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Liotta A, Loroch S, Wallach I, Klewe K, Marcus K, Berndt N. Metabolic Adaptation in Epilepsy: From Acute Response to Chronic Impairment. Int J Mol Sci 2024; 25:9640. [PMID: 39273587 PMCID: PMC11395010 DOI: 10.3390/ijms25179640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 08/29/2024] [Accepted: 09/02/2024] [Indexed: 09/15/2024] Open
Abstract
Epilepsy is characterized by hypersynchronous neuronal discharges, which are associated with an increased cerebral metabolic rate of oxygen and ATP demand. Uncontrolled seizure activity (status epilepticus) results in mitochondrial exhaustion and ATP depletion, which potentially generate energy mismatch and neuronal loss. Many cells can adapt to increased energy demand by increasing metabolic capacities. However, acute metabolic adaptation during epileptic activity and its relationship to chronic epilepsy remains poorly understood. We elicited seizure-like events (SLEs) in an in vitro model of status epilepticus for eight hours. Electrophysiological recording and tissue oxygen partial pressure recordings were performed. After eight hours of ongoing SLEs, we used proteomics-based kinetic modeling to evaluate changes in metabolic capacities. We compared our findings regarding acute metabolic adaptation to published proteomic and transcriptomic data from chronic epilepsy patients. Epileptic tissue acutely responded to uninterrupted SLEs by upregulating ATP production capacity. This was achieved by a coordinated increase in the abundance of proteins from the respiratory chain and oxidative phosphorylation system. In contrast, chronic epileptic tissue shows a 25-40% decrease in ATP production capacity. In summary, our study reveals that epilepsy leads to dynamic metabolic changes. Acute epileptic activity boosts ATP production, while chronic epilepsy reduces it significantly.
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Affiliation(s)
- Agustin Liotta
- Department of Anesthesiology and Intensive Care, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- Institute of Computer-Assisted Cardiovascular Medicine, Deutsches Herzzentrum der Charité (DHZC), 13353 Berlin, Germany
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Stefan Loroch
- Medizinisches Proteom-Center, Center for Protein Diagnostics (PRODI), Medical Faculty, Ruhr-University Bochum, 44801 Bochum, Germany
- QC-MS/Fa. Dr. Loroch, BioMedizinZentrum, Otto-Hahn-Straße 15, 44227 Dortmund, Germany
| | - Iwona Wallach
- Institute of Computer-Assisted Cardiovascular Medicine, Deutsches Herzzentrum der Charité (DHZC), 13353 Berlin, Germany
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Kristoffer Klewe
- QC-MS/Fa. Dr. Loroch, BioMedizinZentrum, Otto-Hahn-Straße 15, 44227 Dortmund, Germany
| | - Katrin Marcus
- Medizinisches Proteom-Center, Center for Protein Diagnostics (PRODI), Medical Faculty, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Nikolaus Berndt
- Institute of Computer-Assisted Cardiovascular Medicine, Deutsches Herzzentrum der Charité (DHZC), 13353 Berlin, Germany
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), Department of Molecular Toxicology, 14558 Nuthetal, Germany
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2
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Bhandare A, Haley M, Torrico Anderson V, Domingos LB, Lopes M, Corrêa SAL, Wall MJ. ArcKR expression modifies synaptic plasticity following epileptic activity: Differential effects with in vitro and in vivo seizure-induction protocols. Epilepsia 2024; 65:2152-2164. [PMID: 38804501 DOI: 10.1111/epi.17981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/25/2024] [Accepted: 03/28/2024] [Indexed: 05/29/2024]
Abstract
OBJECTIVES Pathological forms of neural activity, such as epileptic seizures, modify the expression pattern of multiple proteins, leading to persistent changes in brain function. One such protein is activity-regulated cytoskeleton-associated protein (Arc), which is critically involved in protein-synthesis-dependent synaptic plasticity underlying learning and memory. In the present study, we have investigated how the expression of ArcKR, a form of Arc in which the ubiquitination sites have been mutated, resulting in slowed Arc degradation, modifies group I metabotropic glutamate receptor-mediated long-term depression (G1-mGluR-LTD) following seizures. METHODS We used a knock-in mice line that express ArcKR and two hyperexcitation models: an in vitro model, where hippocampal slices were exposed to zero Mg2+, 6 mM K+; and an in vivo model, where kainic acid was injected unilaterally into the hippocampus. In both models, field excitatory postsynaptic potentials (fEPSPs) were recorded from the CA1 region of hippocampal slices in response to Schaffer collateral stimulation and G1-mGluR-LTD was induced chemically with the group 1 mGluR agonist DHPG. RESULTS In the in vitro model, ArcKR expression enhanced the effects of seizure activity and increased the magnitude of G1-mGluR LTD, an effect that could be blocked with the mGluR5 antagonist MTEP. In the in vivo model, fEPSPs were significantly smaller in slices from ArcKR mice and were less contaminated by population spikes. In this model, the amount of G1-mGluR-LTD was significantly less in epileptic slices from ArcKR mice as compared to wildtype (WT) mice. SIGNIFICANCE We have shown that expression of ArcKR, a form of Arc in which degradation is reduced, significantly modulates the magnitude of G1-mGluR-LTD following epileptic seizures. However, the effect of ArcKR on LTD depends on the epileptic model used, with enhancement of LTD in an in vitro model and a reduction in the kainate mouse model.
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Affiliation(s)
- Amol Bhandare
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Maisy Haley
- School of Life Sciences, University of Warwick, Coventry, UK
| | | | - Luana B Domingos
- Bradford School of Pharmacy and Medical Sciences, University of Bradford, Bradford, UK
| | - Marcia Lopes
- Bradford School of Pharmacy and Medical Sciences, University of Bradford, Bradford, UK
| | - Sonia A L Corrêa
- Bradford School of Pharmacy and Medical Sciences, University of Bradford, Bradford, UK
- Department of Life Sciences, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
| | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry, UK
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3
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Su Y, Cao N, Zhang D, Wang M. The effect of ferroptosis-related mitochondrial dysfunction in the development of temporal lobe epilepsy. Ageing Res Rev 2024; 96:102248. [PMID: 38408490 DOI: 10.1016/j.arr.2024.102248] [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: 10/14/2023] [Revised: 01/27/2024] [Accepted: 02/22/2024] [Indexed: 02/28/2024]
Abstract
Temporal lobe epilepsy (TLE) is the most common form of epileptic syndrome. It has been established that due to its complex pathogenesis, a considerable proportion of TLE patients often progress to drug-resistant epilepsy. Ferroptosis has emerged as an important neuronal death mechanism in TLE, which is primarily influenced by lipid accumulation and oxidative stress. In previous studies of ferroptosis, more attention has been focused on the impact of changes in the levels of proteins related to the redox equilibrium and signaling pathways on epileptic seizures. However, it is worth noting that the oxidative-reduction changes in different organelles may have different pathophysiological significance in the process of ferroptosis-related diseases. Mitochondria, as a key organelle involved in ferroptosis, its structural damage and functional impairment can lead to energy metabolism disorders and disruption of the excitatory inhibitory balance, significantly increasing the susceptibility to epileptic seizures. Therefore, secondary mitochondrial dysfunction in the process of ferroptosis could play a crucial role in TLE pathogenesis. This review focuses on ferroptosis and mitochondria, discussing the pathogenic role of ferroptosis-related mitochondrial dysfunction in TLE, thus aiming to provide novel insights and potential implications of ferroptosis-related secondary mitochondrial dysfunction in epileptic seizures and to offer new insights for the precise exploration of ferroptosis-related therapeutic targets for TLE patients.
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Affiliation(s)
- Yang Su
- Department of Laboratory Medicine, West China Hospital of Sichuan University, China
| | - Ningrui Cao
- West China School of Medicine, Sichuan University, Chengdu, China
| | - Dingkun Zhang
- Laboratory of Clinical Proteomics and Metabolomics, Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Minjin Wang
- Department of Laboratory Medicine, West China Hospital of Sichuan University, China; Department of Neurology, West China Hospital of Sichuan University, China.
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Carvalho-Rosa JD, Rodrigues NC, Silva-Cruz A, Vaz SH, Cunha-Reis D. Epileptiform activity influences theta-burst induced LTP in the adult hippocampus: a role for synaptic lipid raft disruption in early metaplasticity? Front Cell Neurosci 2023; 17:1117697. [PMID: 37228704 PMCID: PMC10203237 DOI: 10.3389/fncel.2023.1117697] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 04/13/2023] [Indexed: 05/27/2023] Open
Abstract
Non-epileptic seizures are identified as a common epileptogenic trigger. Early metaplasticity following seizures may contribute to epileptogenesis by abnormally altering synaptic strength and homeostatic plasticity. We now studied how in vitro epileptiform activity (EA) triggers early changes in CA1 long-term potentiation (LTP) induced by theta-burst stimulation (TBS) in rat hippocampal slices and the involvement of lipid rafts in these early metaplasticity events. Two forms of EA were induced: (1) interictal-like EA evoked by Mg2+ withdrawal and K+ elevation to 6 mM in the superfusion medium or (2) ictal-like EA induced by bicuculline (10 μM). Both EA patterns induced and LTP-like effect on CA1 synaptic transmission prior to LTP induction. LTP induced 30 min post EA was impaired, an effect more pronounced after ictal-like EA. LTP recovered to control levels 60 min post interictal-like EA but was still impaired 60 min after ictal-like EA. The synaptic molecular events underlying this altered LTP were investigated 30 min post EA in synaptosomes isolated from these slices. EA enhanced AMPA GluA1 Ser831 phosphorylation but decreased Ser845 phosphorylation and the GluA1/GluA2 ratio. Flotillin-1 and caveolin-1 were markedly decreased concomitantly with a marked increase in gephyrin levels and a less prominent increase in PSD-95. Altogether, EA differentially influences hippocampal CA1 LTP thorough regulation of GluA1/GluA2 levels and AMPA GluA1 phosphorylation suggesting that altered LTP post-seizures is a relevant target for antiepileptogenic therapies. In addition, this metaplasticity is also associated with marked alterations in classic and synaptic lipid raft markers, suggesting these may also constitute promising targets in epileptogenesis prevention.
