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Lawande NV, Conklin EA, Christian‐Hinman CA. Sex and gonadectomy modify behavioral seizure susceptibility and mortality in a repeated low-dose kainic acid systemic injection paradigm in mice. Epilepsia Open 2023; 8:1512-1522. [PMID: 37715318 PMCID: PMC10690657 DOI: 10.1002/epi4.12828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023] Open
Abstract
OBJECTIVE Sex differences in epilepsy appear driven in part due to effects of gonadal steroids, with varying results in experimental models based on species, strain, and method of seizure induction. Furthermore, removing the main source of these steroids via gonadectomy may impact seizure characteristics differently in males and females. Repeated low-dose kainic acid (RLDKA) systemic injection paradigms were recently shown to reliably induce status epilepticus (SE) and hippocampal histopathology in C57BL/6J mice. Here, we investigated whether seizure susceptibility in a RLDKA injection protocol exhibits a sex difference and whether gonadectomy differentially influences response to this seizure induction paradigm in males and females. METHODS Adult C57BL/6J mice were left gonad-intact as controls or gonadectomized (females: ovariectomized, OVX; males: orchidectomized, ORX). At least 2 weeks later, KA was injected ip, every 30 minutes at 7.5 mg/kg or less until the animal reached SE, defined by at least 5 generalized seizures (GS, Racine stage 3 or higher). Parameters of susceptibility to GS induction, SE development, and mortality rates were quantified. RESULTS No differences in seizure susceptibility or mortality were observed between control males and control females. Gonadectomized mice exhibited increased susceptibility and reduced latency to both GS and SE in comparison to corresponding controls of the same sex, but the effects were stronger in males. In addition, ORX males, but not OVX females, exhibited strongly increased seizure-induced mortality. SIGNIFICANCE The RLDKA protocol is notable for its efficacy in inducing SE and seizure-induced histopathology in C57BL/6J mice, the background for many transgenic strains in current use in epilepsy research. The present results indicate that this protocol may be beneficial for investigating the effects of gonadal hormone replacement on seizure susceptibility, mortality, and seizure-induced histopathology, and that gonadectomy unmasks sex differences in susceptibility to seizures and mortality not observed in gonad-intact controls.
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Affiliation(s)
- Niraj V. Lawande
- Department of Molecular and Integrative PhysiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | | | - Catherine A. Christian‐Hinman
- Department of Molecular and Integrative PhysiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- Neuroscience ProgramUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- Beckman Institute for Advanced Science and TechnologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
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Lawande NV, Conklin EA, Christian-Hinman CA. Sex and gonadectomy modify behavioral seizure susceptibility and mortality in a repeated low-dose kainic acid systemic injection paradigm in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541824. [PMID: 37292790 PMCID: PMC10245840 DOI: 10.1101/2023.05.22.541824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Objective Sex differences in epilepsy appear driven in part due to effects of gonadal steroids, with varying results in experimental models based on species, strain, and method of seizure induction. Furthermore, removing a main source of these steroids via gonadectomy may impact seizure characteristics differently in males and females. Repeated low-dose kainic acid (RLDKA) systemic injection paradigms were recently shown to reliably induce status epilepticus (SE) and hippocampal histopathology in C57BL/6J mice. Here, we investigated whether seizure susceptibility in a RLDKA injection protocol exhibits a sex difference, and whether gonadectomy differentially influences response to this seizure induction paradigm in males and females. Methods Adult C57BL/6J mice were left gonad-intact as controls or gonadectomized (females: ovariectomized, OVX; males: orchidectomized, ORX). At least 2 weeks later, KA was injected i.p. every 30 minutes at 7.5 mg/kg or less until the animal reached SE, defined by at least 5 generalized seizures (GS, Racine stage 3 or higher). Parameters of susceptibility to GS induction, SE development, and mortality rates were quantified. Results No differences in seizure susceptibility or mortality were observed between control males and control females. ORX males exhibited increased susceptibility and reduced latency to both GS and SE, but OVX females exhibited increased susceptibility and reduced latency to SE only. However, ORX males, but not OVX females, exhibited strongly increased seizure-induced mortality. Significance The RLDKA protocol is notable for its efficacy in inducing SE and seizure-induced histopathology in C57BL/6J mice, the background for many transgenic strains in current use in epilepsy research. The present results indicate that this protocol may be beneficial for investigating the effects of gonadal hormone replacement on seizure susceptibility, mortality, and seizure-induced histopathology, and that gonadectomy unmasks sex differences in susceptibility to seizures and mortality not observed in gonad-intact controls.
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Affiliation(s)
- Niraj V. Lawande
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
| | - Elisabeth A. Conklin
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
| | - Catherine A. Christian-Hinman
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
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D'Amora M, Galgani A, Marchese M, Tantussi F, Faraguna U, De Angelis F, Giorgi FS. Zebrafish as an Innovative Tool for Epilepsy Modeling: State of the Art and Potential Future Directions. Int J Mol Sci 2023; 24:ijms24097702. [PMID: 37175408 PMCID: PMC10177843 DOI: 10.3390/ijms24097702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/20/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
This article discusses the potential of Zebrafish (ZF) (Danio Rerio), as a model for epilepsy research. Epilepsy is a neurological disorder affecting both children and adults, and many aspects of this disease are still poorly understood. In vivo and in vitro models derived from rodents are the most widely used for studying both epilepsy pathophysiology and novel drug treatments. However, researchers have recently obtained several valuable insights into these two fields of investigation by studying ZF. Despite the relatively simple brain structure of these animals, researchers can collect large amounts of data in a much shorter period and at lower costs compared to classical rodent models. This is particularly useful when a large number of candidate antiseizure drugs need to be screened, and ethical issues are minimized. In ZF, seizures have been induced through a variety of chemoconvulsants, primarily pentylenetetrazol (PTZ), kainic acid (KA), and pilocarpine. Furthermore, ZF can be easily genetically modified to test specific aspects of monogenic forms of human epilepsy, as well as to discover potential convulsive phenotypes in monogenic mutants. The article reports on the state-of-the-art and potential new fields of application of ZF research, including its potential role in revealing epileptogenic mechanisms, rather than merely assessing iatrogenic acute seizure modulation.
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Affiliation(s)
- Marta D'Amora
- Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Department of Biology, University of Pisa, 56125 Pisa, Italy
| | - Alessandro Galgani
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, 56126 Pisa, Italy
| | - Maria Marchese
- Molecular Medicine and Neurobiology-ZebraLab, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | | | - Ugo Faraguna
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, 56126 Pisa, Italy
- Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | | | - Filippo Sean Giorgi
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, 56126 Pisa, Italy
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Activation of the PI3K/AKT/mTOR Pathway in Cajal–Retzius Cells Leads to Their Survival and Increases Susceptibility to Kainate-Induced Seizures. Int J Mol Sci 2023; 24:ijms24065376. [PMID: 36982451 PMCID: PMC10048971 DOI: 10.3390/ijms24065376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 02/15/2023] [Accepted: 03/08/2023] [Indexed: 03/14/2023] Open
Abstract
Cajal–Retzius cells (CRs) are a class of transient neurons in the mammalian cortex that play a critical role in cortical development. Neocortical CRs undergo almost complete elimination in the first two postnatal weeks in rodents and the persistence of CRs during postnatal life has been detected in pathological conditions related to epilepsy. However, it is unclear whether their persistence is a cause or consequence of these diseases. To decipher the molecular mechanisms involved in CR death, we investigated the contribution of the PI3K/AKT/mTOR pathway as it plays a critical role in cell survival. We first showed that this pathway is less active in CRs after birth before massive cell death. We also explored the spatio-temporal activation of both AKT and mTOR pathways and reveal area-specific differences along both the rostro–caudal and medio–lateral axes. Next, using genetic approaches to maintain an active pathway in CRs, we found that the removal of either PTEN or TSC1, two negative regulators of the pathway, lead to differential CR survivals, with a stronger effect in the Pten model. Persistent cells in this latter mutant are still active. They express more Reelin and their persistence is associated with an increase in the duration of kainate-induced seizures in females. Altogether, we show that the decrease in PI3K/AKT/mTOR activity in CRs primes these cells to death by possibly repressing a survival pathway, with the mTORC1 branch contributing less to the phenotype.
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Costa AM, Gol M, Lucchi C, Biagini G. Antiepileptogenic effects of trilostane in the kainic acid model of temporal lobe epilepsy. Epilepsia 2023; 64:1376-1389. [PMID: 36861666 DOI: 10.1111/epi.17561] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/20/2023] [Accepted: 02/27/2023] [Indexed: 03/03/2023]
Abstract
OBJECTIVE Epileptogenesis after status epilepticus (SE) has a faster onset in rats treated to reduce brain levels of the anticonvulsant neurosteroid allopregnanolone with the 5α-reductase inhibitor finasteride; however, it still has to be evaluated whether treatments aimed at increasing allopregnanolone levels could result in the opposite effect of delaying epileptogenesis. This possibility could be tested using the peripherally active inhibitor of 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase trilostane, which has been shown repeatedly to increase allopregnanolone levels in the brain. METHODS Trilostane (50 mg/kg) was administered subcutaneously once daily for up to six consecutive days, starting 10 min after intraperitoneal administration of kainic acid (15 mg/kg). Seizures were evaluated by video-electrocorticographic recordings for 70 days maximum, and endogenous neurosteroid levels were assessed by liquid chromatography-electrospray tandem mass spectrometry. Immunohistochemical staining was performed to evaluate the presence of brain lesions. RESULTS Trilostane did not alter the latency of kainic acid-induced SE onset or its overall duration. When compared to the vehicle-treated group, rats receiving six daily trilostane injections presented a remarkable delay of the first spontaneous electrocorticographic seizure and subsequent tonic-clonic spontaneous recurrent seizures (SRSs). Conversely, rats treated with only the first trilostane injection during SE did not differ from vehicle-treated rats in developing the SRSs. Notably, trilostane did not modify neuronal cell densities or the overall damage in the hippocampus. In comparison to the vehicle group, repeated administration of trilostane significantly decreased the activated microglia morphology in the subiculum. As expected, allopregnanolone and other neurosteroid levels were remarkably increased in the hippocampus and neocortex of rats treated for 6 days with trilostane, but pregnanolone was barely detectable. Neurosteroids returned to basal levels after a week of trilostane washout. SIGNIFICANCE Overall, these results suggest that trilostane led to a remarkable increase in allopregnanolone brain levels, which was associated with protracted effects on epileptogenesis.
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Affiliation(s)
- Anna Maria Costa
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Mohammad Gol
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,PhD School of Clinical and Experimental Medicine, University of Modena and Reggio Emilia, Modena, Italy
| | - Chiara Lucchi
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Giuseppe Biagini
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
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Cutia CA, Leverton LK, Christian-Hinman CA. Sex and estrous cycle stage shape left-right asymmetry in chronic hippocampal seizures in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524965. [PMID: 36712086 PMCID: PMC9882284 DOI: 10.1101/2023.01.20.524965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Lateralization of hippocampal function is indicated by varied outcomes of patients with neurological disorders that selectively affect one hemisphere of this structure, such as temporal lobe epilepsy (TLE). The intrahippocampal kainic acid (IHKA) injection model of TLE allows for targeted damage to the left or right hippocampus, enabling systematic comparison of effects of left-right asymmetry on seizure and non-seizure outcomes. Although varying non-seizure phenotypic outcomes based on injection side in dorsal hippocampus were recently evaluated in this model, differences in chronic seizure patterns in left- (IHKA-L) vs. right-injected (IHKA-R) IHKA animals have yet to be evaluated. Here, we evaluated hippocampal seizure incidence in male and female IHKA-L and IHKA-R mice. Females displayed increased electrographic seizure activity compared to males at both 2 months and 4 months post-injection (mpi). In addition, IHKA-L females showed higher seizure frequency than IHKA-R on diestrus and estrus at 2 mpi, but seizure duration and time in seizures were only higher in IHKA-L females on diestrus. These cycle stage-associated changes, however, did not persist to 4 mpi. Furthermore, this lateralized difference in seizure burden was not observed in males. These results indicate for the first time that the side of IHKA injection can shape chronic electrographic seizure burden. Overall, these results demonstrate a female-specific left-right asymmetry in hippocampal function can interact with estrous cycle stage to shape chronic seizures in mice with epilepsy, with implications for neural activity and behavior in both normal and disease states.
