT-NIM), Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Iohanna Deckmann
- Translational Research Group in Autism Spectrum Disorders (GETTEA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation (INCT-NIM), Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Gustavo Brum Schwingel
- Translational Research Group in Autism Spectrum Disorders (GETTEA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation (INCT-NIM), Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Bruna Rabelo
- Translational Research Group in Autism Spectrum Disorders (GETTEA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation (INCT-NIM), Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Rafael Kazmierzak de Moraes
- Translational Research Group in Autism Spectrum Disorders (GETTEA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation (INCT-NIM), Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Marília Rockenbach
- Translational Research Group in Autism Spectrum Disorders (GETTEA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation (INCT-NIM), Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Mayara Vendramin Pasquetti
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Graduate Program in Biological Science: Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Carmem Gottfried
- Translational Research Group in Autism Spectrum Disorders (GETTEA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- National Institute of Science and Technology on Neuroimmunomodulation (INCT-NIM), Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Maria Elisa Calcagnotto
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Graduate Program in Biological Science: Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Graduate Program in Neuroscience, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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C-Met Receptors Deficiency Was Involved in Absence Seizures Development in WAG/Rij Rats. ARCHIVES OF NEUROSCIENCE 2023. [DOI: 10.5812/ans-132959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Background: A variety of receptors may be involved in the pathogenesis of absence seizures. The c-Met receptors have a critical role in modulating the GABAergic interneurons and creating a balance between excitatory and inhibitory neurotransmission, sensorimotor gating, and normal synaptic plasticity. Objectives: This study aimed to assess the changes of the c-Met receptor during the appearance of absence attacks in the experimental model of absence epilepsy. Methods: A total of 48 animals were divided into four groups of two- and six-month-old WAG/Rij and Wistar rats. Epileptic WAG/Rij rats showing SWP in electrocorticogram (ECoG) were included in the epileptic group. The two-month-old WAG/Rij rats as well as two- and six-month-old Wistar rats not exhibiting SWP in ECoG were selected as the non-epileptic. Gene (RT-PCR) and protein expression (western blotting) of c-Met receptors as well as c-Met protein distribution (immunohistochemistry) in the somatosensory cortex and hippocampus were assessed during seizure development of the absence attacks. Results: According to the study findings, a lower c-Met gene and protein expression, as well as a lower protein distribution, were observed in the hippocampus (P < 0.001, P < 0.05, and P < 0.001, respectively) and cortex (P < 0.01, P < 0.001 and P < 0.001, respectively) of the two-month-old WAG/Rij rats compared to the same-age Wistar rats. Moreover, the data revealed a reduction of hippocampal and cortical c-Met protein expression (P < 0.001, for both) in six-month-old WAG/Rij rats compared to two-month-old ones. Six-month-old WAG/Rij rats had a lower cortical c-Met gene (P < 0.05) and protein expression (P < 0.001) as well as lower hippocampal and cortical protein distribution (P < 0.05 and P < 0.001) than the same-age Wistar rats. Conclusions: In sum, the c-Met receptor was found to play a significant role in the development of absence epilepsy. This receptor, therefore, may have been considered as an effective goal for absence seizure inhibition.
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Kolesnikova TO, Demin KA, Costa FV, Zabegalov KN, de Abreu MS, Gerasimova EV, Kalueff AV. Towards Zebrafish Models of CNS Channelopathies. Int J Mol Sci 2022; 23:ijms232213979. [PMID: 36430455 PMCID: PMC9693542 DOI: 10.3390/ijms232213979] [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: 09/14/2022] [Revised: 11/06/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022] Open
Abstract
Channelopathies are a large group of systemic disorders whose pathogenesis is associated with dysfunctional ion channels. Aberrant transmembrane transport of K+, Na+, Ca2+ and Cl- by these channels in the brain induces central nervous system (CNS) channelopathies, most commonly including epilepsy, but also migraine, as well as various movement and psychiatric disorders. Animal models are a useful tool for studying pathogenesis of a wide range of brain disorders, including channelopathies. Complementing multiple well-established rodent models, the zebrafish (Danio rerio) has become a popular translational model organism for neurobiology, psychopharmacology and toxicology research, and for probing mechanisms underlying CNS pathogenesis. Here, we discuss current prospects and challenges of developing genetic, pharmacological and other experimental models of major CNS channelopathies based on zebrafish.
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Affiliation(s)
| | - Konstantin A. Demin
- Institute of Translational Biomedicine, St. Petersburg State University, 199034 St. Petersburg, Russia
- Institute of Experimental Medicine, Almazov National Medical Research Centre, Ministry of Healthcare of Russian Federation, 197341 St. Petersburg, Russia
| | - Fabiano V. Costa
- Neurobiology Program, Sirius University of Science and Technology, 354349 Sochi, Russia
| | | | - Murilo S. de Abreu
- Moscow Institute of Physics and Technology, 141701 Moscow, Russia
- Correspondence: (M.S.d.A.); (A.V.K.); Tel.: +55-54-99605-9807 (M.S.d.A.); +1-240-899-9571 (A.V.K.); Fax: +1-240-899-9571 (A.V.K.)
| | - Elena V. Gerasimova
- Neurobiology Program, Sirius University of Science and Technology, 354349 Sochi, Russia
| | - Allan V. Kalueff
- Neurobiology Program, Sirius University of Science and Technology, 354349 Sochi, Russia
- Institute of Translational Biomedicine, St. Petersburg State University, 199034 St. Petersburg, Russia
- Institute of Experimental Medicine, Almazov National Medical Research Centre, Ministry of Healthcare of Russian Federation, 197341 St. Petersburg, Russia
- Moscow Institute of Physics and Technology, 141701 Moscow, Russia
- Laboratory of Preclinical Bioscreening, Granov Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of Russian Federation, 197758 St. Petersburg, Russia
- Ural Federal University, 620002 Yekaterinburg, Russia
- Scientific Research Institute of Neurosciences and Medicine, 630117 Novosibirsk, Russia
- Correspondence: (M.S.d.A.); (A.V.K.); Tel.: +55-54-99605-9807 (M.S.d.A.); +1-240-899-9571 (A.V.K.); Fax: +1-240-899-9571 (A.V.K.)
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Szulczyk B, Pasierski M, Gawlak M. Prefrontal cortex pyramidal neurons express functional Nav1.8 tetrodotoxin-resistant sodium currents. Clin Exp Pharmacol Physiol 2021; 49:350-359. [PMID: 34750860 DOI: 10.1111/1440-1681.13610] [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: 08/12/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 11/27/2022]
Abstract
It has been repeatedly proved that Nav1.8 tetrodotoxin (TTX)-resistant sodium currents are expressed in peripheral sensory neurons where they play important role in nociception. There are very few publications that show the presence of TTX-resistant sodium currents in central neurons. The aim of this study was to assess if functional Nav1.8 TTX-resistant sodium currents are expressed in prefrontal cortex pyramidal neurons. All recordings were performed in the presence of TTX in the extracellular solution to block TTX-sensitive sodium currents. The TTX-resistant sodium current recorded in this study was mainly carried by the Nav1.8 sodium channel isoform because the Nav1.9 current was inhibited by the -65 mV holding potential that we used throughout the study. Moreover, the sodium current that we recorded was inhibited by treatment with the selective Nav1.8 inhibitor A-803467. Confocal microscopy experiments confirmed the presence of the Nav1.8 α subunit in prefrontal cortex pyramidal neurons. Activation and steady state inactivation properties of TTX-resistant sodium currents were also assessed in this study and they were similar to activation and inactivation properties of TTX-resistant sodium currents expressed in dorsal root ganglia (DRG) neurons. Moreover, this study showed that carbamazepine (60 µM) inhibited the maximal amplitude of the TTX-resistant sodium current. Furthermore, we found that carbamazepine shifts steady state inactivation curve of TTX-resistant sodium currents toward hyperpolarization. This study suggests that the Nav1.8 TTX-resistant sodium channel is expressed not only in DRG neurons, but also in cortical neurons and may be molecular target for antiepileptic drugs such as carbamazepine.
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Affiliation(s)
- Bartłomiej Szulczyk
- Department of Pharmacodynamics, The Medical University of Warsaw, Warsaw, Poland
| | - Michał Pasierski
- Department of Pharmacodynamics, The Medical University of Warsaw, Warsaw, Poland
| | - Maciej Gawlak
- Department of Pharmacodynamics, The Medical University of Warsaw, Warsaw, Poland
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Pal R, Kumar B, Akhtar MJ, Chawla PA. Voltage gated sodium channel inhibitors as anticonvulsant drugs: A systematic review on recent developments and structure activity relationship studies. Bioorg Chem 2021; 115:105230. [PMID: 34416507 DOI: 10.1016/j.bioorg.2021.105230] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 12/28/2022]
Abstract
Voltage-gated sodium channel blockers are one of the vital targets for the management of several central nervous system diseases, including epilepsy, chronic pain, psychiatric disorders, and spasticity. The voltage-gated sodium channels play a key role in controlling cellular excitability. This reduction in excitotoxicity is also applied to improve the symptoms of epileptic conditions. The effectiveness of antiepileptic drugs as sodium channel depends upon the reversible blocking of the spontaneous discharge without blocking its propagation. There are number of antiepileptic drug(s) which are in pipeline to flour the market to conquer abnormal neuronal excitability. They inhibit the seizures through the inhibition of complex voltage- and frequency-dependent ionic currents through sodium channels. Over the past decade, the sodium channel is one of the most explored targets to control or treat the seizure, but there has not been any game-changing discovery yet. Although there are large numbers of drugs approved for the treatment of epilepsy, however they are associated with several acute to chronic side effects. Many research groups have tirelessly worked for better therapeutic medication on this popular target to treat epileptic seizures. The review quotes briefly the developments of the approved examples of sodium channel blockers as anticonvulsant drugs. Medicinal chemists have tried the design and development of some more potent anticonvulsant drugs to minimize the toxicity that are discussed here, and an emphasis is given for their possible mechanism and the structure-activity relationship (SAR).