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Affiliation(s)
- José D. Carvalho-Rosa
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
- BioISI–Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Nádia C. Rodrigues
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Armando Silva-Cruz
- BioISI–Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Sandra H. Vaz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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5
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Vasilopoulos N, Kaplanian A, Vinos M, Katsaiti Y, Christodoulou O, Denaxa M, Skaliora I. The role of selective SATB1 deletion in somatostatin expressing interneurons on endogenous network activity and the transition to epilepsy. J Neurosci Res 2023; 101:424-447. [PMID: 36541427 DOI: 10.1002/jnr.25156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 10/24/2022] [Accepted: 12/03/2022] [Indexed: 12/24/2022]
Abstract
Somatostatin (SST) expressing interneurons are the second most abundant group of inhibitory neurons in the neocortex. They mainly target the apical dendrites of excitatory pyramidal cells and are implicated in feedforward and feedback inhibition. In the present study, we employ a conditional knockout mouse, in which the transcription factor Satb1 is selectively deleted in SST-expressing interneurons resulting to the reduction of their number across the somatosensory barrel field. Our goal was to investigate the effect of the reduced number of Satb1 mutant SST-interneurons on (i) the endogenous cortical network activity (spontaneously recurring Up/Down states), and (ii) the transition to epileptiform activity. By conducting LFP recordings in acute brain slices from young male and female mice, we demonstrate that mutant animals exhibit significant changes in network excitability, reflected in increased Up state occurrence, decreased Up state duration and higher levels of extracellular spiking activity. Epileptiform activity was induced through two distinct and widely used in vitro protocols: the low magnesium and the 4-Aminopyridine (4-AP) model. In the former, slices from mutant animals manifested shorter latency for the expression of stable seizure-like events. In contrast, when epilepsy was induced by 4-AP, no significant differences were reported. We conclude that normal SST-interneuron function has a significant role both in the regulation of the endogenous network activity, and in the transition to seizure-like discharges in a context-dependent manner.
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Affiliation(s)
- Nikos Vasilopoulos
- Centre for Basic Research, Biomedical Research Foundation of the Academy of Athens (BRFAA), Athens, Greece
| | - Ani Kaplanian
- Centre for Basic Research, Biomedical Research Foundation of the Academy of Athens (BRFAA), Athens, Greece
| | - Michael Vinos
- Centre for Basic Research, Biomedical Research Foundation of the Academy of Athens (BRFAA), Athens, Greece.,Department of History and Philosophy of Science, National and Kapodistrian University of Athens (NKUA), Athens, Greece
| | - Yolanda Katsaiti
- Biomedical Sciences Research Center "Alexander Fleming", Vari, Greece.,Department of Biology, National and Kapodistrian University of Athens (NKUA), Athens, Greece
| | - Ourania Christodoulou
- Biomedical Sciences Research Center "Alexander Fleming", Vari, Greece.,Department of Biology, University of Crete, Heraklion, Greece
| | - Myrto Denaxa
- Biomedical Sciences Research Center "Alexander Fleming", Vari, Greece
| | - Irini Skaliora
- Centre for Basic Research, Biomedical Research Foundation of the Academy of Athens (BRFAA), Athens, Greece.,Department of History and Philosophy of Science, National and Kapodistrian University of Athens (NKUA), Athens, Greece
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6
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Reiss Y, Bauer S, David B, Devraj K, Fidan E, Hattingen E, Liebner S, Melzer N, Meuth SG, Rosenow F, Rüber T, Willems LM, Plate KH. The neurovasculature as a target in temporal lobe epilepsy. Brain Pathol 2023; 33:e13147. [PMID: 36599709 PMCID: PMC10041171 DOI: 10.1111/bpa.13147] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/21/2022] [Indexed: 01/06/2023] Open
Abstract
The blood-brain barrier (BBB) is a physiological barrier maintaining a specialized brain micromilieu that is necessary for proper neuronal function. Endothelial tight junctions and specific transcellular/efflux transport systems provide a protective barrier against toxins, pathogens, and immune cells. The barrier function is critically supported by other cell types of the neurovascular unit, including pericytes, astrocytes, microglia, and interneurons. The dysfunctionality of the BBB is a hallmark of neurological diseases, such as ischemia, brain tumors, neurodegenerative diseases, infections, and autoimmune neuroinflammatory disorders. Moreover, BBB dysfunction is critically involved in epilepsy, a brain disorder characterized by spontaneously occurring seizures because of abnormally synchronized neuronal activity. While resistance to antiseizure drugs that aim to reduce neuronal hyperexcitability remains a clinical challenge, drugs targeting the neurovasculature in epilepsy patients have not been explored. The use of novel imaging techniques permits early detection of BBB leakage in epilepsy; however, the detailed mechanistic understanding of causes and consequences of BBB compromise remains unknown. Here, we discuss the current knowledge of BBB involvement in temporal lobe epilepsy with the emphasis on the neurovasculature as a therapeutic target.
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Affiliation(s)
- Yvonne Reiss
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University, Frankfurt, Germany.,Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany
| | - Sebastian Bauer
- Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Center of Neurology and Neurosurgery, University Hospital, Goethe University, Frankfurt, Germany
| | - Bastian David
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Kavi Devraj
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University, Frankfurt, Germany.,Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany
| | - Elif Fidan
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University, Frankfurt, Germany.,Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany
| | - Elke Hattingen
- Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany.,Institute of Neuroradiology, Center of Neurology and Neurosurgery, University Hospital, Goethe University, Frankfurt, Germany
| | - Stefan Liebner
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University, Frankfurt, Germany.,Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany
| | - Nico Melzer
- Department of Neurology, Heinrich-Heine University of Düsseldorf, Düsseldorf, Germany
| | - Sven G Meuth
- Department of Neurology, Heinrich-Heine University of Düsseldorf, Düsseldorf, Germany
| | - Felix Rosenow
- Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Center of Neurology and Neurosurgery, University Hospital, Goethe University, Frankfurt, Germany
| | - Theodor Rüber
- Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Center of Neurology and Neurosurgery, University Hospital, Goethe University, Frankfurt, Germany.,Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Laurent M Willems
- Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Center of Neurology and Neurosurgery, University Hospital, Goethe University, Frankfurt, Germany
| | - Karl H Plate
- Institute of Neurology (Edinger Institute), University Hospital, Goethe University, Frankfurt, Germany.,Center for Personalized Translational Epilepsy Research (CePTER), University Hospital, Goethe University, Frankfurt, Germany
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7
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Nasarudeen R, Singh A, Rana ZS, Punnakkal P. Epileptiform activity induced metaplasticity impairs bidirectional plasticity in the hippocampal CA1 synapses via GluN2B NMDA receptors. Exp Brain Res 2022; 240:3339-3349. [DOI: 10.1007/s00221-022-06486-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 10/10/2022] [Indexed: 11/09/2022]
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8
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Azilinon M, Makhalova J, Zaaraoui W, Medina Villalon S, Viout P, Roussel T, El Mendili MM, Ridley B, Ranjeva J, Bartolomei F, Jirsa V, Guye M. Combining sodium MRI, proton MR spectroscopic imaging, and intracerebral EEG in epilepsy. Hum Brain Mapp 2022; 44:825-840. [PMID: 36217746 PMCID: PMC9842896 DOI: 10.1002/hbm.26102] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 09/12/2022] [Accepted: 09/17/2022] [Indexed: 01/25/2023] Open
Abstract
Whole brain ionic and metabolic imaging has potential as a powerful tool for the characterization of brain diseases. We combined sodium MRI (23 Na MRI) and 1 H-MR Spectroscopic Imaging (1 H-MRSI), assessing changes within epileptogenic networks in comparison with electrophysiologically normal networks as defined by stereotactic EEG (SEEG) recordings analysis. We applied a multi-echo density adapted 3D projection reconstruction pulse sequence at 7 T (23 Na-MRI) and a 3D echo-planar spectroscopic imaging sequence at 3 T (1 H-MRSI) in 19 patients suffering from drug-resistant focal epilepsy who underwent presurgical SEEG. We investigated 23 Na MRI parameters including total sodium concentration (TSC) and the sodium signal fraction associated with the short component of T2 * decay (f), alongside the level of metabolites N-acetyl aspartate (NAA), choline compounds (Cho), and total creatine (tCr). All measures were extracted from spherical regions of interest (ROIs) centered between two adjacent SEEG electrode contacts and z-scored against the same ROI in controls. Group comparison showed a significant increase in f only in the epileptogenic zone (EZ) compared to controls and compared to patients' propagation zone (PZ) and non-involved zone (NIZ). TSC was significantly increased in all patients' regions compared to controls. Conversely, NAA levels were significantly lower in patients compared to controls, and lower in the EZ compared to PZ and NIZ. Multiple regression analyzing the relationship between sodium and metabolites levels revealed significant relations in PZ and in NIZ but not in EZ. Our results are in agreement with the energetic failure hypothesis in epileptic regions associated with widespread tissue reorganization.