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Affiliation(s)
- Cathryn A. Cutia
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
| | - Leanna K. Leverton
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
| | - Catherine A. Christian-Hinman
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
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Barker-Haliski M, Pitsch J, Galanopoulou AS, Köhling R. A companion to the preclinical common data elements for phenotyping seizures and epilepsy in rodent models. A report of the TASK3-WG1C: Phenotyping working group of the ILAE/AES joint translational task force. Epilepsia Open 2022. [PMID: 36461665 DOI: 10.1002/epi4.12676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 05/23/2022] [Indexed: 12/04/2022] Open
Abstract
Epilepsy is a heterogeneous disorder characterized by spontaneous seizures and behavioral comorbidities. The underlying mechanisms of seizures and epilepsy across various syndromes lead to diverse clinical presentation and features. Similarly, animal models of epilepsy arise from numerous dissimilar inciting events. Preclinical seizure and epilepsy models can be evoked through many different protocols, leaving the phenotypic reporting subject to diverse interpretations. Serendipity can also play an outsized role in uncovering novel drivers of seizures or epilepsy, with some investigators even stumbling into epilepsy research because of a new genetic cross or unintentional drug effect. The heightened emphasis on rigor and reproducibility in preclinical research, including that which is conducted for epilepsy, underscores the need for standardized phenotyping strategies. To address this goal as part of the TASK3-WG1C Working Group of the International League Against Epilepsy (ILAE)/American Epilepsy Society (AES) Joint Translational Task Force, we developed a case report form (CRF) to describe the common data elements (CDEs) necessary for the phenotyping of seizure-like behaviors in rodents. This companion manuscript describes the use of the proposed CDEs and CRF for the visual, behavioral phenotyping of seizure-like behaviors. These phenotyping CDEs and accompanying CRF can be used in parallel with video-electroencephalography (EEG) studies or as a first visual screen to determine whether a model manifests seizure-like behaviors before utilizing more specialized diagnostic tests, like video-EEG. Systematic logging of seizure-like behaviors may help identify models that could benefit from more specialized diagnostic tests to determine whether these are epileptic seizures, such as video-EEG.
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Affiliation(s)
- Melissa Barker-Haliski
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Julika Pitsch
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Isabelle Rapin Division of Child Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York, USA
- Dominick P Purpura Department of Neuroscience, Isabelle Rapin Division of Child Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Rüdiger Köhling
- Oscar-Langendorff-Institut für Physiologie, Universitätsmedizin Rostock, Rostock, Germany
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Hophing L, Kyriakopoulos P, Bui E. Sex and gender differences in epilepsy. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 164:235-276. [PMID: 36038205 DOI: 10.1016/bs.irn.2022.06.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Sex and gender differences in epilepsy are important influencing factors in epilepsy care. In epilepsy, the hormonal differences between the sexes are important as they impact specific treatment considerations for patients at various life stages particularly during early adulthood with establishment of the menstrual cycle, pregnancy, perimenopause and menopause. Choice of antiseizure medication may have direct consequences on hormonal cycles, hormonal contraception, pregnancy and fetal risk of major congenital malformation. Conversely hormones whether intrinsic or extrinsically administered may have direct impact on antiseizure medications and seizure control. This chapter explores these important influences on the management of persons with epilepsy.
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Affiliation(s)
- Lauren Hophing
- Krembil Brain Institute, University Health Network, University of Toronto, Toronto, Canada
| | | | - Esther Bui
- Krembil Brain Institute, University Health Network, University of Toronto, Toronto, Canada.
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Sahin H, Yucel O, Emik S, Senturk GE. Protective Effects of Intranasally Administrated Oxytocin-Loaded Nanoparticles on Pentylenetetrazole-Kindling Epilepsy in Terms of Seizure Severity, Memory, Neurogenesis, and Neuronal Damage. ACS Chem Neurosci 2022; 13:1923-1937. [PMID: 35713692 PMCID: PMC9264347 DOI: 10.1021/acschemneuro.2c00124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
![]()
Pentylenetetrazole
(PTZ)-induced kindling is an animal model for
studying human temporal lobe epilepsy (TLE), which is characterized
by alterations of hippocampal neurons and memory. Although the intranasal
(IN) administration of oxytocin (OT) has limited efficiency, nanoparticles
(NPs) are a promising candidate to deliver OT to the brain. However,
there are very limited data on epilepsy research about oxytocin-loaded
nanoparticles (NP-OTs). The aim of this study is to investigate the
effects of IN administration of chronic NP-OTs on the hippocampus
of PTZ-induced male epileptic rats in terms of seizure severity, memory,
neurogenesis, and neuronal damage. Saline/OT/NP-OTs were administrated
to both control (Ctrl) and PTZ groups intranasally. Consequently,
saline and PTZ were injected, respectively, 25 times every 48 h. Then,
seizure severity (score and latency) was calculated for the PTZ groups.
A spatial working memory evaluation test (SWMET) was performed after
the last injection. Hippocampus histopathology, neurogenesis, and
apoptosis were demonstrated. Serum total antioxidant status (TAS)
and total oxidant status (TOS) levels and the oxidative stress index
(OSI) were measured. We showed that OTs and NP-OTs prevented the kindling
development and had positive effects on seizure severity. SWMET-related
behaviors were also recovered in the PTZ + NP-OT group. A significant
increase of neurogenesis and decrease of apoptosis in the hippocampus
of the PTZ + NP-OT group were observed, while OTs and NP-OTs had protective
effects against PTZ-induced damage to hippocampal neurons. Our results
indicate that the chronic administration of NP-OTs may have positive
effects on hippocampal damage via increasing neurogenesis and decreasing
apoptosis and seizure severity.
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Affiliation(s)
- Hakan Sahin
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University─Cerrahpasa, Istanbul 34098, Turkey
| | - Oguz Yucel
- Department of Chemical Engineering, Faculty of Engineering, Istanbul University─Cerrahpasa, Istanbul 34320, Turkey
| | - Serkan Emik
- Department of Chemical Engineering, Faculty of Engineering, Istanbul University─Cerrahpasa, Istanbul 34320, Turkey
| | - Gozde Erkanli Senturk
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University─Cerrahpasa, Istanbul 34098, Turkey
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Neuroplastic alterations in cannabinoid receptors type 1 (CB1) in animal models of epileptic seizures. Neurosci Biobehav Rev 2022; 137:104675. [PMID: 35460705 DOI: 10.1016/j.neubiorev.2022.104675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/16/2022] [Accepted: 04/17/2022] [Indexed: 01/01/2023]
Abstract
Currently, there is an urgent need to better comprehend neuroplastic alterations in cannabinoid receptors type 1 (CB1) and to understand the biological meaning of these alterations in epileptic disorders. The present study reviewed neuroplastic changes in CB1 distribution, expression, and functionality in animal models of epileptic seizures. Neuroplastic alterations in CB1 were consistently observed in chemical, genetic, electrical, and febrile seizure models. Most studies assessed changes in hippocampal and cortical CB1, while thalamic, hypothalamic, and brainstem nuclei were rarely investigated. Additionally, the relationship between CB1 alteration and the control of brain excitability through modulation of specific neuronal networks, such as striatonigral, nigrotectal and thalamocortical pathways, and inhibitory projections to hippocampal pyramidal neurons, were all presented and discussed in the present review. Neuroplastic alterations in CB1 detected in animal models of epilepsy may reflect two different scenarios: (1) endogenous adaptations aimed to control neuronal hyperexcitability in epilepsy or (2) pathological alterations that facilitate neuronal hyperexcitability. Additionally, a better comprehension of neuroplastic and functional alterations in CB1 can improve pharmacological therapies for epilepsies and their comorbidities.
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Walters JM, Kim EC, Zhang J, Jeong HG, Bajaj A, Baculis B, Tracy G, Ibrahim B, Christian-Hinman CA, Llano DA, Huesmann GR, Chung HJ. Pharmacological inhibition of STriatal-Enriched protein tyrosine Phosphatase by TC-2153 reduces hippocampal excitability and seizure propensity. Epilepsia 2022; 63:1211-1224. [PMID: 35188269 PMCID: PMC9586517 DOI: 10.1111/epi.17192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 12/30/2021] [Accepted: 02/01/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVE STriatal-Enriched protein tyrosine Phosphatase (STEP) is a brain-specific tyrosine phosphatase. Membrane-bound STEP61 is the only isoform expressed in hippocampus and cortex. Genetic deletion of STEP enhances excitatory synaptic currents and long-term potentiation in the hippocampus. However, whether STEP61 affects seizure susceptibility is unclear. Here we investigated the effects of STEP inhibitor TC-2153 on seizure propensity in a murine model displaying kainic acid (KA)-induced status epilepticus and its effect on hippocampal excitability. METHODS Adult male and female C57BL/6J mice received intraperitoneal injection of either vehicle (2.8% dimethylsulfoxide [DMSO] in saline) or TC-2153 (10 mg/kg) and then either saline or KA (30 mg/kg) 3 h later before being monitored for behavioral seizures. A subset of female mice was ovariectomized (OVX). Acute hippocampal slices from Thy1-GCaMP6s mice were treated with either DMSO or TC-2153 (10 μM) for 1 h, and then incubated in artificial cerebrospinal fluid (ACSF) and potassium chloride (15 mM) for 2 min prior to live calcium imaging. Pyramidal neurons in dissociated rat hippocampal culture (DIV 8-10) were pre-treated with DMSO or TC-2153 (10 µM) for 1 h before whole-cell patch-clamp recording. RESULTS TC-2153 treatment significantly reduced KA-induced seizure severity, with greater trend seen in female mice. OVX abolished this TC-2153-induced decrease in seizure severity in female mice. TC-2153 application significantly decreased overall excitability of acute hippocampal slices from both sexes. Surprisingly, TC-2153 treatment hyperpolarized resting membrane potential and decreased firing rate, sag voltage, and hyperpolarization-induced current (Ih ) of cultured hippocampal pyramidal neurons. SIGNIFICANCE This study is the first to demonstrate that pharmacological inhibition of STEP with TC-2153 decreases seizure severity and hippocampal activity in both sexes, and dampens hippocampal neuronal excitability and Ih . We propose that the antiseizure effects of TC-2153 are mediated by its unexpected action on suppressing neuronal intrinsic excitability.
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Affiliation(s)
- Jennifer M. Walters
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Eung Chang Kim
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jiaren Zhang
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Han Gil Jeong
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Archit Bajaj
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Brian Baculis
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Gregory Tracy
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Baher Ibrahim
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Catherine A. Christian-Hinman
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Daniel A. Llano
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Graham R. Huesmann
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Neurology, Carle Foundation Hospital, Urbana, IL, USA
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Hee Jung Chung
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Dept. of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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12
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Sears SMS, Roberts SH, Hewett SJ. Hyperexcitability and brain morphological differences in mice lacking the cystine/glutamate antiporter, system x c. J Neurosci Res 2021; 99:3339-3353. [PMID: 34747522 DOI: 10.1002/jnr.24971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 09/11/2021] [Accepted: 09/16/2021] [Indexed: 01/17/2023]
Abstract
System xc - (Sxc - ) is a heteromeric antiporter (L-cystine/L-glutamate exchanger) expressed predominately on astrocytes in the central nervous system. Its activity contributes importantly to the maintenance of the ambient extracellular glutamate levels, as well as, to cellular redox homeostasis. Since alterations in glutamate levels and redox modifications could cause structural changes, we analyzed gross regional morphology of thionin-stained brain sections and cellular and subcellular morphology of Golgi-Cox stained layer V pyramidal neurons in the primary motor cortex (PM1) of mice naturally null for SLC7A11 (SLC7A11sut/sut )-the gene that encodes the substrate specific light chain (xCT) for Sxc - . Intriguingly, in comparison to age- and sex-matched wild-type (SLC7A11+/+ ) littermate controls, we found morphologic changes-including increased dendritic complexity and mushroom spine area in males and reduced corpus callosum and soma size in females-that have previously been described, in each case, as morphological correlates of excitability. Consistent with this, we found that both male and female SLC7A11sut/sut mice had lower convulsive seizure thresholds and greater seizure severity than their sex-matched wild-type (SLC7A11+/+ ) littermates after acute challenge with two pharmacologically distinct chemoconvulsants: the Glu receptor agonist, kainic acid (KA), or the GABAA receptor antagonist, pentylenetetrazole (PTZ). These results suggest that the loss of Sxc - signaling in males and females perturbs excitatory/inhibitory (E/I) balance in vivo, potentially through its regulation of cellular and subcellular morphology.