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Affiliation(s)
- Rohit Pal
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga 142001, Punjab, India
| | - Bhupinder Kumar
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga 142001, Punjab, India
| | - Md Jawaid Akhtar
- Department of Pharmaceutical Chemistry, College of Pharmacy, National University of Science and Technology, PO620, PC 130 Azaiba, Bousher, Muscat, Sultanate of Oman
| | - Pooja A Chawla
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga 142001, Punjab, India.
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Prakash C, Mishra M, Kumar P, Kumar V, Sharma D. Response of Voltage-Gated Sodium and Calcium Channels Subtypes on Dehydroepiandrosterone Treatment in Iron-Induced Epilepsy. Cell Mol Neurobiol 2021; 41:279-292. [PMID: 32318899 DOI: 10.1007/s10571-020-00851-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/14/2020] [Indexed: 12/28/2022]
Abstract
Epilepsy is a neurological disorder characterized by the occurrence of spontaneous and recurrent seizures. In post-traumatic epilepsy (PTE), the mechanism of epileptogenesis is very complex and seems to be linked with voltage-gated ion channels. Dehydroepiandrosterone (DHEA), a neurosteroid have shown beneficial effect against various neurological disorders. We investigated antiepileptic effect of DHEA with respect to expression of voltage-gated ion channels subtypes in iron-induced epilepsy. Iron (FeCl3) solution was intracartically injected to induce epilepsy in rats and DHEA was intraperitoneally administered for 21 days. Results showed markedly increased epileptiform seizures activity along with up-regulation of Nav1.1 and Nav1.6, and down-regulation of Cav2.1α at the mRNA and protein level in the cortex and hippocampus of epileptic rats. Moreover, the study demonstrated that these channels subtypes were predominantly expressed in the neurons. DHEA treatment has countered the epileptic seizures, down-regulated Nav1.1 and Nav1.6, and up-regulated Cav2.1α without affecting their cellular localization. In conclusion, the present study demonstrates antiepileptic potential of DHEA, escorted by regulation of Nav1.1, Nav1.6, and Cav2.1α subtypes in the neurons of iron-induced epileptic rats.
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Affiliation(s)
- Chandra Prakash
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Monika Mishra
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Pavan Kumar
- Department of Developmental Neurogenetics, Medical University of South Carolina, Charleston, SC, USA
| | - Vikas Kumar
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Deepak Sharma
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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Terlau J, Yang J, Khastkhodaei Z, Seidenbecher T, Luhmann HJ, Pape H, Lüttjohann A. Spike‐wave discharges in absence epilepsy: segregation of electrographic components reveals distinct pathways of seizure activity. J Physiol 2020; 598:2397-2414. [DOI: 10.1113/jp279483] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/24/2020] [Indexed: 12/15/2022] Open
Affiliation(s)
- Jonas Terlau
- Institute of Physiology IWestfälische Wilhelms University Münster Münster Germany
| | - Jenq‐Wei Yang
- Institute of PhysiologyUniversity Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Zeinab Khastkhodaei
- Institute of PhysiologyUniversity Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Thomas Seidenbecher
- Institute of Physiology IWestfälische Wilhelms University Münster Münster Germany
| | - Heiko J. Luhmann
- Institute of PhysiologyUniversity Medical Center of the Johannes Gutenberg University Mainz Mainz Germany
| | - Hans‐Christian Pape
- Institute of Physiology IWestfälische Wilhelms University Münster Münster Germany
| | - Annika Lüttjohann
- Institute of Physiology IWestfälische Wilhelms University Münster Münster Germany
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Halász P, Bódizs R, Ujma PP, Fabó D, Szűcs A. Strong relationship between NREM sleep, epilepsy and plastic functions - A conceptual review on the neurophysiology background. Epilepsy Res 2019; 150:95-105. [PMID: 30712997 DOI: 10.1016/j.eplepsyres.2018.11.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 10/08/2018] [Accepted: 11/15/2018] [Indexed: 12/15/2022]
Abstract
The aim of this review is to summarize and discuss the strong bond between NREM sleep and epilepsy underlain by the shared link and effect on brain plasticity. Beyond the seizure occurrence rate, sleep relatedness may manifest in the enhancement of interictal epileptic discharges (spikes and pathological ripples). The number of the discharges as well as their propagation increase during NREM sleep, unmasking the epileptic network that is hidden during wakefulness. The interictal epileptic discharges associate with different sleep constituents (sleep slow waves, spindling and high frequency oscillations); known to play essential role in memory and learning. We highlight three major groups of epilepsies, in which sleep-related plastic functions suffer an epileptic derailment. In absence epilepsy mainly involving the thalamo-cortical system, sleep spindles transform to generalized spike-wave activity. In mesio-temporal epilepsy affecting the hippocampal declarative memory system, the sharp wave ripples derail to dysfunctional epileptic oscillations (spikes and pathological ripples). Idiopathic childhood epilepsies affecting the perisylvian network may progress to catastrophic status electricus during NREM sleep. In these major epilepsies, NREM sleep has a pivotal role in the development and course of the disorder. Epilepsy is born in-, and exhibits its pathological properties during NREM sleep. Interictal discharges are important causative agents in this process.
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Affiliation(s)
- Péter Halász
- National Institute of Clinical Neuroscience, Amerikai út 57. Budapest, H-1145, Hungary.
| | - Róbert Bódizs
- Semmelweis University, Institute of Behavioral Sciences, Nagyvárad tér 4, Budapest, H-1089, Hungary
| | - Péter Przemyslaw Ujma
- Semmelweis University, Institute of Behavioral Sciences, Nagyvárad tér 4, Budapest, H-1089, Hungary
| | - Dániel Fabó
- National Institute of Clinical Neuroscience, Amerikai út 57. Budapest, H-1145, Hungary
| | - Anna Szűcs
- National Institute of Clinical Neuroscience, Amerikai út 57. Budapest, H-1145, Hungary
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Kumar V, Prakash C, Singh R, Sharma D. Curcumin's antiepileptic effect, and alterations in Na v1.1 and Na v1.6 expression in iron-induced epilepsy. Epilepsy Res 2018; 150:7-16. [PMID: 30605865 DOI: 10.1016/j.eplepsyres.2018.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 12/08/2018] [Accepted: 12/14/2018] [Indexed: 10/27/2022]
Abstract
The present study was carried out to evaluate: the antiepileptic effect of dietary curcumin, and the effect of epileptic state and curcumin on the molecular expression of voltage-activated Na+ channel subtypes Nav1.1 and Nav1.6 in the iron-induced experimental epilepsy in the rat. Rats were divided into four groups; Group I (control rats), Group II (epileptic rats), Group III (curcumin-fed epileptic rats), and Group IV (curcumin-fed rats). Curcumin was fed chronically to rats approximately at the dose of 100 mg/kg body wt. The animals were made epileptic by intracortical injection of FeCl3. The mRNA and protein expressions of Nav1.1 and Nav1.6 were examined by RT-PCR analysis and immuno-histochemistry. Results showed a significant increase (upregulation) in the expression of both Nav1.1 and Nav1.6 with seizure activity in the cortex and hippocampus of epileptic rats. Epileptic rats fed with curcumin showed a marked decrease in epileptiform activity, and reduced mRNA and protein levels of Nav1.1. It appears that the antiepileptic action of curcumin may be associated with the downregulation of Nav1.1 in the cortex.
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Affiliation(s)
- Vikas Kumar
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Chandra Prakash
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Rameshwar Singh
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Deepak Sharma
- Neurobiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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12
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Liao Q, Li S, Siu SWI, Morlighem JÉRL, Wong CTT, Wang X, Rádis-Baptista G, Lee SMY. Novel neurotoxic peptides from Protopalythoa variabilis virtually interact with voltage-gated sodium channel and display anti-epilepsy and neuroprotective activities in zebrafish. Arch Toxicol 2018; 93:189-206. [DOI: 10.1007/s00204-018-2334-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/10/2018] [Indexed: 02/06/2023]
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13
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Suppressive effect of Rho-kinase inhibitors Y-27632 and fasudil on spike-and-wave discharges in genetic absence epilepsy rats from Strasbourg (GAERS). Naunyn Schmiedebergs Arch Pharmacol 2018; 391:1275-1283. [PMID: 30073384 DOI: 10.1007/s00210-018-1546-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 07/19/2018] [Indexed: 12/20/2022]
Abstract
Rho/Rho-kinase (ROCK) signaling contributes to neuroinflammation, epileptogenesis, and seizures in convulsive-type epilepsies. However, this pathway has not been investigated in absence epilepsy. We investigated RhoA activity in genetic absence epilepsy rats from Strasburg (GAERS) and the effects of ROCK inhibitors Y-27632 and fasudil on spike-and-wave discharges (SWDs) of GAERS. ROCK level and activity were measured by Western blot analysis in the brain areas involved in absence seizures (i.e., cortex and thalamus) and hippocampus. Male GAERS were stereotaxically implanted with bilateral cortical electrodes for electroencephalogram (EEG) recordings and/or guide cannula into the right ventricle. ROCK inhibitors were administered by intraperitoneal injection (1-10 mg/kg for Y-27632 or fasudil) or intracerebroventricular injection (7-20 nmol/5 μl for Y-27632 or 10-100 nmol/5 μl for fasudil). EEG was recorded under freely moving conditions. Compared with Wistar rats, GAERS exhibited increased RhoA activity in the somatosensory cortex but not in the thalamus or hippocampus. The single systemic administration of Y-27632 and fasudil partially suppressed the duration and frequency of absence seizure, respectively. However, local brain administration caused a widespread suppressive effect on the total seizure duration, number of seizures, and the average individual seizure length. In summary, Rho/ROCK signaling may be involved in the pathophysiology of absence epilepsy. Furthermore, ROCK inhibitors can control the expression of absence seizure in GAERS, thus indicating that Y-27632 and fasudil have the potential to be used as novel anti-absence drugs.
