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Chong D, Jones NC, Schittenhelm RB, Anderson A, Casillas-Espinosa PM. Multi-omics Integration and Epilepsy: Towards a Better Understanding of Biological Mechanisms. Prog Neurobiol 2023:102480. [PMID: 37286031 DOI: 10.1016/j.pneurobio.2023.102480] [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: 02/15/2023] [Revised: 05/09/2023] [Accepted: 06/03/2023] [Indexed: 06/09/2023]
Abstract
The epilepsies are a group of complex neurological disorders characterised by recurrent seizures. Approximately 30% of patients fail to respond to anti-seizure medications, despite the recent introduction of many new drugs. The molecular processes underlying epilepsy development are not well understood and this knowledge gap impedes efforts to identify effective targets and develop novel therapies against epilepsy. Omics studies allow a comprehensive characterisation of a class of molecules. Omics-based biomarkers have led to clinically validated diagnostic and prognostic tests for personalised oncology, and more recently for non-cancer diseases. We believe that, in epilepsy, the full potential of multi-omics research is yet to be realised and we envisage that this review will serve as a guide to researchers planning to undertake omics-based mechanistic studies.
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Affiliation(s)
- Debbie Chong
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, 3004, Victoria, Australia
| | - Nigel C Jones
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, 3004, Victoria, Australia; Department of Medicine (The Royal Melbourne Hospital), The University of Melbourne, 3000, Victoria, Australia; Department of Neurology, Alfred Health, Melbourne, 3004, Victoria, Australia
| | - Ralf B Schittenhelm
- Monash Proteomics & Metabolomics Facility and Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, 3800, Australia
| | - Alison Anderson
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, 3004, Victoria, Australia; Department of Medicine (The Royal Melbourne Hospital), The University of Melbourne, 3000, Victoria, Australia; Department of Neurology, Alfred Health, Melbourne, 3004, Victoria, Australia
| | - Pablo M Casillas-Espinosa
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, 3004, Victoria, Australia; Department of Medicine (The Royal Melbourne Hospital), The University of Melbourne, 3000, Victoria, Australia; Department of Neurology, Alfred Health, Melbourne, 3004, Victoria, Australia
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2
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Tilelli CQ, Flôres LR, Cota VR, Castro OWD, Garcia-Cairasco N. Amygdaloid complex anatomopathological findings in animal models of status epilepticus. Epilepsy Behav 2021; 121:106831. [PMID: 31864944 DOI: 10.1016/j.yebeh.2019.106831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 11/15/2019] [Accepted: 11/25/2019] [Indexed: 12/13/2022]
Abstract
Temporal lobe epileptic seizures are one of the most common and well-characterized types of epilepsies. The current knowledge on the pathology of temporal lobe epilepsy relies strongly on studies of epileptogenesis caused by experimentally induced status epilepticus (SE). Although several temporal lobe structures have been implicated in the epileptogenic process, the hippocampal formation is the temporal lobe structure studied in the greatest amount and detail. However, studies in human patients and animal models of temporal lobe epilepsy indicate that the amygdaloid complex can be also an important seizure generator, and several pathological processes have been shown in the amygdala during epileptogenesis. Therefore, in the present review, we systematically selected, organized, described, and analyzed the current knowledge on anatomopathological data associated with the amygdaloid complex during SE-induced epileptogenesis. Amygdaloid complex participation in the epileptogenic process is evidenced, among others, by alterations in energy metabolism, circulatory, and fluid regulation, neurotransmission, immediate early genes expression, tissue damage, cell suffering, inflammation, and neuroprotection. We conclude that major efforts should be made in order to include the amygdaloid complex as an important target area for evaluation in future research on SE-induced epileptogenesis. This article is part of the Special Issue "NEWroscience 2018".
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Affiliation(s)
- Cristiane Queixa Tilelli
- Laboratory of Physiology, Campus Centro-Oeste Dona Lindu, Universidade Federal de São João del-Rei, Av. Sebastião Gonçalves Coelho, 400, Bairro Belvedere, Divinópolis, MG 35.501-296, Brazil.
| | - Larissa Ribeiro Flôres
- Laboratory of Physiology, Campus Centro-Oeste Dona Lindu, Universidade Federal de São João del-Rei, Av. Sebastião Gonçalves Coelho, 400, Bairro Belvedere, Divinópolis, MG 35.501-296, Brazil
| | - Vinicius Rosa Cota
- Laboratory of Neuroengineering and Neuroscience (LINNce), Department of Electrical Engineering, Campus Santo Antônio, Universidade Federal de São João del-Rei, Praça Frei Orlando, 170, Centro, São João Del Rei, MG 36307-352, Brazil
| | - Olagide Wagner de Castro
- Institute of Biological Sciences and Health, Campus A. C. Simões, Universidade Federal de Alagoas, Av. Lourival Melo Mota, s/n, Tabuleiro do Martins, Maceió, AL 57072-970, Brazil
| | - Norberto Garcia-Cairasco
- Neurophysiology and Experimental Neuroethology Laboratory (LNNE), Department of Physiology, School of Medicine, Universidade de São Paulo, Av. Bandeirantes, 3900, Monte Alegre, Ribeirão Preto, SP 14049-900, Brazil.
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Lin DQ, Cai XY, Wang CH, Yang B, Liang RS. Optimal concentration of necrostatin-1 for protecting against hippocampal neuronal damage in mice with status epilepticus. Neural Regen Res 2020; 15:936-943. [PMID: 31719260 PMCID: PMC6990772 DOI: 10.4103/1673-5374.268903] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 03/10/2019] [Accepted: 08/13/2019] [Indexed: 02/05/2023] Open
Abstract
Hippocampal neurons undergo various forms of cell death after status epilepticus. Necrostatin-1 specifically inhibits necroptosis mediated by receptor interacting protein kinase 1 (RIP1) and RIP3 receptors. However, there are no reports of necroptosis in mouse models of status epilepticus. Therefore, in this study, we investigated the effects of necrostatin-1 on hippocampal neurons in mice with status epilepticus, and, furthermore, we tested different amounts of the compound to identify the optimal concentration for inhibiting necroptosis and apoptosis. A mouse model of status epilepticus was produced by intraperitoneal injection of kainic acid, 12 mg/kg. Different concentrations of necrostatin-1 (10, 20, 40, and 80 μM) were administered into the lateral ventricle 15 minutes before kainic acid injection. Hippocampal damage was assessed by hematoxylin-eosin staining 24 hours after the model was successfully produced. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining, western blot assay and immunohistochemistry were used to evaluate the expression of apoptosis-related and necroptosis-related proteins. Necrostatin-1 alleviated damage to hippocampal tissue in the mouse model of epilepsy. The 40 μM concentration of necrostatin-1 significantly decreased the number of apoptotic cells in the hippocampal CA1 region. Furthermore, necrostatin-1 significantly downregulated necroptosis-related proteins (MLKL, RIP1, and RIP3) and apoptosis-related proteins (cleaved-Caspase-3, Bax), and it upregulated the expression of anti-apoptotic protein Bcl-2. Taken together, our findings show that necrostatin-1 effectively inhibits necroptosis and apoptosis in mice with status epilepticus, with the 40 μM concentration of the compound having an optimal effect. The experiments were approved by the Animal Ethics Committee of Fujian Medical University, China (approval No. 2016-032) on November 9, 2016.
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Affiliation(s)
- Dong-Qi Lin
- Department of Cardiothoracic Surgery, the Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong Province, China
- Department of Neurosurgery, Union Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Xin-Ying Cai
- Clinical Research Center, Shantou Central Hospital, Affiliated Shantou Hospital of Sun Yat-sen University, Shantou, Guangdong Province, China
| | - Chun-Hua Wang
- Department of Neurosurgery, Union Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Bin Yang
- Department of Neurosurgery, Union Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Ri-Sheng Liang
- Department of Neurosurgery, Union Hospital, Fujian Medical University, Fuzhou, Fujian Province, China
- Correspondence to: Ri-Sheng Liang, .
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Rosal Lustosa Í, Soares JI, Biagini G, Lukoyanov NV. Neuroplasticity in Cholinergic Projections from the Basal Forebrain to the Basolateral Nucleus of the Amygdala in the Kainic Acid Model of Temporal Lobe Epilepsy. Int J Mol Sci 2019; 20:ijms20225688. [PMID: 31766245 PMCID: PMC6887742 DOI: 10.3390/ijms20225688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/08/2019] [Accepted: 11/10/2019] [Indexed: 02/06/2023] Open
Abstract
The amygdala is a cerebral region whose function is compromised in temporal lobe epilepsy (TLE). Patients with TLE present cognitive and emotional dysfunctions, of which impairments in recognizing facial expressions have been clearly attributed to amygdala damage. However, damage to the amygdala has been scarcely addressed, with the majority of studies focusing on the hippocampus. The aim of this study was to evaluate epilepsy-related plasticity of cholinergic projections to the basolateral nucleus (BL) of the amygdala. Adult rats received kainic acid (KA) injections and developed status epilepticus. Weeks later, they showed spontaneous recurrent seizures documented by behavioral observations. Changes in cholinergic innervation of the BL were investigated by using an antibody against the vesicular acetylcholine transporter (VAChT). In KA-treated rats, it was found that (i) the BL shrunk to 25% of its original size (p < 0.01 vs. controls, Student’s t-test), (ii) the density of vesicular acetylcholine transporter-immunoreactive (VAChT-IR) varicosities was unchanged, (iii) the volumes of VAChT-IR cell bodies projecting to the BL from the horizontal limb of the diagonal band of Broca, ventral pallidum, and subcommissural part of the substantia innominata were significantly increased (p < 0.05, Bonferroni correction). These results illustrate significant changes in the basal forebrain cholinergic cells projecting to the BL in the presence of spontaneous recurrent seizures.