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Affiliation(s)
- Sheila M S Sears
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, New York, USA
| | - Sarah H Roberts
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, New York, USA
| | - Sandra J Hewett
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, New York, USA
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13
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Hong GP, Kim MH, Kim HJ. Sex-related Differences in Glial Fibrillary Acidic Protein-positive GABA Regulate Neuropathology Following Pilocarpine-induced Status Epilepticus. Neuroscience 2021; 472:157-166. [PMID: 34400247 DOI: 10.1016/j.neuroscience.2021.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 07/28/2021] [Accepted: 08/03/2021] [Indexed: 12/31/2022]
Abstract
Status epilepticus (SE) is a life-threatening neurological disorder that causes neuronal death and glial activation. Studies have explained the clinical side effects and lack of effectiveness of neurological disorder treatments based on sex-related differences in brain structure and function. However, the sex-specific outcomes of seizure disorders and the underlying mechanisms remain unknown. We compared SE-induced behavioral and pathophysiological changes in male and female mice. The time taken to reach stage 6 seizure following pilocarpine injection was shorter in male mice than in female mice, and the prevalence of SE was higher in male mice than in female mice. Fluoro-Jade B staining revealed more extensive SE-induced hippocampal neuronal death in male mice than in female mice. Glial cells were more activated in male mice than in female mice. In contrast, astrocyte-derived γ-aminobutyric acid (GABA)-immunostaining was less expressed in male mice than in female mice. Moreover, the mRNA levels of inflammatory cytokines released from activated glial cells were higher in male mice than in female mice. Notably, the mRNA level of astrocytic γ-aminobutyric acid transporter (GAT-3) involved in extracellular GABA uptake was lower in female mice than in male mice, while the mRNA levels of glutamate/aspartate transporter (GLAST (EAAT1)) and glutamate transporter (GLT-1 (EAAT2)) involved in extracellular glutamate uptake were higher in female mice. Our findings suggest that male mice are more vulnerable to SE than female mice, resulting in more extensive neuronal cell death and glial activation in male mice, partly due to increased GAT-3 expression that subsequently leads to reduced glial fibrillary acidic protein (GFAP)-positive GABA content assessed with anti-GABA antibodies.
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Affiliation(s)
- Geum Pyo Hong
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea; Department of Medical Laser, Graduate School, Dankook University, Cheonan, Republic of Korea
| | - Mi-Hye Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea; Department of Medical Laser, Graduate School, Dankook University, Cheonan, Republic of Korea
| | - Hee Jung Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea.
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14
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Gummadavelli A, Martin R, Goshay D, Sieu LA, Xu J, Gruenbaum BF, McCafferty C, Gerrard JL, Blumenfeld H. Cortical low-frequency power correlates with behavioral impairment in animal model of focal limbic seizures. Epilepsia 2021; 62:1960-1970. [PMID: 34240747 PMCID: PMC8349876 DOI: 10.1111/epi.16964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/29/2021] [Accepted: 06/01/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Impairment in consciousness is a debilitating symptom during and after seizures; however, its mechanism remains unclear. Limbic seizures have been shown to spread to arousal circuitry to result in a "network inhibition" phenomenon. However, prior animal model studies did not relate physiological network changes to behavioral responses during or following seizures. METHODS Focal onset limbic seizures were induced while rats were performing an operant conditioned behavioral task requiring response to an auditory stimulus to quantify how and when impairment of behavioral response occurs. Correct responses were rewarded with sucrose. Cortical and hippocampal electrophysiology measured by local field potential recordings was analyzed for changes in low- and high-frequency power in relation to behavioral responsiveness during seizures. RESULTS As seen in patients with seizures, ictal (p < .0001) and postictal (p = .0015) responsiveness was variably impaired. Analysis of cortical and hippocampal electrophysiology revealed that ictal (p = .002) and postictal (p = .009) frontal cortical low-frequency 3-6-Hz power was associated with poor behavioral performance. In contrast, the hippocampus showed increased power over a wide frequency range during seizures, and suppression postictally, neither of which were related to behavioral impairment. SIGNIFICANCE These findings support prior human studies of temporal lobe epilepsy as well as anesthetized animal models suggesting that focal limbic seizures depress consciousness through remote network effects on the cortex, rather than through local hippocampal involvement. By identifying the cortical physiological changes associated with impaired arousal and responsiveness in focal seizures, these results may help guide future therapies to restore ictal and postictal consciousness, improving quality of life for people with epilepsy.
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Affiliation(s)
- Abhijeet Gummadavelli
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
| | - Reese Martin
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
| | - Derek Goshay
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
| | - Lim-Anna Sieu
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
| | - Jingwen Xu
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
| | - Benjamin F. Gruenbaum
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
| | - Cian McCafferty
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
| | - Jason L. Gerrard
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
| | - Hal Blumenfeld
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
- Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
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15
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Reddy DS. Brain structural and neuroendocrine basis of sex differences in epilepsy. HANDBOOK OF CLINICAL NEUROLOGY 2021; 175:223-233. [PMID: 33008527 DOI: 10.1016/b978-0-444-64123-6.00016-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This chapter reviews the current information about sex differences in epilepsy and potential mechanisms underlying sex differences in seizure susceptibility and epilepsy. The susceptibility to and occurrence of seizures are generally higher in men than women. There is gender-specific epilepsies such as catamenial epilepsy, a neuroendocrine condition in which seizures are most often clustered around the perimenstrual or periovulatory period in adult women. Structural differences in cerebral morphology, the structural and functional circuits may render men and women differentially vulnerable to seizure disorders and epileptogenic processes. Changes in seizure sensitivity are evident at puberty, pregnancy, and menopause, often attributed to circulating steroid hormones and neurosteroids as well as neuroplasticity in receptor systems. An improved understanding of the sexual dimorphism in neural circuits and the neuroendocrine basis of sex differences or resistance to protective drugs is essential to develop sex-specific therapies for seizure conditions.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, United States.
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16
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Absence epilepsy in male and female WAG/Rij rats: A longitudinal EEG analysis of seizure expression. Epilepsy Res 2021; 176:106693. [PMID: 34225231 DOI: 10.1016/j.eplepsyres.2021.106693] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/15/2021] [Accepted: 06/18/2021] [Indexed: 12/26/2022]
Abstract
The WAG/Rij strain of rats is commonly used as a preclinical model of genetic absence epilepsy. While widely utilized, the developmental trajectory of absence seizure expression has been only partially described. Moreover, sex differences in this strain have been under-explored. Here, we longitudinally monitored male and female WAG/Rij rats to quantify cortical spike-and-wave discharges (SWDs) monthly, from 4 to 10 months of age. In both male and female WAG/Rij rats, absence seizure susceptibility increased with age. In contrast to previous reports, we found a robust and consistent increase in absence epilepsy susceptibility in male WAG/Rij rats in comparison to females across months. The increased absence seizure susceptibility was characterized by increased number and duration of SWDs, and consequently increased total SWDs duration. These findings highlight a previously un-recognized sex difference in a model of absence epilepsy and narrow the knowledge gap of age-dependent expression of SWDs in the WAG/Rij strain.
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17
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Videira G, Gabriel D, Freitas J, Samões R, Chorão R, Lopes J, Ramalheira J, Lemos C, Leal B, da Silva AM, Chaves J. Female preponderance in genetic generalized epilepsies. Seizure 2021; 91:167-171. [PMID: 34171625 DOI: 10.1016/j.seizure.2021.06.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/26/2021] [Accepted: 06/10/2021] [Indexed: 10/21/2022] Open
Abstract
INTRODUCTION Epilepsy is more prevalent in men but Genetic Generalized Epilepsies (GGE) seem to be more common in women. A predominant maternal inheritance has been previously described in GGE. Our objective was to determine sex and inheritance patterns in a GGE population compared to mesial temporal lobe epilepsy with hippocampal sclerosis (MTLEHS). METHODS We performed a prospective observational study including adult GGE and MTLEHS patients followed up at a tertiary epilepsy center from January 2016 to December 2019. Patients' familial history was obtained by a detailed questionnaire. Clinical and demographic data was retrieved from clinical notes. RESULTS A cohort of 641 patients, 403 with GGE and 238 with MTLEHS, was analyzed. GGE was more common in women than MTLEHS (58.8% vs 44.5%, OR=1.63, p = 0.004). Compared to MTLEHS patients, more GGE patients had familial history of epilepsy (45.4% vs 25.2%; p<0.001). The GGE group had a higher percentage of female relatives with epilepsy (55% vs 37%; p = 0.006). The prevalence of maternal inheritance was not different between GGE and MTLEHS groups (62.9% vs 57.7%; p = 0.596). Photosensitivity was more common in females than in males (44.7% vs 34.3%, p = 0.036). CONCLUSION There is a female preponderance in GGE when compared to MTLEHS, as both GGE patients and their affected relatives are more frequently women. The prevalence of maternal inheritance was not higher in GGE than in MTLEHS.
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Affiliation(s)
- Gonçalo Videira
- Neurology Department, Centro Hospitalar Universitário do Porto, Portugal.
| | - Denis Gabriel
- Neurology Department, Centro Hospitalar Universitário do Porto, Portugal
| | - Joel Freitas
- Neurophysiology Department, Centro Hospitalar Universitário do Porto, Portugal
| | - Raquel Samões
- Neurology Department, Centro Hospitalar Universitário do Porto, Portugal
| | - Rui Chorão
- Neurophysiology Department, Centro Hospitalar Universitário do Porto, Portugal
| | - João Lopes
- Neurophysiology Department, Centro Hospitalar Universitário do Porto, Portugal
| | - João Ramalheira
- Neurophysiology Department, Centro Hospitalar Universitário do Porto, Portugal
| | - Carolina Lemos
- UnIGENe, IBMC - Institute for Molecular and Cell Biology, i3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Portugal; Abel Salazar Biomedical Sciences Institute, University of Porto, Portugal
| | - Bárbara Leal
- Immunogenetics Laboratory, Pathology and Molecular Immunology Department, Abel Salazar Biomedical Sciences Institute, University of Porto, Portugal; Biomedical Investigation Multidisciplinary Unit, Abel Salazar Biomedical Sciences Institute, University of Porto, Portugal
| | - António Martins da Silva
- Neurophysiology Department, Centro Hospitalar Universitário do Porto, Portugal; Biomedical Investigation Multidisciplinary Unit, Abel Salazar Biomedical Sciences Institute, University of Porto, Portugal
| | - João Chaves
- Neurology Department, Centro Hospitalar Universitário do Porto, Portugal; Biomedical Investigation Multidisciplinary Unit, Abel Salazar Biomedical Sciences Institute, University of Porto, Portugal
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Reddy DS, Thompson W, Calderara G. Molecular mechanisms of sex differences in epilepsy and seizure susceptibility in chemical, genetic and acquired epileptogenesis. Neurosci Lett 2021; 750:135753. [PMID: 33610673 PMCID: PMC7994197 DOI: 10.1016/j.neulet.2021.135753] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 02/03/2021] [Accepted: 02/14/2021] [Indexed: 02/07/2023]
Abstract
This article provides a succinct overview of sex differences in epilepsy and putative molecular mechanisms underlying sex differences in seizure susceptibility in chemical, genetic, and acquired epileptogenesis. The susceptibility to excitability episodes and occurrence of epileptic seizures are generally higher in men than women. The precise molecular mechanisms remain unclear, but differences in regional morphology and neural circuits in men and women may explain differential vulnerability to seizures and epileptogenic cascades. Changes in seizure sensitivity can be attributed to steroid hormones, including fluctuations in neurosteroids as well as neuroplasticity in their receptor signaling systems. Other potential neurobiological bases for sex differences in epilepsies include differences in brain development, neurogenesis, neuronal chloride homeostasis, and neurotrophic and glial responses. In catamenial epilepsy, a gender-specific neuroendocrine condition, epileptic seizures are most often clustered around a specific menstrual period in adult women. A deeper understanding of the molecular and neural network basis of sex differences in seizures and response to antiepileptic drugs is highly warranted for designing effective, sex-specific therapies for epilepsy, epileptogenesis, and seizure disorders.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University College of Medicine, Bryan, TX, United States.
| | - Wesley Thompson
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University College of Medicine, Bryan, TX, United States
| | - Gianmarco Calderara
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University College of Medicine, Bryan, TX, United States
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19
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Serotonin Pretreatment Abolishes Sex-specific NMDA-induced Seizure Behavior in Developing Rats. Neuroscience 2021; 463:184-196. [PMID: 33838289 DOI: 10.1016/j.neuroscience.2021.03.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 11/24/2022]
Abstract
Neuronal excitability and susceptibility to excitotoxic damage can be sex-specific, with neurons from males usually being more 'easily excitable' compared to neurons from females, especially during development. Increased excitability at an individual neuronal level can lead to the formation of hyperexcitable neuronal networks, which, consequently can make the brain more seizure prone. Both animal and clinical data suggest that males experience more frequent and severe seizures than do females. Serotonin (5-hydroxytryptamine; 5-HT) can mediate neuronal excitability and seizure behavior, often serving as an anticonvulsant. Importantly, 5-HT signaling during parts of the perinatal period is sexually dimorphic. Sex differences during development have been reported in both serotonin levels and receptor type (excitatory vs. inhibitory) expression in a manner that may leave the male brain more vulnerable to over-excitation. Thus, we aimed to determine if the anticonvulsant effects of 5-HT were sex- and/or age-dependent in juvenile animals. We report a baseline sex difference in N-methyl-d-aspartate (NMDA)-induced seizure behavior and hippocampal neuronal loss, with postnatal day (PND) 14 males exhibiting more severe seizure behavior compared to females. Pretreatment with the general 5-HT receptor agonist 5-methoxytryptamine (5-MT) abolishes baseline sex differences, providing an anticonvulsant effect for males only. These sex differences appear to be at least in part organized by testosterone, as females given neonatal androgen exhibit a seizure behavior profile in between that of males and females.