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14
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Pathophysiology of absence epilepsy: Insights from genetic models. Neurosci Lett 2018; 667:53-65. [DOI: 10.1016/j.neulet.2017.02.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/08/2017] [Accepted: 02/12/2017] [Indexed: 11/21/2022]
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15
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Jarre G, Altwegg-Boussac T, Williams MS, Studer F, Chipaux M, David O, Charpier S, Depaulis A, Mahon S, Guillemain I. Building Up Absence Seizures in the Somatosensory Cortex: From Network to Cellular Epileptogenic Processes. Cereb Cortex 2017; 27:4607-4623. [DOI: 10.1093/cercor/bhx174] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 06/22/2017] [Indexed: 01/14/2023] Open
Affiliation(s)
- Guillaume Jarre
- Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France
- Inserm, U1216, F-38000 Grenoble, France
| | - Tristan Altwegg-Boussac
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Mark S. Williams
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Florian Studer
- Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France
- Inserm, U1216, F-38000 Grenoble, France
| | - Mathilde Chipaux
- Pediatric Neurosurgery Department, Fondation Ophtalmologique A. de Rothschild, 75019 Paris, France
| | - Olivier David
- Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France
- Inserm, U1216, F-38000 Grenoble, France
- CHU de Grenoble, F-38000 Grenoble, France
| | - Stéphane Charpier
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
- UPMC Univ Paris 06, F-75005, Paris, France
| | - Antoine Depaulis
- Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France
- Inserm, U1216, F-38000 Grenoble, France
- CHU de Grenoble, F-38000 Grenoble, France
| | - Séverine Mahon
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Isabelle Guillemain
- Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France
- Inserm, U1216, F-38000 Grenoble, France
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16
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Russo E, Citraro R, Constanti A, Leo A, Lüttjohann A, van Luijtelaar G, De Sarro G. Upholding WAG/Rij rats as a model of absence epileptogenesis: Hidden mechanisms and a new theory on seizure development. Neurosci Biobehav Rev 2016; 71:388-408. [DOI: 10.1016/j.neubiorev.2016.09.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 09/19/2016] [Indexed: 02/06/2023]
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17
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Williams MS, Altwegg-Boussac T, Chavez M, Lecas S, Mahon S, Charpier S. Integrative properties and transfer function of cortical neurons initiating absence seizures in a rat genetic model. J Physiol 2016; 594:6733-6751. [PMID: 27311433 DOI: 10.1113/jp272162] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 05/23/2016] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Absence seizures are accompanied by spike-and-wave discharges in cortical electroencephalograms. These complex paroxysmal activities, affecting the thalamocortical networks, profoundly alter cognitive performances and preclude conscious perception. Here, using a well-recognized genetic model of absence epilepsy, we investigated in vivo how information processing was impaired in the ictogenic neurons, i.e. the population of cortical neurons responsible for seizure initiation. In between seizures, ictogenic neurons were more prone to generate bursting activity and their firing response to weak depolarizing events was considerably facilitated compared to control neurons. In the course of seizures, information processing became unstable in ictogenic cells, alternating between an increased and a decreased responsiveness to excitatory inputs, depending on the spike and wave patterns. The state-dependent modulation in the excitability of ictogenic neurons affects their inter-seizure transfer function and their time-to-time responsiveness to incoming inputs during absences. ABSTRACT Epileptic seizures result from aberrant cellular and/or synaptic properties that can alter the capacity of neurons to integrate and relay information. During absence seizures, spike-and-wave discharges (SWDs) interfere with incoming sensory inputs and preclude conscious experience. The Genetic Absence Epilepsy Rats from Strasbourg (GAERS), a well-established animal model of absence epilepsy, allows exploration of the cellular basis of this impaired information processing. Here, by combining in vivo electrocorticographic and intracellular recordings from GAERS and control animals, we investigated how the pro-ictogenic properties of seizure-initiating cortical neurons modify their integrative properties and input-output operation during inter-ictal periods and during the spike (S-) and wave (W-) cortical patterns alternating during seizures. In addition to a sustained depolarization and an excessive firing rate in between seizures, ictogenic neurons exhibited a pronounced hyperpolarization-activated depolarization compared to homotypic control neurons. Firing frequency versus injected current relations indicated an increased sensitivity of GAERS cells to weak excitatory inputs, without modifications in the trial-to-trial variability of current-induced firing. During SWDs, the W-component resulted in paradoxical effects in ictogenic neurons, associating an increased membrane input resistance with a reduction in the current-evoked firing responses. Conversely, the collapse of cell membrane resistance during the S-component was accompanied by an elevated current-evoked firing relative to W-sequences, which remained, however, lower compared to inter-ictal periods. These findings show a dynamic modulation of ictogenic neurons' intrinsic properties that may alter inter-seizure cortical function and participate in compromising information processing in cortical networks during absences.
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Affiliation(s)
- Mark S Williams
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Tristan Altwegg-Boussac
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Mario Chavez
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Sarah Lecas
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France.,UPMC Univ Paris 06, F-75005, Paris, France
| | - Séverine Mahon
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Stéphane Charpier
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France.,UPMC Univ Paris 06, F-75005, Paris, France
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18
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Tan NN, Tang HL, Lin GW, Chen YH, Lu P, Li HJ, Gao MM, Zhao QH, Yi YH, Liao WP, Long YS. Epigenetic Downregulation of Scn3a Expression by Valproate: a Possible Role in Its Anticonvulsant Activity. Mol Neurobiol 2016; 54:2831-2842. [PMID: 27013471 DOI: 10.1007/s12035-016-9871-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 03/17/2016] [Indexed: 12/20/2022]
Abstract
Upregulation of sodium channel SCN3A expression in epileptic tissues is known to contribute to enhancing neuronal excitability and the development of epilepsy. Therefore, certain strategies to reduce SCN3A expression may be helpful for seizure control. Here, we reveal a novel role of valproate (VPA) in the epigenetic downregulation of Scn3a expression. We found that VPA, instead of carbamazepine (CBZ) and lamotrigine (LTG), could significantly downregulate Scn3a expression in mouse Neuro-2a cells. Luciferase assays and CpG methylation analyses showed that VPA induced the methylation at the -39C site in Scn3a promoter which decreased the promoter activity. We further showed that VPA downregulated the expression of methyl-CpG-binding domain protein 2 (MBD2) at the posttranscriptional level and knockdown of MBD2 increased Scn3a expression. In addition, we found that VPA induced the expression of fat mass and obesity-associated (FTO) protein and FTO knockdown abolished the repressive effects of VPA on MBD2 and Nav1.3 expressions. Furthermore, VPA, instead of other two anticonvulsant drugs, induced the expressions of Scn3a and Mbd2 and reduced Fto expression in the hippocampus of VPA-treated seizure mice. Taken together, this study suggests an epigenetic pathway for the VPA-induced downregulation of Scn3a expression, which provides a possible role of this pathway in the anticonvulsant action of VPA.
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Affiliation(s)
- Na-Na Tan
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Hui-Ling Tang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Guo-Wang Lin
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Yong-Hong Chen
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Ping Lu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Hai-Jun Li
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Mei-Mei Gao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Qi-Hua Zhao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Yong-Hong Yi
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Wei-Ping Liao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Yue-Sheng Long
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changang East Road, Guangzhou, 510260, China. .,Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China.
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19
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Focal interictal epileptiform discharges in idiopathic generalized epilepsy. Neurol Sci 2016; 37:1071-7. [PMID: 26956566 DOI: 10.1007/s10072-016-2538-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 02/24/2016] [Indexed: 10/22/2022]
Abstract
Are idiopathic generalized epilepsies (IGEs) truly generalized? Do IGEs represent a continuum or rather distinct syndromes? Focal changes in the electroencephalography (EEG) have been reported in IGEs. The aim of this work is to investigate focal interictal epileptiform discharges (IEDs) in IGEs, and their relation to clinical variables. Forty-one IGE patients (classified according to ILAE, 2001) were recruited from a tertiary center (age 23 ± 10.938 years). Their files were reviewed and they were subjected to clinical examination and interictal EEG. Patients with focal IEDs were compared to those without focal IEDs. Nine patients had juvenile myoclonic epilepsy (JME) and 32 had idiopathic epilepsy with generalized tonic-clonic seizures only (EGTCSA). Focal IEDs were found in 20 patients, mostly in the frontal (45.5 %) and temporal (31.8 %) distribution. Patients with focal IEDs were treated with a larger number of combined antiepileptic drugs (AEDs) (p value = 0.022). No significant difference was found between the two groups regarding age, sex, age at onset, epilepsy syndrome, seizure frequency, family history, AEDs used (sodium valproate and carbamazepine) and their doses. Seventeen EGTCSA patients had focal IEDs. They were treated with larger number of combined AEDs (p value = 0.0142). No significant difference was found between the EGTCSA patients with and those without focal IEDs regarding age, sex, age at onset, seizure frequency, family history and AEDs doses. Caution must be applied in the interpretation of interictal focal IEDs. These focal changes may be related to prognosis, however this needs further investigation.
