1
|
Berisha DE, Rizvi B, Chappel-Farley MG, Tustison N, Taylor L, Dave A, Sattari NS, Chen IY, Lui KK, Janecek JC, Keator D, Neikrug AB, Benca RM, Yassa MA, Mander BA. Cerebrovascular pathology mediates associations between hypoxemia during rapid eye movement sleep and medial temporal lobe structure and function in older adults. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.28.577469. [PMID: 38328085 PMCID: PMC10849660 DOI: 10.1101/2024.01.28.577469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Obstructive sleep apnea (OSA) is common in older adults and is associated with medial temporal lobe (MTL) degeneration and memory decline in aging and Alzheimer's disease (AD). However, the underlying mechanisms linking OSA to MTL degeneration and impaired memory remains unclear. By combining magnetic resonance imaging (MRI) assessments of cerebrovascular pathology and MTL structure with clinical polysomnography and assessment of overnight emotional memory retention in older adults at risk for AD, cerebrovascular pathology in fronto-parietal brain regions was shown to statistically mediate the relationship between OSA-related hypoxemia, particularly during rapid eye movement (REM) sleep, and entorhinal cortical thickness. Reduced entorhinal cortical thickness was, in turn, associated with impaired overnight retention in mnemonic discrimination ability across emotional valences for high similarity lures. These findings identify cerebrovascular pathology as a contributing mechanism linking hypoxemia to MTL degeneration and impaired sleep-dependent memory in older adults.
Collapse
Affiliation(s)
- Destiny E. Berisha
- Department of Neurobiology and Behavior, University of California Irvine, Irvine CA, 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine CA, 92697, USA
| | - Batool Rizvi
- Department of Neurobiology and Behavior, University of California Irvine, Irvine CA, 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine CA, 92697, USA
| | - Miranda G. Chappel-Farley
- Department of Neurobiology and Behavior, University of California Irvine, Irvine CA, 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine CA, 92697, USA
| | - Nicholas Tustison
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine CA, 92697, USA
| | - Lisa Taylor
- Department of Neurobiology and Behavior, University of California Irvine, Irvine CA, 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine CA, 92697, USA
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine CA, 92697, USA
| | - Abhishek Dave
- Department of Cognitive Sciences, University of California Irvine, Irvine CA, 92697, USA
| | - Negin S. Sattari
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine CA, 92697, USA
| | - Ivy Y. Chen
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine CA, 92697, USA
| | - Kitty K. Lui
- San Diego State University/University of California San Diego, Joint Doctoral Program in Clinical Psychology, San Diego, CA, 92093, USA
| | - John C. Janecek
- Department of Neurobiology and Behavior, University of California Irvine, Irvine CA, 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine CA, 92697, USA
| | - David Keator
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine CA, 92697, USA
| | - Ariel B. Neikrug
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine CA, 92697, USA
| | - Ruth M. Benca
- Department of Neurobiology and Behavior, University of California Irvine, Irvine CA, 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine CA, 92697, USA
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine CA, 92697, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Psychiatry, University of Wisconsin-Madison, Madison, 53706, WI, USA
- Department of Psychiatry and Behavioral Medicine, Wake Forest University, Winston-Salem, NC, 27109, USA
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine CA, 92697, USA
| | - Michael A. Yassa
- Department of Neurobiology and Behavior, University of California Irvine, Irvine CA, 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine CA, 92697, USA
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine CA, 92697, USA
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine CA, 92697, USA
- Department of Neurology, University of California Irvine, Irvine CA, 92697, USA
| | - Bryce A. Mander
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine CA, 92697, USA
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine CA, 92697, USA
- Department of Cognitive Sciences, University of California Irvine, Irvine CA, 92697, USA
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine CA, 92697, USA
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine CA, 92697, USA
| |
Collapse
|
2
|
Saviuk M, Sleptsova E, Redkin T, Turubanova V. Unexplained Causes of Glioma-Associated Epilepsies: A Review of Theories and an Area for Research. Cancers (Basel) 2023; 15:5539. [PMID: 38067243 PMCID: PMC10705208 DOI: 10.3390/cancers15235539] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/25/2023] Open
Abstract
Approximately 30% of glioma patients are able to survive beyond one year postdiagnosis. And this short time is often overshadowed by glioma-associated epilepsy. This condition severely impairs the patient's quality of life and causes great suffering. The genetic, molecular and cellular mechanisms underlying tumour development and epileptogenesis remain incompletely understood, leading to numerous unanswered questions. The various types of gliomas, namely glioblastoma, astrocytoma and oligodendroglioma, demonstrate distinct seizure susceptibility and disease progression patterns. Patterns have been identified in the presence of IDH mutations and epilepsy, with tumour location in cortical regions, particularly the frontal lobe, showing a more frequent association with seizures. Altered expression of TP53, MGMT and VIM is frequently detected in tumour cells from individuals with epilepsy associated with glioma. However, understanding the pathogenesis of these modifications poses a challenge. Moreover, hypoxic effects induced by glioma and associated with the HIF-1a factor may have a significant impact on epileptogenesis, potentially resulting in epileptiform activity within neuronal networks. We additionally hypothesise about how the tumour may affect the functioning of neuronal ion channels and contribute to disruptions in the blood-brain barrier resulting in spontaneous depolarisations.
Collapse
Affiliation(s)
- Mariia Saviuk
- Institute of Neurosciences, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (M.S.); (E.S.); (T.R.)
- Cell Death Investigation and Therapy Laboratory, Anatomy and Embryology Unit, Department of Human Structure and Repair, Faculty of Medicine and Health Sciences, Ghent University, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Ekaterina Sleptsova
- Institute of Neurosciences, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (M.S.); (E.S.); (T.R.)
| | - Tikhon Redkin
- Institute of Neurosciences, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (M.S.); (E.S.); (T.R.)
| | - Victoria Turubanova
- Institute of Neurosciences, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (M.S.); (E.S.); (T.R.)
| |
Collapse
|
3
|
Jablonski J, Hoffmann L, Blümcke I, Fejtová A, Uebe S, Ekici AB, Gnatkovsky V, Kobow K. Experimental Epileptogenesis in a Cell Culture Model of Primary Neurons from Rat Brain: A Temporal Multi-Scale Study. Cells 2021; 10:cells10113004. [PMID: 34831225 PMCID: PMC8616120 DOI: 10.3390/cells10113004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 12/24/2022] Open
Abstract
Understanding seizure development requires an integrated knowledge of different scales of organization of epileptic networks. We developed a model of “epilepsy-in-a-dish” based on dissociated primary neuronal cells from neonatal rat hippocampus. We demonstrate how a single application of glutamate stimulated neurons to generate spontaneous synchronous spiking activity with further progression into spontaneous seizure-like events after a distinct latency period. By computational analysis, we compared the observed neuronal activity in vitro with intracranial electroencephalography (EEG) data recorded from epilepsy patients and identified strong similarities, including a related sequence of events with defined onset, progression, and termination. Next, a link between the neurophysiological changes with network composition and cellular structure down to molecular changes was established. Temporal development of epileptiform network activity correlated with increased neurite outgrowth and altered branching, increased ratio of glutamatergic over GABAergic synapses, and loss of calbindin-positive interneurons, as well as genome-wide alterations in DNA methylation. Differentially methylated genes were engaged in various cellular activities related to cellular structure, intracellular signaling, and regulation of gene expression. Our data provide evidence that a single short-term excess of glutamate is sufficient to induce a cascade of events covering different scales from molecule- to network-level, all of which jointly contribute to seizure development.
Collapse
Affiliation(s)
- Janos Jablonski
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
| | - Lucas Hoffmann
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
| | - Ingmar Blümcke
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
| | - Anna Fejtová
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany;
| | - Steffen Uebe
- NGS Core Unit, Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (S.U.); (A.B.E.)
| | - Arif B. Ekici
- NGS Core Unit, Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (S.U.); (A.B.E.)
| | - Vadym Gnatkovsky
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany;
| | - Katja Kobow
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
- Correspondence: ; Tel.: +49-9131-8522859
| |
Collapse
|
4
|
Ala‐Kurikka T, Pospelov A, Summanen M, Alafuzoff A, Kurki S, Voipio J, Kaila K. A physiologically validated rat model of term birth asphyxia with seizure generation after, not during, brain hypoxia. Epilepsia 2021; 62:908-919. [PMID: 33338272 PMCID: PMC8246723 DOI: 10.1111/epi.16790] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Birth asphyxia (BA) is often associated with seizures that may exacerbate the ensuing hypoxic-ischemic encephalopathy. In rodent models of BA, exposure to hypoxia is used to evoke seizures, that commence already during the insult. This is in stark contrast to clinical BA, in which seizures are typically seen upon recovery. Here, we introduce a term-equivalent rat model of BA, in which seizures are triggered after exposure to asphyxia. METHODS Postnatal day 11-12 male rat pups were exposed to steady asphyxia (15 min; air containing 5% O2 + 20% CO2 ) or to intermittent asphyxia (30 min; three 5 + 5-min cycles of 9% and 5% O2 at 20% CO2 ). Cortical activity and electrographic seizures were recorded in freely behaving animals. Simultaneous electrode measurements of intracortical pH, Po2 , and local field potentials (LFPs) were made under urethane anesthesia. RESULTS Both protocols decreased blood pH to <7.0 and brain pH from 7.3 to 6.7 and led to a fall in base excess by 20 mmol·L-1 . Electrographic seizures with convulsions spanning the entire Racine scale were triggered after intermittent but not steady asphyxia. In the presence of 20% CO2 , brain Po2 was only transiently affected by 9% ambient O2 but fell below detection level during the steps to 5% O2 , and LFP activity was nearly abolished. Post-asphyxia seizures were strongly suppressed when brain pH recovery was slowed down by 5% CO2 . SIGNIFICANCE The rate of brain pH recovery has a strong influence on post-asphyxia seizure propensity. The recurring hypoxic episodes during intermittent asphyxia promote neuronal excitability, which leads to seizures only after the suppressing effect of the hypercapnic acidosis is relieved. The present rodent model of BA is to our best knowledge the first one in which, consistent with clinical BA, behavioral and electrographic seizures are triggered after and not during the BA-mimicking insult.