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20
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Christian CA, Reddy DS, Maguire J, Forcelli PA. Sex Differences in the Epilepsies and Associated Comorbidities: Implications for Use and Development of Pharmacotherapies. Pharmacol Rev 2021; 72:767-800. [PMID: 32817274 DOI: 10.1124/pr.119.017392] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The epilepsies are common neurologic disorders characterized by spontaneous recurrent seizures. Boys, girls, men, and women of all ages are affected by epilepsy and, in many cases, by associated comorbidities as well. The primary courses of treatment are pharmacological, dietary, and/or surgical, depending on several factors, including the areas of the brain affected and the severity of the epilepsy. There is a growing appreciation that sex differences in underlying brain function and in the neurobiology of epilepsy are important factors that should be accounted for in the design and development of new therapies. In this review, we discuss the current knowledge on sex differences in epilepsy and associated comorbidities, with emphasis on those aspects most informative for the development of new pharmacotherapies. Particular focus is placed on sex differences in the prevalence and presentation of various focal and generalized epilepsies; psychiatric, cognitive, and physiologic comorbidities; catamenial epilepsy in women; sex differences in brain development; the neural actions of sex and stress hormones and their metabolites; and cellular mechanisms, including brain-derived neurotrophic factor signaling and neuronal-glial interactions. Further attention placed on potential sex differences in epilepsies, comorbidities, and drug effects will enhance therapeutic options and efficacy for all patients with epilepsy. SIGNIFICANCE STATEMENT: Epilepsy is a common neurological disorder that often presents together with various comorbidities. The features of epilepsy and seizure activity as well as comorbid afflictions can vary between men and women. In this review, we discuss sex differences in types of epilepsies, associated comorbidities, pathophysiological mechanisms, and antiepileptic drug efficacy in both clinical patient populations and preclinical animal models.
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Affiliation(s)
- Catherine A Christian
- Department of Molecular and Integrative Physiology, Neuroscience Program, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois (C.A.C.); Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas (D.S.R.); Neuroscience Department, Tufts University School of Medicine, Boston, Massachusetts (J.M.); and Departments of Pharmacology and Physiology and Neuroscience, Georgetown University, Washington, D.C. (P.A.F.)
| | - Doodipala Samba Reddy
- Department of Molecular and Integrative Physiology, Neuroscience Program, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois (C.A.C.); Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas (D.S.R.); Neuroscience Department, Tufts University School of Medicine, Boston, Massachusetts (J.M.); and Departments of Pharmacology and Physiology and Neuroscience, Georgetown University, Washington, D.C. (P.A.F.)
| | - Jamie Maguire
- Department of Molecular and Integrative Physiology, Neuroscience Program, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois (C.A.C.); Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas (D.S.R.); Neuroscience Department, Tufts University School of Medicine, Boston, Massachusetts (J.M.); and Departments of Pharmacology and Physiology and Neuroscience, Georgetown University, Washington, D.C. (P.A.F.)
| | - Patrick A Forcelli
- Department of Molecular and Integrative Physiology, Neuroscience Program, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois (C.A.C.); Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas (D.S.R.); Neuroscience Department, Tufts University School of Medicine, Boston, Massachusetts (J.M.); and Departments of Pharmacology and Physiology and Neuroscience, Georgetown University, Washington, D.C. (P.A.F.)
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Hanci F, Türay S, Balci P, Kabakuş N. Reflex Epilepsy with Hot Water: Clinical and EEG Findings, Treatment, and Prognosis in Childhood. Neuropediatrics 2020; 51:336-340. [PMID: 32294767 DOI: 10.1055/s-0040-1709455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Hot water epilepsy (HWE) is a subtype of reflex epilepsy in which seizures are triggered by the head being immersed in hot water. Hot water or bathing epilepsy is the type of reflex epilepsy most frequently encountered in our clinic. We describe our patients with HWE and also discuss the clinical features, therapeutic approaches, and prognosis. Eleven patients (10 boys, 1 girl), aged 12 months to 13 years, admitted to the pediatric neurology clinic between January 2018 and August 2019, and diagnosed with HWE or bathing epilepsy based on International League Against Epilepsy (ILAE)-2017, were followed up prospectively for ∼18 months. Patients' clinical and electroencephalography (EEG) findings and treatment details were noted. All 11 patients' seizures were triggered by hot water. Age at first seizure was between 2 months and 12 years. Seizure types were generalized motor seizures, absence, and atonic. EEG was normal in two patients, but nine patients had epileptiform discharges. Magnetic resonance imaging of the brain was performed and reported as normal (except in one case). Histories of prematurity were present in two patients, unprovoked seizures in one, and low birth weight and depressed birth in the other. Patients with HWE have normal neuromuscular development and neurological examination results, together with prophylaxis or seizure control with a single antiepileptic drug, suggesting that it is a self-limited reflex epilepsy.
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Affiliation(s)
- Fatma Hanci
- Division of Child Neurology, Department of Pediatrics, Abant İzzet Baysal University, Bolu, Turkey
| | - Sevim Türay
- Division of Child Neurology, Department of Pediatrics, Düzce University, Düzce, Turkey
| | - Paşa Balci
- Department of Pediatrics, Abant İzzet Baysal University, Bolu, Turkey
| | - Nimet Kabakuş
- Division of Child Neurology, Department of Pediatrics, Abant İzzet Baysal University, Bolu, Turkey
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22
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Cho SJ, Park E, Baker A, Reid AY. Age Bias in Zebrafish Models of Epilepsy: What Can We Learn From Old Fish? Front Cell Dev Biol 2020; 8:573303. [PMID: 33015065 PMCID: PMC7511771 DOI: 10.3389/fcell.2020.573303] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022] Open
Abstract
Zebrafish are a powerful tool for investigating epilepsy. Mammalian seizures can be recapitulated molecularly, behaviorally, and electrophysiologically, using a fraction of the resources required for experiments in mammals. Larval zebrafish offer exceptionally economical and high-throughput approaches and are amenable to state-of-the-art genetic engineering techniques, providing valuable transgenic models of human diseases. For these reasons, larvae tend to be chosen for studying epilepsy, but the value of adult zebrafish may be underappreciated. Zebrafish exhibit transient larval - adult duality. The incompletely developed neural system of larval zebrafish may limit the translation of complex neurological disorders. Larval zebrafish go through dynamic changes during ontogenesis, whereas adult zebrafish are physiologically more stable. Adult zebrafish have a full range of complex brain structures and functions, such as an endothelial blood-brain barrier and adult neurogenesis, both are significant factors in epilepsy research. This review highlights the differences between larval and adult zebrafish that should be considered in pathophysiological and pharmacological studies of epilepsy.
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Affiliation(s)
- Sung-Joon Cho
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Collaborative Program in Neuroscience, University of Toronto, Toronto, ON, Canada
- Keenan Research Center, St. Michael’s Hospital, Li Ka Shing Knowledge Institute, Toronto, ON, Canada
| | - Eugene Park
- Keenan Research Center, St. Michael’s Hospital, Li Ka Shing Knowledge Institute, Toronto, ON, Canada
| | - Andrew Baker
- Keenan Research Center, St. Michael’s Hospital, Li Ka Shing Knowledge Institute, Toronto, ON, Canada
- Department of Anesthesia and Surgery, University of Toronto, Toronto, ON, Canada
| | - Aylin Y. Reid
- Division of Fundamental Neurobiology, Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
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23
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Ahmed Juvale II, Che Has AT. The evolution of the pilocarpine animal model of status epilepticus. Heliyon 2020; 6:e04557. [PMID: 32775726 PMCID: PMC7393986 DOI: 10.1016/j.heliyon.2020.e04557] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/05/2020] [Accepted: 07/22/2020] [Indexed: 02/02/2023] Open
Abstract
The pilocarpine animal model of status epilepticus is a well-established, clinically translatable model that satisfies all of the criteria essential for an animal model of status epilepticus: a latency period followed by spontaneous recurrent seizures, replication of behavioural, electrographic, metabolic, and neuropathological changes, as well as, pharmacoresistance to anti-epileptic drugs similar to that observed in human status epilepticus. However, this model is also characterized by high mortality rates and studies in recent years have also seen difficulties in seizure induction due to pilocarpine resistant animals. This can be attributed to differences in rodent strains, species, gender, and the presence of the multi-transporter, P-glycoprotein at the blood brain barrier. The current paper highlights the various alterations made to the original pilocarpine model over the years to combat both the high mortality and low induction rates. These range from the initial lithium-pilocarpine model to the more recent Reduced Intensity Status Epilepticus (RISE) model, which finally brought the mortality rates down to 1%. These modifications are essential to improve animal welfare and future experimental outcomes.
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Affiliation(s)
- Iman Imtiyaz Ahmed Juvale
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Ahmad Tarmizi Che Has
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia
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Deng XL, Feng L, Wang ZX, Zhao YE, Zhan Q, Wu XM, Xiao B, Shu Y. The Runx1/Notch1 Signaling Pathway Participates in M1/M2 Microglia Polarization in a Mouse Model of Temporal Lobe Epilepsy and in BV-2 Cells. Neurochem Res 2020; 45:2204-2216. [PMID: 32632543 DOI: 10.1007/s11064-020-03082-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 06/03/2020] [Accepted: 07/01/2020] [Indexed: 12/14/2022]
Abstract
Microglial activation and phenotypic shift play vital roles in many neurological diseases. Runt-related transcription factor-1 (Runx1), which is localized on microglia, inhibits amoeboid microglial proliferation. Preliminary data have indicated that the interaction of Runx1 with the Notch1 pathway affects the hemogenic endothelial cell shift. However, little is known about the effect of Runx1 and the Notch1 signaling pathway on the phenotypic shift of microglia during neuroinflammation, especially in temporal lobe epilepsy (TLE). A mouse model of TLE induced by pilocarpine and the murine microglia cell line BV-2 were used in this study. The proportion of microglia was analyzed using flow cytometry. Western blot (WB) analysis and quantitative real-time polymerase chain reaction were used to analyze protein and gene transcript levels, respectively. Immunohistochemistry was used to show the distribution of Runx1. In the present study, we first found that in a male mouse model of TLE induced by pilocarpine, flow cytometry revealed a time-dependent M2-to-M1 microglial transition after status epilepticus. The dynamic expression patterns of Runx1 and the downstream Notch1/Jagged1/Hes5 signaling pathway molecules in the epileptic hippocampus were determined. Next, Runx1 knockdown by small interfering RNA in BV-2 cells strongly promoted an M2-to-M1 microglial phenotype shift and inhibited Notch1/Jagged1/Hes5 pathway expression. In conclusion, Runx1 may play a critical role in the M2-to-M1 microglial phenotype shift via the Notch1 signaling pathway during epileptogenesis in a TLE mouse model and in BV-2 cells.