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Affiliation(s)
- Ítalo Rosal Lustosa
- Clinical and Experimental Medicine PhD Program, University of Modena and Reggio Emilia, 41125 Modena, Italy;
| | - Joana I. Soares
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal;
- Instituto de Biologia Molecular e Celular da Universidade do Porto, 4200-135 Porto, Portugal
- Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, 4200-319 Porto, Portugal
- Programa Doutoral em Neurociências, Universidade do Porto, 4200-319 Porto, Portugal
| | - Giuseppe Biagini
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
- Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, 41125 Modena, Italy
- Correspondence: (G.B.); (N.V.L.)
| | - Nikolai V. Lukoyanov
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal;
- Instituto de Biologia Molecular e Celular da Universidade do Porto, 4200-135 Porto, Portugal
- Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, 4200-319 Porto, Portugal
- Correspondence: (G.B.); (N.V.L.)
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Yu Y, Hasegawa D, Hamamoto Y, Mizoguchi S, Kuwabara T, Fujiwara-Igarashi A, Tsuboi M, Chambers JK, Fujita M, Uchida K. Neuropathologic features of the hippocampus and amygdala in cats with familial spontaneous epilepsy. Am J Vet Res 2018; 79:324-332. [PMID: 29466043 DOI: 10.2460/ajvr.79.3.324] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate epilepsy-related neuropathologic changes in cats of a familial spontaneous epileptic strain (ie, familial spontaneous epileptic cats [FSECs]). ANIMALS 6 FSECs, 9 age-matched unrelated healthy control cats, and 2 nonaffected (without clinical seizures)dams and 1 nonaffected sire of FSECs. PROCEDURES Immunohistochemical analyses were used to evaluate hippocampal sclerosis, amygdaloid sclerosis, mossy fiber sprouting, and granule cell pathological changes. Values were compared between FSECs and control cats. RESULTS Significantly fewer neurons without gliosis were detected in the third subregion of the cornu ammonis (CA) of the dorsal and ventral aspects of the hippocampus as well as the central nucleus of the amygdala in FSECs versus control cats. Gliosis without neuronal loss was also observed in the CA4 subregion of the ventral aspect of the hippocampus. No changes in mossy fiber sprouting and granule cell pathological changes were detected. Moreover, similar changes were observed in the dams and sire without clinical seizures, although to a lesser extent. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that the lower numbers of neurons in the CA3 subregion of the hippocampus and the central nucleus of the amygdala were endophenotypes of familial spontaneous epilepsy in cats. In contrast to results of other veterinary medicine reports, severe epilepsy-related neuropathologic changes (eg, hippocampal sclerosis, amygdaloid sclerosis, mossy fiber sprouting, and granule cell pathological changes) were not detected in FSECs. Despite the use of a small number of cats with infrequent seizures, these findings contributed new insights on the pathophysiologic mechanisms of genetic-related epilepsy in cats.
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Jarero-Basulto JJ, Gasca-Martínez Y, Rivera-Cervantes MC, Ureña-Guerrero ME, Feria-Velasco AI, Beas-Zarate C. Interactions Between Epilepsy and Plasticity. Pharmaceuticals (Basel) 2018; 11:ph11010017. [PMID: 29414852 PMCID: PMC5874713 DOI: 10.3390/ph11010017] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/01/2018] [Accepted: 02/06/2018] [Indexed: 02/06/2023] Open
Abstract
Undoubtedly, one of the most interesting topics in the field of neuroscience is the ability of the central nervous system to respond to different stimuli (normal or pathological) by modifying its structure and function, either transiently or permanently, by generating neural cells and new connections in a process known as neuroplasticity. According to the large amount of evidence reported in the literature, many stimuli, such as environmental pressures, changes in the internal dynamic steady state of the organism and even injuries or illnesses (e.g., epilepsy) may induce neuroplasticity. Epilepsy and neuroplasticity seem to be closely related, as the two processes could positively affect one another. Thus, in this review, we analysed some neuroplastic changes triggered in the hippocampus in response to seizure-induced neuronal damage and how these changes could lead to the establishment of temporal lobe epilepsy, the most common type of focal human epilepsy.
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Affiliation(s)
- José J Jarero-Basulto
- Cellular Neurobiology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Yadira Gasca-Martínez
- Cellular Neurobiology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Martha C Rivera-Cervantes
- Cellular Neurobiology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Mónica E Ureña-Guerrero
- Neurotransmission Biology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Alfredo I Feria-Velasco
- Cellular Neurobiology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Carlos Beas-Zarate
- Development and Neural Regeneration Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
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Abstract
OBJECTIVE Epilepsy is a chronic neurological disease characterised with seizures. The aetiology of the most generalised epilepsies cannot be explicitly determined and the seizures are pronounced to be genetically determined by disturbances of receptors in central nervous system. Besides, neurotransmitter distributions or other metabolic problems are supposed to involve in epileptogenesis. Lack of adequate data about pharmacological agents that have antiepileptogenic effects point to need of research on this field. Thus, in this review, inflammatory aspects of epileptogenesis has been focussed via considering several concepts like role of immune system, blood-brain barrier and antibody involvement in epileptogenesis. METHODS We conducted an evidence-based review of the literatures in order to evaluate the possible participation of inflammatory processes to epileptogenesis and also, promising agents which are effective to these processes. We searched PubMed database up to November 2015 with no date restrictions. RESULTS In the present review, 163 appropriate articles were included. Obtained data suggests that inflammatory processes participate to epileptogenesis in several ways like affecting fibroblast growth factor-2 and tropomyosin receptor kinase B signalling pathways, detrimental proinflammatory pathways [such as the interleukin-1 beta (IL-1β)-interleukin-1 receptor type 1 (IL-1R1) system], mammalian target of rapamycin pathway, microglial activities, release of glial inflammatory proteins (such as macrophage inflammatory protein, interleukin 6, C-C motif ligand 2 and IL-1β), adhesion molecules that are suggested to function in signalling pathways between neurons and microglia and also linkage between these molecules and proinflammatory cytokines. CONCLUSION The literature research indicated that inflammation is a part of epileptogenesis. For this reason, further studies are necessary for assessing agents that will be effective in clinical use for therapeutic treatment of epileptogenesis.
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Bednarczyk J, Dębski KJ, Bot AM, Lukasiuk K. MBD3 expression and DNA binding patterns are altered in a rat model of temporal lobe epilepsy. Sci Rep 2016; 6:33736. [PMID: 27650712 PMCID: PMC5030630 DOI: 10.1038/srep33736] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 09/02/2016] [Indexed: 12/18/2022] Open
Abstract
The aim of the present study was to examine involvement of MBD3 (methyl-CpG-binding domain protein 3), a protein involved in reading DNA methylation patterns, in epileptogenesis and epilepsy. We used a well-characterized rat model of temporal lobe epilepsy that is triggered by status epilepticus, evoked by electrical stimulation of the amygdala. Stimulated and sham-operated animals were sacrificed 14 days after stimulation. We found that MBD3 transcript was present in neurons, oligodendrocytes, and astrocytes in both control and epileptic animals. We detected the nuclear localization of MBD3 protein in neurons, mature oligodendrocytes, and a subpopulation of astrocytes but not in microglia. Amygdala stimulation significantly increased the level of MBD3 immunofluorescence. Immunoprecipitation followed by mass spectrometry and Western blot revealed that MBD3 in the adult brain assembles the NuRD complex, which also contains MTA2, HDAC2, and GATAD2B. Using chromatin immunoprecipitation combined with deep sequencing, we observed differences in the occupancy of DNA regions by MBD3 protein between control and stimulated animals. This was not followed by subsequent changes in the mRNA expression levels of selected MBD3 targets. Our data demonstrate for the first time alterations in the MBD3 expression and DNA occupancy in the experimental model of epilepsy.