Collapse
Affiliation(s)
- Tommi Ala‐Kurikka
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Alexey Pospelov
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Milla Summanen
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Aleksander Alafuzoff
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Samu Kurki
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Juha Voipio
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
| | - Kai Kaila
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| |
Collapse
|
5
|
Rubin BR, Milner TA, Pickel VM, Coleman CG, Marques-Lopes J, Van Kempen TA, Kazim SF, McEwen BS, Gray JD, Pereira AC. Sex and age differentially affect GABAergic neurons in the mouse prefrontal cortex and hippocampus following chronic intermittent hypoxia. Exp Neurol 2019; 325:113075. [PMID: 31837319 DOI: 10.1016/j.expneurol.2019.113075] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/22/2019] [Accepted: 09/30/2019] [Indexed: 12/12/2022]
Abstract
Obstructive sleep apnea (OSA), a chronic sleep disorder characterized by repetitive reduction or cessation of airflow during sleep, is widely prevalent and is associated with adverse neurocognitive sequelae including increased risk of Alzheimer's disease (AD). In humans, OSA is more common in elderly males. OSA is characterized by sleep fragmentation and chronic intermittent hypoxia (CIH), and recent epidemiological studies point to CIH as the best predictor of neurocognitive sequelae associated with OSA. The sex- and age- specific effects of OSA-associated CIH on specific cell populations such as γ-aminobutyric acid (GABA)-ergic neurons in the hippocampus and the medial prefrontal cortex (mPFC), regions important for cognitive function, remain largely unknown. The present study examined the effect of 35 days of either moderate (10% oxygen) or severe (5% oxygen) CIH on GABAergic neurons in the mPFC and hippocampus of young and aged male and female mice as well as post-accelerated ovarian failure (AOF) female mice. In the mPFC and hippocampus, the number of GABA-labeled neurons increased in aged and young severe CIH males compared to controls but not in young moderate CIH males. This change was not representative of the individual GABAergic cell subpopulations, as the number of parvalbumin-labeled neurons decreased while the number of somatostatin-labeled neurons increased in the hippocampus of severe CIH young males only. In all female groups, the number of GABA-labeled cells was not different between CIH and controls. However, in the mPFC, CIH increased the number of parvalbumin-labeled neurons in young females and the number of somatostatin-labeled cells in AOF females but decreased the number of somatostatin-labeled cells in aged females. In the hippocampus, CIH decreased the number of somatostatin-labeled neurons in young females. CIH decreased the density of vesicular GABA transporter in the mPFC of AOF females only. These findings suggest sex-specific changes in GABAergic neurons in the hippocampus and mPFC with males showing an increase of this cell population as compared to their female counterparts following CIH. Age at exposure and severity of CIH also differentially affect the GABAergic cell population in mice.
Collapse
Affiliation(s)
- Batsheva R Rubin
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065, United States of America; Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, United States of America.
| | - Teresa A Milner
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065, United States of America; Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, United States of America.
| | - Virginia M Pickel
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, United States of America
| | - Christal G Coleman
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, United States of America
| | - Jose Marques-Lopes
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, United States of America
| | - Tracey A Van Kempen
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, United States of America
| | - Syed Faraz Kazim
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065, United States of America; Department of Neurology, Icahn School of Medicine, Mount Sinai, New York, NY 10029, United States of America; Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States of America
| | - Bruce S McEwen
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065, United States of America
| | - Jason D Gray
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065, United States of America
| | - Ana C Pereira
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065, United States of America; Department of Neurology, Icahn School of Medicine, Mount Sinai, New York, NY 10029, United States of America; Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States of America.
| |
Collapse
|
6
|
Salas J, Reddy N, Orru E, Carson KA, Chavez-Valdez R, Burton VJ, Stafstrom CE, Northington FJ, Huisman TAGM. The Role of Diffusion Tensor Imaging in Detecting Hippocampal Injury Following Neonatal Hypoxic-Ischemic Encephalopathy. J Neuroimaging 2018; 29:252-259. [PMID: 30325083 DOI: 10.1111/jon.12572] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 09/12/2018] [Accepted: 10/03/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Neonatal hypoxic-ischemic injury of the brain and resultant encephalopathy (HIE) leads to major developmental impairments by school age. Conventional/anatomical MRI often fails to detect hippocampal injury in mild cases. We hypothesize that diffusion tensor imaging (DTI) has greater sensitivity for identifying subtle hippocampal injury. METHODS We retrospectively analyzed DTI data collected from a cohort of neonates with HIE and controls. Conventional MRI sequences were classified qualitatively according to severity using a modified Barkovich scale. Using multivariate linear regression, we compared hippocampal DTI scalars of HIE patients and controls. Spearman correlation was used to test the association of DTI scalars in the hippocampal and thalamic regions. A multiple regression analysis tested the association of the DTI scalars with short-term outcomes. RESULTS Fifty-five neonates with HIE (42% males) and 13 controls (54% males) were included. Hippocampal DTI scalars were similar between HIE and control groups, even when restricting the HIE group to those with moderate-to-severe injury (8 subjects). DTI scalars of the thalamus were significantly lower in the moderate-to-severely affected patients compared to controls (right fractional anisotropy [FA] .148 vs. .182, P = .01; left FA .147 vs. .181, P = .03). Hippocampal and thalamic DTI scalars were correlated (P < .001). Hippocampal DTI scalars were not associated with short-term outcomes. CONCLUSIONS Quantitative DTI analysis of the hippocampus in neonates following HIE is a feasible technique to examine neuronal injury. Although DTI scalars were useful in identifying thalamic injury in our cohort, hippocampal DTI analysis did not provide additional information regarding hippocampal injury following HIE.
Collapse
Affiliation(s)
- Jacqueline Salas
- Division of Neonatology, Department of Pediatrics, The Johns Hopkins University School of Medicine, The Charlotte R. Bloomberg Children's Center, Baltimore, MD.,Neuro-Intensive Care Nursery Group, The Johns Hopkins School of Medicine, Baltimore, MD
| | - Nihaal Reddy
- Division of Pediatric Radiology and Pediatric Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Emanuele Orru
- Division of Pediatric Radiology and Pediatric Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Kathryn A Carson
- Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Raul Chavez-Valdez
- Division of Neonatology, Department of Pediatrics, The Johns Hopkins University School of Medicine, The Charlotte R. Bloomberg Children's Center, Baltimore, MD.,Neuro-Intensive Care Nursery Group, The Johns Hopkins School of Medicine, Baltimore, MD
| | - Vera Joanna Burton
- Neuro-Intensive Care Nursery Group, The Johns Hopkins School of Medicine, Baltimore, MD.,Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD
| | - Carl E Stafstrom
- Neuro-Intensive Care Nursery Group, The Johns Hopkins School of Medicine, Baltimore, MD.,Division of Pediatric Neurology, Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD
| | - Frances J Northington
- Division of Neonatology, Department of Pediatrics, The Johns Hopkins University School of Medicine, The Charlotte R. Bloomberg Children's Center, Baltimore, MD.,Neuro-Intensive Care Nursery Group, The Johns Hopkins School of Medicine, Baltimore, MD
| | - Thierry A G M Huisman
- Division of Pediatric Radiology and Pediatric Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD.,Neuro-Intensive Care Nursery Group, The Johns Hopkins School of Medicine, Baltimore, MD
| |
Collapse
|
7
|
Rosenberg EC, Lippman-Bell JJ, Handy M, Soldan SS, Rakhade S, Hilario-Gomez C, Folweiler K, Jacobs L, Jensen FE. Regulation of seizure-induced MeCP2 Ser421 phosphorylation in the developing brain. Neurobiol Dis 2018; 116:120-130. [PMID: 29738885 DOI: 10.1016/j.nbd.2018.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 03/23/2018] [Accepted: 05/03/2018] [Indexed: 12/16/2022] Open
Abstract
Neonatal seizures disrupt normal synaptic maturation and often lead to later-life epilepsy and cognitive deficits. During early life, the brain exhibits heightened synaptic plasticity, in part due to a developmental overabundance of CaV1.2 L-type voltage gated calcium (Ca2+) channels (LT-VGCCs) and Ca2+-permeable AMPARs (CP-AMPARs) lacking GluA2 subunits. We hypothesized that early-life seizures overactivate these channels, in turn dysregulating Ca2+-dependent signaling pathways including that of methyl CPG binding protein 2 (MeCP2), a transcription factor implicated in the autism spectrum disorder (ASD) Rett Syndrome. Here, we show that in vivo hypoxia-induced seizures (HS) in postnatal day (P)10 rats acutely induced phosphorylation of the neuronal-specific target of activity-dependent MeCP2 phosphorylation, S421, as well as its upstream activator CaMKII T286. We next identified mechanisms by which activity-dependent Ca2+ influx induced MeCP2 phosphorylation using in vitro cortical and hippocampal neuronal cultures at embryonic day (E)18 + 10 days in vitro (DIV). In contrast to the prevalent role of NMDARs in the adult brain, we found that both CP-AMPARs and LT-VGCCs mediated MeCP2 S421 and CaMKII T286 phosphorylation induced by kainic acid (KA) or high potassium chloride (KCl) stimulation. Furthermore, in vivo post-seizure treatment with the broad-spectrum AMPAR antagonist NBQX, the CP-AMPAR blocker IEM-1460, or the LT-VGCC antagonist nimodipine blocked seizure-induced MeCP2 phosphorylation. Collectively, these results demonstrate that early-life seizures dysregulate critical activity-dependent developmental signaling pathways, in part via CP-AMPAR and LT-VGCC activation, providing novel age-specific therapeutic targets for convergent pathways underlying epilepsy and ASDs.