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20
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Wu XL, Huang H, Huang YY, Yuan JX, Zhou X, Chen YM. Reduced Pumilio-2 expression in patients with temporal lobe epilepsy and in the lithium-pilocarpine induced epilepsy rat model. Epilepsy Behav 2015; 50:31-9. [PMID: 26101106 DOI: 10.1016/j.yebeh.2015.05.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 05/08/2015] [Accepted: 05/09/2015] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Drosophila Pumilio (Pum), a homolog of mammalian Pum2, plays an important role in translational regulation in the central nervous system (CNS), particularly for dendrite outgrowth and neuronal excitability. We investigated the expression pattern and cellular distribution of Pum2 in patients with drug-refractory temporal lobe epilepsy (TLE) and rats with lithium chloride-pilocarpine-induced epilepsy. METHODS Real-time quantitative PCR (RT-qPCR), Western blot, immunohistochemistry, and double-labeled immunofluorescence were utilized to determine the expression level and distribution of Pum2 in temporal neocortex tissues from patients with intractable TLE (n=20) and patients with severe head trauma (n=20) in addition to the hippocampus and adjacent cortex of rats with lithium chloride-pilocarpine-induced TLE and controls. RESULTS Pum2 was expressed in the cell bodies and dendrites of neurons but did not colocalize with glial fibrillary acidic protein-positive astrocytes or propidium iodide (PI) in nuclei. The expression of Pum2 was significantly reduced in patients and rats with TLE in comparison to controls (P<0.05). CONCLUSION Pum2 expression was less in patients with TLE and a rodent model of epilepsy, suggesting that decreased expression of Pum2 may be involved in the pathogenesis of TLE.
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Affiliation(s)
- Xu-Ling Wu
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Hao Huang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Yun-Yi Huang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Jin-Xian Yuan
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Xin Zhou
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Yang-Mei Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China.
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21
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Scicchitano F, van Rijn CM, van Luijtelaar G. Unilateral and Bilateral Cortical Resection: Effects on Spike-Wave Discharges in a Genetic Absence Epilepsy Model. PLoS One 2015; 10:e0133594. [PMID: 26262879 PMCID: PMC4532477 DOI: 10.1371/journal.pone.0133594] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 06/29/2015] [Indexed: 12/28/2022] Open
Abstract
Research Question Recent discoveries have challenged the traditional view that the thalamus is the primary source driving spike-and-wave discharges (SWDs). At odds, SWDs in genetic absence models have a cortical focal origin in the deep layers of the perioral region of the somatosensory cortex. The present study examines the effect of unilateral and bilateral surgical resection of the assumed focal cortical region on the occurrence of SWDs in anesthetized WAG/Rij rats, a well described and validated genetic absence model. Methods Male WAG/Rij rats were used: 9 in the resected and 6 in the control group. EEG recordings were made before and after craniectomy, after unilateral and after bilateral removal of the focal region. Results SWDs decreased after unilateral cortical resection, while SWDs were no longer noticed after bilateral resection. This was also the case when the resected areas were restricted to layers I-IV with layers V and VI intact. Conclusions These results suggest that SWDs are completely abolished after bilateral removal of the focal region, most likely by interference with an intracortical columnar circuit. The evidence suggests that absence epilepsy is a network type of epilepsy since interference with only the local cortical network abolishes all seizures.
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Affiliation(s)
- Francesca Scicchitano
- Department of Health Science, School of Medicine and Surgery, University “Magna Graecia” of Catanzaro, Viale Europa—Germaneto, 88100, Catanzaro, Italy
| | - Clementina M. van Rijn
- Department of Biological Psychology, Donders Centre for Cognition, Donders Institution of Brain, Cognition and Behavior, Radboud University, Nijmegen, The Netherlands
| | - Gilles van Luijtelaar
- Department of Biological Psychology, Donders Centre for Cognition, Donders Institution of Brain, Cognition and Behavior, Radboud University, Nijmegen, The Netherlands
- * E-mail:
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22
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Depaulis A, David O, Charpier S. The genetic absence epilepsy rat from Strasbourg as a model to decipher the neuronal and network mechanisms of generalized idiopathic epilepsies. J Neurosci Methods 2015; 260:159-74. [PMID: 26068173 DOI: 10.1016/j.jneumeth.2015.05.022] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/28/2015] [Accepted: 05/28/2015] [Indexed: 12/31/2022]
Abstract
First characterized in 1982, the genetic absence epilepsy rat from Strasbourg (GAERS) has emerged as an animal model highly reminiscent of a specific form of idiopathic generalized epilepsy. Both its electrophysiological (spike-and-wave discharges) and behavioral (behavioral arrest) features fit well with those observed in human patients with typical absence epilepsy and required by clinicians for diagnostic purposes. In addition, its sensitivity to antiepileptic drugs closely matches what has been described in the clinic, making this model one of the most predictive. Here, we report how the GAERS, thanks to its spontaneous, highly recurrent and easily recognizable seizures on electroencephalographic recordings, allows to address several key-questions about the pathophysiology and genetics of absence epilepsy. In particular, it offers the unique possibility to explore simultaneously the neural circuits involved in the generation of seizures at different levels of integration, using multiscale methodologies, from intracellular recording to functional magnetic resonance imaging. In addition, it has recently allowed to perform proofs of concept for innovative therapeutic strategies such as responsive deep brain stimulation or synchrotron-generated irradiation based radiosurgery.
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Affiliation(s)
- Antoine Depaulis
- Inserm, U836, F-38000 Grenoble, France; Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, F-38000 Grenoble, France; CHU de Grenoble, Hôpital Michallon, F-38000 Grenoble, France.
| | - Olivier David
- Inserm, U836, F-38000 Grenoble, France; Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, F-38000 Grenoble, France
| | - Stéphane Charpier
- Brain and Spine Institute, Pitié-Salpêtrière Hospital, Paris, France; Pierre and Marie Curie University, Paris, France
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23
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Blanchard MG, Willemsen MH, Walker JB, Dib-Hajj SD, Waxman SG, Jongmans MCJ, Kleefstra T, van de Warrenburg BP, Praamstra P, Nicolai J, Yntema HG, Bindels RJM, Meisler MH, Kamsteeg EJ. De novo gain-of-function and loss-of-function mutations of SCN8A in patients with intellectual disabilities and epilepsy. J Med Genet 2015; 52:330-7. [PMID: 25725044 PMCID: PMC4413743 DOI: 10.1136/jmedgenet-2014-102813] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 02/05/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND Mutations of SCN8A encoding the neuronal voltage-gated sodium channel NaV1.6 are associated with early-infantile epileptic encephalopathy type 13 (EIEE13) and intellectual disability. Using clinical exome sequencing, we have detected three novel de novo SCN8A mutations in patients with intellectual disabilities, and variable clinical features including seizures in two patients. To determine the causality of these SCN8A mutations in the disease of those three patients, we aimed to study the (dys)function of the mutant sodium channels. METHODS The functional consequences of the three SCN8A mutations were assessed using electrophysiological analyses in transfected cells. Genotype-phenotype correlations of these and other cases were related to the functional analyses. RESULTS The first mutant displayed a 10 mV hyperpolarising shift in voltage dependence of activation (gain of function), the second did not form functional channels (loss of function), while the third mutation was functionally indistinguishable from the wildtype channel. CONCLUSIONS Comparison of the clinical features of these patients with those in the literature suggests that gain-of-function mutations are associated with severe EIEE, while heterozygous loss-of-function mutations cause intellectual disability with or without seizures. These data demonstrate that functional analysis of missense mutations detected by clinical exome sequencing, both inherited and de novo, is valuable for clinical interpretation in the age of massive parallel sequencing.
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Affiliation(s)
- Maxime G Blanchard
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marjolein H Willemsen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jaclyn B Walker
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Sulayman D Dib-Hajj
- The Center for Neuroscience & Regeneration Research, Yale School of Medicine, New Haven, Connecticut, USA The Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Stephen G Waxman
- The Center for Neuroscience & Regeneration Research, Yale School of Medicine, New Haven, Connecticut, USA The Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Marjolijn C J Jongmans
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Tjitske Kleefstra
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bart P van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Peter Praamstra
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost Nicolai
- Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands Epilepsy Center Kempenhaeghe, Heeze, The Netherlands
| | - Helger G Yntema
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
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Lüttjohann A, van Luijtelaar G. Dynamics of networks during absence seizure's on- and offset in rodents and man. Front Physiol 2015; 6:16. [PMID: 25698972 PMCID: PMC4318340 DOI: 10.3389/fphys.2015.00016] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/11/2015] [Indexed: 11/13/2022] Open
Abstract
Network mechanisms relevant for the generation, maintenance and termination of spike-wave discharges (SWD), the neurophysiological hallmark of absence epilepsy, are still enigmatic and widely discussed. Within the last years, however, improvements in signal analytical techniques, applied to both animal and human fMRI, EEG, MEG, and ECoG data, greatly increased our understanding and challenged several, dogmatic concepts of SWD. This review will summarize these recent data, demonstrating that SWD are not primary generalized, are not sudden and unpredictable events. It will disentangle different functional contributions of structures within the cortico-thalamo-cortical system, relevant for the generation, generalization, maintenance, and termination of SWD and will present a new “network based” scenario for these oscillations. Similarities and differences between rodent and human data are presented demonstrating that in both species a local cortical onset zone of SWD exists, although with different locations; that in both some forms of cortical and thalamic precursor activity can be found, and that SWD occur through repetitive cyclic activity between cortex and thalamus. The focal onset zone in human data could differ between patients with varying spatial and temporal dynamics; in rats the latter is still poorly investigated.