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Affiliation(s)
- Xian-Lian Deng
- Department of Neurology, Xiangya Hospital, Central South University, 87 Xiang Ya Road, Changsha, 410008, Hunan, China
| | - Li Feng
- Department of Neurology, Xiangya Hospital, Central South University, 87 Xiang Ya Road, Changsha, 410008, Hunan, China
| | - Zi-Xin Wang
- Department of Neurology, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China
| | - Yue-E Zhao
- Department of Neurology, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China
| | - Qiong Zhan
- Department of Neurology, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China
| | - Xiao-Mei Wu
- Department of Neurology, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, 87 Xiang Ya Road, Changsha, 410008, Hunan, China.
| | - Yi Shu
- Department of Neurology, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China.
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Suzuki T, Kidokoro H, Kubota T, Fukasawa T, Suzui R, Tsuji T, Kato T, Yamamoto H, Ohno A, Nakata T, Saitoh S, Okumura A, Natsume J. Transient cortical diffusion restriction in children immediately after prolonged febrile seizures. Eur J Paediatr Neurol 2020; 27:30-36. [PMID: 32473849 DOI: 10.1016/j.ejpn.2020.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/29/2020] [Accepted: 05/10/2020] [Indexed: 11/18/2022]
Abstract
AIM Little is known about acute febrile status epilepticus-induced injury of extrahippocampal structures. To clarify the presence and clinical significance of acute extrahippocampal injuries, we performed diffusion-weighted imaging (DWI) in children immediately after prolonged febrile seizure (PFS). METHOD We performed a retrospective cohort study in children younger than 6 years old who visited one of two hospitals due to PFSs between January 2013 and October 2018. PFS was defined as a febrile seizure that persisted for 15 min or longer. We collected brain DWI data within 6 h of the end of PFS. When the initial DWI detected an abnormality, a follow-up DWI was performed a few days later. RESULTS The study population consisted of 101 patients with PFSs. DWI was performed within 6 h in 51 patients, while the remaining 50 patients did not undergo imaging because of good recovery of consciousness. Restricted cortical diffusion was evident in 9 (18%) patients on initial DWI. All of them underwent DWI within 100 min after PFS. Restricted cortical diffusion was associated with male sex, asymmetrical PFS symptoms, and a shorter duration between the end of the seizure and DWI, but was not associated with seizure duration. All cortical abnormalities had resolved on follow-up DWI of these patients within 72 h after the initial imaging, but ipsilateral hippocampal hyperintensity appeared in one patient. All 9 patients with restricted cortical diffusion were finally diagnosed with PFS and discharged without sequelae. CONCLUSIONS Some children with PFSs exhibit transient restricted diffusion in the regional cortex on DWI performed immediately after the end of PFS. These transient diffusion changes were not associated with unfavorable epileptic sequelae or neuroimaging in the short-term.
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Affiliation(s)
- Takeshi Suzuki
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan; Department of Pediatrics, Anjo Kosei Hospital, Anjo, Japan
| | - Hiroyuki Kidokoro
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Tetsuo Kubota
- Department of Pediatrics, Anjo Kosei Hospital, Anjo, Japan
| | | | - Ryosuke Suzui
- Department of Pediatrics, Okazaki City Hospital, Okazaki, Japan
| | - Takeshi Tsuji
- Department of Pediatrics, Okazaki City Hospital, Okazaki, Japan
| | - Toru Kato
- Department of Pediatrics, Okazaki City Hospital, Okazaki, Japan
| | - Hiroyuki Yamamoto
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsuko Ohno
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tomohiko Nakata
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medicinal Sciences, Nagoya, Japan
| | - Akihisa Okumura
- Department of Pediatrics, Aichi Medical University, Nagakute, Japan
| | - Jun Natsume
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
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26
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Armas-Capote N, Maglio LE, Pérez-Atencio L, Martin-Batista E, Reboreda A, Barios JA, Hernandez G, Alvarez de la Rosa D, Lamas JA, Barrio LC, Giraldez T. SGK1.1 Reduces Kainic Acid-Induced Seizure Severity and Leads to Rapid Termination of Seizures. Cereb Cortex 2019; 30:3184-3197. [DOI: 10.1093/cercor/bhz302] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 10/19/2019] [Accepted: 11/08/2019] [Indexed: 12/17/2022] Open
Abstract
Abstract
Approaches to control epilepsy, one of the most important idiopathic brain disorders, are of great importance for public health. We have previously shown that in sympathetic neurons the neuronal isoform of the serum and glucocorticoid-regulated kinase (SGK1.1) increases the M-current, a well-known target for seizure control. The effect of SGK1.1 activation on kainate-induced seizures and neuronal excitability was studied in transgenic mice that express a permanently active form of the kinase, using electroencephalogram recordings and electrophysiological measurements in hippocampal brain slices. Our results demonstrate that SGK1.1 activation leads to reduced seizure severity and lower mortality rates following status epilepticus, in an M-current–dependent manner. EEG is characterized by reduced number, shorter duration, and early termination of kainate-induced seizures in the hippocampus and cortex. Hippocampal neurons show decreased excitability associated to increased M-current, without altering basal synaptic transmission or other neuronal properties. Altogether, our results reveal a novel and selective anticonvulsant pathway that promptly terminates seizures, suggesting that SGK1.1 activation can be a potent factor to secure the brain against permanent neuronal damage associated to epilepsy.
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Affiliation(s)
- Natalia Armas-Capote
- Departamento de Ciencias Medicas Basicas-Fisiologia and Instituto de Tecnologías Biomedicas (ITB), Universidad de La Laguna, Tenerife, 38071 Spain
| | - Laura E Maglio
- Departamento de Ciencias Medicas Basicas-Fisiologia and Instituto de Tecnologías Biomedicas (ITB), Universidad de La Laguna, Tenerife, 38071 Spain
| | - Leonel Pérez-Atencio
- Unidad de Neurologia Experimental, Hospital Ramon y Cajal-IRYCIS, Madrid, 28034 Spain
| | - Elva Martin-Batista
- Departamento de Ciencias Medicas Basicas-Fisiologia and Instituto de Tecnologías Biomedicas (ITB), Universidad de La Laguna, Tenerife, 38071 Spain
| | - Antonio Reboreda
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Vigo, 36310 Spain
| | - Juan A Barios
- Systems Engineering and Automation Department, Miguel Hernandez University, Elche, 03202 Spain
| | - Guadalberto Hernandez
- Departamento de Ciencias Medicas Basicas-Fisiologia and Instituto de Tecnologías Biomedicas (ITB), Universidad de La Laguna, Tenerife, 38071 Spain
| | - Diego Alvarez de la Rosa
- Departamento de Ciencias Medicas Basicas-Fisiologia and Instituto de Tecnologías Biomedicas (ITB), Universidad de La Laguna, Tenerife, 38071 Spain
| | - José Antonio Lamas
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Vigo, 36310 Spain
| | - Luis C Barrio
- Unidad de Neurologia Experimental, Hospital Ramon y Cajal-IRYCIS, Madrid, 28034 Spain
| | - Teresa Giraldez
- Departamento de Ciencias Medicas Basicas-Fisiologia and Instituto de Tecnologías Biomedicas (ITB), Universidad de La Laguna, Tenerife, 38071 Spain
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27
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Dreier JW, Li J, Sun Y, Christensen J. Evaluation of Long-term Risk of Epilepsy, Psychiatric Disorders, and Mortality Among Children With Recurrent Febrile Seizures: A National Cohort Study in Denmark. JAMA Pediatr 2019; 173:1164-1170. [PMID: 31589251 PMCID: PMC6784760 DOI: 10.1001/jamapediatrics.2019.3343] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Febrile seizures occur in 2% to 5% of children between the ages of 3 months and 5 years. Many affected children experience recurrent febrile seizures. However, little is known about the association between recurrent febrile seizures and subsequent prognosis. OBJECTIVE To estimate the risk of recurrent febrile seizures and whether there is an association over long-term follow-up between recurrent febrile seizures and epilepsy, psychiatric disorders, and death in a large, nationwide, population-based cohort in Denmark. DESIGN, SETTING, AND PARTICIPANTS This population-based cohort study evaluated data from all singleton children born in Denmark between January 1, 1977, and December 31, 2011, who were identified through the Danish Civil Registration System. Children born in Denmark who were alive and residing in Denmark at age 3 months were included (N = 2 103 232). The study was conducted from September 1, 2017, to June 1, 2019. EXPOSURES Hospital contacts with children who developed febrile seizures between age 3 months and 5 years. MAIN OUTCOMES AND MEASURES Children diagnosed with epilepsy were identified in the Danish National Patient Register and children diagnosed with psychiatric disorders were identified in the Psychiatric Central Research Register. Competing risk regression and Cox proportional hazards regression were used to estimate the cumulative and relative risk of febrile seizures, recurrent febrile seizures, epilepsy, psychiatric disorders, and death. RESULTS Of the 2 103 232 children (1 024 049 [48.7%] girls) in the study population, a total of 75 593 children (3.6%) were diagnosed with a first febrile seizure between 1977 and 2016. Febrile seizures were more common in boys (3.9%; 95% CI, 3.9%-4.0%) than in girls (3.3%; 95% CI, 3.2%-3.3%), corresponding to a 21% relative risk difference (hazard ratio, 1.21; 95% CI, 1.19-1.22). However, the risks of recurrent febrile seizures, epilepsy, psychiatric disorders, and death were similar in boys and girls. The risk of (recurrent) febrile seizures increased with the number of febrile seizures: 3.6% at birth, 22.7% (95% CI, 22.4%-23.0%) after the first febrile seizure, 35.6% (95% CI, (34.9%-36.3%) after the second febrile seizure, and 43.5% (95% CI, (42.3%-44.7%) after the third febrile seizure. The risk of epilepsy increased progressively with the number of hospital admissions with febrile seizures. The 30-year cumulative risk of epilepsy was 2.2% (95% CI, (2.1%-2.2%) at birth compared with 15.8% (95% CI, 14.6%-16.9%) after the third febrile seizure, while the corresponding estimates for risk of psychiatric disorders were 17.2% (95% CI, 17.2%-17.3%) at birth and 29.1% (95% CI, 27.2%-31.0%) after the third febrile seizure. Mortality was increased among children with recurrent febrile seizures (1.0%; 95% CI, 0.9%-1.0% at birth vs 1.9%; 95% CI, 1.4%-2.7% after the third febrile seizure), although this risk was associated primarily with children who later developed epilepsy. CONCLUSIONS AND RELEVANCE A history of recurrent febrile seizures appears to be associated with a risk of epilepsy and psychiatric disorders, but increased mortality was found only in individuals who later developed epilepsy.
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Affiliation(s)
- Julie Werenberg Dreier
- National Centre for Register-Based Research, Department of Economics and Business Economics, Aarhus University, Aarhus, Denmark,Centre for Integrated Register-Based Research, Centre for Integrated Register-Based Research, Aarhus University, Aarhus University, Aarhus, Denmark
| | - Jiong Li
- Department of Clinical Epidemiology, Aarhus University, Aarhus, Denmark
| | - Yuelian Sun
- National Centre for Register-Based Research, Department of Economics and Business Economics, Aarhus University, Aarhus, Denmark,Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Jakob Christensen
- National Centre for Register-Based Research, Department of Economics and Business Economics, Aarhus University, Aarhus, Denmark,Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
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28
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Yue Z, Freedman IG, Vincent P, Andrews JP, Micek C, Aksen M, Martin R, Zuckerman D, Perrenoud Q, Neske GT, Sieu LA, Bo X, Cardin JA, Blumenfeld H. Up and Down States of Cortical Neurons in Focal Limbic Seizures. Cereb Cortex 2019; 30:3074-3086. [PMID: 31800015 DOI: 10.1093/cercor/bhz295] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 08/18/2019] [Accepted: 08/20/2019] [Indexed: 12/31/2022] Open
Abstract
Recent work suggests an important role for cortical-subcortical networks in seizure-related loss of consciousness. Temporal lobe seizures disrupt subcortical arousal systems, which may lead to depressed cortical function and loss of consciousness. Extracellular recordings show ictal neocortical slow waves at about 1 Hz, but it is not known whether these simply represent seizure propagation or alternatively deep sleep-like activity, which should include cortical neuronal Up and Down states. In this study, using in vivo whole-cell recordings in a rat model of focal limbic seizures, we directly examine the electrophysiological properties of cortical neurons during seizures and deep anesthesia. We found that during seizures, the membrane potential of frontal cortical secondary motor cortex layer 5 neurons fluctuates between Up and Down states, with decreased input resistance and increased firing rate in Up states when compared to Down states. Importantly, Up and Down states in seizures are not significantly different from those in deep anesthesia, in terms of membrane potential, oscillation frequency, firing rate, and input resistance. By demonstrating these fundamental similarities in cortical electrophysiology between deep anesthesia and seizures, our results support the idea that a state of decreased cortical arousal may contribute to mechanisms of loss of consciousness during seizures.