Collapse
Affiliation(s)
- Evan C Rosenberg
- Boston Children's Hospital, Department of Neurology, Boston, MA 02115, United States; New York University Langone Medical Center, New York, NY 10016, United States
| | - Jocelyn J Lippman-Bell
- Perelman School of Medicine, University of Pennsylvania, Department of Neurology, Philadelphia, PA 19104, United States; Boston Children's Hospital, Department of Neurology, Boston, MA 02115, United States; Philadelphia College of Osteopathic Medicine, Department of Biomedical Sciences, Philadelphia, PA 19131, United States
| | - Marcus Handy
- Perelman School of Medicine, University of Pennsylvania, Department of Neurology, Philadelphia, PA 19104, United States
| | - Samantha S Soldan
- Perelman School of Medicine, University of Pennsylvania, Department of Neurology, Philadelphia, PA 19104, United States
| | - Sanjay Rakhade
- Boston Children's Hospital, Department of Neurology, Boston, MA 02115, United States
| | | | - Kaitlyn Folweiler
- Perelman School of Medicine, University of Pennsylvania, Department of Neurology, Philadelphia, PA 19104, United States
| | - Leah Jacobs
- Perelman School of Medicine, University of Pennsylvania, Department of Neurology, Philadelphia, PA 19104, United States
| | - Frances E Jensen
- Perelman School of Medicine, University of Pennsylvania, Department of Neurology, Philadelphia, PA 19104, United States; Boston Children's Hospital, Department of Neurology, Boston, MA 02115, United States.
| |
Collapse
|
8
|
Pozdnyakova N. Consequences of perinatal hypoxia in developing brain: Changes in GABA transporter functioning in cortical, hippocampal and thalamic rat nerve terminals. Int J Dev Neurosci 2017; 63:1-7. [DOI: 10.1016/j.ijdevneu.2017.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 06/26/2017] [Accepted: 09/05/2017] [Indexed: 12/15/2022] Open
Affiliation(s)
- Natalia Pozdnyakova
- Department of NeurochemistryPalladin Institute of Biochemistry, National Academy of Sciences of UkraineLeontovicha Str. 9Kiev01030Ukraine
| |
Collapse
|
9
|
Ortega-Ibarra J, López-Pérez S, Morales-Villagrán A. An electrochemiluminescent method for glutamate measurement in small microdialysate samples in asphyxiated young rats. LUMINESCENCE 2017; 33:47-53. [PMID: 28718955 DOI: 10.1002/bio.3371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/16/2017] [Accepted: 05/28/2017] [Indexed: 11/08/2022]
Abstract
Glutamate (Glu) quantification has been performed by a combination of intracerebral microdialysis through which the samples are obtained and analyzed by high performance liquid chromatography (HPLC); its measurement requires a large expenditure of time (15-30 min per sample) and special training. Therefore, an alternative method is presented here, based on the electrochemiluminescence produced by the use of an enzymatic reactor, containing glutamate-oxidase, mixed and incubated with microdialysate from dorsal striatum (DS) and prefrontal cortex (PFC) of young rats asphyxiated during the neonatal period, under a global asphyxia model in order to test this method. Using this approach, we found high extracellular Glu concentration in the DS of asphyxiated animals, but only during K+ stimulation, while in the PFC, only a delay in the rise of Glu after K+ stimulation was observed, without any difference in extracellular Glu content when compared with controls. This new method permitted a fast measurement of Glu in brain dialysate samples, it significantly reduces the cost of the analysis per sample, since only a single device and pump are needed without using columns and high pressure inside the system or complex hardware and software to control pumps, detector, fraction collector or any other peripheral used in HPLC.
Collapse
Affiliation(s)
- Jorge Ortega-Ibarra
- Laboratory of Neurophysiology and Neurochemistry, Department of Cellular and Molecular Biology, CUCBA, University of Guadalajara, Jalisco, Mexico
| | - Silvia López-Pérez
- Laboratory of Neurophysiology and Neurochemistry, Department of Cellular and Molecular Biology, CUCBA, University of Guadalajara, Jalisco, Mexico
| | - Alberto Morales-Villagrán
- Laboratory of Neurophysiology and Neurochemistry, Department of Cellular and Molecular Biology, CUCBA, University of Guadalajara, Jalisco, Mexico
| |
Collapse
|
10
|
Robinson SD, Lee TW, Christie DL, Birch NP. Tissue plasminogen activator inhibits NMDA-receptor-mediated increases in calcium levels in cultured hippocampal neurons. Front Cell Neurosci 2015; 9:404. [PMID: 26500501 PMCID: PMC4598481 DOI: 10.3389/fncel.2015.00404] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/23/2015] [Indexed: 01/15/2023] Open
Abstract
NMDA receptors (NMDARs) play a critical role in neurotransmission, acting as essential mediators of many forms of synaptic plasticity, and also modulating aspects of development, synaptic transmission and cell death. NMDAR-induced responses are dependent on a range of factors including subunit composition and receptor location. Tissue-type plasminogen activator (tPA) is a serine protease that has been reported to interact with NMDARs and modulate NMDAR activity. In this study we report that tPA inhibits NMDAR-mediated changes in intracellular calcium levels in cultures of primary hippocampal neurons stimulated by low (5 μM) but not high (50 μM) concentrations of NMDA. tPA also inhibited changes in calcium levels stimulated by presynaptic release of glutamate following treatment with bicucculine/4-aminopyridine (4-AP). Inhibition was dependent on the proteolytic activity of tPA but was unaffected by α2-antiplasmin, an inhibitor of the tPA substrate plasmin, and receptor-associated protein (RAP), a pan-ligand blocker of the low-density lipoprotein receptor, two proteins previously reported to modulate NMDAR activity. These findings suggest that tPA can modulate changes in intracellular calcium levels in a subset of NMDARs expressed in cultured embryonic hippocampal neurons through a mechanism that involves the proteolytic activity of tPA and synaptic NMDARs.
Collapse
Affiliation(s)
- Samuel D Robinson
- School of Biological Sciences and Centre for Brain Research, University of Auckland Auckland, New Zealand
| | - Tet Woo Lee
- School of Biological Sciences and Centre for Brain Research, University of Auckland Auckland, New Zealand
| | - David L Christie
- School of Biological Sciences and Centre for Brain Research, University of Auckland Auckland, New Zealand ; Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland Auckland, New Zealand
| | - Nigel P Birch
- School of Biological Sciences and Centre for Brain Research, University of Auckland Auckland, New Zealand ; Brain Research New Zealand, Rangahau Roro Aotearoa, University of Auckland Auckland, New Zealand
| |
Collapse
|
11
|
Sun H, Juul HM, Jensen FE. Models of hypoxia and ischemia-induced seizures. J Neurosci Methods 2015; 260:252-60. [PMID: 26434705 DOI: 10.1016/j.jneumeth.2015.09.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 09/22/2015] [Indexed: 01/19/2023]
Abstract
Despite greater understanding and improved management, seizures continue to be a major problem in childhood. Neonatal seizures are often refractory to conventional antiepileptic drugs, and can result in later life epilepsy and cognitive deficits, conditions for which there are no specific treatments. Hypoxic and/or ischemic encephalopathy (HIE) is the most common cause for neonatal seizures, and accounts for more than two-thirds of neonatal seizure cases. A better understanding of the cellular and molecular mechanisms is essential for identifying new therapeutic strategies that control the neonatal seizures and its cognitive consequences. This heavily relies on animal models that play a critical role in discovering novel mechanisms underlying both epileptogenesis and associated cognitive impairments. To date, a number of animal models have provided a tremendous amount of information regarding the pathophysiology of HIE-induced neonatal seizures. This review provides an overview on the most important features of the main animal models of HIE-induced seizures. In particular, we focus on the methodology of seizure induction and the characterizations of post-HIE injury consequences. These aspects of HIE-induced seizure models are discussed in the light of the suitability of these models in studying human HIE-induced seizures.
Collapse
Affiliation(s)
- Hongyu Sun
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Halvor M Juul
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Frances E Jensen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
| |
Collapse
|
12
|
López-Pérez SJ, Morales-Villagrán A, Medina-Ceja L. Effect of perinatal asphyxia and carbamazepine treatment on cortical dopamine and DOPAC levels. J Biomed Sci 2015; 22:14. [PMID: 25889791 PMCID: PMC4335632 DOI: 10.1186/s12929-015-0117-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/23/2015] [Indexed: 01/29/2023] Open
Abstract
Background One of the most important manifestations of perinatal asphyxia is the occurrence of seizures, which are treated with antiepileptic drugs, such as carbamazepine. These early seizures, combined with pharmacological treatments, may influence the development of dopaminergic neurotransmission in the frontal cortex. This study aimed to determine the extracellular levels of dopamine and its main metabolite DOPAC in 30-day-old rats that had been asphyxiated for 45 min in a low (8%) oxygen chamber at a perinatal age and treated with daily doses of carbamazepine. Quantifications were performed using microdialysis coupled to a high-performance liquid chromatography (HPLC) system in basal conditions and following the use of the chemical stimulus. Results Significant decreases in basal and stimulated extracellular dopamine and DOPAC content were observed in the frontal cortex of the asphyxiated group, and these decreases were partially recovered in the animals administered daily doses of carbamazepine. Greater basal dopamine concentrations were also observed as an independent effect of carbamazepine. Conclusions Perinatal asphyxia plus carbamazepine affects extracellular levels of dopamine and DOPAC in the frontal cortex and stimulated the release of dopamine, which provides evidence for the altered availability of dopamine in cortical brain areas during brain development.