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Affiliation(s)
- Annika Lüttjohann
- Donders Centre for Cognition, Donders Instiute for Brain, Cognition and Behaviour, Radboud University Nijmegen Nijmegen, Netherlands ; Institute of Physiology I, Westfälische Wilhelms-University Münster Münster, Germany
| | - Gilles van Luijtelaar
- Donders Centre for Cognition, Donders Instiute for Brain, Cognition and Behaviour, Radboud University Nijmegen Nijmegen, Netherlands
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25
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Martin NJ, Ferreiro SF, Barbault F, Nicolas M, Lecellier G, Paetz C, Gaysinski M, Alonso E, Thomas OP, Botana LM, Raharivelomanana P. Indole alkaloids from the Marquesan plant Rauvolfia nukuhivensis and their effects on ion channels. PHYTOCHEMISTRY 2015; 109:84-95. [PMID: 25468537 DOI: 10.1016/j.phytochem.2014.10.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/12/2014] [Accepted: 10/20/2014] [Indexed: 06/04/2023]
Abstract
In addition to the already reported nukuhivensiums 1 and 2, 11 indole alkaloids were isolated from the bark of the plant Rauvolfia nukuhivensis, growing in the Marquesas archipelago. The known sandwicine (3), isosandwicine (4), spegatrine (8), lochneram (9), flavopereirine (13) have been found in this plant together with the norsandwicine (5), isonorsandwicine (6), Nb-methylisosandwicine (7), 10-methoxypanarine (10), nortueiaoine (11), tueiaoine (12). The structure elucidation was performed on the basis of a deep exploration of the NMR and HRESIMS data as well as comparison with literature data for similar compounds. Norsandwicine, 10-methoxypanarine, tueiaoine, and more importantly nukuhivensiums, were shown to significantly induce a reduction of IKr amplitude (HERG current). Molecular modelling through docking was performed in order to illustrate this result.
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Affiliation(s)
- Nicolas J Martin
- Laboratoire EIMS UMR 241 EIO, Université de la Polynésie française, BP 6570, 98702 Faa'a, Tahiti, French Polynesia.
| | - Sara F Ferreiro
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo, Spain.
| | - Florent Barbault
- Laboratoire ITODYS UMR CNRS 7086, Université Paris Diderot, Sorbonne Paris Cité, 15 rue J.-A. de Baïf, 75013 Paris, France.
| | - Mael Nicolas
- Laboratoire EIMS UMR 241 EIO, Université de la Polynésie française, BP 6570, 98702 Faa'a, Tahiti, French Polynesia.
| | - Gaël Lecellier
- Université de Versailles Saint Quentin en Yvelines, 55 Avenue des Etats-Unis, 78035 Versailles Cedex, France; Laboratoire d'Excellence "CORAIL" - Centre de Recherches Insulaires et Observatoire de l'Environnement (CRIOBE), BP 1013 - 98729, Papetoai, Moorea, French Polynesia.
| | - Christian Paetz
- MPI for Chemical Ecology, Hans-Knöll-Strasse 8, 07745 Jena, Germany.
| | - Marc Gaysinski
- Institut de Chimie de Nice-PCRE, UMR 7272 CNRS, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice, France.
| | - Eva Alonso
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo, Spain.
| | - Olivier P Thomas
- Institut de Chimie de Nice-PCRE, UMR 7272 CNRS, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice, France; Institut Méditerranéen de Biodiversité et d́Ecologie marine et continentale, UMR 7263 CNRS - IRD - Aix-Marseille Université - UAPV, Station Marine d́Endoume, Rue de la Batterie des Lions, 13007 Marseille, France.
| | - Luis M Botana
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo, Spain.
| | - Phila Raharivelomanana
- Laboratoire EIMS UMR 241 EIO, Université de la Polynésie française, BP 6570, 98702 Faa'a, Tahiti, French Polynesia.
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Wagner FB, Truccolo W, Wang J, Nurmikko AV. Spatiotemporal dynamics of optogenetically induced and spontaneous seizure transitions in primary generalized epilepsy. J Neurophysiol 2014; 113:2321-41. [PMID: 25552645 DOI: 10.1152/jn.01040.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 12/23/2014] [Indexed: 11/22/2022] Open
Abstract
Transitions into primary generalized epileptic seizures occur abruptly and synchronously across the brain. Their potential triggers remain unknown. We used optogenetics to causally test the hypothesis that rhythmic population bursting of excitatory neurons in a local neocortical region can rapidly trigger absence seizures. Most previous studies have been purely correlational, and it remains unclear whether epileptiform events induced by rhythmic stimulation (e.g., sensory/electrical) mimic actual spontaneous seizures, especially regarding their spatiotemporal dynamics. In this study, we used a novel combination of intracortical optogenetic stimulation and microelectrode array recordings in freely moving WAG/Rij rats, a model of absence epilepsy with a cortical focus in the somatosensory cortex (SI). We report three main findings: 1) Brief rhythmic bursting, evoked by optical stimulation of neocortical excitatory neurons at frequencies around 10 Hz, induced seizures consisting of self-sustained spike-wave discharges (SWDs) for about 10% of stimulation trials. The probability of inducing seizures was frequency-dependent, reaching a maximum at 10 Hz. 2) Local field potential power before stimulation and response amplitudes during stimulation both predicted seizure induction, demonstrating a modulatory effect of brain states and neural excitation levels. 3) Evoked responses during stimulation propagated as cortical waves, likely reaching the cortical focus, which in turn generated self-sustained SWDs after stimulation was terminated. Importantly, SWDs during induced and spontaneous seizures propagated with the same spatiotemporal dynamics. Our findings demonstrate that local rhythmic bursting of excitatory neurons in neocortex at particular frequencies, under susceptible ongoing brain states, is sufficient to trigger primary generalized seizures with stereotypical spatiotemporal dynamics.
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Affiliation(s)
- Fabien B Wagner
- Department of Neuroscience, Brown University, Providence, Rhode Island; School of Engineering, Brown University, Providence, Rhode Island;
| | - Wilson Truccolo
- Department of Neuroscience, Brown University, Providence, Rhode Island; Institute for Brain Science, Brown University, Providence, Rhode Island; and Center for Neurorestoration and Neurotechnology, Department of Veterans Affairs, Providence, Rhode Island
| | - Jing Wang
- School of Engineering, Brown University, Providence, Rhode Island
| | - Arto V Nurmikko
- Department of Neuroscience, Brown University, Providence, Rhode Island; School of Engineering, Brown University, Providence, Rhode Island; Institute for Brain Science, Brown University, Providence, Rhode Island; and
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Alteration of Scn3a expression is mediated via CpG methylation and MBD2 in mouse hippocampus during postnatal development and seizure condition. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:1-9. [PMID: 25459751 DOI: 10.1016/j.bbagrm.2014.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 10/13/2014] [Accepted: 11/12/2014] [Indexed: 12/21/2022]
Abstract
Increased expression of sodium channel SCN3A, an embryonic-expressed gene, has been identified in epileptic tissues, which is believed to contribute to the development of epilepsy. However, the regulatory mechanism of SCN3A expression under epileptic condition is still unknown. Here we showed a high level of Scn3a mRNA expression in mouse embryonic hippocampus with gradually decreasing to a low level during the postnatal development and a methylation of a specific CpG site (-39C) in the Scn3a promoter was increased in hippocampus during postnatal development, corresponding to the downregulation of Scn3a expression. Furthermore, in vitro methylation and -39C>T mutation of the Scn3a promoter decreased the reporter gene expression, suggesting an important role of the -39C site in regulating gene expression. We then demonstrated that the sequence containing -39C was a MBD2-binding motif and the CpG methylation of the promoter region increased the capability of MBD2's binding to the motif. Knockdown of MBD2 in mouse N1E-115 cells led to the -39C methylation and the downregulation of Scn3a transcription by decreasing the Scn3a promoter activity. In the hippocampus of seizure mice, the expressions of Scn3a and Mbd2 were upregulated after 10-day KA treatment. At the same time point, the -39C site was demethylated and the capability of MBD2's binding to the Scn3a promoter motif was decreased. Taken together, these findings suggest that CpG methylation and MBD2 are involved in altering Scn3a expression during postnatal development and seizure condition.