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Affiliation(s)
- Joanna Bednarczyk
- Laboratory of Epileptogenesis, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Konrad J. Dębski
- Laboratory of Epileptogenesis, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
- Laboratory of Bioinformatics, Neurobiology Center, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Anna M. Bot
- Laboratory of Epileptogenesis, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Lukasiuk
- Laboratory of Epileptogenesis, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
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Wulsin AC, Solomon MB, Privitera MD, Danzer SC, Herman JP. Hypothalamic-pituitary-adrenocortical axis dysfunction in epilepsy. Physiol Behav 2016; 166:22-31. [PMID: 27195458 DOI: 10.1016/j.physbeh.2016.05.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 04/04/2016] [Accepted: 05/11/2016] [Indexed: 12/27/2022]
Abstract
Epilepsy is a common neurological disease, affecting 2.4million people in the US. Among the many different forms of the disease, temporal lobe epilepsy (TLE) is one of the most frequent in adults. Recent studies indicate the presence of a hyperactive hypothalamopituitary- adrenocortical (HPA) axis and elevated levels of glucocorticoids in TLE patients. Moreover, in these patients, stress is a commonly reported trigger of seizures, and stress-related psychopathologies, including depression and anxiety, are highly prevalent. Elevated glucocorticoids have been implicated in the development of stress-related psychopathologies. Similarly, excess glucocorticoids have been found to increase neuronal excitability, epileptiform activity and seizure susceptibility. Thus, patients with TLE may generate abnormal stress responses that both facilitate ictal discharges and increase vulnerability for the development of comorbid psychopathologies. Here, we will examine the evidence that the HPA axis is disrupted in TLE, consider potential mechanisms by which this might occur, and discuss the implications of HPA dysfunction for seizuretriggering and psychiatric comorbidities.
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Affiliation(s)
- Aynara C Wulsin
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH, United States; Neuroscience Program, University of Cincinnati, College of Medicine, Cincinnati, OH, United States; Department of Anesthesia, Cincinnati Childrens Hospital Medical Center, Cincinnati, OH, United States; Department of Pediatrics, Cincinnati Childrens Hospital Medical Center, Cincinnati, OH, United States.
| | - Matia B Solomon
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH, United States; Neuroscience Program, University of Cincinnati, College of Medicine, Cincinnati, OH, United States
| | - Michael D Privitera
- Department of Neurology, Neuroscience Institute, University of Cincinnati, Cincinnati, OH, United States
| | - Steve C Danzer
- Neuroscience Program, University of Cincinnati, College of Medicine, Cincinnati, OH, United States; Department of Anesthesia, Cincinnati Childrens Hospital Medical Center, Cincinnati, OH, United States; Department of Pediatrics, Cincinnati Childrens Hospital Medical Center, Cincinnati, OH, United States
| | - James P Herman
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, College of Medicine, Cincinnati, OH, United States; Neuroscience Program, University of Cincinnati, College of Medicine, Cincinnati, OH, United States.
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10
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Yilmazer-Hanke D, O'Loughlin E, McDermott K. Contribution of amygdala pathology to comorbid emotional disturbances in temporal lobe epilepsy. J Neurosci Res 2015; 94:486-503. [DOI: 10.1002/jnr.23689] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/07/2015] [Accepted: 10/16/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Deniz Yilmazer-Hanke
- Department of Biomedical Sciences, School of Medicine; Creighton University; Omaha Nebraska
- Department of Anatomy and Neuroscience; University College; Cork Ireland
| | - Elaine O'Loughlin
- Department of Anatomy and Neuroscience; University College; Cork Ireland
- Ann Romney Centre for Neurologic Diseases, Brigham and Women's Hospital; Harvard Medical School; Boston Massachusetts
| | - Kieran McDermott
- Department of Anatomy and Neuroscience; University College; Cork Ireland
- Graduate Entry Medical School; University of Limerick; Limerick Ireland
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11
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Maia GH, Quesado JL, Soares JI, do Carmo JM, Andrade PA, Andrade JP, Lukoyanov NV. Loss of hippocampal neurons after kainate treatment correlates with behavioral deficits. PLoS One 2014; 9:e84722. [PMID: 24409306 PMCID: PMC3883667 DOI: 10.1371/journal.pone.0084722] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 11/18/2013] [Indexed: 11/18/2022] Open
Abstract
Treating rats with kainic acid induces status epilepticus (SE) and leads to the development of behavioral deficits and spontaneous recurrent seizures later in life. However, in a subset of rats, kainic acid treatment does not induce overt behaviorally obvious acute SE. The goal of this study was to compare the neuroanatomical and behavioral changes induced by kainate in rats that developed convulsive SE to those who did not. Adult male Wistar rats were treated with kainic acid and tested behaviorally 5 months later. Rats that had experienced convulsive SE showed impaired performance on the spatial water maze and passive avoidance tasks, and on the context and tone retention tests following fear conditioning. In addition, they exhibited less anxiety-like behaviors than controls on the open-field and elevated plus-maze tests. Histologically, convulsive SE was associated with marked neuron loss in the hippocampal CA3 and CA1 fields, and in the dentate hilus. Rats that had not experienced convulsive SE after kainate treatment showed less severe, but significant impairments on the spatial water maze and passive avoidance tasks. These rats had fewer neurons than control rats in the dentate hilus, but not in the hippocampal CA3 and CA1 fields. Correlational analyses revealed significant relationships between spatial memory indices of rats and neuronal numbers in the dentate hilus and CA3 pyramidal field. These results show that a part of the animals that do not display intense behavioral seizures (convulsive SE) immediately after an epileptogenic treatment, later in life, they may still have noticeable structural and functional changes in the brain.
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Affiliation(s)
- Gisela H. Maia
- Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
- Neural Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - José L. Quesado
- Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - Joana I. Soares
- Neural Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - Joana M. do Carmo
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - Pedro A. Andrade
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - José P. Andrade
- Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - Nikolai V. Lukoyanov
- Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
- Neural Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
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12
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Solmaz İ, Gürkanlar D, Gökçil Z, Göksoy C, Özkan M, Erdoğan E. Antiepileptic activity of melatonin in guinea pigs with pentylenetetrazol-induced seizures. Neurol Res 2013; 31:989-95. [DOI: 10.1179/174313209x385545] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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13
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Scholl EA, Dudek FE, Ekstrand JJ. Neuronal degeneration is observed in multiple regions outside the hippocampus after lithium pilocarpine-induced status epilepticus in the immature rat. Neuroscience 2013; 252:45-59. [PMID: 23896573 DOI: 10.1016/j.neuroscience.2013.07.045] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 01/25/2023]
Abstract
Although hippocampal sclerosis is frequently identified as a possible epileptic focus in patients with temporal lobe epilepsy, neuronal loss has also been observed in additional structures, including areas outside the temporal lobe. The claim from several researchers using animal models of acquired epilepsy that the immature brain can develop epilepsy without evidence of hippocampal neuronal death raises the possibility that neuronal death in some of these other regions may also be important for epileptogenesis. The present study used the lithium pilocarpine model of acquired epilepsy in immature animals to assess which structures outside the hippocampus are injured acutely after status epilepticus. Sprague-Dawley rat pups were implanted with surface EEG electrodes, and status epilepticus was induced at 20 days of age with lithium pilocarpine. After 72 h, brain tissue from 12 animals was examined with Fluoro-Jade B, a histochemical marker for degenerating neurons. All animals that had confirmed status epilepticus demonstrated Fluoro-Jade B staining in areas outside the hippocampus. The most prominent staining was seen in the thalamus (mediodorsal, paratenial, reuniens, and ventral lateral geniculate nuclei), amygdala (ventral lateral, posteromedial, and basomedial nuclei), ventral premammillary nuclei of hypothalamus, and paralimbic cortices (perirhinal, entorhinal, and piriform) as well as parasubiculum and dorsal endopiriform nuclei. These results demonstrate that lithium pilocarpine-induced status epilepticus in the immature rat brain consistently results in neuronal injury in several distinct areas outside of the hippocampus. Many of these regions are similar to areas damaged in patients with temporal lobe epilepsy, thus suggesting a possible role in epileptogenesis.