Collapse
Affiliation(s)
- Silvia J López-Pérez
- Laboratorio de Neurofisiología y Neuroquímica, Departamento de Biología Celular y Molecular, CUCBA, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez #2100, Predio Las Agujas, Zapopan, Jalisco, C.P 44600, Mexico.
| | - Alberto Morales-Villagrán
- Laboratorio de Neurofisiología y Neuroquímica, Departamento de Biología Celular y Molecular, CUCBA, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez #2100, Predio Las Agujas, Zapopan, Jalisco, C.P 44600, Mexico.
| | - Laura Medina-Ceja
- Laboratorio de Neurofisiología y Neuroquímica, Departamento de Biología Celular y Molecular, CUCBA, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez #2100, Predio Las Agujas, Zapopan, Jalisco, C.P 44600, Mexico.
| |
Collapse
|
13
|
Pozdnyakova N, Dudarenko M, Yatsenko L, Himmelreich N, Krupko O, Borisova T. Perinatal hypoxia: different effects of the inhibitors of GABA transporters GAT1 and GAT3 on the initial velocity of [3H]GABA uptake by cortical, hippocampal, and thalamic nerve terminals. Croat Med J 2014; 55:250-8. [PMID: 24891283 PMCID: PMC4049216 DOI: 10.3325/cmj.2014.55.250] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
AIM. To analyze the effects of highly selective blocker GAT1, NO-711, and substrate inhibitor GAT3, β-alanine, on the initial velocity of [(3)H]GABA uptake by cortical, hippocampal, and thalamic nerve terminals (synaptosomes) after perinatal hypoxia. METHODS. Animals were divided into two groups: control (n=17) and hypoxia (n=12). Rats in the hypoxia group underwent hypoxia and seizures (airtight chamber, 4% O2 and 96% N2) at the age of 10-12 postnatal days and were used in the experiments 8-9 weeks after hypoxia. RESULTS. In cortical synaptosomes, the effects of NO-711 (30 μΜ) and β-alanine (100 μΜ) on [(3)H]GABA uptake were similar in control and hypoxia groups. In hippocampal synaptosomes, NO-711 inhibited 84.3% of the initial velocity of [(3)H]GABA uptake in normal conditions and 80.1% after hypoxia, whereas the effect of β-alanine was increased after hypoxia from 14.4% to 22.1%. In thalamic synaptosomes, the effect of NO-711 was decreased by 79.6% in controls and by 70.9% in hypoxia group, whereas the effect of β-alanine was increased after hypoxia from 20.2% to 30.2%. CONCLUSIONS. The effectiveness of β-alanine to influence GABA uptake was increased in hippocampal and thalamic nerve terminals as a result of perinatal hypoxia and the effectiveness of NO-711 in thalamic nerve terminals was decreased. These results may indicate changes in the ratio of active GAT1/GAT3 expressed in the plasma membrane of nerve terminals after perinatal hypoxia. We showed a possibility to modulate non-GAT1 GABA transporter activity in different brain regions by exogenous and endogenous β-alanine.
Collapse
Affiliation(s)
| | | | | | | | | | - Tatiana Borisova
- Tatiana Borisova, Palladin Institute of Biochemistry, NAS of Ukraine, 9 Leontovicha Street, Kiev, 01601, Ukraine,
| |
Collapse
|
14
|
Abstract
BACKGROUND Neonatal seizures can result in chronic epilepsy and long-term behavioral and cognitive deficits. Levetiracetam (LEV), an antiepileptic drug that binds to the synaptic vesicle protein 2A (SV2A), has been increasingly used off-label for the therapy of neonatal seizures. Preclinical data regarding the acute or long-term efficacy of LEV are lacking. METHODS We tested the anticonvulsant efficacy of LEV in a rat model of hypoxia-induced neonatal seizures. In addition, we evaluated the protective effects of postnatal day (P)10 LEV treatment on later-life kainic acid (KA)-induced seizure susceptibility and seizure-induced neuronal injury. Western blot and immunohistochemistry were used to assess the developmental regulation of SV2A in the rat and human brain. RESULTS LEV pretreatment at P10 significantly decreased the cumulative duration of behavioral and electrographic seizures at both 25 and 50 mg/kg. At P40, KA-induced seizures and neuronal loss were significantly diminished in rats previously treated with LEV. LEV target SV2A is present in both neonatal rat and human brain and increases steadily to adulthood. CONCLUSION LEV suppressed acute seizures induced by perinatal hypoxia and diminished later-life seizure susceptibility and seizure-induced neuronal injury, providing evidence for disease modification. These results support consideration of a clinical trial of LEV in neonatal seizures.
Collapse
|
15
|
Agochukwu NB, Solomon BD, Gropman AL, Muenke M. Epilepsy in Muenke syndrome: FGFR3-related craniosynostosis. Pediatr Neurol 2012; 47:355-61. [PMID: 23044018 PMCID: PMC4133743 DOI: 10.1016/j.pediatrneurol.2012.07.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Accepted: 07/18/2012] [Indexed: 12/21/2022]
Abstract
Epilepsy, a neurologic disorder characterized by the predisposition to recurrent unprovoked seizures, is reported in more than 300 genetic syndromes. Muenke syndrome is an autosomal-dominant craniosynostosis syndrome characterized by unilateral or bilateral coronal craniosynostosis, hearing loss, intellectual disability, and relatively subtle limb findings such as carpal bone fusion and tarsal bone fusion. Muenke syndrome is caused by a single defining point mutation in the fibroblast growth factor receptor 3 (FGFR3) gene. Epilepsy rarely occurs in individuals with Muenke syndrome, and little detail is reported on types of epilepsy, patient characteristics, and long-term outcomes. We present seven patients with Muenke syndrome and seizures. A review of 789 published cases of Muenke syndrome, with a focus on epilepsy and intracranial anomalies in Muenke syndrome, revealed epilepsy in six patients, with intracranial anomalies in five. The occurrence of epilepsy in Muenke syndrome within our cohort of 58 patients, of whom seven manifested epilepsy, and the intracranial anomalies and epilepsy reported in the literature, suggest that patients with Muenke syndrome may be at risk for epilepsy and intracranial anomalies. Furthermore, the impact of Muenke syndrome on the central nervous system may be greater than previously thought.
Collapse
Affiliation(s)
- Nneamaka B. Agochukwu
- Clinical Research Training Program, National Institutes of Health, Bethesda, Maryland,Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Benjamin D. Solomon
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Andrea L. Gropman
- Department of Neurology, Children’s National Medical Center, Washington, DC,Department of Neurology, George Washington University of the Health Sciences, Washington, DC
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland,Communications should be addressed to: Dr. Muenke; Medical, Genetics Branch; National Human Genome Research Institute; National, Institutes of Health; Building 35, Room 1B-203, MSC 3717; Bethesda, MD 20892.
| |
Collapse
|
16
|
Kim JA, Connors BW. High temperatures alter physiological properties of pyramidal cells and inhibitory interneurons in hippocampus. Front Cell Neurosci 2012; 6:27. [PMID: 22783167 PMCID: PMC3390787 DOI: 10.3389/fncel.2012.00027] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/13/2012] [Indexed: 01/14/2023] Open
Abstract
Temperature has multiple effects on neurons, yet little is known about the effects of high temperature on the physiology of mammalian central neurons. Hyperthermia can influence behavior and cause febrile seizures. We studied the effects of acute hyperthermia on the immature hippocampus in vitro by recording from pyramidal neurons and inhibitory oriens-lacunosum moleculare (O-LM) interneurons (identified by green fluorescent protein (GFP) expression in the GIN mouse line). Warming to 41°C caused depolarization, spontaneous action potentials, reduced input resistance and membrane time constant, and increased spontaneous synaptic activity of most pyramidal cells and O-LM interneurons. Pyramidal neurons of area CA3 were more strongly excited by hyperthermia than those of area CA1. About 90% of O-LM interneurons in both CA1 and CA3 increased their firing rates at hyperthermic temperatures; interneurons in CA3 fired faster than those in CA1 on average. Blockade of fast synaptic transmission did not abolish the effect of hyperthermia on neuronal excitability. Our results suggest that hyperthermia increases hippocampal excitability, particularly in seizure-prone area CA3, by altering the intrinsic membrane properties of pyramidal cells and interneurons.
Collapse
Affiliation(s)
- Jennifer A Kim
- Department of Neuroscience, Brown University, Providence RI, USA
| | | |
Collapse
|
17
|
Experimental models of seizures and epilepsies. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 105:57-82. [PMID: 22137429 DOI: 10.1016/b978-0-12-394596-9.00003-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epilepsy is one of the most common neurological conditions that affect people of all ages. Epilepsy is characterized by occurrence of spontaneous recurrent seizures. Currently available drugs are ineffective in controlling seizures in approximately one-third of patients with epilepsy. Moreover, these drugs are associated with adverse effects, and none of them are effective in preventing development of epilepsy following an insult or injury. To develop an effective therapeutic strategy that can interfere with the process of development of epilepsy (epileptogenesis), it is crucial to study the changes that occur in the brain after an injury and before epilepsy develops. It is not possible to determine these changes in human tissue for obvious ethical reasons. Over the years, experimental models of epilepsies have contributed immensely in improving our understanding of mechanism of epileptogenesis as well as of seizure generation. There are many models that replicate at least some of the characteristics of human epilepsy. Each model has its advantages and disadvantages, and the investigator should be aware of this before selecting a specific model for his/her studies. Availability of a good animal model is a key to the development of an effective treatment. Unfortunately, there are many epilepsy syndromes, specifically pediatric, which still lack a valid animal model. It is vital that more research is done to develop animal models for such syndromes.