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Affiliation(s)
- Mikhael Azilinon
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Julia Makhalova
- APHM, Timone Hospital, CEMEREMMarseilleFrance,Epileptology DepartmentAPHM, Timone HospitalMarseilleFrance
| | - Wafaa Zaaraoui
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Samuel Medina Villalon
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance,Epileptology DepartmentAPHM, Timone HospitalMarseilleFrance
| | - Patrick Viout
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Tangi Roussel
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Mohamed M. El Mendili
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Ben Ridley
- IRCCS Istituto delle Scienze Neurologiche di BolognaBolognaItaly
| | - Jean‐Philippe Ranjeva
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Fabrice Bartolomei
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance,Epileptology DepartmentAPHM, Timone HospitalMarseilleFrance
| | - Viktor Jirsa
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance
| | - Maxime Guye
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
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9
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Hagiwara A, Bydder M, Oughourlian TC, Yao J, Salamon N, Jahan R, Villablanca JP, Enzmann DR, Ellingson BM. Sodium MR Neuroimaging. AJNR Am J Neuroradiol 2021; 42:1920-1926. [PMID: 34446457 PMCID: PMC8583254 DOI: 10.3174/ajnr.a7261] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/28/2021] [Indexed: 12/26/2022]
Abstract
Sodium MR imaging has the potential to complement routine proton MR imaging examinations with the goal of improving diagnosis, disease characterization, and clinical monitoring in neurologic diseases. In the past, the utility and exploration of sodium MR imaging as a valuable clinical tool have been limited due to the extremely low MR signal, but with recent improvements in imaging techniques and hardware, sodium MR imaging is on the verge of becoming clinically realistic for conditions that include brain tumors, ischemic stroke, and epilepsy. In this review, we briefly describe the fundamental physics of sodium MR imaging tailored to the neuroradiologist, focusing on the basics necessary to understand factors that play into making sodium MR imaging feasible for clinical settings and describing current controversies in the field. We will also discuss the current state of the field and the potential future clinical uses of sodium MR imaging in the diagnosis, phenotyping, and therapeutic monitoring in neurologic diseases.
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Affiliation(s)
- A Hagiwara
- From the UCLA Brain Tumor Imaging Laboratory (A.H., M.B., T.C.O., J.Y., B.M.E.), Center for Computer Vision and Imaging Biomarkers
- Department of Radiological Sciences (A.H., M.B., J.Y., N.S., R.J., J.P.V., D.R.E., B.M.E.)
| | - M Bydder
- From the UCLA Brain Tumor Imaging Laboratory (A.H., M.B., T.C.O., J.Y., B.M.E.), Center for Computer Vision and Imaging Biomarkers
- Department of Radiological Sciences (A.H., M.B., J.Y., N.S., R.J., J.P.V., D.R.E., B.M.E.)
| | - T C Oughourlian
- From the UCLA Brain Tumor Imaging Laboratory (A.H., M.B., T.C.O., J.Y., B.M.E.), Center for Computer Vision and Imaging Biomarkers
- Neuroscience Interdepartmental Program (T.C.O., B.M.E.)
| | - J Yao
- From the UCLA Brain Tumor Imaging Laboratory (A.H., M.B., T.C.O., J.Y., B.M.E.), Center for Computer Vision and Imaging Biomarkers
- Department of Bioengineering (J.Y., B.M.E.), Henry Samueli School of Engineering and Applied Science, University of California Los Angeles, Los Angeles, California
- Department of Radiological Sciences (A.H., M.B., J.Y., N.S., R.J., J.P.V., D.R.E., B.M.E.)
| | - N Salamon
- Department of Radiological Sciences (A.H., M.B., J.Y., N.S., R.J., J.P.V., D.R.E., B.M.E.)
| | - R Jahan
- Department of Radiological Sciences (A.H., M.B., J.Y., N.S., R.J., J.P.V., D.R.E., B.M.E.)
| | - J P Villablanca
- Department of Radiological Sciences (A.H., M.B., J.Y., N.S., R.J., J.P.V., D.R.E., B.M.E.)
| | - D R Enzmann
- Department of Radiological Sciences (A.H., M.B., J.Y., N.S., R.J., J.P.V., D.R.E., B.M.E.)
| | - B M Ellingson
- From the UCLA Brain Tumor Imaging Laboratory (A.H., M.B., T.C.O., J.Y., B.M.E.), Center for Computer Vision and Imaging Biomarkers
- Department of Bioengineering (J.Y., B.M.E.), Henry Samueli School of Engineering and Applied Science, University of California Los Angeles, Los Angeles, California
- Department of Radiological Sciences (A.H., M.B., J.Y., N.S., R.J., J.P.V., D.R.E., B.M.E.)
- Neuroscience Interdepartmental Program (T.C.O., B.M.E.)
- Department of Psychiatry and Biobehavioral Sciences (B.M.E.), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
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Tukker AM, Westerink RHS. Novel test strategies for in vitro seizure liability assessment. Expert Opin Drug Metab Toxicol 2021; 17:923-936. [PMID: 33595380 PMCID: PMC8367052 DOI: 10.1080/17425255.2021.1876026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/11/2021] [Indexed: 12/18/2022]
Abstract
INTRODUCTION The increasing incidence of mental illnesses and neurodegenerative diseases results in a high demand for drugs targeting the central nervous system (CNS). These drugs easily reach the CNS, have a high affinity for CNS targets, and are prone to cause seizures as an adverse drug reaction. Current seizure liability assessment heavily depends on in vivo or ex vivo animal models and is therefore ethically debated, labor intensive, expensive, and not always predictive for human risk. AREAS COVERED The demand for CNS drugs urges the development of alternative safety assessment strategies. Yet, the complexity of the CNS hampers reliable detection of compound-induced seizures. This review provides an overview of the requirements of in vitro seizure liability assays and highlights recent advances, including micro-electrode array (MEA) recordings using rodent and human cell models. EXPERT OPINION Successful and cost-effective replacement of in vivo and ex vivo models for seizure liability screening can reduce animal use for drug development, while increasing the predictive value of the assays, particularly if human cell models are used. However, these novel test strategies require further validation and standardization as well as additional refinements to better mimic the human in vivo situation and increase their predictive value.
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Affiliation(s)
- Anke M. Tukker
- School of Health Sciences, Purdue University, Hall for Discovery and Learning Research (DLR 339), INUSA
| | - Remco H. S. Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, TD Utrecht, The Netherlands
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11
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A Novel Potassium Nanosensor Powers up the Detection of Extracellular K + Dynamics in Neuroscience. Neurosci Bull 2020; 36:1573-1575. [PMID: 32870467 DOI: 10.1007/s12264-020-00572-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 05/18/2020] [Indexed: 10/23/2022] Open
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12
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The adenosine A1 receptor agonist WAG 994 suppresses acute kainic acid-induced status epilepticus in vivo. Neuropharmacology 2020; 176:108213. [PMID: 32615188 DOI: 10.1016/j.neuropharm.2020.108213] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 12/22/2022]
Abstract
Status epilepticus (SE) is a neurological emergency characterized by continuous seizure activity lasting longer than 5 min, often with no recovery between seizures (Trinka et al., 2015). SE is refractory to benzodiazepine and second-line treatments in about 30% cases. Novel treatment approaches are urgently needed as refractory SE is associated with mortality rates of up to 70%. Robust adenosinergic anticonvulsant effects have been known for decades, but translation into seizure treatments was hampered by cardiovascular side effects. However, the selective adenosine A1 receptor agonist SDZ WAG 994 (WAG) displays diminished cardiovascular side effects compared to classic A1R agonists and was safely administered systemically in human clinical trials. Here, we investigate the anticonvulsant efficacy of WAG in vitro and in vivo. WAG robustly inhibited high-K+-induced continuous epileptiform activity in rat hippocampal slices (IC50 = 52.5 nM). Importantly, WAG acutely suppressed SE in vivo induced by kainic acid (20 mg/kg i.p.) in mice. After SE was established, mice received three i.p. injections of WAG or diazepam (DIA, 5 mg/kg). Interestingly, DIA did not attenuate SE while the majority of WAG-treated mice (1 mg/kg) were seizure-free after three injections. Anticonvulsant effects were retained when a lower dose of WAG (0.3 mg/kg) was used. Importantly, all WAG-treated mice survived kainic acid induced SE. In summary, we report for the first time that an A1R agonist with an acceptable human side-effect profile can acutely suppress established SE in vivo. Our results suggest that WAG stops or vastly attenuates SE while DIA fails to mitigate SE in this model.
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13
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Liu J, Li F, Wang Y, Pan L, Lin P, Zhang B, Zheng Y, Xu Y, Liao H, Ko G, Fei F, Xu C, Du Y, Shin K, Kim D, Jang SS, Chung HJ, Tian H, Wang Q, Guo W, Nam JM, Chen Z, Hyeon T, Ling D. A sensitive and specific nanosensor for monitoring extracellular potassium levels in the brain. NATURE NANOTECHNOLOGY 2020; 15:321-330. [PMID: 32042163 DOI: 10.1038/s41565-020-0634-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
Extracellular potassium concentration affects the membrane potential of neurons, and, thus, neuronal activity. Indeed, alterations of potassium levels can be related to neurological disorders, such as epilepsy and Alzheimer's disease, and, therefore, selectively detecting extracellular potassium would allow the monitoring of disease. However, currently available optical reporters are not capable of detecting small changes in potassium, in particular, in freely moving animals. Furthermore, they are susceptible to interference from sodium ions. Here, we report a highly sensitive and specific potassium nanosensor that can monitor potassium changes in the brain of freely moving mice undergoing epileptic seizures. An optical potassium indicator is embedded in mesoporous silica nanoparticles, which are shielded by an ultrathin layer of a potassium-permeable membrane, which prevents diffusion of other cations and allows the specific capturing of potassium ions. The shielded nanosensor enables the spatial mapping of potassium ion release in the hippocampus of freely moving mice.