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Key Words
- AA
- ACH
- ACo
- AD
- AHC
- AI
- AM
- AO
- APir
- AStr
- AV
- Acb
- AcbSh
- BAOT
- BLA
- BLP
- BLV
- BMA
- BMP
- BSTIA
- BSTM
- CA
- CL
- CM
- CPu
- CeL
- CeM
- Cg1-3
- DEn
- DG
- DI
- DLG
- DP
- EEG
- Ent
- Fluoro-jade B
- Fr1-3
- GABA
- GI
- GP
- HC
- Hil
- I
- IL
- LDDM
- LDVL
- LHb
- LM
- LO
- LOT
- LPLR
- LPMR
- LSD
- LSI
- LSV
- LaD
- LaV
- MD
- MGD
- MGM
- MGP
- MGV
- MHb
- MO
- MS
- MTu
- MeA
- MePD
- MePV
- NAc
- Oc2L
- P
- PC
- PF
- PLCo
- PMCo
- PMD
- PMV
- PRh
- PT
- PVA
- PVP
- PaS
- Par1
- Pir
- Po
- PrS
- RSA
- RSG
- Re
- Rh
- Rt
- S
- SG
- SI
- SNR
- STh
- TLE
- Te1,3
- VL
- VLG
- VLO
- VM
- VP
- VPL
- VPM
- VTR
- ZI
- accumbens
- accumbens shell
- agranular insular cortex
- amygdalopiriform transition area
- amygdalostriatal transition area
- anterior amygdaloid area
- anterior cingulate
- anterior cortical nucleus
- anterior hypothalamic area
- anterior hypothalamic area, central
- anterior olfactory nucleus
- anterodorsal nucleus
- anteromedial
- anteroventral nucleus
- basolateral nucleus, anterior
- basolateral nucleus, posterior
- basolateral nucleus, ventral
- basomedial nucleus, anterior
- basomedial nucleus, posterior
- bed nucleus accessory olfactory tract
- bed nucleus stria terminalis, intraamygdaloid division
- bed stria terminalis nuclei
- caudate putamen
- central nucleus, lateral
- central nucleus, medial
- centrolateral nucleus
- centromedial nucleus
- cornu ammonis
- dentate gyrus
- dorsal endopiriform nucleus
- dorsal peduncular
- dorsolateral geniculate nucleus
- dysgranular insular cortex
- electroencephalogram
- entorhinal cortex
- frontal cortex
- globus pallidus
- granular insular cortex
- hilus
- hippocampus
- immature brain
- infralimbic
- intercalated masses
- lateral habenula
- lateral mammillary
- lateral nucleus, dorsal
- lateral nucleus, ventral
- lateral orbital cortex
- lateral septal, dorsal
- lateral septal, intermediate
- lateral septal, ventral
- laterodorsal nucleus, dorsomedial
- laterodorsal nucleus, ventrolateral
- lateroposterior nucleus, lateral rostral
- lateroposterior nucleus, medial rostral
- lithium pilocarpine
- medial geniculate nucleus, dorsal
- medial geniculate nucleus, medial
- medial geniculate nucleus, ventral
- medial globus pallidus
- medial habenula
- medial nucleus, anterior
- medial nucleus, posterodorsal
- medial nucleus, posteroventral
- medial orbital cortex
- medial septal
- medial tuberal
- mediodorsal nucleus
- nucleus accumbens
- nucleus lateral olfactory tract
- occipital cortex
- paracentral
- parafasicular
- parasubiculum
- paratenial
- paraventricular nucleus, anterior
- paraventricular nucleus, posterior
- parietal cortex
- perirhinal cortex
- piriform cortex
- post-natal day
- posterior nucleus
- posterolateral cortical nucleus
- posteromedial cortical nucleus
- premammillary nucleus, dorsal
- premammillary nucleus, ventral
- presubiculum
- reticular nucleus
- retrosplenial agranular cortex
- retrosplenial granular cortex
- reuniens nucleus
- rhomboid nucleus
- status epilepticus
- subiculum
- substantia innominate
- substantia nigra pars reticulate
- subthalamic nucleus
- suprageniculate nucleus
- temporal cortex
- temporal lobe epilepsy
- vRe
- ventral pallidum
- ventral posterolateral nucleus
- ventral posteromedial nucleus
- ventral reuniens nucleus
- ventral tegmental area
- ventrolateral geniculate nucleus
- ventrolateral nucleus
- ventrolateral orbital cortex
- ventromedial nucleus
- zona incerta
- γ-aminobutyric acid
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Affiliation(s)
- E A Scholl
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States
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Seif-Eddeine H, Treiman DM. Problems and controversies in status epilepticus: a review and recommendations. Expert Rev Neurother 2012; 11:1747-58. [PMID: 22091598 DOI: 10.1586/ern.11.160] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Status epilepticus (SE) is a neurologic emergency that require immediate vigorous treatment in order to prevent serious morbidity or even death. Several investigators have suggested that the underlying etiology is the primary determinant of outcome. We believe that this may be true in aggressively treated SE, but not when the treatment is less than optimal. In this article, we will discuss the factors that have been implicated in affecting SE outcomes, and argue, on the basis of both human and experimental animal data, that aggressive treatment is necessary and appropriate for all presentations of SE in order to maximize the probability of a successful outcome even when the etiology suggests a poor prognosis.
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Affiliation(s)
- Hussam Seif-Eddeine
- Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, USA
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Pereno GL, Balaszczuk V, Beltramino CA. Effect of sex differences and gonadal hormones on kainic acid-induced neurodegeneration in the bed nucleus of the stria terminalis of the rat. ACTA ACUST UNITED AC 2012; 64:283-9. [DOI: 10.1016/j.etp.2010.08.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Revised: 08/29/2010] [Accepted: 08/29/2010] [Indexed: 12/12/2022]
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16
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Jaako K, Aonurm-Helm A, Kalda A, Anier K, Zharkovsky T, Shastin D, Zharkovsky A. Repeated citalopram administration counteracts kainic acid-induced spreading of PSA-NCAM-immunoreactive cells and loss of reelin in the adult mouse hippocampus. Eur J Pharmacol 2011; 666:61-71. [DOI: 10.1016/j.ejphar.2011.05.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 04/12/2011] [Accepted: 05/03/2011] [Indexed: 11/28/2022]
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Gangarossa G, Di Benedetto M, O'Sullivan GJ, Dunleavy M, Alcacer C, Bonito-Oliva A, Henshall DC, Waddington JL, Valjent E, Fisone G. Convulsant doses of a dopamine D1 receptor agonist result in Erk-dependent increases in Zif268 and Arc/Arg3.1 expression in mouse dentate gyrus. PLoS One 2011; 6:e19415. [PMID: 21559295 PMCID: PMC3086923 DOI: 10.1371/journal.pone.0019415] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 03/29/2011] [Indexed: 11/19/2022] Open
Abstract
Activation of dopamine D1 receptors (D1Rs) has been shown to induce epileptiform activity. We studied the molecular changes occurring in the hippocampus in response to the administration of the D1-type receptor agonist, SKF 81297. SKF 81297 at 2.5 and 5.0 mg/kg induced behavioural seizures. Electrophysiological recordings in the dentate gyrus revealed the presence of epileptiform discharges peaking at 30-45 min post-injection and declining by 60 min. Seizures were prevented by the D1-type receptor antagonist, SCH 23390, or the cannabinoid CB1 receptor agonist, CP 55,940. The effect of SKF 81297 was accompanied by increased phosphorylation of the extracellular signal-regulated protein kinases 1 and 2 (ERK), in the granule cells of the dentate gyrus. This effect was also observed in response to administration of other D1-type receptor agonists, such as SKF83822 and SKF83959. In addition, SKF 81297 increased the phosphorylation of the ribosomal protein S6 and histone H3, two downstream targets of ERK. These effects were prevented by genetic inactivation of D1Rs, or by pharmacological inhibition of ERK. SKF 81297 was also able to enhance the levels of Zif268 and Arc/Arg3.1, two immediate early genes involved in transcriptional regulation and synaptic plasticity. These changes may be involved in forms of activity-dependent plasticity linked to the manifestation of seizures and to the ability of dopamine to affect learning and memory.
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Affiliation(s)
| | | | - Gerard J. O'Sullivan
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Mark Dunleavy
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Cristina Alcacer
- Institut National de la Santé et de la Recherche Médicale, UMR-S 839, Paris, France
- Université Pierre et Marie Curie, Paris, France
- Institut du Fer à Moulin, Paris, France
| | | | - David C. Henshall
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - John L. Waddington
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Emmanuel Valjent
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Gilberto Fisone
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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18
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Jeong EA, Jeon BT, Kim JB, Kim JS, Cho YW, Lee DH, Kim HJ, Kang SS, Cho GJ, Choi WS, Roh GS. Phosphorylation of 14-3-3ζ at serine 58 and neurodegeneration following kainic acid-induced excitotoxicity. Anat Cell Biol 2010; 43:150-6. [PMID: 21189996 PMCID: PMC2998790 DOI: 10.5115/acb.2010.43.2.150] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 05/28/2010] [Accepted: 05/31/2010] [Indexed: 11/27/2022] Open
Abstract
Oxidative stress-induced cell death leads to phosphorylation of 14-3-3ζ at serine 58. 14-3-3ζ is detected at significant levels in cerebrospinal fluid after kainic acid (KA)-induced seizures. Here we examined temporal changes in 14-3-3ζ phosphorylation in the hippocampus and amygdala of mice after KA treatment. Mice were killed at 2, 6, 24, or 48 h after KA (30 mg/kg) injection. We observed an increase in TUNEL and Fluoro-Jade B (FJB)-stained neurons in the hippocampus and amygdala of KA-treated mice. Phospho (p)-14-3-3ζ and p-JNK expression was increased in the hippocampus 2 and 6 h after KA treatment, respectively. In immunohistochemical analysis, p-14-3-3ζ-positive cells were present in the CA3 region of the hippocampus and the central nucleus of amygdala (CeA) of KA-treated mice. Thus, phosphorylation of 14-3-3ζ at serine 58 may play an important role in KA-induced hippocampal and amygdaloid neuronal damage.