Collapse
|
18
|
Downregulation of hippocampal GABA after hypoxia-induced seizures in neonatal rats. Neurochem Res 2011; 36:2409-16. [PMID: 21833845 DOI: 10.1007/s11064-011-0565-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Revised: 05/28/2011] [Accepted: 07/27/2011] [Indexed: 02/04/2023]
Abstract
This study aims to determine the expression of Gamma-aminobutyric acid (GABA) following hypoxia in neonatal rats and explore how it may increase susceptibility to epilepsy later in life. A modified model of neonatal hypoxia-induced epileptic susceptibility was simulated by 17 min of hypoxia (5% O(2) and 95% N(2)) in postnatal day (P) 10 rats. Hippocampal glutamate decarboxylase (GAD) and parvalbumin (PV) during the development with or without hypoxia were examined using immunohistochemistry. No detectable neuronal loss was observed in the hippocampus either immediately or 14 days after hypoxia. During the development GAD- and PV-immunoreactivity increased substantially during P 11-13 and reached mature expression in the control rats, and decreased significantly at different time points except for a transient increase during P 11-13 in the hypoxic groups. Our study indicates that downregulation of hippocampal GABA after hypoxia-induced seizures in neonatal rats may contribute to higher epileptic susceptibility in later life.
Collapse
|
19
|
Pozdnyakova N, Yatsenko L, Parkhomenko N, Himmelreich N. Perinatal hypoxia induces a long-lasting increase in unstimulated gaba release in rat brain cortex and hippocampus. The protective effect of pyruvate. Neurochem Int 2011; 58:14-21. [DOI: 10.1016/j.neuint.2010.10.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 10/14/2010] [Indexed: 10/18/2022]
|
20
|
Samoilova M, Weisspapir M, Abdelmalik P, Velumian AA, Carlen PL. Chronicin vitroketosis is neuroprotective but not anti-convulsant. J Neurochem 2010; 113:826-35. [DOI: 10.1111/j.1471-4159.2010.06645.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
21
|
Sensitivity to seizure-like activity in Drosophila following acute hypoxia and hypercapnia. Brain Res 2010; 1316:120-8. [DOI: 10.1016/j.brainres.2009.12.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 12/08/2009] [Accepted: 12/12/2009] [Indexed: 11/21/2022]
|
22
|
Nitric oxide alters GABAergic synaptic transmission in cultured hippocampal neurons. Brain Res 2009; 1297:23-31. [PMID: 19699726 DOI: 10.1016/j.brainres.2009.08.044] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 08/11/2009] [Accepted: 08/13/2009] [Indexed: 01/23/2023]
Abstract
Nitric oxide (NO) production increases during hypoxia/ischemia-reperfusion in the immature brain and is associated with neurotoxicity. NO at physiologic concentrations has been shown to modulate GABAergic (gamma-aminobutyric acid) synaptic transmission in the adult brain. However, the effects of neurotoxic concentrations of NO (relevant to hypoxia-ischemia) on GABAergic synaptic transmission remain unknown. The present study tests the hypothesis that nNOS is expressed at GABAergic synapses and that exposure to neurotoxic concentrations of NO results in enhanced GABAergic synaptic transmission in cultured hippocampal neurons (days-in-vitro 10-14) prepared from fetal rats. Using double immunocytochemistry techniques, we were able to demonstrate that nNOS is co-localized to both presynaptic and postsynaptic markers of GABAergic synapses. The effects of NO on GABAergic synaptic transmission were then studied using whole cell patch-clamp electrophysiology. Spontaneous and miniature inhibitory postsynaptic currents (sIPSCS and mIPSCs) were recorded prior to and after exposure to 250 microM of the NO donor diethyleneamine/nitric oxide adduct (DETA-NO). Exposure to DETA-NO resulted in increased sIPSCs and mIPSCs frequency, indicating that neurotoxic concentrations of NO enhance GABAergic synaptic transmission in cultured hippocampal neurons. Because GABA synapses appear to be excitatory in the immature brain, this effect may contribute to overall enhanced synaptic transmission and hyperexcitability. We speculate that NO represents one of the mechanisms by which hypoxia-ischemia increases seizure susceptibility in the immature brain.
Collapse
|
23
|
Repeated hypoxic episodes induce seizures and alter hippocampal network activities in mice. Neuroscience 2009; 161:599-613. [DOI: 10.1016/j.neuroscience.2009.03.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 02/08/2009] [Accepted: 03/15/2009] [Indexed: 11/23/2022]
|
24
|
Viggiano D. The hyperactive syndrome: metanalysis of genetic alterations, pharmacological treatments and brain lesions which increase locomotor activity. Behav Brain Res 2008; 194:1-14. [PMID: 18656502 DOI: 10.1016/j.bbr.2008.06.033] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 06/26/2008] [Accepted: 06/29/2008] [Indexed: 01/01/2023]
Abstract
The large number of transgenic mice realized thus far with different purposes allows addressing new questions, such as which animals, over the entire set of transgenic animals, show a specific behavioural abnormality. In the present study, we have used a metanalytical approach to organize a database of genetic modifications, brain lesions and pharmacological interventions that increase locomotor activity in animal models. To further understand the resulting data set, we have organized a second database of the alterations (genetic, pharmacological or brain lesions) that reduce locomotor activity. Using this approach, we estimated that 1.56% of the genes in the genome yield to hyperactivity and 0.75% of genes produce hypoactivity when altered. These genes have been classified into genes for neurotransmitter systems, hormonal, metabolic systems, ion channels, structural proteins, transcription factors, second messengers and growth factors. Finally, two additional classes included animals with neurodegeneration and inner ear abnormalities. The analysis of the database revealed several unexpected findings. First, the genes that, when mutated, induce hyperactive behaviour do not pertain to a single neurotransmitter system. In fact, alterations in most neurotransmitter systems can give rise to a hyperactive phenotype. In contrast, fewer changes can decrease locomotor activity. Specifically, genetic and pharmacological alterations that enhance the dopamine, orexin, histamine, cannabinoids systems or that antagonize the cholinergic system induce an increase in locomotor activity. Similarly, imbalances in the two main neurotransmitters of the nervous system, GABA and glutamate usually result in hyperactive behaviour. It is remarkable that no genetic alterations pertaining to the GABA system have been reported to reduce locomotor behaviour. Other neurotransmitters, such as norepinephrine and serotonin, have a more complex influence. For instance, a decrease in norepinephrine synthesis usually results in hypoactive behaviour. However, a chronic increase in norepinephrine may result in hypoactivity too. Similarly, changes in both directions of serotonin levels may reduce locomotor activity, whereas alterations in specific serotonin receptors can induce hyperactivity. The lesion of at least 12 different brain regions can increase locomotor activity too. Comparatively, few focal lesions decrease locomotor activity. Finally, a large number of toxic events can increase locomotor activity, particularly if delivered during the prepuberal time window. These data show that there is a net imbalance in the number of altered genes/brain lesions/toxics that induce hyperactivity versus hypoactive behaviour. Although some of these data may be explained in terms of the activating role of subcortical systems (such as catecholamines), the larger number of alterations that induce hyperactivity suggests a different scenario. Specifically, we hypothesize (i) the existence of a control system that continuously inhibit a basally hyperactive locomotor tone and (ii) that this control system is highly vulnerable (intrinsic fragility) to any change in the genetic asset or to any toxic/drug delivered during prepuberal stages. Brain lesion studies suggest that the putative control system is located along an axis that connects the olfactory bulb and the enthorhinal cortex (enthorhinal-hippocampal-septal-prefrontal cortex-olfactory bulb axis). We suggest that the increased locomotor activity in many psychiatric diseases may derive from the interference with the development of this brain axis during a specific postnatal time window.
Collapse
Affiliation(s)
- Davide Viggiano
- Department of Health Sciences, Faculty of Scienze del Benessere, University of Molise, Via De Sanctis III Edificio Polifunzionale, 86100 Campobasso, Italy.
| |
Collapse
|
25
|
Reime Kinjo E, Arida RM, Mara de Oliveira D, da Silva Fernandes MJ. The Na+/K+ATPase activity is increased in the hippocampus after multiple status epilepticus induced by pilocarpine in developing rats. Brain Res 2006; 1138:203-7. [PMID: 17270150 DOI: 10.1016/j.brainres.2006.12.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 12/18/2006] [Accepted: 12/22/2006] [Indexed: 11/30/2022]
Abstract
The effects of repetitive pilocarpine-induced status epilepticus (SE) in the hippocampal Na(+)/K(+)ATPase activity were studied in developing rat. Na(+)/K(+)ATPase is a membrane-bound enzyme responsible for the active transport of sodium and potassium ions through the membrane. It is necessary to maintain neuronal excitability. The malfunction of this enzyme has been associated with neuronal hyperexcitability. The pilocarpine-induced status epilepticus in developing rats leads to neuronal hyperexcitability and brain damage. We examined the activity of the Na(+)/K(+)ATPase enzyme in hippocampus of rats submitted to 1 episode of status epilepticus on postnatal day 9 and to 3 episodes of pilocarpine-induced status epilepticus on postnatal days 7, 8 and 9. Our findings showed that one status epilepticus episode does not modify the Na(+)/K(+)ATPase activity in hippocampus of rats studied 7 or 30 days later (at P16 or P39). However, an increase in the Na(+)/K(+)ATPase activity was detected in hippocampus of rats submitted to three consecutive status epilepticus during the development studied 7 (+142%) and 30 (+400%) days following the injections. In addition, a significant reduction in the Na(+)/K(+)ATPase activity was observed in control rats at P39 compared to P16. Our data suggest that multiple pilocarpine-induced status epilepticus in developing rats induce long-lasting increase in the Na(+)/K(+)ATPase activity in the hippocampus, reflecting hyperexcitability.