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Affiliation(s)
- Zongwei Yue
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.,Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, China
| | - Isaac G Freedman
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Peter Vincent
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - John P Andrews
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Christopher Micek
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Mark Aksen
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Reese Martin
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - David Zuckerman
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Quentin Perrenoud
- Department of Neuroscience Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Garrett T Neske
- Department of Neuroscience Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Lim-Anna Sieu
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Xiao Bo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Jessica A Cardin
- Department of Neuroscience Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Hal Blumenfeld
- Department of Neurology Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.,Department of Neuroscience Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.,Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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29
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Forsgård JA, Metsähonkala L, Kiviranta AM, Cizinauskas S, Junnila JJT, Laitinen-Vapaavuori O, Jokinen TS. Seizure-precipitating factors in dogs with idiopathic epilepsy. J Vet Intern Med 2018; 33:701-707. [PMID: 30576009 PMCID: PMC6430923 DOI: 10.1111/jvim.15402] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 11/21/2018] [Indexed: 02/03/2023] Open
Abstract
Background Stress, sleep deprivation, and infectious diseases are important seizure‐precipitating factors in human epilepsy patients. However, these factors have not been thoroughly studied in epileptic dogs. Objective Seizure‐precipitating factors are common in dogs with idiopathic epilepsy and the occurrence of these factors associate with the dogs' signalment, personality, and epilepsy‐related factors. Animals Fifty dogs with diagnosed idiopathic epilepsy from the hospital populations of University Veterinary Teaching Hospital of University of Helsinki and Referral Animal Hospital Aisti. Methods In a retrospective cross‐sectional observational study, owners were interviewed about their dogs' possible seizure‐precipitating factors according to a predefined questionnaire. The dogs were identified and selected by searching the medical records of the participating animal hospitals. Results The prevalence of seizure‐precipitating factors in the study population was 74% (37/50). The most frequently reported factors included stress‐related situations, sleep deprivation, weather, and hormonal factors. In dogs with focal onset seizures, the number of precipitating factors was 1.9 (95% CI 1.1‐3.4) times higher compared to dogs with generalized seizures. Conclusions and Clinical Importance Seizure‐precipitating factors are common in dogs with idiopathic epilepsy, and the nature of these factors is consistent with those of human patients. Aside from antiepileptic medication, acknowledging and avoiding seizure‐precipitating factors could help veterinarians achieve better treatment outcomes.
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Affiliation(s)
- Johanna A Forsgård
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Liisa Metsähonkala
- Pediatric Neurologist, Hospital of Children and Adolescents, Helsinki University Central Hospital, Helsinki, Finland
| | - Anna-Mariam Kiviranta
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | | | | | - Outi Laitinen-Vapaavuori
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Tarja S Jokinen
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
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30
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Andrews JP, Yue Z, Ryu JH, Neske G, McCormick DA, Blumenfeld H. Mechanisms of decreased cholinergic arousal in focal seizures: In vivo whole-cell recordings from the pedunculopontine tegmental nucleus. Exp Neurol 2018; 314:74-81. [PMID: 30543800 DOI: 10.1016/j.expneurol.2018.11.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/04/2018] [Accepted: 11/29/2018] [Indexed: 10/27/2022]
Abstract
Focal limbic seizures often impair consciousness/awareness with major negative impact on quality of life. Recent work has shown that limbic seizures depress brainstem arousal systems, including reduced action potential firing in a key node: cholinergic neurons of the pedunculopontine tegmental nucleus (PPT). In vivo whole-cell recordings have not previously been achieved in PPT, but are used here with the goal of elucidating the mechanisms of reduced PPT cholinergic neuronal activity. An established model of focal limbic seizures was used in rats following brief hippocampal stimulation under light anesthesia. Whole-cell in vivo recordings were obtained from PPT neurons using custom-fabricated 9-10 mm tapered patch pipettes, and cholinergic neurons were identified histologically. Average membrane potential, input resistance, membrane potential fluctuations and variance were analyzed during seizures. A subset of PPT neurons exhibited reduced firing and hyperpolarization during seizures and stained positive for choline acetyltransferase. These PPT neurons showed a mean membrane potential hyperpolarization of -3.82 mV (±0.81 SEM, P < .05) during seizures, and also showed significantly increased input resistance, fewer excitatory post-synaptic potential (EPSP)-like events (P < .05), and reduced membrane potential variance (P < .01). The combination of increased input resistance, decreased EPSP-like events and decreased variance weigh against active ictal inhibition and support withdrawal of excitatory input as the dominant mechanism of decreased activity of cholinergic neurons in the PPT. Further identifying synaptic mechanisms of depressed arousal during seizures may lead to new treatments to improve ictal and postictal cognition.
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Affiliation(s)
- John P Andrews
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Zongwei Yue
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Jun Hwan Ryu
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Garrett Neske
- Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - David A McCormick
- Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Hal Blumenfeld
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
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31
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Santos VR, Kobayashi I, Hammack R, Danko G, Forcelli PA. Impact of strain, sex, and estrous cycle on gamma butyrolactone-evoked absence seizures in rats. Epilepsy Res 2018; 147:62-70. [PMID: 30261353 PMCID: PMC6226012 DOI: 10.1016/j.eplepsyres.2018.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/03/2018] [Accepted: 09/15/2018] [Indexed: 12/19/2022]
Abstract
Childhood absence epilepsy (CAE) is the most common pediatric epilepsy syndrome and is characterized by typical absence seizures (AS). AS are non-convulsive epileptic seizures characterized by a sudden loss of awareness and bilaterally generalized synchronous 2.5-4 Hz spike and slow-wave discharges (SWD). Gamma butyrolactone (GBL) is an acute pharmacological model of AS and induces bilaterally synchronous SWDs and behavioral arrest. Despite the long use of this model, little is known about its strain and sex-dependent features. We compared the dose-response profile of GBL-evoked SWDs in three rat strains (Long Evans, Sprague-Dawley, and Wistar), and examined the modulatory effects of estrous cycle on SWDs in female Wistar rats. We evaluated the number of seizures, the cumulative time seizing, and the average seizure duration as a function of dose, strain, and sex/estrous phase. Long Evans rats displayed the greatest sensitivity to GBL, followed by Wistar rats, and then by Sprague-Dawley rats. GBL-evoked SWDs were modulated by estrous cycle in female rats, with the lowest sensitivity to GBL occurring during metestrus. Wistar rats showed the greatest variability as a function of dose, and the least variability within dose; these features make this strain desirable for interventional studies. Moreover, our finding that the SWD response to GBL differs as a function of estrous cycle underscores the importance of cycle monitoring in studies examining female animals using this model. Together, these strain and sex-dependent findings provide guidance for future studies.
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Affiliation(s)
- Victor R Santos
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Ihori Kobayashi
- Department of Psychiatry and Behavioral Sciences, Howard University College of Medicine, United States
| | - Robert Hammack
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Gregory Danko
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Patrick A Forcelli
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States; Department of Neuroscience, Georgetown University School of Medicine, United States; Interdisciplinary Program in Neuroscience, Georgetown University School of Medicine, United States.
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32
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Neuropsychiatric Phenotypes Produced by GABA Reduction in Mouse Cortex and Hippocampus. Neuropsychopharmacology 2018; 43:1445-1456. [PMID: 29362511 PMCID: PMC5916365 DOI: 10.1038/npp.2017.296] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 10/25/2017] [Accepted: 11/24/2017] [Indexed: 01/09/2023]
Abstract
Whereas cortical GAD67 reduction and subsequent GABA level decrease are consistently observed in schizophrenia and depression, it remains unclear how these GABAergic abnormalities contribute to specific symptoms. We modeled cortical GAD67 reduction in mice, in which the Gad1 gene is genetically ablated from ~50% of cortical and hippocampal interneurons. Mutant mice showed a reduction of tissue GABA in the hippocampus and cortex including mPFC, and exhibited a cluster of effort-based behavior deficits including decreased home-cage wheel running and increased immobility in both tail suspension and forced swim tests. Since saccharine preference, progressive ratio responding to food, and learned helplessness task were normal, such avolition-like behavior could not be explained by anhedonia or behavioral despair. In line with the prevailing view that dopamine in anterior cingulate cortex (ACC) plays a role in evaluating effort cost for engaging in actions, we found that tail-suspension triggered dopamine release in ACC of controls, which was severely attenuated in the mutant mice. Conversely, ACC dopamine release by progressive ratio responding to reward, during which animals were allowed to effortlessly perform the nose-poking, was not affected in mutants. These results suggest that cortical GABA reduction preferentially impairs the effort-based behavior which requires much effort with little benefit, through a deficit of ACC dopamine release triggered by high-effort cost behavior, but not by reward-seeking behavior. Collectively, a subset of negative symptoms with a reduced willingness to expend costly effort, often observed in patients with schizophrenia and depression, may be attributed to cortical GABA level reduction.
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Savic I, Engel J. Reprint of "Structural and functional correlates of epileptogenesis--does gender matter?". Neurobiol Dis 2018; 72 Pt B:131-5. [PMID: 25448763 DOI: 10.1016/j.nbd.2014.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/15/2014] [Accepted: 05/22/2014] [Indexed: 11/30/2022] Open
Abstract
In the majority of neuropsychiatric conditions, marked gender-based differences have been found in the epidemiology,clinical manifestations, and therapy of disease. One possible reason is that sex differences in cerebral morphology, structural and functional connections, render men and women differentially vulnerable to various disease processes. The present review addresses this issue with respect to the functional and structural correlates to some forms of epilepsy.
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Feng L, Motelow JE, Ma C, Biche W, McCafferty C, Smith N, Liu M, Zhan Q, Jia R, Xiao B, Duque A, Blumenfeld H. Seizures and Sleep in the Thalamus: Focal Limbic Seizures Show Divergent Activity Patterns in Different Thalamic Nuclei. J Neurosci 2017; 37:11441-11454. [PMID: 29066556 PMCID: PMC5700426 DOI: 10.1523/jneurosci.1011-17.2017] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 10/09/2017] [Accepted: 10/14/2017] [Indexed: 01/12/2023] Open
Abstract
The thalamus plays diverse roles in cortical-subcortical brain activity patterns. Recent work suggests that focal temporal lobe seizures depress subcortical arousal systems and convert cortical activity into a pattern resembling slow-wave sleep. The potential simultaneous and paradoxical role of the thalamus in both limbic seizure propagation, and in sleep-like cortical rhythms has not been investigated. We recorded neuronal activity from the central lateral (CL), anterior (ANT), and ventral posteromedial (VPM) nuclei of the thalamus in an established female rat model of focal limbic seizures. We found that population firing of neurons in CL decreased during seizures while the cortex exhibited slow waves. In contrast, ANT showed a trend toward increased neuronal firing compatible with polyspike seizure discharges seen in the hippocampus. Meanwhile, VPM exhibited a remarkable increase in sleep spindles during focal seizures. Single-unit juxtacellular recordings from CL demonstrated reduced overall firing rates, but a switch in firing pattern from single spikes to burst firing during seizures. These findings suggest that different thalamic nuclei play very different roles in focal limbic seizures. While limbic nuclei, such as ANT, appear to participate directly in seizure propagation, arousal nuclei, such as CL, may contribute to depressed cortical function, whereas sleep spindles in relay nuclei, such as VPM, may interrupt thalamocortical information flow. These combined effects could be critical for controlling both seizure severity and impairment of consciousness. Further understanding of differential effects of seizures on different thalamocortical networks may lead to improved treatments directly targeting these modes of impaired function.SIGNIFICANCE STATEMENT Temporal lobe epilepsy has a major negative impact on quality of life. Previous work suggests that the thalamus plays a critical role in thalamocortical network modulation and subcortical arousal maintenance, but its precise seizure-associated functions are not known. We recorded neuronal activity in three different thalamic regions and found divergent activity patterns, which may respectively participate in seizure propagation, impaired level of conscious arousal, and altered relay of information to the cortex during focal limbic seizures. These very different activity patterns within the thalamus may help explain why focal temporal lobe seizures often disrupt widespread network function, and can help guide future treatments aimed at restoring normal thalamocortical network activity and cognition.