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Affiliation(s)
- Eun Ae Jeong
- Department of Anatomy and Neurobiology, Institute of Health Sciences, Medical Research Center for Neural Dysfunction, Biomedical Center (BK21), Gyeongsang National University School of Medicine, Jinju, Korea
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Liu X, Wen F, Yang J, Chen L, Wei YQ. A review of current applications of mass spectrometry for neuroproteomics in epilepsy. MASS SPECTROMETRY REVIEWS 2010; 29:197-246. [PMID: 19598206 DOI: 10.1002/mas.20243] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The brain is unquestionably the most fascinating organ, and the hippocampus is crucial in memory storage and retrieval and plays an important role in stress response. In temporal lobe epilepsy (TLE), the seizure origin typically involves the hippocampal formation. Despite tremendous progress, current knowledge falls short of being able to explain its function. An emerging approach toward an improved understanding of the complex molecular mechanisms that underlie functions of the brain and hippocampus is neuroproteomics. Mass spectrometry has been widely used to analyze biological samples, and has evolved into an indispensable tool for proteomics research. In this review, we present a general overview of the application of mass spectrometry in proteomics, summarize neuroproteomics and systems biology-based discovery of protein biomarkers for epilepsy, discuss the methodology needed to explore the epileptic hippocampus proteome, and also focus on applications of ingenuity pathway analysis (IPA) in disease research. This neuroproteomics survey presents a framework for large-scale protein research in epilepsy that can be applied for immediate epileptic biomarker discovery and the far-reaching systems biology understanding of the protein regulatory networks. Ultimately, knowledge attained through neuroproteomics could lead to clinical diagnostics and therapeutics to lessen the burden of epilepsy on society.
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Affiliation(s)
- Xinyu Liu
- National Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
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20
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Pereno GL, Balaszczuk V, Beltramino CA. Kainic acid-induced early genes activation and neuronal death in the medial extended amygdala of rats. ACTA ACUST UNITED AC 2010; 63:291-9. [PMID: 20185282 DOI: 10.1016/j.etp.2010.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 12/23/2009] [Accepted: 02/08/2010] [Indexed: 01/03/2023]
Abstract
The medial extended amygdala modulates pheromonal perception, influencing emotional and social behavior. As the amygdala is part of neuronal circuits that are very sensitive to excitability, its neurons are targets of seizures in temporal lobe epilepsy. It has been suggested that the hippocampus is strongly involved this pathology. There is less consistent information, however, on the effects of this disease in the amygdala. The effects of status epilepticus on the medial extended amygdala were analyzed by immunohistochemistry for neural stress and by the amino-cupric-silver technique for neuronal death in rats after kainic acid (KA) administration. Sixty adult Wistar male rats were used. Thirty animals received an injection of KA, and 30 were injected with saline. After 2, 4, 12, 24 and 48 h survival the brains were stained for Fos and FosB and for neuronal death. In the present study we show that KA induces Fos and FosB expression in neurons of the medial extended amygdala after 2, 4-48 h, with time courses that are different between them and from control animals. While Fos-IR peaks at 2-4 h post KA and then decreases, FosB-IR increases in the same period reaching its highest expression at 24-48 h. Moreover, KA injection produced massive neuronal death with a peak at 24 h. This neurodegeneration paralleled FosB-IR protein expression. These findings show that KA produces neuronal stress and activation of early genes and neuronal death in the medial extended amygdala, demonstrating the vulnerability of its neurons to the epileptogenic effects of KA.
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Affiliation(s)
- Germán L Pereno
- Cátedra de Neurofisiología y Psicofisiología, Facultad de Psicología, Universidad Nacional de Córdoba 5000, Córdoba, Argentina.
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Qashu F, Figueiredo TH, Aroniadou-Anderjaska V, Apland JP, Braga MFM. Diazepam administration after prolonged status epilepticus reduces neurodegeneration in the amygdala but not in the hippocampus during epileptogenesis. Amino Acids 2010; 38:189-97. [PMID: 19127342 PMCID: PMC2811765 DOI: 10.1007/s00726-008-0227-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 12/17/2008] [Indexed: 11/24/2022]
Abstract
An episode of status epilepticus (SE), if left untreated, can lead to death, or brain damage with long-term neurological consequences, including the development of epilepsy. The most common first-line treatment of SE is administration of benzodiazepines (BZs). However, the efficacy of BZs in terminating seizures is reduced with time after the onset of SE; this is accompanied by a reduced efficacy in protecting the hippocampus against neuronal damage, and is associated with impaired function and internalization of hippocampal GABA(A) receptors. In the present study, using Fluoro-Jade C staining, we found that administration of diazepam to rats at 3 h after the onset of kainic acid-induced SE, at a dose sufficient to terminate SE, had no protective effect on the hippocampus, but produced a significant reduction in neuronal degeneration in the amygdala, piriform cortex, and endopiriform nucleus, examined on days 7-9 after SE. Thus, in contrast to the hippocampus, the amygdala and other limbic structures are responsive to neuroprotection by BZs after prolonged SE, suggesting that GABA(A) receptors are not significantly altered in these structures during SE.
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Affiliation(s)
- Felicia Qashu
- Neuroscience Program, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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22
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Pereno G, Beltramino C. Differential role of gonadal hormones on kainic acid–induced neurodegeneration in medial amygdaloid nucleus of female and male rats. Neuroscience 2009; 163:952-63. [DOI: 10.1016/j.neuroscience.2009.06.059] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 06/24/2009] [Accepted: 06/27/2009] [Indexed: 11/30/2022]
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Fritsch B, Qashu F, Figueiredo TH, Aroniadou-Anderjaska V, Rogawski MA, Braga MF. Pathological alterations in GABAergic interneurons and reduced tonic inhibition in the basolateral amygdala during epileptogenesis. Neuroscience 2009; 163:415-29. [PMID: 19540312 PMCID: PMC2733834 DOI: 10.1016/j.neuroscience.2009.06.034] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 06/11/2009] [Accepted: 06/15/2009] [Indexed: 11/18/2022]
Abstract
An acute brain insult such as traumatic head/brain injury, stroke, or an episode of status epilepticus can trigger epileptogenesis, which, after a latent, seizure-free period, leads to epilepsy. The discovery of effective pharmacological interventions that can prevent the development of epilepsy requires knowledge of the alterations that occur during epileptogenesis in brain regions that play a central role in the induction and expression of epilepsy. In the present study, we investigated pathological alterations in GABAergic interneurons in the rat basolateral amygdala (BLA), and the functional impact of these alterations on inhibitory synaptic transmission, on days 7 to 10 after status epilepticus induced by kainic acid. Using design-based stereology combined with glutamic acid decarboxylase (GAD) 67 immunohistochemistry, we found a more extensive loss of GABAergic interneurons compared to the loss of principal cells. Fluoro-Jade C staining showed that neuronal degeneration was still ongoing. These alterations were accompanied by an increase in the levels of GAD and the alpha1 subunit of the GABA(A) receptor, and a reduction in the GluK1 (previously known as GluR5) subunit, as determined by Western blots. Whole-cell recordings from BLA pyramidal neurons showed a significant reduction in the frequency and amplitude of action potential-dependent spontaneous inhibitory postsynaptic currents (IPSCs), a reduced frequency but not amplitude of miniature IPSCs, and impairment in the modulation of IPSCs via GluK1-containing kainate receptors (GluK1Rs). Thus, in the BLA, GABAergic interneurons are more vulnerable to seizure-induced damage than principal cells. Surviving interneurons increase their expression of GAD and the alpha1 GABA(A) receptor subunit, but this does not compensate for the interneuronal loss; the result is a dramatic reduction of tonic inhibition in the BLA circuitry. As activation of GluK1Rs by ambient levels of glutamate facilitates GABA release, the reduced level and function of these receptors may contribute to the reduction of tonic inhibitory activity. These alterations at a relatively early stage of epileptogenesis may facilitate the progress towards the development of epilepsy.
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Affiliation(s)
- Brita Fritsch
- Epilepsy Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Felicia Qashu
- Neuroscience Program, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Taiza H. Figueiredo
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Vassiliki Aroniadou-Anderjaska
- Neuroscience Program, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Michael A. Rogawski
- Epilepsy Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Maria F.M. Braga
- Neuroscience Program, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
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Rabie T, Mühlhofer W, Bruckner T, Schwab A, Bauer AT, Zimmermann M, Bonke D, Marti HH, Schenkel J. Transient protective effect of B-vitamins in experimental epilepsy in the mouse brain. J Mol Neurosci 2009; 41:74-9. [PMID: 19777382 DOI: 10.1007/s12031-009-9286-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 08/05/2009] [Indexed: 01/28/2023]
Abstract
The regulation of programmed cell death in the nervous system of vertebrates is a complex mechanism aimed to remove superfluous or damaged cells. Epileptic seizures can lead to an activation of pathways resulting in neuronal cell death. B-vitamins might have a neuroprotective potential reducing cell death following appropriate stimulation. Here, the role of the B-vitamins B(1) (thiamine), B(6) (pyridoxine), and B(12) (cobalamine) was investigated in a mouse model of experimental epilepsy induced by kainate. B-vitamin pre-treated animals showed a significantly reduced epileptic score during the first 15 min after kainate injection. The molecular response to kainate showed a bi-phased time course with early induction of Bcl-2 expression within 12 h and a second induction after 7 days of kainate exposure. B-vitamin pre-treatment resulted in significant higher Bcl-2 expression in control animals (no kainate) and at 12 h within the early phase. Bcl-2 expression was not affected by B-vitamins within the second phase. BAX expression was not significantly influenced during the whole experiment. Three days after kainate stimulation, the number of TdT-mediated dUTP-biotin nick end labeling-positive cells in the hippocampal region was lower in B-vitamin-treated animals. Therefore, B-vitamin pre-treatment may attenuate the response to epileptic stimulation.