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Affiliation(s)
- Jianan Liu
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
| | - Fangyuan Li
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
- Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Science, Zhejiang University, Hangzhou, China
- Key Laboratory of Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Yi Wang
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Limin Pan
- Department of Chemistry, Seoul National University, Seoul, Republic of Korea
| | - Peihua Lin
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
- Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Science, Zhejiang University, Hangzhou, China
| | - Bo Zhang
- Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Yanrong Zheng
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yingwei Xu
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Hongwei Liao
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
- Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Science, Zhejiang University, Hangzhou, China
| | - Giho Ko
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
| | - Fan Fei
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Cenglin Xu
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yang Du
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
- Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Science, Zhejiang University, Hangzhou, China
| | - Kwangsoo Shin
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
| | - Dokyoon Kim
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea
- Department of Bionano Engineering and Bionanotechnology, Hanyang University, Ansan, Republic of Korea
| | - Sung-Soo Jang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - He Tian
- Center of Electron Microscope, State Key Laboratory of Silicon Material, School of Material Science and Engineering, Zhejiang University, Hangzhou, China
| | - Qi Wang
- Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Wei Guo
- CAS Key Laboratory of Bio-Inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Jwa-Min Nam
- Department of Chemistry, Seoul National University, Seoul, Republic of Korea
| | - Zhong Chen
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Taeghwan Hyeon
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea.
- School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea.
| | - Daishun Ling
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
- Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Science, Zhejiang University, Hangzhou, China.
- Key Laboratory of Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China.
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Kainate receptors have different modulatory effect in seizure-like events and slow rhythmic activity in entorhinal cortex ex vivo. Brain Res Bull 2019; 153:279-288. [PMID: 31550521 DOI: 10.1016/j.brainresbull.2019.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 11/22/2022]
Abstract
In the neocortex, neurons form functional networks, the members of which exhibit a variable degree of synchronization. Slow rhythmic activity may be regarded as a balanced interplay of excitatory and inhibitory neuronal network activity, which is essential in learning and memory consolidation. On the other hand, seizures may be considered as hypersynchronized network states occurring in epileptic diseases. The brain slice method and multi-electrode array (MEA) systems offer a good opportunity for the modelling of cortical spontaneous activities by examining their initiation and propagation. Our main goals were to characterise and compare spontaneous activities developing in different conditions and cortical network states. The role of kainate receptors in these processes was also tested. According to our results, there are demonstrable dissimilarities between slow rhythmic activities vs. seizure-like events developing in the rat entorhinal cortex ex vivo in normal vs. epileptic conditions. Propagation velocity, time scale, activity pattern and pharmacological sensitivity are all different. Kainate receptors play a role in network activity in entorhinal cortex, they are capable to prolong the duration of the events of epileptiform activity. Their regulatory effect is more prominent under epileptic than under normal conditions.
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15
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Kraus L, Hetsch F, Schneider UC, Radbruch H, Holtkamp M, Meier JC, Fidzinski P. Dimethylethanolamine Decreases Epileptiform Activity in Acute Human Hippocampal Slices in vitro. Front Mol Neurosci 2019; 12:209. [PMID: 31551707 PMCID: PMC6743366 DOI: 10.3389/fnmol.2019.00209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 08/09/2019] [Indexed: 01/13/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy with about 30% of patients developing pharmacoresistance. These patients continue to suffer from seizures despite polytherapy with antiepileptic drugs (AEDs) and have an increased risk for premature death, thus requiring further efforts for the development of new antiepileptic therapies. The molecule dimethylethanolamine (DMEA) has been tested as a potential treatment in various neurological diseases, albeit the functional mechanism of action was never fully understood. In this study, we investigated the effects of DMEA on neuronal activity in single-cell recordings of primary neuronal cultures. DMEA decreased the frequency of spontaneous synaptic events in a concentration-dependent manner with no apparent effect on resting membrane potential (RMP) or action potential (AP) threshold. We further tested whether DMEA can exert antiepileptic effects in human brain tissue ex vivo. We analyzed the effect of DMEA on epileptiform activity in the CA1 region of the resected hippocampus of TLE patients in vitro by recording extracellular field potentials in the pyramidal cell layer. Epileptiform burst activity in resected hippocampal tissue from TLE patients remained stable over several hours and was pharmacologically suppressed by lacosamide, demonstrating the applicability of our platform to test antiepileptic efficacy. Similar to lacosamide, DMEA also suppressed epileptiform activity in the majority of samples, albeit with variable interindividual effects. In conclusion, DMEA might present a new approach for treatment in pharmacoresistant TLE and further studies will be required to identify its exact mechanism of action and the involved molecular targets.
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Affiliation(s)
- Larissa Kraus
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Berlin, Germany
- Berlin Institute of Health (BIH), Zoologisches Institut, Technische Universität Braunschweig, Braunschweig, Germany
| | - Florian Hetsch
- Zoologisches Institut, Technische Universität Braunschweig, Braunschweig, Germany
| | - Ulf C. Schneider
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurosurgery, Berlin, Germany
| | - Helena Radbruch
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neuropathology, Berlin, Germany
| | - Martin Holtkamp
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Berlin, Germany
- Berlin Institute of Health (BIH), Zoologisches Institut, Technische Universität Braunschweig, Braunschweig, Germany
| | - Jochen C. Meier
- Berlin Institute of Health (BIH), Zoologisches Institut, Technische Universität Braunschweig, Braunschweig, Germany
- Zoologisches Institut, Technische Universität Braunschweig, Braunschweig, Germany
| | - Pawel Fidzinski
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Berlin, Germany
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16
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Balogh V, Szádeczky-Kardoss K, Varró P, Világi I, Borbély S. Analysis of Propagation of Slow Rhythmic Activity Induced in Ex Vivo Rat Brain Slices. Brain Connect 2019; 9:649-660. [PMID: 31179725 DOI: 10.1089/brain.2018.0650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Slow wave oscillation is a synchronous oscillatory mechanism that is a characteristic wave type of the cerebral cortex during physiological deep sleep or anesthesia. It may play an important role in cortical analysis of sensory input. Our goal was (1) to develop optimal conditions for the induction of this slow rhythmic activity in adult rat cortical slices, (2) to identify connections through which the activity propagates between coupled cortical regions, and (3) to study the pattern of horizontal and vertical flow of activity developed spontaneously in cortical slices. Experiments were performed on intact or differently incised rat cortical slices. According to our results, spontaneous cortical activity develops reliably in slightly modified artificial cerebrospinal fluid, first in the entorhinal cortical region of horizontally cut slices and then it spreads directly to the perirhinal (PRh) cortex. The activity readily generated in layer 2/3 of the entorhinal cortex then quickly spreads vertically to upper layer 2-3 in the same area and to the neighboring regions, that is, to the PRh cortex. Synchronization of activity in neighboring cortical areas occurs through both callosal connections and layer 2-3 intrinsic network, which are important in the propagation of spontaneous, inherent cortical slow wave activity.
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Affiliation(s)
- Veronika Balogh
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary.,Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | | | - Petra Varró
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
| | - Ildikó Világi
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
| | - Sándor Borbély
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary.,Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
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17
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Inhibition and oscillations in the human brain tissue in vitro. Neurobiol Dis 2019; 125:198-210. [DOI: 10.1016/j.nbd.2019.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/22/2018] [Accepted: 02/07/2019] [Indexed: 01/22/2023] Open
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18
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Chizhov AV, Amakhin DV, Zaitsev AV. Mathematical model of Na-K-Cl homeostasis in ictal and interictal discharges. PLoS One 2019; 14:e0213904. [PMID: 30875397 PMCID: PMC6420042 DOI: 10.1371/journal.pone.0213904] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 03/04/2019] [Indexed: 12/22/2022] Open
Abstract
Despite big experimental data on the phenomena and mechanisms of the generation of ictal and interictal discharges (IDs and IIDs), mathematical models that can describe the synaptic interactions of neurons and the ionic dynamics in biophysical detail are not well-established. Based on experimental recordings of combined hippocampal-entorhinal cortex slices from rats in a high-potassium and a low-magnesium solution containing 4-aminopyridine as well as previous observations of similar experimental models, this type of mathematical model has been developed. The model describes neuronal excitation through the application of the conductance-based refractory density approach for three neuronal populations: two populations of glutamatergic neurons with hyperpolarizing and depolarizing GABAergic synapses and one GABAergic population. The ionic dynamics account for the contributions of voltage-gated and synaptic channels, active and passive transporters, and diffusion. The relatively slow dynamics of potassium, chloride, and sodium ion concentrations determine the transitions from pure GABAergic IIDs to IDs and GABA-glutamatergic IIDs. The model reproduces different types of IIDs, including those initiated by interneurons; repetitive IDs; tonic and bursting modes of an ID composed of clustered IID-like events. The simulations revealed contributions from different ionic channels to the ion concentration dynamics before and during ID generation. The proposed model is a step forward to an optimal mathematical description of the mechanisms of epileptic discharges.