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Sitnikova E, Rutskova EM, Raevsky VV. Reduction of epileptic spike-wave activity in WAG/Rij rats fostered by Wistar dams. Brain Res 2014; 1594:305-9. [PMID: 25449890 DOI: 10.1016/j.brainres.2014.10.067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 10/06/2014] [Accepted: 10/29/2014] [Indexed: 10/24/2022]
Abstract
In WAG/Rij rat genetic model of absence epilepsy, the first spike-wave discharges (EEG hallmark of absence epilepsy) are known to appear after puberty, and their incidence increases with age. WAG/Rij rats are known to have a genetic predisposition to absence epilepsy, and further development of epilepsy might be influenced by epigenetic factors. This preliminary study examined the effect of early postnatal factors on the incidence of epileptic spike-wave discharges in adulthood. The newborn WAG/Rij rats were fostered by Wistar dams (from birth throughout the weaning age), and their EEG was examined continuously from 5 to 13 months of age. It was found that the number and duration of absence seizures was reduced in WAG/Rij rats adopted by Wistar dams as compared with the age-matched control WAG/Rij rats nursed by their own mothers. These data indicate that natural (epigenetic) factors, such as maternal care during suckling period, affect development of seizure activity in genetically prone subjects. It is suggested that improvement of primarily care-giving environment in subjects with genetic predisposition to absence epilepsy is a way to reduce epileptic activity in later life.
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Affiliation(s)
- Evgenia Sitnikova
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova str., 5A, Moscow 117485, Russia.
| | - Elizaveta M Rutskova
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova str., 5A, Moscow 117485, Russia.
| | - Vladimir V Raevsky
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova str., 5A, Moscow 117485, Russia.
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Szilágyi T, Száva I, Metz EJ, Mihály I, Orbán-Kis K. Untangling the pathomechanisms of temporal lobe epilepsy—The promise of epileptic biomarkers and novel therapeutic approaches. Brain Res Bull 2014; 109:1-12. [DOI: 10.1016/j.brainresbull.2014.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/11/2014] [Accepted: 08/14/2014] [Indexed: 12/30/2022]
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Tian C, Wang K, Ke W, Guo H, Shu Y. Molecular identity of axonal sodium channels in human cortical pyramidal cells. Front Cell Neurosci 2014; 8:297. [PMID: 25294986 PMCID: PMC4172021 DOI: 10.3389/fncel.2014.00297] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/04/2014] [Indexed: 11/13/2022] Open
Abstract
Studies in rodents revealed that selective accumulation of Na+ channel subtypes at the axon initial segment (AIS) determines action potential (AP) initiation and backpropagation in cortical pyramidal cells (PCs); however, in human cortex, the molecular identity of Na+ channels distributed at PC axons, including the AIS and the nodes of Ranvier, remains unclear. We performed immunostaining experiments in human cortical tissues removed surgically to cure brain diseases. We found strong immunosignals of Na+ channels and two channel subtypes, NaV1.2 and NaV1.6, at the AIS of human cortical PCs. Although both channel subtypes were expressed along the entire AIS, the peak immunosignals of NaV1.2 and NaV1.6 were found at proximal and distal AIS regions, respectively. Surprisingly, in addition to the presence of NaV1.6 at the nodes of Ranvier, NaV1.2 was also found in a subpopulation of nodes in the adult human cortex, different from the absence of NaV1.2 in myelinated axons in rodents. NaV1.1 immunosignals were not detected at either the AIS or the nodes of Ranvier of PCs; however, they were expressed at interneuron axons with different distribution patterns. Further experiments revealed that parvalbumin-positive GABAergic axon cartridges selectively innervated distal AIS regions with relatively high immunosignals of NaV1.6 but not the proximal NaV1.2-enriched compartments, suggesting an important role of axo-axonic cells in regulating AP initiation in human PCs. Together, our results show that both NaV1.2 and NaV1.6 (but not NaV1.1) channel subtypes are expressed at the AIS and the nodes of Ranvier in adult human cortical PCs, suggesting that these channel subtypes control neuronal excitability and signal conduction in PC axons.
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Affiliation(s)
- Cuiping Tian
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and University of Chinese Academy of Sciences Shanghai, China
| | - Kaiyan Wang
- Department of Neurology, Huashan Hospital, Fudan University Shanghai, China
| | - Wei Ke
- State Key Laboratory of Cognitive Neuroscience and Learning and International Data Group/McGovern Institute for Brain Research, School of Brain and Cognitive Sciences, Beijing Normal University Beijing, China ; Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University Beijing, China
| | - Hui Guo
- Department of Neurosurgery, Shanghai Quyang Hospital, Tongji University Shanghai, China
| | - Yousheng Shu
- State Key Laboratory of Cognitive Neuroscience and Learning and International Data Group/McGovern Institute for Brain Research, School of Brain and Cognitive Sciences, Beijing Normal University Beijing, China ; Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University Beijing, China
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Tenney JR, Fujiwara H, Horn PS, Vannest J, Xiang J, Glauser TA, Rose DF. Low- and high-frequency oscillations reveal distinct absence seizure networks. Ann Neurol 2014; 76:558-67. [PMID: 25042348 DOI: 10.1002/ana.24231] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 07/11/2014] [Accepted: 07/14/2014] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The aim of this study was to determine the frequency-dependent, spatiotemporal involvement of corticothalamic networks to the generation of absence seizures. METHODS Magnetoencephalography recordings were obtained in 12 subjects (44 seizures) with untreated childhood absence seizures. Time-frequency analysis of each seizure was performed to determine bandwidths with significant power at ictal onset. Source localization was then completed to determine brain regions contributing to generalized spike and wave discharges seen on electroencephalogram. RESULTS Significant power in the time-frequency analysis was seen within 1 to 20Hz, 20 to 70Hz, and 70 to 150Hz bandwidths. Source localization revealed that sources localized to the frontal cortex similarly for the low- and gamma-frequency bandwidths, whereas at the low-frequency bandwidth (3-20Hz) significantly more sources localized to the parietal cortex (odds ratio [OR] = 16.7). Cortical sources within the high-frequency oscillation (HFO) bandwidth (70-150Hz) localized primarily to the frontal region compared to the parietal (OR = 7.32) or temporal (OR = 2.78) areas. INTERPRETATION Neuromagnetic activity within frontal and parietal cortical regions provides further confirmation of hemodynamic changes reported using functional magnetic resonance imaging that have been associated with absence seizures. The frequency-dependent nature of these networks has not previously been reported, and the presence of HFOs during absence seizures is a novel finding. Co-occurring frontal and parietal corticothalamic networks may interact to produce a pathological state that contributes to the generation of spike and wave discharges. The clinical and pathophysiological implications of HFOs within the frontal cortical region are unclear and should be further investigated.
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Affiliation(s)
- Jeffrey R Tenney
- Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH
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Seneviratne U, Cook M, D'Souza W. Focal abnormalities in idiopathic generalized epilepsy: A critical review of the literature. Epilepsia 2014; 55:1157-69. [DOI: 10.1111/epi.12688] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Udaya Seneviratne
- Department of Medicine; St. Vincent's Hospital; University of Melbourne; Melbourne Victoria Australia
- Department of Neuroscience; Monash Medical Centre; Melbourne Victoria Australia
| | - Mark Cook
- Department of Medicine; St. Vincent's Hospital; University of Melbourne; Melbourne Victoria Australia
| | - Wendyl D'Souza
- Department of Medicine; St. Vincent's Hospital; University of Melbourne; Melbourne Victoria Australia
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Kovács Z, Dobolyi Á, Juhász G, Kékesi KA. Lipopolysaccharide induced increase in seizure activity in two animal models of absence epilepsy WAG/Rij and GAERS rats and Long Evans rats. Brain Res Bull 2014; 104:7-18. [DOI: 10.1016/j.brainresbull.2014.03.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 02/04/2023]
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Brain protein expression changes in WAG/Rij rats, a genetic rat model of absence epilepsy after peripheral lipopolysaccharide treatment. Brain Behav Immun 2014; 35:86-95. [PMID: 24021561 DOI: 10.1016/j.bbi.2013.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 09/02/2013] [Accepted: 09/02/2013] [Indexed: 12/16/2022] Open
Abstract
Peripheral injection of bacterial lipopolysaccharide (LPS) facilitates 8-10Hz spike-wave discharges (SWD) characterizing absence epilepsy in WAG/Rij rats. It is unknown however, whether peripherally administered LPS is able to alter the generator areas of epileptic activity at the molecular level. We injected 1mg/kg dose of LPS intraperitoneally into WAG/Rij rats, recorded the body temperature and EEG, and examined the protein expression changes of the proteome 12h after injection in the fronto-parietal cortex and thalamus. We used fluorescent two-dimensional differential gel electrophoresis to investigate the expression profile. We found 16 differentially expressed proteins in the fronto-parietal cortex and 35 proteins in the thalamus. It is known that SWD genesis correlates with the transitional state of sleep-wake cycle thus we performed meta-analysis of the altered proteins in relation to inflammation, epilepsy as well as sleep. The analysis revealed that all categories are highly represented by the altered proteins and these protein-sets have considerable overlap. Protein network modeling suggested that the alterations in the proteome were largely induced by the immune response, which invokes the NFkB signaling pathway. The proteomics and computational analysis verified the known functional interplay between inflammation, epilepsy and sleep and highlighted proteins that are involved in their common synaptic mechanisms. Our physiological findings support the phenomenon that high dose of peripheral LPS injection increases SWD-number, modifies its duration as well as the sleep-wake stages and decreases body temperature.