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Affiliation(s)
- Li Feng
- Departments of Neurology
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China, and
| | | | | | | | | | | | | | - Qiong Zhan
- Department of Neurology, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | | | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China, and
| | | | - Hal Blumenfeld
- Departments of Neurology,
- Neuroscience, and
- Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520
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Inhibition of IL-1β Signaling Normalizes NMDA-Dependent Neurotransmission and Reduces Seizure Susceptibility in a Mouse Model of Creutzfeldt-Jakob Disease. J Neurosci 2017; 37:10278-10289. [PMID: 28924012 DOI: 10.1523/jneurosci.1301-17.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/31/2017] [Accepted: 08/23/2017] [Indexed: 11/21/2022] Open
Abstract
Creutzfeldt-Jakob disease (CJD) is a neurodegenerative disorder caused by prion protein (PrP) misfolding, clinically recognized by cognitive and motor deficits, electroencephalographic abnormalities, and seizures. Its neurophysiological bases are not known. To assess the potential involvement of NMDA receptor (NMDAR) dysfunction, we analyzed NMDA-dependent synaptic plasticity in hippocampal slices from Tg(CJD) mice, which model a genetic form of CJD. Because PrP depletion may result in functional upregulation of NMDARs, we also analyzed PrP knock-out (KO) mice. Long-term potentiation (LTP) at the Schaffer collateral-commissural synapses in the CA1 area of ∼100-d-old Tg(CJD) mice was comparable to that of wild-type (WT) controls, but there was an inversion of metaplasticity, with increased GluN2B phosphorylation, which is indicative of enhanced NMDAR activation. Similar but less marked changes were seen in PrP KO mice. At ∼300 d of age, the magnitude of LTP increased in Tg(CJD) mice but decreased in PrP KO mice, indicating divergent changes in hippocampal synaptic responsiveness. Tg(CJD) but not PrP KO mice were intrinsically more susceptible than WT controls to focal hippocampal seizures induced by kainic acid. IL-1β-positive astrocytes increased in the Tg(CJD) hippocampus, and blocking IL-1 receptor signaling restored normal synaptic responses and reduced seizure susceptibility. These results indicate that alterations in NMDA-dependent glutamatergic transmission in Tg(CJD) mice do not depend solely on PrP functional loss. Moreover, astrocytic IL-1β plays a role in the enhanced synaptic responsiveness and seizure susceptibility, suggesting that targeting IL-1β signaling may offer a novel symptomatic treatment for CJD.SIGNIFICANCE STATEMENT Dementia and myoclonic jerks develop in individuals with Creutzfeldt-Jakob disease (CJD), an incurable brain disorder caused by alterations in prion protein structure. These individuals are prone to seizures and have high brain levels of the inflammatory cytokine IL-1β. Here we show that blocking IL-1β receptors with anakinra, the human recombinant form of the endogenous IL-1 receptor antagonist used to treat rheumatoid arthritis, normalizes hippocampal neurotransmission and reduces seizure susceptibility in a CJD mouse model. These results link neuroinflammation to defective neurotransmission and the enhanced susceptibility to seizures in CJD and raise the possibility that targeting IL-1β with clinically available drugs may be beneficial for symptomatic treatment of the disease.
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Löscher W, Ferland RJ, Ferraro TN. The relevance of inter- and intrastrain differences in mice and rats and their implications for models of seizures and epilepsy. Epilepsy Behav 2017; 73. [PMID: 28651171 PMCID: PMC5909069 DOI: 10.1016/j.yebeh.2017.05.040] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
It is becoming increasingly clear that the genetic background of mice and rats, even in inbred strains, can have a profound influence on measures of seizure susceptibility and epilepsy. These differences can be capitalized upon through genetic mapping studies to reveal genes important for seizures and epilepsy. However, strain background and particularly mixed genetic backgrounds of transgenic animals need careful consideration in both the selection of strains and in the interpretation of results and conclusions. For instance, mice with targeted deletions of genes involved in epilepsy can have profoundly disparate phenotypes depending on the background strain. In this review, we discuss findings related to how this genetic heterogeneity has and can be utilized in the epilepsy field to reveal novel insights into seizures and epilepsy. Moreover, we discuss how caution is needed in regards to rodent strain or even animal vendor choice, and how this can significantly influence seizure and epilepsy parameters in unexpected ways. This is particularly critical in decisions regarding the strain of choice used in generating mice with targeted deletions of genes. Finally, we discuss the role of environment (at vendor and/or laboratory) and epigenetic factors for inter- and intrastrain differences and how such differences can affect the expression of seizures and the animals' performance in behavioral tests that often accompany acute and chronic seizure testing.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
| | - Russell J Ferland
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Neurology, Albany Medical College, Albany, NY, United States
| | - Thomas N Ferraro
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, United States
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37
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Yang W, Westbroek EM, Anderson-Keightly H, Caplan JM, Rong X, Hung AL, Braileanu M, Wang JY, Colby GP, Coon AL, Tamargo RJ, Ahn ES, Huang J. Male Gender Associated with Post-Treatment Seizure Risk of Pediatric Arteriovenous Malformation Patients. Neurosurgery 2017; 80:899-907. [DOI: 10.1093/neuros/nyx018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/10/2017] [Indexed: 11/13/2022] Open
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Reddy DS. The neuroendocrine basis of sex differences in epilepsy. Pharmacol Biochem Behav 2016; 152:97-104. [PMID: 27424276 DOI: 10.1016/j.pbb.2016.07.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 06/25/2016] [Accepted: 07/12/2016] [Indexed: 01/22/2023]
Abstract
Epilepsy affects people of all ages and both genders. Sex differences are well known in epilepsy. Seizure susceptibility and the incidence of epilepsy are generally higher in men than women. In addition, there are gender-specific epilepsies such as catamenial epilepsy, a neuroendocrine condition in which seizures are most often clustered around the perimenstrual or periovulatory period in adult women with epilepsy. Changes in seizure sensitivity are also evident at puberty, pregnancy, and menopause. Sex differences in seizure susceptibility and resistance to antiseizure drugs can be studied in experimental models. An improved understanding of the neuroendocrine basis of sex differences or resistance to protective drugs is essential to develop targeted therapies for sex-specific seizure conditions. This article provides a brief overview of the current status of sex differences in seizure susceptibility and the potential mechanisms underlying the gender differences in seizure sensitivity.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA.
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Sato SM, Woolley CS. Acute inhibition of neurosteroid estrogen synthesis suppresses status epilepticus in an animal model. eLife 2016; 5. [PMID: 27083045 PMCID: PMC4862752 DOI: 10.7554/elife.12917] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 04/11/2016] [Indexed: 12/31/2022] Open
Abstract
Status epilepticus (SE) is a common neurological emergency for which new treatments are needed. In vitro studies suggest a novel approach to controlling seizures in SE: acute inhibition of estrogen synthesis in the brain. Here, we show in rats that systemic administration of an aromatase (estrogen synthase) inhibitor after seizure onset strongly suppresses both electrographic and behavioral seizures induced by kainic acid (KA). We found that KA-induced SE stimulates synthesis of estradiol (E2) in the hippocampus, a brain region commonly involved in seizures and where E2 is known to acutely promote neural activity. Hippocampal E2 levels were higher in rats experiencing more severe seizures. Consistent with a seizure-promoting effect of hippocampal estrogen synthesis, intra-hippocampal aromatase inhibition also suppressed seizures. These results reveal neurosteroid estrogen synthesis as a previously unknown factor in the escalation of seizures and suggest that acute administration of aromatase inhibitors may be an effective treatment for SE. DOI:http://dx.doi.org/10.7554/eLife.12917.001 Seizures occur when connected groups of cells in the brain become over-active and fire together. Current anti-seizure medications work by reducing brain activity generally. Although this is often effective in controlling seizures, it can also lead to negative side effects like drowsiness, dizziness or difficulty concentrating. A better alternative would be to target a factor that promotes activity especially during seizures. Most people think of estrogens as being female sex hormones. However, estrogens are also made in the brain of both sexes, where they could promote activity during seizures. Sato and Woolley therefore set out to test a two-part hypothesis: that seizures stimulate the production of estrogen in the brain, and that inhibiting this production process just as seizures begin would make seizures less severe. Sato and Woolley studied male and female rats and found that in both sexes, seizures stimulate the production of estrogens in the hippocampus – a part of the brain that is often involved in seizures. Because estrogens are known to increase the activity of cells in the hippocampus, this suggested that estrogens that are produced in the brain during seizures could make seizures worse. Sato and Woolley tested this by injecting rats with a drug that inhibits estrogen production, called an aromatase inhibitor, shortly after seizures began. The drug strongly suppressed seizures, whereas control rats that did not receive the injection continued to have seizures. Overall, Sato and Woolley show that the production of estrogen in the brain escalates seizure activity, and suggest that aromatase inhibitors may be useful for controlling seizures. Several questions remain that require further study. How does seizure activity lead to estrogen being made in the brain? How do estrogen levels go back down after a seizure? What circumstances other than seizures stimulate brain estrogen production, and what roles does this production process play in activity that is not related to seizures? DOI:http://dx.doi.org/10.7554/eLife.12917.002
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Affiliation(s)
- Satoru M Sato
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Catherine S Woolley
- Department of Neurobiology, Northwestern University, Evanston, United States
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40
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Twele F, Töllner K, Brandt C, Löscher W. Significant effects of sex, strain, and anesthesia in the intrahippocampal kainate mouse model of mesial temporal lobe epilepsy. Epilepsy Behav 2016; 55:47-56. [PMID: 26736063 DOI: 10.1016/j.yebeh.2015.11.027] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 11/24/2015] [Accepted: 11/24/2015] [Indexed: 01/12/2023]
Abstract
The intrahippocampal kainate mouse model of mesial temporal lobe epilepsy is increasingly being used for studies on epileptogenesis and antiepileptogenesis. Almost all previous studies used male mice for this purpose, and no study is available in this or other models of acquired epilepsy that directly compared epileptogenesis in female and male rodents. Epidemiological studies suggest that gender may affect susceptibility to epilepsy and its prognosis; therefore, one goal of this study was to investigate whether sex has an influence on latent period and epileptogenesis in the intrahippocampal kainate model in mice. Another aspect that was examined in the present study was whether mouse strain differences in epileptogenesis exist. Finally, we examined the effects of different types of anesthesia (chloral hydrate, isoflurane) on kainate-induced status epilepticus (SE) and epileptogenesis. Continuous (24/7) video-EEG monitoring was used during SE and the 2 weeks following SE as well as 4-6 weeks after SE. In male NMRI mice with chloral hydrate anesthesia during kainate injection, SE was followed by a seizure-free latent period of 10-14 days if hippocampal paroxysmal discharges (HPDs) recorded from the kainate focus were considered the onset of epilepsy. Anesthesia with isoflurane led to a more rapid onset and higher severity of SE, and not all male NMRI mice exhibited a seizure-free latent period. Female NMRI mice differed from male animals in the lack of any clear latent period, independently of anesthesia type. Furthermore, HPDs were only rarely observed. These problems were not resolved by decreasing the dose of kainate or using other strains (C57BL/6, FVB/N) of female mice. The present data are the first to demonstrate marked sex-related differences in the latent period following brain injury in a rodent model of acquired epilepsy. Furthermore, our data demonstrate that the choice of anesthestic agent during kainate administration affects SE severity and as a consequence, the latent period, which may explain some of the differences reported for this model in the literature.