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Affiliation(s)
- Anton V. Chizhov
- Computational Physics Laboratory, Ioffe Institute, Saint Petersburg, Russia
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- * E-mail:
| | - Dmitry V. Amakhin
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Aleksey V. Zaitsev
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
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19
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Zhou Z, Ikegaya Y, Koyama R. The Astrocytic cAMP Pathway in Health and Disease. Int J Mol Sci 2019; 20:E779. [PMID: 30759771 PMCID: PMC6386894 DOI: 10.3390/ijms20030779] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/06/2019] [Accepted: 02/08/2019] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are major glial cells that play critical roles in brain homeostasis. Abnormalities in astrocytic functions can lead to brain disorders. Astrocytes also respond to injury and disease through gliosis and immune activation, which can be both protective and detrimental. Thus, it is essential to elucidate the function of astrocytes in order to understand the physiology of the brain to develop therapeutic strategies against brain diseases. Cyclic adenosine monophosphate (cAMP) is a major second messenger that triggers various downstream cellular machinery in a wide variety of cells. The functions of astrocytes have also been suggested as being regulated by cAMP. Here, we summarize the possible roles of cAMP signaling in regulating the functions of astrocytes. Specifically, we introduce the ways in which cAMP pathways are involved in astrocyte functions, including (1) energy supply, (2) maintenance of the extracellular environment, (3) immune response, and (4) a potential role as a provider of trophic factors, and we discuss how these cAMP-regulated processes can affect brain functions in health and disease.
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Affiliation(s)
- Zhiwen Zhou
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033, Japan.
- Center for Information and Neural Networks, Suita City, Osaka 565-0871, Japan.
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033, Japan.
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Abstract
The brain is the most complex organ of the body, and many pathological processes underlying various brain disorders are poorly understood. Limited accessibility hinders observation of such processes in the in vivo brain, and experimental freedom is often insufficient to enable informative manipulations. In vitro preparations (brain slices or cultures of dissociated neurons) offer much better accessibility and reduced complexity and have yielded valuable new insights into various brain disorders. Both types of preparations have their advantages and limitations with regard to lifespan, preservation of in vivo brain structure, composition of cell types, and the link to behavioral outcome is often unclear in in vitro models. While these limitations hamper general usage of in vitro preparations to study, e.g., brain development, in vitro preparations are very useful to study neuronal and synaptic functioning under pathologic conditions. This chapter addresses several brain disorders, focusing on neuronal and synaptic functioning, as well as network aspects. Recent progress in the fields of brain circulation disorders, excitability disorders, and memory disorders will be discussed, as well as limitations of current in vitro models.
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Ruan LY, Fan JT, Hong W, Zhao H, Li MH, Jiang L, Fu YH, Xing YX, Chen C, Wang JS. Isoniazid-induced hepatotoxicity and neurotoxicity in rats investigated by 1H NMR based metabolomics approach. Toxicol Lett 2018; 295:256-269. [DOI: 10.1016/j.toxlet.2018.05.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 04/09/2018] [Accepted: 05/27/2018] [Indexed: 10/28/2022]
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22
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Hassel B, Mariussen E, Idland AV, Dahl GT, Ræder J, Frihagen F, Berg JP, Chaudhry FA, Wyller TB, Watne LO. CSF sodium at toxic levels precedes delirium in hip fracture patients. Neurotoxicology 2018; 69:11-16. [PMID: 30149051 DOI: 10.1016/j.neuro.2018.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/20/2018] [Accepted: 08/21/2018] [Indexed: 10/28/2022]
Abstract
Delirium is an acute state of confusion and a fluctuating level of consciousness. It is precipitated by physical illness or trauma, such as pneumonia, heart infarction, or hip fracture. Delirium is common among elderly hospitalized patients, and as many as 50% of hip fracture patients may develop delirium. Delirium may precipitate dementia, but recent studies indicate that delirium is caused by unknown neurotoxic mechanisms that are different from those that are associated with dementia. Experimental studies have shown that high extracellular levels of sodium are neurotoxic. We sampled lumbar cerebrospinal fluid (CSF) from hip fracture patients during hip surgery and analyzed metal ions that influence neuronal function. Eight patients who developed delirium after surgery had 21% higher CSF sodium than 17 patients who did not develop delirium (median value 175 mmol/L; range 154-188, vs. 145 mmol/L (112-204; p < 0.008) or 39 patients who underwent elective surgery under spinal anesthesia without developing delirium (145 mmol/L; 140-149; p = 0.0004). Seven patients who had developed delirium before CSF sampling had a median CSF sodium of 150 mmol/L (144-185; p = 0.3). CSF potassium was also 21% higher in patients who developed delirium (p = 0.024), but remained within the physiological range. Serum sodium and potassium were normal in all patient groups. This study, on a small sample of patients, confirms the neurotoxic potential and clinical importance of high extracellular levels of sodium in the brain. High CSF sodium would likely affect cerebral function and could precipitate delirium; further, it could interact with dementia-specific mechanisms to precipitate dementia development.
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Affiliation(s)
- Bjørnar Hassel
- Department of Neurohabilitation and Complex Neurology, Oslo University Hospital, University of Oslo, Oslo, Norway; Norwegian Defence Research Establishment (FFI), Kjeller, Norway.
| | - Espen Mariussen
- Norwegian Defence Research Establishment (FFI), Kjeller, Norway; Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Ane-Victoria Idland
- Oslo Delirium Research Group, Department of Geriatric Medicine, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Gry T Dahl
- Department of Anesthesiology, Diakonhjemmet Hospital, Oslo, Norway
| | - Johan Ræder
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Anesthesiology, Oslo University Hospital, Oslo, Norway
| | - Frede Frihagen
- Division of Orthopaedic Surgery, Oslo University Hospital, Oslo, Norway
| | - Jens Petter Berg
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | | | - Torgeir B Wyller
- Oslo Delirium Research Group, Department of Geriatric Medicine, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Leiv O Watne
- Oslo Delirium Research Group, Department of Geriatric Medicine, Oslo University Hospital, Oslo, Norway; Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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23
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Campos G, Fortuna A, Falcão A, Alves G. In vitro and in vivo experimental models employed in the discovery and development of antiepileptic drugs for pharmacoresistant epilepsy. Epilepsy Res 2018; 146:63-86. [PMID: 30086482 DOI: 10.1016/j.eplepsyres.2018.07.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 06/16/2018] [Accepted: 07/20/2018] [Indexed: 12/23/2022]
Abstract
Epilepsy is one of the most common chronic, recurrent and progressive neurological diseases. In spite of the large number of antiepileptic drugs currently available for the suppression of seizures, about one-third of patients develop drug-resistant epilepsy, even when they are administered the most appropriate treatment available. Thus, nonclinical models can be valuable tools for the elucidation of the mechanisms underlying the development of pharmacoresistance and also for the development of new therapeutic agents that may be promising therapeutic approaches for this unmet medical need. Up today, several epilepsy and seizure models have been developed, exhibiting similar physiopathological features of human drug-resistant epilepsy; moreover, pharmacological response to antiepileptic drugs clinically available tends to be similar in animal models and humans. Therefore, they should be more intensively used in the preclinical discovery and development of new candidates to antiepileptic drugs. Although useful, in vitro models cannot completely replicate the complexity of a living being and their potential for a systematic use in antiepileptic drug screening is limited. The whole-animal models are the most commonly employed and they can be classified as per se drug-resistant due to an inherent poor drug response or be based on the selection of subgroups of epileptic animals that respond or not to a specific antiepileptic drug. Although more expensive and time-consuming, the latter are chronic models of epilepsy that better exhibit the disease-associated alterations found in human epilepsy. Several antiepileptic drugs in development or already marketed have been already tested and shown to be effective in these models of drug-resistant epilepsy, constituting a new hope for the treatment of drug-resistant epilepsy. This review will provide epilepsy researchers with detailed information on the in vitro and in vivo nonclinical models of interest in drug-resistant epilepsy, which may enable a refined selection of most relevant models for understanding the mechanisms of the disease and developing novel antiepileptic drugs.
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Affiliation(s)
- Gonçalo Campos
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506, Covilhã, Portugal
| | - Ana Fortuna
- CIBIT - Coimbra Institute for Biomedical Imaging and Translational Research, University of Coimbra, Portugal; Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal
| | - Amílcar Falcão
- CIBIT - Coimbra Institute for Biomedical Imaging and Translational Research, University of Coimbra, Portugal; Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal
| | - Gilberto Alves
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506, Covilhã, Portugal.