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Are alterations in transmitter receptor and ion channel expression responsible for epilepsies? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 813:211-29. [PMID: 25012379 DOI: 10.1007/978-94-017-8914-1_17] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neuronal voltage-gated ion channels and ligand-gated synaptic receptors play a critical role in maintaining the delicate balance between neuronal excitation and inhibition within neuronal networks in the brain. Changes in expression of voltage-gated ion channels, in particular sodium, hyperpolarization-activated cyclic nucleotide-gated (HCN) and calcium channels, and ligand-gated synaptic receptors, in particular GABA and glutamate receptors, have been reported in many types of both genetic and acquired epilepsies, in animal models and in humans. In this chapter we review these and discuss the potential pathogenic role they may play in the epilepsies.
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Maheshwari A, Noebels JL. Monogenic models of absence epilepsy: windows into the complex balance between inhibition and excitation in thalamocortical microcircuits. PROGRESS IN BRAIN RESEARCH 2014; 213:223-52. [PMID: 25194492 DOI: 10.1016/b978-0-444-63326-2.00012-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Absence epilepsy is a common disorder that arises in childhood and can be refractory to medical treatment. Single genetic mutations in mice, at times found in patients with absence epilepsy, provide the unique opportunity to bridge the gap between dysfunction at the genetic level and pathological oscillations within the thalamocortical circuit. Interestingly, unlike other forms of epilepsy, only genes related to ion channels have so far been linked to absence phenotypes. Here, we delineate a paradigm which attempts to unify the various monogenic models based on decades of research. While reviewing the particular impact of these individual mutations, we posit a framework involving fast feedforward disinhibition as one common mechanism that can lead to increased tonic inhibition in the cortex and/or thalamus. Enhanced tonic inhibition hyperpolarizes principal cells, deinactivates T-type calcium channels, and leads to reciprocal burst firing within the thalamocortical loop. We also review data from pharmacologic and polygenic models in light of this paradigm. Ultimately, many questions remain unanswered regarding the pathogenesis of absence epilepsy.
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Affiliation(s)
- Atul Maheshwari
- Department of Neurology, Developmental Neurogenetics Laboratory, Baylor College of Medicine Houston, TX, USA.
| | - Jeffrey L Noebels
- Department of Neurology, Developmental Neurogenetics Laboratory, Baylor College of Medicine Houston, TX, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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van Luijtelaar G, Mishra AM, Edelbroek P, Coman D, Frankenmolen N, Schaapsmeerders P, Covolato G, Danielson N, Niermann H, Janeczko K, Kiemeneij A, Burinov J, Bashyal C, Coquillette M, Lüttjohann A, Hyder F, Blumenfeld H, van Rijn CM. Anti-epileptogenesis: Electrophysiology, diffusion tensor imaging and behavior in a genetic absence model. Neurobiol Dis 2013; 60:126-38. [PMID: 23978468 DOI: 10.1016/j.nbd.2013.08.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 08/14/2013] [Indexed: 11/18/2022] Open
Abstract
The beneficial effects of chronic and early pharmacological treatment with ethosuximide on epileptogenesis were studied in a genetic absence epilepsy model comorbid for depression. It was also investigated whether there is a critical treatment period and treatment length. Cortical excitability in the form of electrical evoked potentials, but also to cortico-thalamo-cortical network activity (spike-wave discharges, SWD and afterdischarges), white matter changes representing extra cortico-thalamic functions and depressive-like behavior were investigated. WAG/Rij rats received either ethosuximide for 2 months (post natal months 2-3 or 4-5), or ethosuximide for 4 months (2-5) in their drinking water, while control rats drank plain water. EEG measurements were made during treatment, and 6 days and 2 months post treatment. Behavioral test were also done 6 days post treatment. DTI was performed ex vivo post treatment. SWD were suppressed during treatment, and 6 days and 2 months post treatment in the 4 month treated group, as well as the duration of AD elicited by cortical electrical stimulation 6 days post treatment. Increased fractional anisotropy in corpus callosum and internal capsula on DTI was found, an increased P8 evoked potential amplitude and a decreased immobility in the forced swim test. Shorter treatments with ETX had no large effects on any parameter. Chronic ETX has widespread effects not only within but also outside the circuitry in which SWD are initiated and generated, including preventing epileptogenesis and reducing depressive-like symptoms. The treatment of patients before symptom onset might prevent many of the adverse consequences of chronic epilepsy.
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Affiliation(s)
- Gilles van Luijtelaar
- Donders Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands.
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38
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Xu X, Guo F, Lv X, Feng R, Min D, Ma L, Liu Y, Zhao J, Wang L, Chen T, Shaw C, Hao L, Cai J. Abnormal changes in voltage-gated sodium channels NaV1.1, NaV1.2, NaV1.3, NaV1.6 and in calmodulin/calmodulin-dependent protein kinase II, within the brains of spontaneously epileptic rats and tremor rats. Brain Res Bull 2013; 96:1-9. [DOI: 10.1016/j.brainresbull.2013.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/09/2013] [Accepted: 04/10/2013] [Indexed: 10/26/2022]
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39
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Hargus NJ, Nigam A, Bertram EH, Patel MK. Evidence for a role of Nav1.6 in facilitating increases in neuronal hyperexcitability during epileptogenesis. J Neurophysiol 2013; 110:1144-57. [PMID: 23741036 DOI: 10.1152/jn.00383.2013] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
During epileptogenesis a series of molecular and cellular events occur, culminating in an increase in neuronal excitability, leading to seizure initiation. The entorhinal cortex has been implicated in the generation of epileptic seizures in both humans and animal models of temporal lobe epilepsy. This hyperexcitability is due, in part, to proexcitatory changes in ion channel activity. Sodium channels play an important role in controlling neuronal excitability, and alterations in their activity could facilitate seizure initiation. We sought to investigate whether medial entorhinal cortex (mEC) layer II neurons become hyperexcitable and display proexcitatory behavior of Na channels during epileptogenesis. Experiments were conducted 7 days after electrical induction of status epilepticus (SE), a time point during the latent period of epileptogenesis and before the onset of seizures. mEC layer II stellate neurons from post-SE animals were hyperexcitable, eliciting action potentials at higher frequencies compared with control neurons. Na channel currents recorded from post-SE neurons revealed increases in Na current amplitudes, particularly persistent and resurgent currents, as well as depolarized shifts in inactivation parameters. Immunocytochemical studies revealed increases in voltage-gated Na (Nav) 1.6 isoform levels. The toxin 4,9-anhydro-tetrodotoxin, which has greater selectivity for Nav1.6 over other Na channel isoforms, suppressed neuronal hyperexcitability, reduced macroscopic Na currents, persistent and resurgent Na current densities, and abolished depolarized shifts in inactivation parameters in post-SE neurons. These studies support a potential role for Nav1.6 in facilitating the hyperexcitability of mEC layer II neurons during epileptogenesis.
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Affiliation(s)
- Nicholas J Hargus
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA 22908-0710, USA
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40
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The involvement of limbic structures in typical and atypical absence epilepsy. Epilepsy Res 2013; 103:111-23. [DOI: 10.1016/j.eplepsyres.2012.08.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 08/15/2012] [Accepted: 08/22/2012] [Indexed: 11/21/2022]
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41
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Samotaeva IS, Tillmanns N, van Luijtelaar G, Vinogradova LV. Intracortical microinjections may cause spreading depression and suppress absence seizures. Neuroscience 2012. [PMID: 23200788 DOI: 10.1016/j.neuroscience.2012.11.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Intracerebral microinjection is a commonly used technique for local delivery of biologically active agents. However, it is known that mechanical injury of the cortex can induce spreading depression (SD), a wave of transient cellular depolarization. We examined the effects of intracortical microinjections of a new selective I(h) channel antagonist ORG 34167 and of different control treatments (saline and sham microinjections) on spontaneously occurring spike-wave discharges (SWDs) in WAG/Rij rats, a valid genetic model of absence epilepsy. Electroencephalographic (EEG) recording in awake rats has shown that both the drug and control microinjections are followed by long-term (for more than an hour) suppression of SWDs. dc-EEG recording in WAG/Rij rats has revealed that sham microinjections induce SD in 65% (31/48) cases. Number of SWDs decreased substantially for at least 90 min after the sham injections which induced cortical SD but remained unchanged if SD was not triggered by microinjection. These findings suggest that SD induced by intracortical microinjection may contribute to long-term suppression of non-convulsive epileptic activity after this experimental procedure.
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Affiliation(s)
- I S Samotaeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerova Street, 5A, Moscow 117485, Russian Federation
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42
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Zheng TW, O'Brien TJ, Morris MJ, Reid CA, Jovanovska V, O'Brien P, van Raay L, Gandrathi AK, Pinault D. Rhythmic neuronal activity in S2 somatosensory and insular cortices contribute to the initiation of absence-related spike-and-wave discharges. Epilepsia 2012; 53:1948-58. [PMID: 23083325 DOI: 10.1111/j.1528-1167.2012.03720.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE The origin of bilateral synchronous spike-and-wave discharges (SWDs) that underlie absence seizures has been widely debated. Studies in genetic rodent models suggest that SWDs originate from a restricted region in the somatosensory cortex. The properties of this initiation site remain unknown. Our goal was to characterize the interictal, preictal and ictal neuronal activity in the primary and secondary cortical regions (S1, S2) and in the adjacent insular cortex (IC) in Genetic Absence Epilepsy Rats from Strasbourg (GAERS). METHODS We performed electroencephalography (EEG) recordings in combination with multisite local field potential (LFP) and single cell juxtacellular recordings, and cortical electrical stimulations, in freely moving rats and those under neurolept-anesthesia. KEY FINDINGS The onset of the SWDs was preceded by 5-9 Hz field potential oscillations, which were detected earlier in S2 and IC than in S1. Sustained SWDs could be triggered by a 2-s train of 7-Hz electrical stimuli at a lower current intensity in S2 than in S1. In S2 and IC, subsets of neurons displayed rhythmic firing (5-9 Hz) in between seizures. S2 and IC layers V and VI neurons fired during the same time window, whereas in S1 layer VI, neurons fired before layer V neurons. Just before the spike component of each SW complex, short-lasting high-frequency oscillations consistently occurred in IC ∼20 msec before S1. SIGNIFICANCE Our findings demonstrate that the S2/IC cortical areas are a critical component of the macro-network that is responsible for the generation of absence-related SWDs.