Collapse
Affiliation(s)
- Erika Reime Kinjo
- Depto. de Neurologia e Neurocirurgia, Disciplina de Neurologia Experimental, Universidade Federal de São Paulo, Unifesp. Rua Botucatu, 862 - Edif. Leal Prado, CEP 04023-900, São Paulo, Brazil
| | | | | | | |
Collapse
|
26
|
Bennet L, Dean JM, Wassink G, Gunn AJ. Differential effects of hypothermia on early and late epileptiform events after severe hypoxia in preterm fetal sheep. J Neurophysiol 2006; 97:572-8. [PMID: 17093117 DOI: 10.1152/jn.00957.2006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Moderate cerebral hypothermia is consistently neuroprotective after experimental hypoxia-ischemia; however, its mechanisms remain poorly defined. Using a model of complete umbilical cord occlusion for 25 min in 0.7 gestation fetal sheep, we examined the effects of cerebral hypothermia (fetal extradural temperature reduced from 39.5 +/- 0.2 degrees C to <34 degrees C; mean +/- SD), from 90 min to 70 h after the end of the insult, on postocclusion epileptiform activity. In the first 6 h after the end of occlusion, fetal electroencephalographic (EEG) activity was abnormal with a mixture of fast and slow epileptiform transients superimposed on a suppressed background; seizures started a mean of 8 h after occlusion. There was a close correlation between numbers of these EEG transients and subsequent neuronal loss in the striatum after 3 days recovery (r(2) = 0.65, P = 0.008). Hypothermia was associated with a marked reduction in numbers of epileptiform transients in the first 6 h, reduced amplitude of seizures, and reduced striatal neuronal loss. In conclusion, neuroprotection with delayed, prolonged head cooling after a severe asphyxial insult in the preterm fetus was associated with potent, specific suppression of epileptiform transients in the early recovery phase but not of numbers of delayed seizures.
Collapse
Affiliation(s)
- L Bennet
- Department of Physiology, Faculty of Medicine and Health Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | | | | | | |
Collapse
|
27
|
Soriano FX, Papadia S, Hofmann F, Hardingham NR, Bading H, Hardingham GE. Preconditioning doses of NMDA promote neuroprotection by enhancing neuronal excitability. J Neurosci 2006; 26:4509-18. [PMID: 16641230 PMCID: PMC2561857 DOI: 10.1523/jneurosci.0455-06.2006] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Neuroprotection can be induced by low doses of NMDA, which activate both synaptic and extrasynaptic NMDA receptors. This is in apparent contradiction with our recent findings that extrasynaptic NMDA receptor signaling exerts a dominant inhibitory effect on prosurvival signaling from synaptic NMDA receptors. Here we report that exposure to low preconditioning doses of NMDA results in preferential activation of synaptic NMDA receptors because of a dramatic increase in action potential firing. Both acute and long-lasting phases of neuroprotection in the face of apoptotic or excitotoxic insults are dependent on this firing enhancement. Key mediators of synaptic NMDA receptor-dependent neuroprotection, phosphatidylinositol 3 kinase-Akt (PI3 kinase-Akt) signaling to Forkhead box subgroup O (FOXO) export and glycogen synthase kinase 3beta (GSK3beta) inhibition and cAMP response element-binding protein-dependent (CREB-dependent) activation of brain-derived neurotrophic factor (BDNF), can be induced only by low doses of NMDA via this action potential-dependent route. In contrast, NMDA doses on the other side of the toxicity threshold do not favor synaptic NMDA receptor activation because they strongly suppress firing rates below baseline. The classic bell-shaped curve depicting neuronal fate in response to NMDA dose can be viewed as the net effect of two antagonizing (synaptic vs extrasynaptic) curves: via increased firing the synaptic signaling dominates at low doses, whereas firing becomes suppressed and extrasynaptic signaling dominates as the toxicity threshold is crossed.
Collapse
|
28
|
Dean JM, Gunn AJ, Wassink G, Bennet L. Transient NMDA receptor-mediated hypoperfusion following umbilical cord occlusion in preterm fetal sheep. Exp Physiol 2005; 91:423-33. [PMID: 16317084 DOI: 10.1113/expphysiol.2005.032375] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Exposure to severe hypoxia leads to delayed cerebral and peripheral hypoperfusion. There is evidence in the very immature brain that transient abnormal glutaminergic receptor activity can occur during this phase of recovery. We therefore examined the role of N-methyl-D-aspartate (NMDA) receptor activity in mediating secondary hypoperfusion in preterm fetal sheep at 70% of gestation. Fetuses received either sham asphyxia or asphyxia and were studied for 12 h recovery. The specific, non-competitive NMDA receptor antagonist dizocilpine maleate (2 mg kg-1 bolus plus 0.07 mg kg h-1i.v.) or saline (vehicle) was infused from 15 min after asphyxia until 4 h. In the asphyxia-vehicle group abnormal epileptiform EEG transients were observed during the first 4 h of reperfusion, the peak of which corresponded approximately to the nadir in peripheral and cerebral hypoperfusion. Dizocilpine significantly suppressed this activity (2.7+/-1.3 versus 11.2+/-2.7 counts min-1 at peak frequency, P<0.05) and markedly delayed and attenuated the rise in vascular resistance in both peripheral and cerebral vascular beds observed after asphyxia, effectively preventing the initial deep period of hypoperfusion in carotid blood flow and femoral blood flow (P<0.01). However, while continued infusion did attenuate subsequent transient tachycardia, it did not prevent the development of a secondary phase of persistent but less profound hypoperfusion. In conclusion, the present studies suggest that in the immature brain the initial phase of delayed cerebral and peripheral hypoperfusion following exposure to severe hypoxia is mediated by NMDA receptor activity. The timing of this effect in the cerebral circulation corresponds closely to abnormal EEG activity, suggesting a pathological glutaminergic activation that we speculate is related to evolving brain injury.
Collapse
Affiliation(s)
- Justin M Dean
- Department of Physiology, Faculty of Medicine and Health Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | | | | | | |
Collapse
|
29
|
Levin SG, Kalemenev SV, Godukhin OV. Hyperexcitability of Neurons in Field Ca1 Evoked by Transient Episodes of Hypoxia in Hippocampal Slices from Rats of Different Ages. ACTA ACUST UNITED AC 2005; 35:585-8. [PMID: 16342614 DOI: 10.1007/s11055-005-0097-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- S G Levin
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
| | | | | |
Collapse
|
30
|
Silva AVD, Regondi MC, Cipelletti B, Frassoni C, Cavalheiro EA, Spreafico R. Neocortical and hippocampal changes after multiple pilocarpine-induced status epilepticus in rats. Epilepsia 2005; 46:636-42. [PMID: 15857427 DOI: 10.1111/j.1528-1167.2005.31604.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Multiple episodes of pilocarpine-induced status epilepticus (SE) in developing rats (P7-P9) lead to progressive epileptiform activity and severe cognitive impairment in adulthood. The present work studied possible underlying abnormalities in the neocortex and hippocampus of pilocarpine-treated animals. METHODS Wistar rats were submitted to pilocarpine-induced SE at P7, P8, and P9, and were killed at P35. Immunocytochemistry was performed on 50-microm vibratome sections, by using antibodies against nonphosphorylated neurofilament (SMI-311), parvalbumin (PV), calbindin (CB), calretinin (CR), and glutamate decarboxylase (GAD-65). Ten-micron cryostat sections were processed for immunohistoblot by using antibodies against GluR1, GluR2/3, and GluR4 alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits and NR2ab N-methyl-D-aspartate (NMDA) receptor subunit. RESULTS Adult rats submitted to SE at P7-9 showed: (a) altered distribution of neocortical interneurons; (b) increased cortical and reduced hippocampal GAD-65 expression; and (c) altered expression of hippocampal AMPA and NMDA receptors. CONCLUSIONS We conclude that multiple SE episodes during P7-9 generate long-lasting disturbances that underlie behavioral and electrographic abnormalities later in life.
Collapse
|
31
|
Abstract
The extent that status epilepticus (SE), but also brief seizures, affects neuronal structure and function has been the subject of much clinical and experimental research. There is a reliance on findings from animal research because there have been few prospective clinical studies. This review suggests that the features of seizure-induced injury in the immature brain compared with the adult brain are different and that duration of seizures (SE versus brief), number of seizures, cause of seizures, presence of pre-existing abnormalities, and genetics affect the injury. Increased awareness of age-specific injuries from seizure has promoted research to determine the circumstances under which seizures may produce permanent detrimental effects. Together with recent advances in functional neuroimaging, genomic investigation, and prospective human data, these studies are likely to substantially increase our knowledge of seizure-induced injury, leading to the development of improved algorithms for prevention and treatment of epilepsy.
Collapse
Affiliation(s)
- Sheryl R Haut
- Department of Neurology, Comprehensive Epilepsy Management Center, NY, USA
| | | | | |
Collapse
|
32
|
Doczi J, Bernásková K, Kubová H, Détari L, Világi I, Druga R, Mares P. Long-term changes of activity of cortical neurons after status epilepticus induced at early developmental stages in rats. Neurosci Lett 2003; 352:125-8. [PMID: 14625039 DOI: 10.1016/j.neulet.2003.08.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Spontaneous activity of cortical neurons was studied under urethane anesthesia in adult rats 3 months after convulsive status epilepticus induced by lithium-pilocarpine administration at the age of 12 (SE12 group) or 25 (SE25 group) days. Whereas random firing neurons dominated in control animals (61 out of 98 cells), SE25 animals exhibited a significant increase in the incidence of bursting cells (38 out of 59 units). Similar change in SE12 animals did not reach the level of statistical significance. Status epilepticus at an early developmental stage may result in a long-lasting change in functions of surviving cortical neurons.