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Potassium dynamics and seizures: Why is potassium ictogenic? Epilepsy Res 2018; 143:50-59. [DOI: 10.1016/j.eplepsyres.2018.04.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/26/2018] [Accepted: 04/07/2018] [Indexed: 01/01/2023]
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Chizhov AV, Zefirov AV, Amakhin DV, Smirnova EY, Zaitsev AV. Minimal model of interictal and ictal discharges "Epileptor-2". PLoS Comput Biol 2018; 14:e1006186. [PMID: 29851959 PMCID: PMC6005638 DOI: 10.1371/journal.pcbi.1006186] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 06/18/2018] [Accepted: 05/09/2018] [Indexed: 12/01/2022] Open
Abstract
Seizures occur in a recurrent manner with intermittent states of interictal and ictal discharges (IIDs and IDs). The transitions to and from IDs are determined by a set of processes, including synaptic interaction and ionic dynamics. Although mathematical models of separate types of epileptic discharges have been developed, modeling the transitions between states remains a challenge. A simple generic mathematical model of seizure dynamics (Epileptor) has recently been proposed by Jirsa et al. (2014); however, it is formulated in terms of abstract variables. In this paper, a minimal population-type model of IIDs and IDs is proposed that is as simple to use as the Epileptor, but the suggested model attributes physical meaning to the variables. The model is expressed in ordinary differential equations for extracellular potassium and intracellular sodium concentrations, membrane potential, and short-term synaptic depression variables. A quadratic integrate-and-fire model driven by the population input current is used to reproduce spike trains in a representative neuron. In simulations, potassium accumulation governs the transition from the silent state to the state of an ID. Each ID is composed of clustered IID-like events. The sodium accumulates during discharge and activates the sodium-potassium pump, which terminates the ID by restoring the potassium gradient and thus polarizing the neuronal membranes. The whole-cell and cell-attached recordings of a 4-AP-based in vitro model of epilepsy confirmed the primary model assumptions and predictions. The mathematical analysis revealed that the IID-like events are large-amplitude stochastic oscillations, which in the case of ID generation are controlled by slow oscillations of ionic concentrations. The IDs originate in the conditions of elevated potassium concentrations in a bath solution via a saddle-node-on-invariant-circle-like bifurcation for a non-smooth dynamical system. By providing a minimal biophysical description of ionic dynamics and network interactions, the model may serve as a hierarchical base from a simple to more complex modeling of seizures. In pathological conditions of epilepsy, the functioning of the neural network crucially depends on the ionic concentrations inside and outside neurons. A number of factors that affect neuronal activity is large. That is why the development of a minimal model that reproduces typical seizures could structure further experimental and analytical studies of the pathological mechanisms. Here, on a base of known biophysical models, we present a simple population-type model that includes only four principal variables, the extracellular potassium concentration, the intracellular sodium concentration, the membrane potential and the synaptic resource diminishing due to short-term synaptic depression. A simple modeled neuron is used as an observer of the population activity. We validate the model assumptions with in vitro experiments. Our model reproduces ictal and interictal events, where the latter result in bursts of spikes in single neurons, and the former represent the cluster of spike bursts. Mathematical analysis reveals that the bursts are spontaneous large-amplitude oscillations, which may cluster after a saddle-node on invariant circle bifurcation in the pro-epileptic conditions. Our consideration has significant bearing in understanding pathological neuronal network dynamics.
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Affiliation(s)
- Anton V. Chizhov
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- Computational Physics Laboratory, Ioffe Institute, Saint Petersburg, Russia
- * E-mail:
| | - Artyom V. Zefirov
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- Computational Physics Laboratory, Ioffe Institute, Saint Petersburg, Russia
| | - Dmitry V. Amakhin
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Elena Yu. Smirnova
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- Computational Physics Laboratory, Ioffe Institute, Saint Petersburg, Russia
| | - Aleksey V. Zaitsev
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
- Institute of Experimental Medicine, Almazov National Medical Research Centre, Saint Petersburg, Russia
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Reyes-Garcia SZ, Scorza CA, Araújo NS, Ortiz-Villatoro NN, Jardim AP, Centeno R, Yacubian EMT, Faber J, Cavalheiro EA. Different patterns of epileptiform-like activity are generated in the sclerotic hippocampus from patients with drug-resistant temporal lobe epilepsy. Sci Rep 2018; 8:7116. [PMID: 29740014 PMCID: PMC5940759 DOI: 10.1038/s41598-018-25378-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/19/2018] [Indexed: 12/26/2022] Open
Abstract
Human hippocampal slice preparations from patients with temporal lobe epilepsy (TLE) associated with hippocampal sclerosis (HS) are excellent material for the characterization of epileptiform-like activity. However, it is still unknown if hippocampal regions as cornu Ammonis (CA) 1, CA3 and CA4, generate population epileptiform-like activity. Here, we investigated epileptiform activities of the subiculum, CA1, CA2, CA3, CA4 (induced by elevation of extracellular potassium concentration) and the dentate gyrus (induced with hilar stimulation and elevation of potassium concentration) from sclerotic hippocampi of patients with drug-resistant TLE. Five types of epileptiform-like activity were observed: interictal-like events; periodic ictal spiking; seizure-like events; spreading depression-like events; tonic seizure-like events and no activity. Different susceptibilities to generate epileptiform activity among hippocampal regions were observed; the dentate gyrus was the most susceptible region followed by the subiculum, CA4, CA1, CA2 and CA3. The incidence of epileptiform activity pattern was associated with specific regions of the hippocampal formation. Moreover, it was observed that each region of the hippocampal formation exhibits frequency-specific ranges in each subfield of the sclerotic human tissue. In conclusion, this study demonstrates that epileptiform-like activity may be induced in different regions of the hippocampal formation, including regions that are severely affected by neuronal loss.
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Affiliation(s)
- Selvin Z Reyes-Garcia
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil. .,Departamento de Ciencias Morfológicas, Facultad de Ciencias Médicas, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras.
| | - Carla A Scorza
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Noemi S Araújo
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Nancy N Ortiz-Villatoro
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Anaclara Prada Jardim
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Ricardo Centeno
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Elza Márcia Targas Yacubian
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Jean Faber
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Esper A Cavalheiro
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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Abstract
Resected hippocampal tissue from patients with drug-resistant epilepsy presents a unique possibility to test novel treatment strategies directly in target tissue. The post-resection time for testing and analysis however is normally limited. Acute tissue slices allow for electrophysiological recordings typically up to 12 hours. To enable longer time to test novel treatment strategies such as, e.g., gene-therapy, we developed a method for keeping acute human brain slices viable over a longer period. Our protocol keeps neurons viable well up to 48 hours. Using a dual-flow chamber, which allows for microscopic visualisation of individual neurons with a submerged objective for whole-cell patch-clamp recordings, we report stable electrophysiological properties, such as action potential amplitude and threshold during this time. We also demonstrate that epileptiform activity, monitored by individual dentate granule whole-cell recordings, can be consistently induced in these slices, underlying the usefulness of this methodology for testing and/or validating novel treatment strategies for epilepsy.
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Papageorgiou IE, Valous NA, Lahrmann B, Janova H, Klaft ZJ, Koch A, Schneider UC, Vajkoczy P, Heppner FL, Grabe N, Halama N, Heinemann U, Kann O. Astrocytic glutamine synthetase is expressed in the neuronal somatic layers and down-regulated proportionally to neuronal loss in the human epileptic hippocampus. Glia 2018; 66:920-933. [DOI: 10.1002/glia.23292] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/20/2017] [Accepted: 12/21/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Ismini E. Papageorgiou
- Institute of Physiology and Pathophysiology, University of Heidelberg, Im Neuenheimer Feld 326; Heidelberg D-69120 Germany
- Interdisciplinary Center for Neurosciences, University of Heidelberg, Im Neuenheimer Feld 364; Heidelberg D-69120 Germany
- Present address: Institute of Radiology, Südharz Klinikum Nordhausen gGmbH, Dr.-Robert-Koch-Str. 39; Nordhausen D-99734 Germany
| | - Nektarios A. Valous
- Applied Tumor Immunity Clinical Cooperation Unit, National Center for Tumor Diseases, German Cancer Research Center, Im Neuenheimer Feld 460; Heidelberg D-69120 Germany
- Department of Medical Oncology; National Center for Tumor Diseases, University Hospital Heidelberg, Im Neuenheimer Feld 460; Heidelberg D-69120 Germany
| | - Bernd Lahrmann
- Hamamatsu Tissue Imaging and Analysis Center (TIGA), National Center for Tumor Diseases, BIOQUANT, Im Neuenheimer Feld 267, University of Heidelberg; Heidelberg D-69120 Germany
- Steinbeis Transfer Center for Medical Systems Biology, Heckerstr. 9; Heidelberg D-69124 Germany
| | - Hana Janova
- Division of Clinical Neuroscience; Max Planck Institute of Experimental Medicine, Hermann-Rein-str. 3; Göttingen D-37075 Germany
| | - Zin-Juan Klaft
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1; Berlin D-10117 Germany
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1; Berlin D-10117 Germany
| | - Arend Koch
- Institute of Neuropathology, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, Charitéplatz 1; Berlin D-10117 Germany
| | - Ulf C. Schneider
- Department of Neurosurgery; Charité-Universitätsmedizin Berlin, Campus Virchow Medical Center, Augustenplatz 1; Berlin D-11353 Germany
| | - Peter Vajkoczy
- Department of Neurosurgery; Charité-Universitätsmedizin Berlin, Campus Virchow Medical Center, Augustenplatz 1; Berlin D-11353 Germany
| | - Frank L. Heppner
- Institute of Neuropathology, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, Charitéplatz 1; Berlin D-10117 Germany
| | - Niels Grabe
- Hamamatsu Tissue Imaging and Analysis Center (TIGA), National Center for Tumor Diseases, BIOQUANT, Im Neuenheimer Feld 267, University of Heidelberg; Heidelberg D-69120 Germany
- Steinbeis Transfer Center for Medical Systems Biology, Heckerstr. 9; Heidelberg D-69124 Germany
| | - Niels Halama
- Department of Medical Oncology; National Center for Tumor Diseases, University Hospital Heidelberg, Im Neuenheimer Feld 460; Heidelberg D-69120 Germany
| | - Uwe Heinemann
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1; Berlin D-10117 Germany
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1; Berlin D-10117 Germany
| | - Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, Im Neuenheimer Feld 326; Heidelberg D-69120 Germany
- Interdisciplinary Center for Neurosciences, University of Heidelberg, Im Neuenheimer Feld 364; Heidelberg D-69120 Germany
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Computational model of interictal discharges triggered by interneurons. PLoS One 2017; 12:e0185752. [PMID: 28977038 PMCID: PMC5627938 DOI: 10.1371/journal.pone.0185752] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 09/19/2017] [Indexed: 11/19/2022] Open
Abstract
Interictal discharges (IIDs) are abnormal waveforms registered in the periods before or between seizures. IIDs that are initiated by GABAergic interneurons have not been mathematically modeled yet. In the present study, a mathematical model that describes the mechanisms of these discharges is proposed. The model is based on the experimental recordings of IIDs in pyramidal neurons of the rat entorhinal cortex and estimations of synaptic conductances during IIDs. IIDs were induced in cortico-hippocampal slices by applying an extracellular solution with 4-aminopyridine, high potassium, and low magnesium concentrations. Two different types of IIDs initiated by interneurons were observed. The first type of IID (IID1) was pure GABAergic. The second type of IID (IID2) was induced by GABAergic excitation and maintained by recurrent interactions of both GABA- and glutamatergic neuronal populations. The model employed the conductance-based refractory density (CBRD) approach, which accurately approximates the firing rate of a population of similar Hodgkin-Huxley-like neurons. The model of coupled excitatory and inhibitory populations includes AMPA, NMDA, and GABA-receptor-mediated synapses and gap junctions. These neurons receive both arbitrary deterministic input and individual colored Gaussian noise. Both types of IIDs were successfully reproduced in the model by setting two different depolarized levels for GABA-mediated current reversal potential. It was revealed that short-term synaptic depression is a crucial factor in ceasing each of the discharges, and it also determines their durations and frequencies.