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Affiliation(s)
- Tamer Rabie
- Department of Physiology and Pathophysiology, University of Heidelberg Medical School, Im Neuenheimer Feld 326, 69120, Heidelberg, Germany
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Jaako K, Zharkovsky T, Zharkovsky A. Effects of repeated citalopram treatment on kainic acid-induced neurogenesis in adult mouse hippocampus. Brain Res 2009; 1288:18-28. [DOI: 10.1016/j.brainres.2009.06.089] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Revised: 06/23/2009] [Accepted: 06/26/2009] [Indexed: 02/01/2023]
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The mammalian target of rapamycin signaling pathway mediates epileptogenesis in a model of temporal lobe epilepsy. J Neurosci 2009; 29:6964-72. [PMID: 19474323 DOI: 10.1523/jneurosci.0066-09.2009] [Citation(s) in RCA: 386] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Understanding molecular mechanisms mediating epileptogenesis is critical for developing more effective therapies for epilepsy. We recently found that the mammalian target of rapamycin (mTOR) signaling pathway is involved in epileptogenesis, and mTOR inhibitors prevent epilepsy in a mouse model of tuberous sclerosis complex. Here, we investigated the potential role of mTOR in a rat model of temporal lobe epilepsy initiated by status epilepticus. Acute kainate-induced seizures resulted in biphasic activation of the mTOR pathway, as evident by an increase in phospho-S6 (P-S6) expression. An initial rise in P-S6 expression started approximately 1 h after seizure onset, peaked at 3-6 h, and returned to baseline by 24 h in both hippocampus and neocortex, reflecting widespread stimulation of mTOR signaling by acute seizure activity. After resolution of status epilepticus, a second increase in P-S6 was observed in hippocampus only, which started at 3 d, peaked 5-10 d, and persisted for several weeks after kainate injection, correlating with the development of chronic epileptogenesis within hippocampus. The mTOR inhibitor rapamycin, administered before kainate, blocked both the acute and chronic phases of seizure-induced mTOR activation and decreased kainate-induced neuronal cell death, neurogenesis, mossy fiber sprouting, and the development of spontaneous epilepsy. Late rapamycin treatment, after termination of status epilepticus, blocked the chronic phase of mTOR activation and reduced mossy fiber sprouting and epilepsy but not neurogenesis or neuronal death. These findings indicate that mTOR signaling mediates mechanisms of epileptogenesis in the kainate rat model and that mTOR inhibitors have potential antiepileptogenic effects in this model.
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Epileptogenesis alters gene expression pattern in rats subjected to amygdala-dependent emotional learning. Neuroscience 2009; 159:468-82. [DOI: 10.1016/j.neuroscience.2008.12.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 12/11/2008] [Accepted: 12/31/2008] [Indexed: 11/18/2022]
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Effects of repeated electroconvulsive shock seizures and pilocarpine-induced status epilepticus on emotional behavior in the rat. Epilepsy Behav 2009; 14:293-9. [PMID: 19068237 DOI: 10.1016/j.yebeh.2008.11.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 11/16/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
Abstract
Affective symptoms are frequently observed in patients with epilepsy. Although the etiology of these behavioral complications remains unknown, it is possible that brain damage associated with frequent or prolonged seizures may contribute to their development. To address this issue, we examined the behavioral sequelae of repeated brief seizures evoked by electroconvulsive shock (ECS) and compared them with those resulting from prolonged status epilepticus (SE) induced with pilocarpine. Using the open-field and elevated plus-maze tests, we detected the presence of behavioral alterations indicative of elevated levels of anxiety in rats that were administered a course of ECS seizures. Fear conditioning was also enhanced in these animals. However, the rats that had experienced SE exhibited less anxiety-like behavior than controls and were severely impaired in fear conditioning. These results support the notion that brain lesions caused by either brief repeated seizures or SE is sufficient to induce some affective disturbances.
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Vincent P, Mulle C. Kainate receptors in epilepsy and excitotoxicity. Neuroscience 2009; 158:309-23. [DOI: 10.1016/j.neuroscience.2008.02.066] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 02/12/2008] [Accepted: 02/21/2008] [Indexed: 10/22/2022]
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Mikati MA, Zeinieh M, Habib RA, El Hokayem J, Rahmeh A, El Sabban M, Usta J, Dbaibo G. Changes in sphingomyelinases, ceramide, Bax, Bcl2, and caspase-3 during and after experimental status epilepticus. Epilepsy Res 2008; 81:161-6. [DOI: 10.1016/j.eplepsyres.2008.05.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 05/21/2008] [Accepted: 05/23/2008] [Indexed: 11/28/2022]
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31
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Mouri G, Jimenez-Mateos E, Engel T, Dunleavy M, Hatazaki S, Paucard A, Matsushima S, Taki W, Henshall DC. Unilateral hippocampal CA3-predominant damage and short latency epileptogenesis after intra-amygdala microinjection of kainic acid in mice. Brain Res 2008; 1213:140-51. [PMID: 18455706 DOI: 10.1016/j.brainres.2008.03.061] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 03/18/2008] [Accepted: 03/18/2008] [Indexed: 02/08/2023]
Abstract
Mesial temporal lobe epilepsy is the most common, intractable seizure disorder in adults. It is associated with an asymmetric pattern of hippocampal neuron loss within the endfolium (hilus and CA3) and CA1, with limited pathology in extra-hippocampal regions. We previously developed a model of focally-evoked seizure-induced neuronal death using intra-amygdala kainic acid (KA) microinjection and characterized the acute hippocampal pathology. Here, we sought to characterize the full extent of hippocampal and potential extra-hippocampal damage in this model, and the temporal onset of epileptic seizures. Seizure damage assessed at four stereotaxic levels by FluoroJade B staining was most prominent in ipsilateral hippocampal CA3 where it extended from septal to temporal pole. Minor but significant neuronal injury was present in ipsilateral CA1. Extra-hippocampal neuronal damage was generally limited in extent and restricted to the lateral septal nucleus, injected amygdala and select regions of neocortex ipsilateral to the seizure elicitation side. Continuous surface EEG recorded with implanted telemetry units in freely-moving mice detected spontaneous, epileptic seizures by five days post-KA in all mice. Epileptic seizure number averaged 1-4 per day. Hippocampi from epileptic mice 15 days post-KA displayed unilateral CA3 lesions, astrogliosis and increased neuropeptide Y immunoreactivity suggestive of mossy fiber rearrangement. These studies characterize a mouse model of unilateral hippocampal-dominant neuronal damage and short latency epileptogenesis that may be suitable for studying the cell and molecular pathogenesis of human mesial temporal lobe epilepsy.
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Affiliation(s)
- Genshin Mouri
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin, 2, Ireland
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Yilmazer-Hanke DM, Faber-Zuschratter H, Blümcke I, Bickel M, Becker A, Mawrin C, Schramm J. Axo-somatic inhibition of projection neurons in the lateral nucleus of amygdala in human temporal lobe epilepsy: an ultrastructural study. Exp Brain Res 2007; 177:384-99. [PMID: 17006689 DOI: 10.1007/s00221-006-0680-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Accepted: 08/15/2006] [Indexed: 10/24/2022]
Abstract
Here, we report ultrastructural alterations in the synaptic circuitry of the human amygdala related to neuronal cell densities in surgical specimens of patients suffering from temporal lobe epilepsy (TLE). The neuronal cell densities quantified in the basolateral complex of amygdala were significantly reduced only in the lateral nucleus (LA) of TLE patients as compared to autopsy or non-Ammon's horn sclerosis (AHS) controls (Nissl staining, immunostaining against the neuronal marker NeuN). For this reason, we focussed on the LA to perform a more detailed quantitative ultrastructural analysis, which revealed an inverse correlation between the number of axo-somatic inhibitory synaptic profiles at the somata of glutamic acid decarboxylase (GAD)-negative projection neurons and the extent of perisomatic fibrillary gliosis. In contrast, the density of GAD-immunoreactive interneurons positively correlated with the number of axo-somatic inhibitory synaptic profiles. The fibrillary material in perisomatic glial cell processes was preferentially labeled by the astroglial marker S100B. In addition, a qualitative study of the dendrites of GAD- and parvalbumin (PARV)-containing interneurons showed that they were often contacted by asymmetrical excitatory synapses. Our results are in line with anatomical data from rodents and cats, which show that amygdalar interneurons form axo-somatic inhibitory synapses on GAD-negative projection neurons, whereas the interneurons themselves receive excitatory input from recurrent collaterals of projection neurons and from cortico- and thalamo-amygdalar afferents. The structural reorganization patterns observed in the GABAergic circuitry are compatible with a reduced feedback or feed forward inhibition of amygdalar projection neurons in human TLE.