Collapse
Affiliation(s)
- J Doczi
- Institute of Physiology, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4, Czech Republic
| | | | | | | | | | | | | |
Collapse
|
33
|
Zhang G, Raol YSH, Hsu FC, Brooks-Kayal AR. Long-term alterations in glutamate receptor and transporter expression following early-life seizures are associated with increased seizure susceptibility. J Neurochem 2003; 88:91-101. [PMID: 14675153 DOI: 10.1046/j.1471-4159.2003.02124.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Prolonged seizures in early childhood are associated with an increased risk of development of epilepsy in later life. The mechanism(s) behind this susceptibility to later development of epilepsy is unclear. Increased synaptic activity during development has been shown to permanently alter excitatory neurotransmission and could be one of the mechanisms involved in this increased susceptibility to the development of epilepsy. In the present study we determine the effect of status-epilepticus induced by lithium/pilocarpine at postnatal day 10 (P10 SE) on the expression of glutamate receptor and transporter mRNAs in hippocampal dentate granule cells and protein levels in dentate gyrus of these animals in adulthood. The results revealed a decrease in glutamate receptor 2 (GluR2) mRNA expression and protein levels as well as an increase in protein levels for the excitatory amino acid carrier 1 (EAAC1) in P10 SE rats compared to controls. Expression of glutamate receptor 1 (GluR1) mRNA was decreased in both P10 SE rats and identically handled, lithium-injected littermate controls compared to naive animals, and GluR1 protein levels were significantly lower in lithium-controls than in naive rats, suggesting an effect of either the handling or the lithium on GluR1 expression. These changes in EAA receptors and transporters were accompanied by an increased susceptibility to kainic acid induced seizures in P10 SE rats compared to controls. The current data suggest that early-life status-epilepticus can result in permanent alterations in glutamate receptor and transporter gene expression, which may contribute to a lower seizure threshold.
Collapse
Affiliation(s)
- Guojun Zhang
- Division of Neurology, Pediatric Regional Epilepsy Program, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | | | | | | |
Collapse
|
34
|
Jensen FE. Relationship between encephalopathy and abnormal neuronal activity in the developing brain. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2002; 49:23-35. [PMID: 12040895 DOI: 10.1016/s0074-7742(02)49004-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Infantile spasms represent a unique age-specific epileptic syndrome that is often associated with a focal or diffuse encephalopathy and can result in severe neurodevelopmental delay and retardation. The behavioral and electroencephalogram (EEG) phenotype of infantile spasms is similar, despite its association with multiple neurological disease states. The stereotypy suggests that the spasms originate from a highly age-specific hyperexcitable network. Treatment strategies for infantile spasms remain largely empirical due to the lack of understanding of the underlying neurochemistry and circuitry. This chapter reviews experimental evidence for the presence of unique developmental factors that appear to promote hyperexcitability in the immature brain and that may play a role in the generation of infantile spasms. In addition, this chapter evaluates the potential interplay between an associated developmental encephalopathy and enhanced neuronal hyperexcitability in infantile spasms.
Collapse
Affiliation(s)
- Frances E Jensen
- Department of Neurology, Children's Hospital, Program in Neuroscience Harvard Medical School, Boston, Massachusetts 02115, USA
| |
Collapse
|
35
|
Gao TM, Fung ML. Decreased large conductance Ca(2+)-activated K(+) channel activity in dissociated CA1 hippocampal neurons in rats exposed to perinatal and postnatal hypoxia. Neurosci Lett 2002; 332:163-6. [PMID: 12399006 DOI: 10.1016/s0304-3940(02)00946-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hypoxia is a major cause of neonatal encephalopathy and seizures, and an increased neuronal excitability may be an underlying mechanism. To determine the role of Ca(2+)-activated K(+) channels in hyperexcitability, we measured large unitary conductance (>200 pS, BK(Ca)) currents in symmetrical 140/140 mM K(+) using inside-out configuration in CA1 pyramidal cells acutely dissociated from the hippocampus of rats exposed to normoxia or hypoxia (at 10% inspired O(2)) for 4 weeks after birth. About 53% of the patches contained BK(Ca) channels in the normoxic group, but only 20% in the hypoxic one. There were no differences in channel conductance or reversal potential between the groups. Yet, the open probability of BK(Ca) channels was much less in hypoxic neurons than that in the control, because of a decrease in channel open time and a prolongation of the closed time. These were partially recovered by an oxidizing but not by reducing agent, suggesting an involvement of redox mechanism. Results indicate that the Ca(2+)-activated K(+) channel activities in hippocampal CA1 neurons are modulated by hypoxia during maturation. The reduction in BK(Ca) activity may contribute to hypoxia-induced neuronal hyperexcitability.
Collapse
Affiliation(s)
- Tian-Ming Gao
- Department of Physiology, The First Military Medical University, Guangzhou, China
| | | |
Collapse
|
36
|
Abstract
Pharmacological neuroprotection against the consequences of seizures can be considered as primary neuroprotection where the object is to diminish the initial insult by suppressing the seizure activity or diminishing the associated ionic fluxes (of which the entry of Na+ and Ca2+ are the most significant), and secondary neuroprotection where the target is some later event in the chain linking ionic changes to altered brain morphology or function. Thus primary neuroprotection is provided by antiepileptic drugs and compounds acting on voltage-sensitive Na+ and Ca2+ channels or on glutamate receptors (NMDA, AMPA/KA or Group I metabotropic). Secondary neuroprotection may be a result of acting on the cascade leading to necrosis (e.g. free radical scavengers, NitricOxide synthase inhibitors, CycloOxygenase-2 inhibitors) or the cascades leading to apoptosis (e.g. MAP-kinase inhibitors, caspase-3 inhibitors). Other approaches may diminish the long-term morphological and functional effects of seizures (e.g. neurotrophin-related therapies). We need improved preclinical tests for identifying novel compounds with potential for providing secondary neuroprotection and antiepileptogenesis. Clinical trials of neuroprotective agents in chronic epilepsy in adults pose major practical difficulties but the severe childhood epilepsies provide opportunities for aggressive testing of novel compounds.
Collapse
Affiliation(s)
- Brian S Meldrum
- GKT School of Biomedical Sciences, Henriette Raphael House, Guy's Campus, London SE1 1UL, UK.
| |
Collapse
|
37
|
Abstract
The perinatal age window is characterized by vulnerability to age-specific patterns of injury. Hypoxia/ischemia occurs in a number of settings both in term and preterm neonates, yet the patterns of response appear dependent upon the age of the infant. In the preterm neonate, hypoxic/ischemic insults result in selective white matter injury, termed periventricular leukomalacia (PVL), with little or no cortical pathology. However, in term babies, hypoxic encephalopathy is the most common cause of seizures, and also can result in cortical infarction. Extracellular glutamate accumulates in the setting of hypoxia/ischemia, and excess activation of glutamate receptors has been implicated in hypoxic/ischemic cellular death. Glutamate receptors are developmentally regulated in both neuronal and glial cells within the brain. Using rodent models, we have shown that hypoxia/ischemia results in selective white matter injury in postnatal day (P) seven rat pups, while hypoxia causes seizures in P10-12 rats, but not at younger or older ages. We have further demonstrated that antagonists of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) glutamate receptor subtype block white matter injury at P7 and seizures at P10. We have shown that AMPA receptors are relatively overexpressed in oligodendrocytes (OLs) within white matter at P7 and in neurons in cortex and hippocampus at P10. Hence maturational patterns of glutamate receptor expression correlate with age-specific regional susceptibility to injury to hypoxia/ischemia. While glutamate receptor blockade represents a rational strategy in the treatment of perinatal hypoxic/ischemic brain injury, it is unclear what role variations in their expression play in normal development and plasticity. Further investigation of patterns of glutamate receptor subunit expression in human brain and in experimental animal models is necessary to determine potential age specific strategies as well as adverse effects.
Collapse
Affiliation(s)
- Frances E Jensen
- Program in Neuroscience, Department of Neurology, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
38
|
Ratzliff ADH, Santhakumar V, Howard A, Soltesz I. Mossy cells in epilepsy: rigor mortis or vigor mortis? Trends Neurosci 2002; 25:140-4. [PMID: 11852145 DOI: 10.1016/s0166-2236(00)02122-6] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mossy cells are bi-directionally connected through a positive feedback loop to granule cells, the principal cells of the dentate gyrus. This recurrent circuit is strategically placed between the entorhinal cortex and the hippocampal CA3 region. In spite of their potentially pro-convulsive arrangement with granule cells, mossy cells have not been seriously considered to promote seizures, because mossy cells, allegedly one of the most vulnerable cell types in the entire mammalian brain, have long been 'known' to die en masse in epilepsy. However, new data suggest that rumors of the rapid demise of the mossy cells might have been greatly exaggerated.