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Contribution of Intrinsic Lactate to Maintenance of Seizure Activity in Neocortical Slices from Patients with Temporal Lobe Epilepsy and in Rat Entorhinal Cortex. Int J Mol Sci 2017; 18:ijms18091835. [PMID: 28832554 PMCID: PMC5618484 DOI: 10.3390/ijms18091835] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 12/20/2022] Open
Abstract
Neuronal lactate uptake supports energy metabolism associated with synaptic signaling and recovery of extracellular ion gradients following neuronal activation. Altered expression of the monocarboxylate transporters (MCT) in temporal lobe epilepsy (TLE) hampers lactate removal into the bloodstream. The resulting increase in parenchymal lactate levels might exert both, anti- and pro-ictogen effects, by causing acidosis and by supplementing energy metabolism, respectively. Hence, we assessed the contribution of lactate to the maintenance of transmembrane potassium gradients, synaptic signaling and pathological network activity in chronic epileptic human tissue. Stimulus induced and spontaneous field potentials and extracellular potassium concentration changes (∆[K⁺]O) were recorded in parallel with tissue pO₂ and pH in slices from TLE patients while blocking MCTs by α-cyano-4-hydroxycinnamic acid (4-CIN) or d-lactate. Intrinsic lactate contributed to the oxidative energy metabolism in chronic epileptic tissue as revealed by the changes in pO₂ following blockade of lactate uptake. However, unlike the results in rat hippocampus, ∆[K⁺]O recovery kinetics and field potential amplitude did not depend on the presence of lactate. Remarkably, inhibition of lactate uptake exerted pH-independent anti-seizure effects both in healthy rat and chronic epileptic tissue and this effect was partly mediated via adenosine 1 receptor activation following decreased oxidative metabolism.
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Ridley B, Marchi A, Wirsich J, Soulier E, Confort-Gouny S, Schad L, Bartolomei F, Ranjeva JP, Guye M, Zaaraoui W. Brain sodium MRI in human epilepsy: Disturbances of ionic homeostasis reflect the organization of pathological regions. Neuroimage 2017; 157:173-183. [PMID: 28602596 DOI: 10.1016/j.neuroimage.2017.06.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 06/01/2017] [Accepted: 06/03/2017] [Indexed: 12/15/2022] Open
Abstract
In light of technical advancements supporting exploration of MR signals other than 1H, sodium (23Na) has received attention as a marker of ionic homeostasis and cell viability. Here, we evaluate for the first time the possibility that 23Na-MRI is sensitive to pathological processes occurring in human epilepsy. A normative sample of 27 controls was used to normalize regions of interest (ROIs) from 1424 unique brain locales on quantitative 23Na-MRI and high-resolution 1H-MPRAGE images. ROIs were based on intracerebral electrodes in ten patients undergoing epileptic network mapping. The stereo-EEG gold standard was used to define regions as belonging to primarily epileptogenic, secondarily irritative and to non-involved regions. Estimates of total sodium concentration (TSC) on 23Na-MRI and cerebrospinal fluid (CSF) on 1H imaging were extracted for each patient ROI, and normalized against the same region in controls. ROIs with disproportionate CSF contributions (ZCSF≥1.96) were excluded. TSC levels were found to be elevated in patients relative to controls except in one patient, who suffered non-convulsive seizures during the scan, in whom we found reduced TSC levels. In the remaining patients, an ANOVA (F1100= 12.37, p<0.0001) revealed a highly significant effect of clinically-defined zones (F1100= 11.13, p<0.0001), with higher normalized TSC in the epileptogenic zone relative to both secondarily irritative (F1100= 11, p=0.0009) and non-involved regions (F1100= 17.8, p<0.0001). We provide the first non-invasive, in vivo evidence of a chronic TSC elevation alongside ZCSF levels within the normative range, associated with the epileptogenic region even during the interictal period in human epilepsy, and the possibility of reduced TSC levels due to seizure. In line with modified homeostatic mechanisms in epilepsy - including altered mechanisms underlying ionic gating, clearance and exchange - we provide the first indication of 23Na-MRI as an assay of altered sodium concentrations occurring in epilepsy associated with the organization of clinically relevant divisions of pathological cortex.
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Affiliation(s)
- Ben Ridley
- Aix-Marseille Univ, CNRS, CRMBM UMR 7339, Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, Marseille, France
| | - Angela Marchi
- APHM, Hôpital de la Timone, Clinical Neurophysiology and Epileptology Department, Marseille, France; Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Jonathan Wirsich
- Aix-Marseille Univ, CNRS, CRMBM UMR 7339, Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, Marseille, France; Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Elisabeth Soulier
- Aix-Marseille Univ, CNRS, CRMBM UMR 7339, Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, Marseille, France
| | - Sylviane Confort-Gouny
- Aix-Marseille Univ, CNRS, CRMBM UMR 7339, Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, Marseille, France
| | - Lothar Schad
- Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany
| | - Fabrice Bartolomei
- Aix Marseille Univ, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France; APHM, Hôpitaux de la Timone, Service de Neurophysiologie Clinique, Marseille, France
| | - Jean-Philippe Ranjeva
- Aix-Marseille Univ, CNRS, CRMBM UMR 7339, Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, Marseille, France
| | - Maxime Guye
- Aix-Marseille Univ, CNRS, CRMBM UMR 7339, Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, Marseille, France.
| | - Wafaa Zaaraoui
- Aix-Marseille Univ, CNRS, CRMBM UMR 7339, Marseille, France; APHM, Hôpital de la Timone, Pôle d'Imagerie Médicale, CEMEREM, Marseille, France
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Human seizures couple across spatial scales through travelling wave dynamics. Nat Commun 2017; 8:14896. [PMID: 28374740 PMCID: PMC5382286 DOI: 10.1038/ncomms14896] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 02/08/2017] [Indexed: 11/21/2022] Open
Abstract
Epilepsy—the propensity toward recurrent, unprovoked seizures—is a devastating disease affecting 65 million people worldwide. Understanding and treating this disease remains a challenge, as seizures manifest through mechanisms and features that span spatial and temporal scales. Here we address this challenge through the analysis and modelling of human brain voltage activity recorded simultaneously across microscopic and macroscopic spatial scales. We show that during seizure large-scale neural populations spanning centimetres of cortex coordinate with small neural groups spanning cortical columns, and provide evidence that rapidly propagating waves of activity underlie this increased inter-scale coupling. We develop a corresponding computational model to propose specific mechanisms—namely, the effects of an increased extracellular potassium concentration diffusing in space—that support the observed spatiotemporal dynamics. Understanding the multi-scale, spatiotemporal dynamics of human seizures—and connecting these dynamics to specific biological mechanisms—promises new insights to treat this devastating disease. The authors record both local and long-range neural activity during human epileptic seizures to study the underlying multi-scale dynamics. They find that coupling of activity across spatial scales increases during seizures through propagating waves that are fit by a model that combines neural activity and potassium concentration dynamics.
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Anti-Epileptic Drug Combination Efficacy in an In Vitro Seizure Model - Phenytoin and Valproate, Lamotrigine and Valproate. PLoS One 2017; 12:e0169974. [PMID: 28076384 PMCID: PMC5226812 DOI: 10.1371/journal.pone.0169974] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 12/24/2016] [Indexed: 11/30/2022] Open
Abstract
In this study, we investigated the relative efficacy of different classes of commonly used anti-epileptic drugs (AEDs) with different mechanisms of action, individually and in combination, to suppress epileptiform discharges in an in vitro model. Extracellular field potential were recorded in 450 μm thick transverse hippocampal slices prepared from juvenile Wistar rats, in which “epileptiform discharges” (ED’s) were produced with a high-K+ (8.5 mM) bicarbonate-buffered saline solution. Single and dual recordings in stratum pyramidale of CA1 and CA3 regions were performed with 3–5 MΩ glass microelectrodes. All drugs—lamotrigine (LTG), phenytoin (PHT) and valproate (VPA)—were applied to the slice by superfusion at a rate of 2 ml/min at 32°C. Effects upon frequency of ED’s were assessed for LTG, PHT and VPA applied at different concentrations, in isolation and in combination. We demonstrated that high-K+ induced ED frequency was reversibly reduced by LTG, PHT and VPA, at concentrations corresponding to human therapeutic blood plasma concentrations. With a protocol using several applications of drugs to the same slice, PHT and VPA in combination displayed additivity of effect with 50μM PHT and 350μM VPA reducing SLD frequency by 44% and 24% individually (n = 19), and together reducing SLD frequency by 66% (n = 19). 20μM LTG reduced SLD frequency by 32% and 350μM VPA by 16% (n = 18). However, in combination there was a supra-linear suppression of ED’s of 64% (n = 18). In another independent set of experiments, similar results of drug combination responses were also found. In conclusion, a combination of conventional AEDs with different mechanisms of action, PHT and VPA, displayed linear additivity of effect on epileptiform activity. More intriguingly, a combination of LTG and VPA considered particularly efficacious clinically showed a supra-additive suppression of ED’s. This approach may be useful as an in vitro platform for assessing drug combination efficacy.