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Affiliation(s)
- Thomas W Zheng
- Departments of Medicine, Surgery and Neurology, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria 3050, Australia
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Huang HY, Lee HW, Chen SD, Shaw FZ. Lamotrigine ameliorates seizures and psychiatric comorbidity in a rat model of spontaneous absence epilepsy. Epilepsia 2012; 53:2005-14. [DOI: 10.1111/j.1528-1167.2012.03664.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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44
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Moeller F, Muthuraman M, Stephani U, Deuschl G, Raethjen J, Siniatchkin M. Representation and propagation of epileptic activity in absences and generalized photoparoxysmal responses. Hum Brain Mapp 2012; 34:1896-909. [PMID: 22431268 DOI: 10.1002/hbm.22026] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 12/13/2011] [Indexed: 11/08/2022] Open
Abstract
Although functional imaging studies described networks associated with generalized epileptic activity, propagation patterns within these networks are not clear. In this study, electroencephalogram (EEG)-based coherent source imaging dynamic imaging of coherent sources (DICS) was applied to different types of generalized epileptiform discharges, namely absence seizures (10 patients) and photoparoxysmal responses (PPR) (eight patients) to describe the representation and propagation of these discharges in the brain. The results of electrical source imaging were compared to EEG-functional magnetic resonance imaging (fMRI) which had been obtained from the same data sets of simultaneous EEG and fMRI recordings. Similar networks were described by DICS and fMRI: (1) absence seizures were associated with thalamic involvement in all patients. Concordant results were also found for brain areas of the default mode network and the occipital cortex. (2) Both DICS and fMRI identified the occipital, parietal, and the frontal cortex in a network associated with PPR. (3) However, only when PPR preceded a generalized tonic-clonic seizure, the thalamus was involved in the generation of PPR as shown by both imaging techniques. Partial directed coherence suggested that during absences, the thalamus acts as a pacemaker while PPR could be explained by a cortical propagation from the occipital cortex via the parietal cortex to the frontal cortex. In conclusion, the electrical source imaging is not only able to describe similar neuronal networks as revealed by fMRI, including deep sources of neuronal activity such as the thalamus, but also demonstrates interactions interactions within these networks and sheds light on pathogenetic mechanisms of absence seizures and PPR.
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Affiliation(s)
- Friederike Moeller
- Department of Neuropediatrics, Christian-Albrechts-University, Kiel, Germany.
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45
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Marini C, Mantegazza M. Na+ channelopathies and epilepsy: recent advances and new perspectives. Expert Rev Clin Pharmacol 2012; 3:371-84. [PMID: 22111617 DOI: 10.1586/ecp.10.20] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mutations of ion channel genes have a major role in the pathogenesis of several epilepsies, confirming that some epilepsies are disorders due to the impairment of ion channel function (channelopathies). Voltage-gated Na(+) channels (VGSCs) play an essential role in neuronal excitability; it is, therefore, not surprising that most mutations associated with epilepsy have been identified in genes coding for VGSCs subunits. Epilepsies linked to VGSCs mutations range in severity from mild disorders, such as benign neonatal-infantile familial seizures and febrile seizures, to severe and drug-resistant epileptic encephalopathies. SCN1A is the most clinically relevant of all of the known epilepsy genes, several hundred mutations have been identified in this gene. This review will summarize recent advances and new perspectives on Na(+) channels and epilepsy. A better understanding of the genetic basis and of how gene defects cause seizures is mandatory to direct future research for newer selective and more efficacious treatments.
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Affiliation(s)
- Carla Marini
- Child Neurology Unit, Pediatric Hospital A. Meyer, University of Firenze, Viale Pieraccini, Florence, Italy.
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46
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Da Silva FHL, Gorter JA, Wadman WJ. Epilepsy as a dynamic disease of neuronal networks. HANDBOOK OF CLINICAL NEUROLOGY 2012; 107:35-62. [DOI: 10.1016/b978-0-444-52898-8.00003-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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47
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Mishra AM, Ellens DJ, Schridde U, Motelow JE, Purcaro MJ, DeSalvo MN, Enev M, Sanganahalli BG, Hyder F, Blumenfeld H. Where fMRI and electrophysiology agree to disagree: corticothalamic and striatal activity patterns in the WAG/Rij rat. J Neurosci 2011; 31:15053-64. [PMID: 22016539 PMCID: PMC3432284 DOI: 10.1523/jneurosci.0101-11.2011] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 07/27/2011] [Accepted: 08/14/2011] [Indexed: 11/21/2022] Open
Abstract
The relationship between neuronal activity and hemodynamic changes plays a central role in functional neuroimaging. Under normal conditions and in neurological disorders such as epilepsy, it is commonly assumed that increased functional magnetic resonance imaging (fMRI) signals reflect increased neuronal activity and that fMRI decreases represent neuronal activity decreases. Recent work suggests that these assumptions usually hold true in the cerebral cortex. However, less is known about the basis of fMRI signals from subcortical structures such as the thalamus and basal ganglia. We used WAG/Rij rats (Wistar albino Glaxo rats of Rijswijk), an established animal model of human absence epilepsy, to perform fMRI studies with blood oxygen level-dependent and cerebral blood volume (CBV) contrasts at 9.4 tesla, as well as laser Doppler cerebral blood flow (CBF), local field potential (LFP), and multiunit activity (MUA) recordings. We found that, during spike-wave discharges, the somatosensory cortex and thalamus showed increased fMRI, CBV, CBF, LFP, and MUA signals. However, the caudate-putamen showed fMRI, CBV, and CBF decreases despite increases in LFP and MUA signals. Similarly, during normal whisker stimulation, the cortex and thalamus showed increases in CBF and MUA, whereas the caudate-putamen showed decreased CBF with increased MUA. These findings suggest that neuroimaging-related signals and electrophysiology tend to agree in the cortex and thalamus but disagree in the caudate-putamen. These opposite changes in vascular and electrical activity indicate that caution should be applied when interpreting fMRI signals in both health and disease from the caudate-putamen, as well as possibly from other subcortical structures.
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Affiliation(s)
- Asht Mangal Mishra
- Departments of Neurology
- Core Center for Quantitative Neuroscience with Magnetic Resonance, Yale University School of Medicine, New Haven, Connecticut 06520
| | | | | | | | | | | | | | - Basavaraju G. Sanganahalli
- Diagnostic Radiology
- Core Center for Quantitative Neuroscience with Magnetic Resonance, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Fahmeed Hyder
- Diagnostic Radiology
- Biomedical Engineering, and
- Core Center for Quantitative Neuroscience with Magnetic Resonance, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Hal Blumenfeld
- Departments of Neurology
- Neurobiology
- Neurosurgery
- Core Center for Quantitative Neuroscience with Magnetic Resonance, Yale University School of Medicine, New Haven, Connecticut 06520
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Chloride-mediated inhibition of the ictogenic neurones initiating genetically-determined absence seizures. Neuroscience 2011; 192:642-51. [DOI: 10.1016/j.neuroscience.2011.06.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 05/13/2011] [Accepted: 06/11/2011] [Indexed: 11/20/2022]
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49
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Wijesinghe R, Camp AJ. Intrinsic neuronal excitability: implications for health and disease. Biomol Concepts 2011; 2:247-59. [PMID: 25962033 DOI: 10.1515/bmc.2011.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 05/30/2011] [Indexed: 11/15/2022] Open
Abstract
The output of a single neuron depends on both synaptic connectivity and intrinsic membrane properties. Changes in both synaptic and intrinsic membrane properties have been observed during homeostatic processes (e.g., vestibular compensation) as well as in several central nervous system (CNS) disorders. Although changes in synaptic properties have been extensively studied, particularly with regard to learning and memory, the contribution of intrinsic membrane properties to either physiological or pathological processes is much less clear. Recent research, however, has shown that alterations in the number, location or properties of voltage- and ligand-gated ion channels can underlie both normal and abnormal physiology, and that these changes arise via a diverse suite of molecular substrates. The literature reviewed here shows that changes in intrinsic neuronal excitability (presumably in concert with synaptic plasticity) can fundamentally modify the output of neurons, and that these modifications can subserve both homeostatic mechanisms and the pathogenesis of CNS disorders including epilepsy, migraine, and chronic pain.
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50
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The prevention of behavioral consequences of idiopathic generalized epilepsy: Evidence from rodent models. Neurosci Lett 2011; 497:177-84. [DOI: 10.1016/j.neulet.2011.02.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Accepted: 02/15/2011] [Indexed: 12/29/2022]
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