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Alvestad S, Goa PE, Qu H, Risa Ø, Brekken C, Sonnewald U, Haraldseth O, Hammer J, Ottersen OP, Håberg A. In vivo mapping of temporospatial changes in manganese enhancement in rat brain during epileptogenesis. Neuroimage 2007; 38:57-66. [PMID: 17822925 DOI: 10.1016/j.neuroimage.2007.07.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 05/31/2007] [Accepted: 07/20/2007] [Indexed: 10/23/2022] Open
Abstract
Mesial temporal lobe epilepsy is associated with structural and functional abnormalities, such as hippocampal sclerosis and axonal reorganization. The temporal evolution of these changes remains to be determined, and there is a need for in vivo imaging techniques that can uncover the epileptogenic processes at an early stage. Manganese-enhanced magnetic resonance imaging may be useful in this regard. The aim of this study was to analyze the temporospatial changes in manganese enhancement in rat brain during the development of epilepsy subsequent to systemic kainate application (10 mg/kg i.p.). MnCl(2) was given systemically on day 2 (early), day 15 (latent), and 11 weeks (chronic phase) after the initial status epilepticus. Twenty-four hours after MnCl(2) injection T1-weighted 3D MRI was performed followed by analysis of manganese enhancement. In the medial temporal lobes, there was a pronounced decrease in manganese enhancement in CA1, CA3, dentate gyrus, entorhinal cortex and lateral amygdala in the early phase. In the latent and chronic phases, recovery of the manganese enhancement was observed in all these structures except CA1. A significant increase in manganese enhancement was detected in the entorhinal cortex and the amygdala in the chronic phase. In the latter phase, the structurally intact cerebellum showed significantly decreased manganese enhancement. The highly differentiated changes in manganese enhancement are likely to represent the net outcome of a number of pathological and pathophysiological events, including cell loss and changes in neuronal activity. Our findings are not consistent with the idea that manganese enhancement primarily reflects changes in glial cells.
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Affiliation(s)
- Silje Alvestad
- Department of Neuroscience, Norwegian University of Science and Technology (NTNU), N-7489 Trondheim, Norway
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Narkilahti S, Jutila L, Alafuzoff I, Karkola K, Paljärvi L, Immonen A, Vapalahti M, Mervaala E, Kälviäinen R, Pitkänen A. Increased expression of caspase 2 in experimental and human temporal lobe epilepsy. Neuromolecular Med 2007; 9:129-44. [PMID: 17627033 DOI: 10.1007/bf02685887] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 09/20/2006] [Accepted: 09/25/2006] [Indexed: 01/24/2023]
Abstract
Temporal lobe epilepsy (TLE) is often caused by a neurodegenerative brain insult that triggers epileptogenesis, and eventually results in spontaneous seizures, i.e., epilepsy. Understanding the mechanisms of cell death is a key for designing new drug therapies for preventing the neurodegeneration associated with TLE. Here, we investigated the expression of caspase 2, a protein involved in programmed cell death, during the course of epilepsy. We investigated caspase 2 expression in hippocampal samples derived from patients operated on for drug refractory TLE. To understand the evolution of altered-caspase 2 expression during the epileptic process, we also examined caspase 2 expression and activity in the rat hippocampus after status epilepticus-induced acute damage, during epileptogenesis, and after the onset of epilepsy. Caspase 2 expression was enhanced in the hippocampal neurons in chronic TLE patients. In rats, status epilepticus-induced caspase 2 labeling paralleled the progression of neurodegeneration. Proteolytic activation and cleavage of caspase 2 was also detected in the rat brain undergoing epileptogenesis. Our data suggest that caspase 2-mediated programmed cell death participates in the seizure-induced degenerative process in experimental and human TLE.
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Affiliation(s)
- Susanna Narkilahti
- A.I. Virtanen Institute for Molecular Sciences, University of Kuopio, and Department of Neurology, Kuopio University Hospital, Finland.
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Tokuhara D, Sakuma S, Hattori H, Matsuoka O, Yamano T. Kainic acid dose affects delayed cell death mechanism after status epilepticus. Brain Dev 2007; 29:2-8. [PMID: 16790331 DOI: 10.1016/j.braindev.2006.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 04/12/2006] [Accepted: 05/08/2006] [Indexed: 01/05/2023]
Abstract
Kainic acid (KA)-induced status epilepticus (SE) produces hippocampal neuronal death, which varies from necrosis to apoptosis or programmed cell death (PCD). We examined whether the type of neuronal death was dependent on KA dose. Adult rats were induced SE by intraperitoneal injection of KA at 9 mg/kg (K9) or 12 mg/kg (K12). Hippocampal neuronal death was assessed by TUNEL staining, electron microscopy, and Western blotting of caspase-3 on days 1, 3 and 7 after SE induction. K12 rats showed higher a mortality rate and shorter latency to the onset of SE when compared with K9 rats. In both groups, acidophilic and pyknotic neurons were evident in CA1 at 24h after SE and neuronal loss developed from day 3. The degenerated neurons became TUNEL-positive on days 3 and 7 in K9 rats but not in K12 rats. Caspase-3 activation was detected on days 3 and 7 in K9 rats but was undetectable in K12 rats. Ultrastructural study revealed shrunken neurons exhibiting pyknotic nuclei containing small and dispersed chromatin clumps 24h after SE in CA1. No cells exhibited apoptosis. On days 3 and 7, the degenerated neurons were necrotic with high electron density and small chromatin clumps. There were no ultrastructural differences between the K9 and K12 groups. These results revealed that differences in KA dose affected the delayed cell death (3 and 7 days after SE); however, no effect was seen on the early cell death (24h after SE). Moderate-dose KA induced necrosis, while low-dose KA induced PCD.
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Affiliation(s)
- Daisuke Tokuhara
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan.
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Kemppainen EJS, Nissinen J, Pitkänen A. Fear conditioning is impaired in systemic kainic acid and amygdala-stimulation models of epilepsy. Epilepsia 2006; 47:820-9. [PMID: 16686646 DOI: 10.1111/j.1528-1167.2006.00542.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The lateral nucleus of the amygdala is critical for fear conditioning, a paradigm of emotional learning, which requires recognition of an unconditioned stimulus as aversive and association of conditioned stimuli with an unconditioned stimulus. Some patients with temporal lobe epilepsy have amygdaloid damage associated with impaired emotional learning. Fear conditioning also is impaired at least in some animal models of epilepsy. We studied whether contextual or tone-cued fear conditioning is impaired in two status epilepticus models of epilepsy and whether impairment correlates with the extent of damage in the lateral nucleus of the amygdala. METHODS We induced epilepsy in rats by either systemic kainic acid administration or electrical amygdala stimulation. Behavioral reactions in all phases of fear conditioning were analyzed from videotapes. Damage to the lateral nucleus of the amygdala was analyzed from thionin-stained sections both histologically and by volumetry. RESULTS Immediate reflexive responses to unconditioned and conditioned stimuli were preserved, whereas the freezing response to an unconditioned stimulus was reduced. Contextual conditioning was severely impaired, whereas tone-cued conditioning was better preserved. The lateral nucleus pathology did not correlate with impaired fear conditioning. CONCLUSIONS These data suggest that processing of complex contextual stimuli is severely affected in experimental epilepsy, whereas conditioning to simple cues is better preserved.
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Affiliation(s)
- E J Samuli Kemppainen
- Epilepsy Research Laboratory, A. I. Virtanen Institute for Molecular Sciences, University of Kuopio, Finland
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Abstract
OBJECTIVES The present study aimed to investigate the levels of the biochemical markers of apoptosis (soluble Fas and Bcl-2) in the sera of children and adolescents with idiopathic epilepsy. MATERIALS AND METHODS The study included 30 children and adolescents (mean age 8.03 +/- 4.49 years) with idiopathic epilepsy, 16 of them were newly diagnosed, and 15 clinically healthy control subjects. Of the included patients, 22 had focal seizures and eight had generalized seizures. In addition to laboratory and radiological investigations needed for diagnosis and follow-up, soluble Fas (s.Fas) and Bcl-2 were assayed in sera of patients and controls by enzyme-linked immunosorbent assay technique. RESULTS Serum levels of s.Fas and Bcl-2 were significantly higher in the patients group than in the control group; however, their levels were comparable in patients with different seizure types. Levels of s.Fas correlated positively with seizure severity and negatively with the duration from the last attack. Bcl-2 levels were positively correlated to each of the duration of epilepsy, the severity of seizures and its frequency. There was a significant positive correlation between serum levels of s.Fas and that of Bcl-2 and both were significantly increased in patients with uncontrolled epilepsy. CONCLUSION The present data demonstrate that markers of apoptosis, both the proapoptotic Fas and the anti-apoptotic Bcl-2, were proportionately elevated in sera of patients with idiopathic epilepsy, and their levels were related to the seizure severity and frequency.
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Affiliation(s)
- M A El-Hodhod
- Department of Pediatrics, Ain Shams University, Cairo, Egypt.