Collapse
Affiliation(s)
- Annad d H Ratzliff
- Dept of Anatomy and Neurobiology, University of California, Irvine 92697-1280, USA
| | | | | | | |
Collapse
|
39
|
Abstract
Neonatal seizures caused by hypoxia can be refractory to conventional anticonvulsants. Currently, there is no effective postnatal intervention for newborn infants with hypoxic encephalopathy to prevent brain injury and long-term neurologic sequelae. We previously developed a rat model of perinatal hypoxia-induced seizures with subsequent long-term increases in seizure susceptibility and showed that these epileptogenic effects are selectively blocked by the alpha-amino-3-hydoxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor antagonist 6-nitro-7-sulfamoylbenzo(f)quinoxaline-2,3-dione. Using this model of perinatal seizures, we evaluated the efficacy of topiramate, a structurally novel anticonvulsant drug recently shown to attenuate AMPA/kainate currents. Topiramate effectively suppressed acute seizures induced by perinatal hypoxia in a dose-related manner with a calculated ED50 of 2.1 mg/kg, i.p. Furthermore, in animals that had seizures suppressed by topiramate during acute hypoxia, there were no long-term increases in susceptibility to kainate-induced seizures and seizure-induced neuronal injury. Our results suggest that topiramate may have clinical potential as a therapeutic agent for refractory seizures in human neonates.
Collapse
Affiliation(s)
- S Koh
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, MA, USA
| | | |
Collapse
|
40
|
Sanchez RM, Jensen FE. Maturational aspects of epilepsy mechanisms and consequences for the immature brain. Epilepsia 2001; 42:577-85. [PMID: 11380563 DOI: 10.1046/j.1528-1157.2001.12000.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- R M Sanchez
- Children's Hospital, Boston and Harvard Medical School, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
41
|
Viapiano MS, Mitridate de Novara AM, Fiszer de Plazas S, Bozzini CE. Prolonged exposure to hypobaric hypoxia transiently reduces GABA(A) receptor number in mice cerebral cortex. Brain Res 2001; 894:31-6. [PMID: 11245812 DOI: 10.1016/s0006-8993(00)03194-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The central nervous system is severely affected by hypoxic conditions, which produce alterations in neural cytoarchitecture and neurotransmission, resulting in a variety of neuropathological conditions such as convulsive states, neurobehavioral impairment and motor CNS alterations. Some of the neuropathologies observed in hypobaric hypoxia, corresponding to high altitude conditions, have been correlated with a loss of balance between excitatory and inhibitory neurotransmission, produced by alterations in glutamatergic and GABAergic receptors. In the present work, we have studied the effect of chronic hypobaric hypoxia (506 hPa, 18 h/day x 21 days) applied to adult male mice on GABA(A) receptors from cerebral cortex, to determine whether hypoxic exposure may irreversibly affect central inhibitory neurotransmission. Saturation curves for [3H]GABA specifically bound to GABA(A) receptors in isolated synaptic membranes showed a 30% decrease in maximal binding capacity after hypoxic exposure (Bmax control, 4.70+/-0.19, hypoxic, 3.33+/-0.10 pmol/mg protein), with no effect on GABA binding sites affinity (Kd control: 159.3+/-13.3 nM, hypoxic: 164.2+/-15.1 nM). Decreased B(max) values were observed up to the 10th post-hypoxic day, returning to control values by the 15th post-hypoxic day. Pharmacological properties of GABA(A) receptor were also affected by hypoxic exposure, with a 45 to 51% increase in the maximal effect by positive allosteric modulators (pentobarbital and 5alpha-pregnan-3alpha-ol-20-one). We conclude that long-term hypoxia produces a significant but reversible reduction on GABA binding to GABA(A) receptor sites in cerebral cortex, which may reflect an adaptive response to this sustained pathophysiological state.
Collapse
Affiliation(s)
- M S Viapiano
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, FMRP-USP, 3900 Bandeirantes Ave., 14049-900 Ribeirão Preto, São Paulo, Brazil.
| | | | | | | |
Collapse
|
42
|
Dube C, Chen K, Eghbal-Ahmadi M, Brunson K, Soltesz I, Baram TZ. Prolonged febrile seizures in the immature rat model enhance hippocampal excitability long term. Ann Neurol 2001. [DOI: 10.1002/1531-8249(200003)47:3<336::aid-ana9>3.0.co;2-w] [Citation(s) in RCA: 233] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
43
|
Dzhala V, Desfreres L, Melyan Z, Ben-Ari Y, Khazipov R. Epileptogenic action of caffeine during anoxia in the neonatal rat hippocampus. Ann Neurol 2001. [DOI: 10.1002/1531-8249(199907)46:1<95::aid-ana14>3.0.co;2-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
44
|
Bowyer JF. Neuronal degeneration in the limbic system of weanling rats exposed to saline, hyperthermia or d-amphetamine. Brain Res 2000; 885:166-71. [PMID: 11102570 DOI: 10.1016/s0006-8993(00)02925-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Neuronal degeneration was detected in the tenia tecta and other regions of the anterior limbic system of male weanling rats 3 days after four doses of 5 mg/kg d-amphetamine (4 x 5 mg/kg AMPH) when seizures occurred during AMPH exposure. Neurodegeneration in the parietal cortex, loss of tyrosine hydroxylase immunoreactivity in the caudate-putamen (CPu) and decreases in CPu tissue dopamine levels in weanlings was much less than those previously observed in adults. The neurotoxicity seen in the parietal cortex and CPu of the weanlings was much less than previously seen in adults even though severe hyperthermia and the behavior of retrograde propulsion occurred during AMPH exposure. Neurodegeneration was not detected in any of the previously mentioned brain regions in controls and weanlings made hyperthermic by a warm environment. However, signs of spontaneous neurodegeneration were seen in the posterior piriform cortex (Pir), posteriolateral cortical amygdaloid nucleus (PLCo), and the amygdalopiriform transition area (APir) of control weanlings. The doses of AMPH and the degree of hyperthermia necessary to induce seizures were substantially lower in weanlings compared to those previously observed in adult rats. Further studies will be necessary to determine if the susceptibility of weanlings to AMPH-induced seizures is related to or dependent on the same processes involved in producing degeneration in the posterior limbic system of saline controls.
Collapse
Affiliation(s)
- J F Bowyer
- Division of Neurotoxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA
| |
Collapse
|
45
|
Abstract
While primary, or idiopathic, epilepsies may exist, in the vast majority of cases epilepsy is a symptom of an underlying brain disease or injury. In these cases, it is difficult if not impossible to dissociate the consequences of epilepsy from the consequences of the underlying disease, the treatment of either the disease or the epilepsy, or the actual seizures themselves. Several cases of apparent complications of epilepsy are presented to illustrate the range of consequences encountered in clinical practice and the difficulty in assigning blame for progressive symptomatology in individual cases. Because of the difficulty in interpreting clinical material, many investigators have turned to epilepsy models in order to address the potential progressive consequences of recurrent seizures. The authors review experimental data, mainly from animal models, that illustrate short-, medium-, and long-term morphological and biochemical changes in the brain occurring after seizures, and attempt to relate these observations to the human condition.
Collapse
Affiliation(s)
- A J Cole
- Epilepsy Service, Massachusetts General Hospital and Department of Neurology, Harvard Medical School, Boston, Massachusetts 02114, USA.
| |
Collapse
|
46
|
Koh S, Ward SL, Lin M, Chen LS. Sleep apnea treatment improves seizure control in children with neurodevelopmental disorders. Pediatr Neurol 2000; 22:36-9. [PMID: 10669203 DOI: 10.1016/s0887-8994(99)00114-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Seizure disorder and sleep apnea are common chronic disorders in children, but the relationship between sleep apnea and seizure control has not been studied in the pediatric population. This retrospective review included nine children with neurodevelopmental disorders who had well-documented sleep apneic episodes and seizure disorders. Seizure frequency was reduced in five patients (56%) in the first 12 months after sleep apnea treatment without changes in their antiepileptic medications. Sleep apnea can be one of the seizure precipitants in children with epilepsy. This study indicates the importance of identifying sleep apnea when treating children with intractable epilepsy, particularly in those who are at high risk.
Collapse
Affiliation(s)
- S Koh
- Division of Neurology, University of Southern California, Los Angeles, USA
| | | | | | | |
Collapse
|
47
|
Jensen FE, Baram TZ. Developmental seizures induced by common early-life insults: short- and long-term effects on seizure susceptibility. MENTAL RETARDATION AND DEVELOPMENTAL DISABILITIES RESEARCH REVIEWS 2000; 6:253-7. [PMID: 11107190 PMCID: PMC3186350 DOI: 10.1002/1098-2779(2000)6:4<253::aid-mrdd4>3.0.co;2-p] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The immature brain is highly susceptible to seizures induced by a variety of insults, including hypoxia, fever, and trauma. Unlike early life epilepsy associated with congenital dysplasias or genetic abnormalities, insults induce a hyperexcitable state in a previously normal brain. Here we evaluate the epileptogenic effects of seizure-inducing stimuli on the developing brain, and the age and regional specificity of these effects.
Collapse
MESH Headings
- Age Factors
- Brain/growth & development
- Brain/pathology
- Brain/physiopathology
- Brain Injuries/complications
- Brain Injuries/pathology
- Brain Injuries/physiopathology
- Causality
- Child
- Child, Preschool
- Disease Models, Animal
- Epilepsy/etiology
- Epilepsy/pathology
- Epilepsy/physiopathology
- Epilepsy, Temporal Lobe/etiology
- Epilepsy, Temporal Lobe/pathology
- Epilepsy, Temporal Lobe/physiopathology
- Humans
- Hypoxia, Brain/complications
- Hypoxia, Brain/pathology
- Hypoxia, Brain/physiopathology
- Infant
- Infant, Newborn
- Seizures/complications
- Seizures/etiology
- Seizures/pathology
- Seizures/physiopathology
- Seizures, Febrile/complications
- Seizures, Febrile/etiology
- Seizures, Febrile/pathology
- Seizures, Febrile/physiopathology
Collapse
Affiliation(s)
- F E Jensen
- Children's Hospital, Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115, USA.
| | | |
Collapse
|