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Buchin A, Chizhov A, Huberfeld G, Miles R, Gutkin BS. Reduced Efficacy of the KCC2 Cotransporter Promotes Epileptic Oscillations in a Subiculum Network Model. J Neurosci 2016; 36:11619-11633. [PMID: 27852771 PMCID: PMC6231544 DOI: 10.1523/jneurosci.4228-15.2016] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 08/04/2016] [Accepted: 08/07/2016] [Indexed: 12/17/2022] Open
Abstract
Pharmacoresistant epilepsy is a chronic neurological condition in which a basal brain hyperexcitability results in paroxysmal hypersynchronous neuronal discharges. Human temporal lobe epilepsy has been associated with dysfunction or loss of the potassium-chloride cotransporter KCC2 in a subset of pyramidal cells in the subiculum, a key structure generating epileptic activities. KCC2 regulates intraneuronal chloride and extracellular potassium levels by extruding both ions. Absence of effective KCC2 may alter the dynamics of chloride and potassium levels during repeated activation of GABAergic synapses due to interneuron activity. In turn, such GABAergic stress may itself affect Cl- regulation. Such changes in ionic homeostasis may switch GABAergic signaling from inhibitory to excitatory in affected pyramidal cells and also increase neuronal excitability. Possibly these changes contribute to periodic bursting in pyramidal cells, an essential component in the onset of ictal epileptic events. We tested this hypothesis with a computational model of a subicular network with realistic connectivity. The pyramidal cell model explicitly incorporated the cotransporter KCC2 and its effects on the internal/external chloride and potassium levels. Our network model suggested the loss of KCC2 in a critical number of pyramidal cells increased external potassium and intracellular chloride concentrations leading to seizure-like field potential oscillations. These oscillations included transient discharges leading to ictal-like field events with frequency spectra as in vitro Restoration of KCC2 function suppressed seizure activity and thus may present a useful therapeutic option. These simulations therefore suggest that reduced KCC2 cotransporter activity alone may underlie the generation of ictal discharges. SIGNIFICANCE STATEMENT Ion regulation in the brain is a major determinant of neural excitability. Intracellular chloride in neurons, a partial determinant of the resting potential and the inhibitory reversal potentials, is regulated together with extracellular potassium via kation chloride cotransporters. During temporal lobe epilepsy, the homeostatic regulation of intracellular chloride is impaired in pyramidal cells, yet how this dysregulation may lead to seizures has not been explored. Using a realistic neural network model describing ion mechanisms, we show that chloride homeostasis pathology provokes seizure activity analogous to recordings from epileptogenic brain tissue. We show that there is a critical percentage of pathological cells required for seizure initiation. Our model predicts that restoration of the chloride homeostasis in pyramidal cells could be a viable antiepileptic strategy.
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Affiliation(s)
- Anatoly Buchin
- École normale supérieure, Paris Sciences et Lettres University, Laboratoire de Neurosciences Cognitives, Institute national de la santé et de la recherche médicale U960, Group for Neural Theory, 75005 Paris, France,
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia
- National Research University Higher School of Economics, Center for Cognition and Decision Making, Moscow 109316, Russia
| | - Anton Chizhov
- Ioffe Institute, Computational Physics Laboratory, St. Petersburg 194021, Russia
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, St. Petersburg 194223, Russia
| | - Gilles Huberfeld
- Université Pierre et Marie Curie, Pitié-Salpêtrière Hôpital, Assistance Publique-Hôpitaux de Paris, Neurophysiology Department, 75013 Paris, France
- Institute national de la santé et de la recherche médicale U1129 "Infantile Epilepsies and Brain Plasticity," Paris Descartes University, Pôle de recherche et d'enseignement supérieur Sorbonne Paris Cité, 75015 Paris, France, and
| | - Richard Miles
- Institut du Cerveau et de la Moelle Epinière, Cortex et Epilepsie Group, 75013 Paris, France
| | - Boris S Gutkin
- École normale supérieure, Paris Sciences et Lettres University, Laboratoire de Neurosciences Cognitives, Institute national de la santé et de la recherche médicale U960, Group for Neural Theory, 75005 Paris, France
- National Research University Higher School of Economics, Center for Cognition and Decision Making, Moscow 109316, Russia
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35
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Amakhin DV, Ergina JL, Chizhov AV, Zaitsev AV. Synaptic Conductances during Interictal Discharges in Pyramidal Neurons of Rat Entorhinal Cortex. Front Cell Neurosci 2016; 10:233. [PMID: 27790093 PMCID: PMC5061778 DOI: 10.3389/fncel.2016.00233] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/26/2016] [Indexed: 11/13/2022] Open
Abstract
In epilepsy, the balance of excitation and inhibition underlying the basis of neural network activity shifts, resulting in neuronal network hyperexcitability and recurrent seizure-associated discharges. Mechanisms involved in ictal and interictal events are not fully understood, in particular, because of controversial data regarding the dynamics of excitatory and inhibitory synaptic conductances. In the present study, we estimated AMPAR-, NMDAR-, and GABAA R-mediated conductances during two distinct types of interictal discharge (IID) in pyramidal neurons of rat entorhinal cortex in cortico-hippocampal slices. Repetitively emerging seizure-like events and IIDs were recorded in high extracellular potassium, 4-aminopyridine, and reduced magnesium-containing solution. An original procedure for estimating synaptic conductance during IIDs was based on the differences among the current-voltage characteristics of the synaptic components. The synaptic conductance dynamics obtained revealed that the first type of IID is determined by activity of GABAA R channels with depolarized reversal potential. The second type of IID is determined by the interplay between excitation and inhibition, with early AMPAR and prolonged depolarized GABAA R and NMDAR-mediated components. The study then validated the contribution of these components to IIDs by intracellular pharmacological isolation. These data provide new insights into the mechanisms of seizures generation, development, and cessation.
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Affiliation(s)
- Dmitry V Amakhin
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences Saint Petersburg, Russia
| | - Julia L Ergina
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences Saint Petersburg, Russia
| | - Anton V Chizhov
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of SciencesSaint Petersburg, Russia; Computational Physics Laboratory, Division of Plasma Physics, Atomic Physics and Astrophysics, Ioffe InstituteSaint Petersburg, Russia
| | - Aleksey V Zaitsev
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences Saint Petersburg, Russia
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Angamo EA, Rösner J, Liotta A, Kovács R, Heinemann U. A neuronal lactate uptake inhibitor slows recovery of extracellular ion concentration changes in the hippocampal CA3 region by affecting energy metabolism. J Neurophysiol 2016; 116:2420-2430. [PMID: 27559140 DOI: 10.1152/jn.00327.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/13/2016] [Indexed: 01/20/2023] Open
Abstract
Astrocyte-derived lactate supports pathologically enhanced neuronal metabolism, but its role under physiological conditions is still a matter of debate. Here, we determined the contribution of astrocytic neuronal lactate shuttle for maintenance of ion homeostasis and energy metabolism. We tested for the effects of α-cyano-4-hydroxycinnamic acid (4-CIN), which could interfere with energy metabolism by blocking monocarboxylate-transporter 2 (MCT2)-mediated neuronal lactate uptake, on evoked potentials, stimulus-induced changes in K+, Na+, Ca2+, and oxygen concentrations as well as on changes in flavin adenine dinucleotide (FAD) autofluorescence in the hippocampal area CA3. MCT2 blockade by 4-CIN reduced synaptically evoked but not antidromic population spikes. This effect was dependent on the activation of KATP channels indicating reduced neuronal ATP synthesis. By contrast, lactate receptor activation by 3,5-dihydroxybenzoic acid (3,5-DHBA) resulted in increased antidromic and orthodromic population spikes suggesting that 4-CIN effects are not mediated by lactate accumulation and subsequent activation of lactate receptors. Recovery kinetics of all ion transients were prolonged and baseline K+ concentration became elevated by blockade of lactate uptake. Lactate contributed to oxidative metabolism as both baseline respiration and stimulus-induced changes in Po2 were decreased, while FAD fluorescence increased likely due to a reduced conversion of FAD into FADH2 These data suggest that lactate shuttle contributes to regulation of ion homeostatsis and synaptic signaling even in the presence of ample glucose.
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Affiliation(s)
| | - Joerg Rösner
- Neuroscience Research Center, Charité Universitätsmedizin, Berlin, Germany
| | - Agustin Liotta
- Department of Anesthesiology and Intensive Care, Charité Universitätsmedizin, Berlin, Germany
| | - Richard Kovács
- Institute for Neurophysiology, Charité Universitätsmedizin, Berlin, Germany; and
| | - Uwe Heinemann
- Neuroscience Research Center, Charité Universitätsmedizin, Berlin, Germany;
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