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Affiliation(s)
- Friederike Twele
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Claudia Brandt
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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41
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Kourdougli N, Varpula S, Chazal G, Rivera C. Detrimental effect of post Status Epilepticus treatment with ROCK inhibitor Y-27632 in a pilocarpine model of temporal lobe epilepsy. Front Cell Neurosci 2015; 9:413. [PMID: 26557054 PMCID: PMC4615811 DOI: 10.3389/fncel.2015.00413] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 09/28/2015] [Indexed: 01/18/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is the most common type of epilepsy in adults where 20-30% of the patients are refractory to currently available anti-epileptic drugs. The RhoA/Rho-kinase signaling pathway activation has been involved in inflammatory responses, neurite outgrowth and neuronal death under pathological conditions such as epileptic insults. Acute preventive administration of ROCK inhibitor has been reported to have beneficial outcomes in Status Epilepticus (SE) epilepsy. In the present study, we evaluate the effect of chronic post SE treatment with the ROCK inhibitor Y-27632 in a rat pilocarpine model of TLE. We used chronic i.p. injections of Y-27632 for 5 days in 6 week old control rats or rats subjected to pilocarpine treatment as a model of TLE. Surprisingly, our findings demonstrate that a systemic administration of Y-27632 in pilocarpine-treated rats increases neuronal death in the CA3 region and ectopic recurrent mossy fiber sprouting (rMFS) in the dentate gyrus of the hippocampal formation. Interestingly, we found that chronic treatment with Y-27632 exacerbates the down-regulation and pathological distribution of the K(+)-Cl(-) cotransporter KCC2, thus providing a putative mechanism for post SE induced neuronal death. The involvement of astrogliosis in this mechanism appears to be intricate as ROCK inhibition reduces reactive astrogliosis in pilocarpine rats. Conversely, in control rats, chronic Y-27632 treatment increases astrogliosis. Together, our findings suggest that Y-27632 has a detrimental effect when chronically used post SE in a rat pilocarpine model of TLE.
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Affiliation(s)
- Nazim Kourdougli
- INSERM Unité 901, INMEDMarseille, France
- Aix-Marseille Université, UMR S901Marseille, France
| | - Saara Varpula
- INSERM Unité 901, INMEDMarseille, France
- Aix-Marseille Université, UMR S901Marseille, France
- Neuroscience Center, University of HelsinkiHelsinki, Finland
| | - Genevieve Chazal
- INSERM Unité 901, INMEDMarseille, France
- Aix-Marseille Université, UMR S901Marseille, France
| | - Claudio Rivera
- INSERM Unité 901, INMEDMarseille, France
- Aix-Marseille Université, UMR S901Marseille, France
- Neuroscience Center, University of HelsinkiHelsinki, Finland
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Bahadir A, Demir S, Orallar H, Beyazcicek E, Oner F. Effects of an Extract of Salvia Miltiorrhiza on a Penicillin-Induced Epilepsy Model in Rats. NEUROPHYSIOLOGY+ 2015. [DOI: 10.1007/s11062-015-9524-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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43
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Römermann K, Bankstahl JP, Löscher W, Bankstahl M. Pilocarpine-induced convulsive activity is limited by multidrug transporters at the rodent blood-brain barrier. J Pharmacol Exp Ther 2015; 353:351-9. [PMID: 25755207 DOI: 10.1124/jpet.114.221952] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
As a result of the growing availability of genetically engineered mouse lines, the pilocarpine post-status epilepticus (SE) model of temporal lobe epilepsy is increasingly used in mice. A discrepancy in pilocarpine sensitivity in FVB/N wild-type versus P-glycoprotein (PGP)-deficient mice precipitated the investigation of the interaction between pilocarpine and two major multidrug transporters at the blood-brain barrier. Doses of pilocarpine necessary for SE induction were determined in male and female wild-type and PGP-deficient mice. Brain and plasma concentrations were measured following low (30-50 mg⋅kg(-1) i.p.) and/or high (200 mg⋅kg(-1) i.p.) doses of pilocarpine in wild-type mice, and mice lacking PGP, breast cancer resistance protein (BCRP), or both transporters, as well as in rats with or without pretreatment with lithium chloride or tariquidar. Concentration equilibrium transport assays (CETA) were performed using cells overexpressing murine PGP or BCRP. Lower pilocarpine doses were necessary for SE induction in PGP-deficient mice. Brain-plasma ratios were higher in mice lacking PGP or PGP and BCRP, which was also observed after pretreatment with tariquidar in mice and in rats. Lithium chloride did not change brain penetration of pilocarpine. CETA confirmed transport of pilocarpine by PGP and BCRP. Pilocarpine is a substrate of PGP and BCRP at the rodent blood-brain barrier, which restricts its convulsive action. Future studies to reveal whether strain differences in pilocarpine sensitivity derive from differences in multidrug transporter expression levels are warranted.
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Affiliation(s)
- K Römermann
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, and Center for Systems Neuroscience, Hannover, Germany
| | - J P Bankstahl
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, and Center for Systems Neuroscience, Hannover, Germany
| | - W Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, and Center for Systems Neuroscience, Hannover, Germany
| | - M Bankstahl
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, and Center for Systems Neuroscience, Hannover, Germany
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44
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Sohrabji F. Estrogen-IGF-1 interactions in neuroprotection: ischemic stroke as a case study. Front Neuroendocrinol 2015; 36:1-14. [PMID: 24882635 PMCID: PMC4247812 DOI: 10.1016/j.yfrne.2014.05.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 05/15/2014] [Accepted: 05/16/2014] [Indexed: 12/25/2022]
Abstract
The steroid hormone 17b-estradiol and the peptide hormone insulin-like growth factor (IGF)-1 independently exert neuroprotective actions in neurologic diseases such as stroke. Only a few studies have directly addressed the interaction between the two hormone systems, however, there is a large literature that indicates potentially greater interactions between the 17b-estradiol and IGF-1 systems. The present review focuses on key issues related to this interaction including IGF-1 and sex differences and common activation of second messenger systems. Using ischemic stroke as a case study, this review also focuses on independent and cooperative actions of estrogen and IGF-1 on neuroprotection, blood brain barrier integrity, angiogenesis, inflammation and post-stroke epilepsy. Finally, the review also focuses on the astrocyte, a key mediator of post stroke repair, as a local source of 17b-estradiol and IGF-1. This review thus highlights areas where significant new research is needed to clarify the interactions between these two neuroprotectants.
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Affiliation(s)
- Farida Sohrabji
- Women's Health in Neuroscience Program, Neuroscience and Experimental Therapeutics, TAMHSC College of Medicine, Bryan, TX 77807, United States.
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45
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The Antiepileptic Effect of Carbamazepine During Estrous Cycle in Pentylenetetrazol-Induced Seizures in Rat. Int J Pept Res Ther 2014. [DOI: 10.1007/s10989-014-9441-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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46
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Kouis P, Mikroulis A, Psarropoulou C. A single episode of juvenile status epilepticus reduces the threshold to adult seizures in a stimulus-specific way. Epilepsy Res 2014; 108:1564-71. [DOI: 10.1016/j.eplepsyres.2014.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/29/2014] [Accepted: 08/02/2014] [Indexed: 11/29/2022]
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47
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Fredsø N, Koch BC, Toft N, Berendt M. Risk factors for survival in a university hospital population of dogs with epilepsy. J Vet Intern Med 2014; 28:1782-8. [PMID: 25252168 PMCID: PMC4895623 DOI: 10.1111/jvim.12443] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 06/17/2014] [Accepted: 07/29/2014] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND Although a common neurological disorder in dogs, long-term outcome of epilepsy is sparsely documented. OBJECTIVES To investigate risk factors for survival and duration of survival in a population of dogs with idiopathic epilepsy or epilepsy associated with a known intracranial cause. ANIMALS One hundred and two client owned dogs; 78 dogs with idiopathic epilepsy and 24 dogs with epilepsy associated with a known intracranial cause. METHODS A retrospective hospital based study with follow-up. Dogs diagnosed with epilepsy between 2002 and 2008 were enrolled in the study. Owners were interviewed by telephone using a structured questionnaire addressing epilepsy status, treatment, death/alive, and cause of death. RESULTS Median life span was 7.6 years, 9.2 years, and 5.8 years for all dogs, and dogs with idiopathic epilepsy or dogs with epilepsy associated with a known intracranial cause (P < .001), respectively. Survival time for dogs with idiopathic epilepsy was significantly (P = .0030) decreased for dogs euthanized because of epilepsy (median: 35 months) compared to dogs euthanized for other reasons (median: 67.5 months). Neutered male dogs with idiopathic epilepsy had a significant (P = .031) shorter survival (median: 38.5 months) after index seizure compared to intact male dogs (median: 71 months). Treatment with two antiepileptic drugs (AED's) did not negatively influence survival (P = .056). CONCLUSION AND CLINICAL IMPORTANCE Dogs with idiopathic epilepsy can in many cases expect a life span close to what is reported for dogs in general. In dogs where mono-therapy is not sufficient, the need for treatment with two AED's is not linked to a poor prognosis.
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Affiliation(s)
- N Fredsø
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
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48
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Distinct modulation of the endocannabinoid system upon kainic acid-induced in vivo seizures and in vitro epileptiform bursting. Mol Cell Neurosci 2014; 62:1-9. [PMID: 25064144 DOI: 10.1016/j.mcn.2014.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/06/2014] [Accepted: 07/23/2014] [Indexed: 12/11/2022] Open
Abstract
There is clear evidence on the neuroprotective role of the endocannabinoid (eCB) signaling cascade in various models of epilepsy. In particular, increased levels of eCBs protect against kainic acid (KA)-induced seizures. However, the molecular mechanisms underlying this effect and its age-dependence are still unknown. To clarify this issue, we investigated which step of the biosynthetic and catabolic pathways of the eCBs may be responsible for the eCB-mediated neuroprotection in the hippocampus of P14 and P56-70 KA-treated rats. We found that both anandamide and N-palmitoylethanolamine, together with their biosynthetic enzyme significantly increased in the hippocampus of younger KA-treated rats, while decreasing in adults. In contrast, the levels of the other major eCB, 2-arachidonoylglycerol, similar to its biosynthetic enzyme, were higher in the hippocampus of P56-70 compared to P14 rats. In line with these data, extracellular field recordings in CA1 hippocampus showed that enhancement of endogenous AEA and 2-AG significantly counteracted KA-induced epileptiform bursting in P56-70 and P14 rats, respectively. On the contrary, while the CB1R antagonist SR141716 per se did not affect the population spike, it did worsen KA-induced bursts, confirming increased eCB tone upon KA treatment. Altogether these data indicate an age-specific alteration of the eCB system caused by KA and provide insights for the protective mechanism of the cannabinoid system against epileptiform discharges.
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Structural and functional correlates of epileptogenesis - does gender matter? Neurobiol Dis 2014; 70:69-73. [PMID: 24943053 DOI: 10.1016/j.nbd.2014.05.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/15/2014] [Accepted: 05/22/2014] [Indexed: 01/10/2023] Open
Abstract
In the majority of neuropsychiatric conditions, marked gender-based differences have been found in the epidemiology, clinical manifestations, and therapy of disease. One possible reason is that sex differences in cerebral morphology, structural and functional connections, render men and women differentially vulnerable to various disease processes. The present review addresses this issue with respect to the functional and structural correlates to some forms of epilepsy.
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Van Meervenne SAE, Volk HA, Matiasek K, Van Ham LML. The influence of sex hormones on seizures in dogs and humans. Vet J 2014; 201:15-20. [PMID: 24878266 DOI: 10.1016/j.tvjl.2014.05.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 05/01/2014] [Accepted: 05/04/2014] [Indexed: 11/27/2022]
Abstract
Epilepsy is the most common chronic neurological disorder in both humans and dogs. The effect of sex hormones on seizures is well documented in human medicine. Catamenial epilepsy is defined as an increase in frequency and severity of seizures during certain periods of the menstrual cycle. Oestradiol increases seizure activity and progesterone is believed to exhibit a protective effect. The role of androgens is controversial and there is a lack of research focusing on androgens and epilepsy. Indeed, little is known about the influence of sex hormones on epilepsy in dogs. Sterilisation is believed to improve seizure control, but no systematic research has been conducted in this field. This review provides an overview of the current literature on the influence of sex hormones on seizures in humans. The literature on idiopathic epilepsy in dogs was assessed to identify potential risk factors related to sex and sterilisation status. In general, there appears to be an over-representation of male dogs with idiopathic epilepsy but no explanation for this difference in prevalence between sexes has been reported. In addition, no reliable conclusions can be drawn on the effect of sterilisation due to the lack of focused research and robust scientific evidence.
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Affiliation(s)
- Sofie A E Van Meervenne
- Läckeby Djursjukhus, Örntorp 201, 39598 Läckeby, Sweden; Department of Small Animal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
| | - Holger A Volk
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield AL9 7TA, UK
| | - Kaspar Matiasek
- Section of Clinical & Comparative Neuropathology, Ludwig Maximilians University, Veterinärstrasse. 13, D-80539 Munich, Germany
| | - Luc M L Van Ham
- Department of Small Animal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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