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de Guzman P, Inaba Y, Biagini G, Baldelli E, Mollinari C, Merlo D, Avoli M. Subiculum network excitability is increased in a rodent model of temporal lobe epilepsy. Hippocampus 2006; 16:843-60. [PMID: 16897722 DOI: 10.1002/hipo.20215] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In this study, we used in vitro electrophysiology along with immunohistochemistry and molecular techniques to study the subiculum--a limbic structure that gates the information flow from and to the hippocampus--in pilocarpine-treated epileptic rats. Comparative data were obtained from age-matched nonepileptic controls (NEC). Subicular neurons in hippocampal-entorhinal cortex (EC) slices of epileptic rats were: (i) hyperexcitable when activated by CA1 or EC inputs; and (ii) generated spontaneous postsynaptic potentials at higher frequencies than NEC cells. Analysis of pharmacologically isolated, GABA(A) receptor-mediated inhibitory postsynaptic potentials revealed more positive reversal potentials in epileptic tissue (-67.8 +/- 6.3 mV, n = 16 vs. -74.8 +/- 3.6 mV in NEC, n = 13; P < 0.001) combined with a reduction in peak conductance (17.6 +/- 11.3 nS vs. 41.1 +/- 26.7 nS in NEC; P < 0.003). These electrophysiological data correlated in the epileptic subiculum with (i) reduced levels of mRNA expression and immunoreactivity of the neuron-specific potassium-chloride cotransporter 2; (ii) decreased number of parvalbumin-positive cells; and (iii) increased synaptophysin (a putative marker of sprouting) immunoreactivity. These findings identify an increase in network excitability within the subiculum of pilocarpine-treated, epileptic rats and point at a reduction in inhibition as an underlying mechanism.
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Affiliation(s)
- Philip de Guzman
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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Fujikawa DG. Prolonged seizures and cellular injury: understanding the connection. Epilepsy Behav 2005; 7 Suppl 3:S3-11. [PMID: 16278099 DOI: 10.1016/j.yebeh.2005.08.003] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Accepted: 08/17/2005] [Indexed: 10/25/2022]
Abstract
Status epilepticus (SE)-induced neuronal death is morphologically necrotic and is initiated by excessive glutamate release, which activates postsynaptic N-methyl-D-aspartate (NMDA) receptors and triggers receptor-mediated calcium influx (excitotoxicity). This results in activation of intracellular proteases and neuronal nitric oxide synthase, with generation of free radicals, and damage to cellular membranes, structural proteins, and essential enzymes. Programmed cell death mechanisms, such as p53 activation, activation of cell death-promoting Bcl-2 family members, and endonuclease-induced DNA laddering, occur in SE-induced neuronal death. Caspase-independent excitotoxic mechanisms, such as NMDA-induced calpain I activation, with activation and translocation of the cell death-promoting Bcl-2 family member Bid from cytoplasm to mitochondria, and subsequent translocation of apoptosis-inducing factor and endonuclease G to nuclei (which cause large-scale and internucleosomal DNA cleavage, respectively), may be triggered by SE. Poly(ADP-ribose) polymerase-1 (PARP-1) activation and cysteinyl cathepsin and DNase II release from lysosomes may occur following SE as well, but these events await future investigation. In the future, rational combinations of central nervous system-penetrable neuroprotective agents, based on our knowledge of excitotoxic mechanisms, may be useful in refractory human SE.
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Affiliation(s)
- Denson G Fujikawa
- Experimental Neurology Laboratory, VA Greater Los Angeles Healthcare System, Sepulveda, CA, USA.
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Chen S, Buckmaster PS. Stereological analysis of forebrain regions in kainate-treated epileptic rats. Brain Res 2005; 1057:141-52. [PMID: 16122711 DOI: 10.1016/j.brainres.2005.07.058] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Revised: 07/21/2005] [Accepted: 07/22/2005] [Indexed: 12/18/2022]
Abstract
Patients and models of temporal lobe epilepsy display neuron loss in the hippocampal formation, but neuropathological changes also occur in other forebrain regions. We sought to evaluate the specificity and extent of volume loss of the major forebrain regions in epileptic rats months after kainate-induced status epilepticus. In systematic series of Nissl-stained sections, the areas of major forebrain regions were measured, and volumes were estimated using the Cavalieri principle. In some regions, the optical fractionator method was used to estimate neuron numbers. Most kainate-treated rats showed significant volume loss in the amygdala, olfactory cortex, and septal region, but others displayed different patterns, with significant loss only in the hippocampus or thalamus, for example. Average volume loss was most severe in the amygdala and olfactory cortex (82-83% of controls), especially the caudal parts of both regions. In the piriform cortex (including the endopiriform nucleus) of epileptic rats, an average of approximately one-third of Nissl-stained neurons and one-third of the GABAergic interneurons labeled by in situ hybridization for GAD67 mRNA were lost, and the extent of neuron loss was correlated with the extent of volume loss. Volumetric analysis of major forebrain regions was insensitive to specific neuron loss in subregions such as layer III of the entorhinal cortex and the hilus of the dentate gyrus. These findings provide quantitative evidence that kainate-treated rats tend to display extensive neuron and volume loss in the amygdala and olfactory cortex, although the patterns and extent of loss in forebrain regions vary considerably among individuals. In this status epilepticus-based model, extrahippocampal damage appears to be more extensive and hippocampal damage appears to be less extensive than that reported for patients with temporal lobe epilepsy.
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Affiliation(s)
- Shaoyun Chen
- Department of Comparative Medicine, Stanford University, Stanford, CA 94305-5342, USA
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Juárez BI, Portillo-Salazar H, González-Amaro R, Mandeville P, Aguirre JR, Jiménez ME. Participation of N-methyl-D-aspartate receptors on methylmercury-induced DNA damage in rat frontal cortex. Toxicology 2005; 207:223-9. [PMID: 15596253 DOI: 10.1016/j.tox.2004.09.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2004] [Revised: 09/08/2004] [Accepted: 09/11/2004] [Indexed: 11/24/2022]
Abstract
Methylmercury (MeHg) inhibits glutamate uptake by astrocytes, which can contribute to neuronal loss through excitotoxicity. We explored the extent at which this phenomenon is involved in MeHg-induced DNA damage in the rat cortex. MeHg amounts that increase extracellular glutamate (1.5, 7.5 and 15 nmol, according to previous reports) were stereotaxically injected in the frontal cortex of adult rats before DNA-damage determination by means of a quantitative TUNEL assay. After either 24 or 48 h, the cortex of all exposed animals showed significant increments of damaged DNA, compared with rats that only received sterile saline. In parallel experiments, we found that the administration of a non competitive NMDA receptor antagonist (MK-801, 10 mg/kg, i.p.) 1 h before MeHg injection, significantly reduced DNA damage. These results demonstrate that activation of NMDA receptors contributes importantly to MeHg neurotoxicity.
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Affiliation(s)
- Bertha I Juárez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, Av. V. Carranza 2405, 78210 San Luis Potosí, S.L.P., México
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Abstract
PURPOSE Several experimental models of human temporal lobe epilepsy have shown that apoptotic death of neurons is an important part of this degenerative disease. However, the role of apoptotic regulators is not clear during the epileptogenesis. Therefore we investigated the expression pattern of bcl-2 family of genes during the formation of kindling model of epilepsy in rats. METHODS We examined the expression pattern of bax, bcl-2, bcl-xL, mtd, and bcl-w both at messenger RNA (mRNA) and protein level in the brain tissues during the formation of epilepsy with kindling model in adult rats, which has been the most acceptable form of experimental model of human epilepsy. We also assessed the onset of DNA fragmentation by using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. RESULTS Animals have started to have epileptic discharges after day 10 of kindling model. Recurrent subthreshold electrical stimuli induced not only epileptic foci but also the expression of bax, an inducer of apoptosis, in this time period. Conversely, bcl-xL, which is an inhibitor of apoptosis, had an opposite pattern of expression both at mRNA and protein level during the formation of epilepsy. We did not observe DNA fragmentation by TUNEL staining. CONCLUSIONS Our study shows differential expression of Bax and Bcl-xL at the CA1 region during the formation of hippocampal kindling model. The absence of DNA fragmentation during this period suggests that epileptic changes in neurons have the potential to induce DNA fragmentation by altering the expression levels of Bax and Bcl-xL.
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MESH Headings
- Animals
- DNA Fragmentation
- Disease Models, Animal
- Electric Stimulation
- Electrodes, Implanted
- Epilepsy, Temporal Lobe/genetics
- Epilepsy, Temporal Lobe/metabolism
- Gene Expression
- Genes, bcl-2/genetics
- Genes, bcl-2/physiology
- Hippocampus/metabolism
- Hippocampus/physiology
- Immunohistochemistry
- In Situ Nick-End Labeling/methods
- Kindling, Neurologic/genetics
- Male
- Proto-Oncogene Proteins c-bcl-2/genetics
- Proto-Oncogene Proteins c-bcl-2/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- bcl-2-Associated X Protein
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Affiliation(s)
- Kamil Can Akcali
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey.
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Zienowicz M, Wisłowska A, Lehner M, Taracha E, Skórzewska A, Maciejak P, Płaźnik A. The effect of fluoxetine in a model of chemically induced seizures--behavioral and immunocytochemical study. Neurosci Lett 2004; 373:226-31. [PMID: 15619548 DOI: 10.1016/j.neulet.2004.10.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Revised: 10/01/2004] [Accepted: 10/05/2004] [Indexed: 11/16/2022]
Abstract
The aim of this study was to examine the effects of acute fluoxetine treatment on pentylenetetrazol-induced convulsions in order to shape a model of seizures associated with treatment with antidepressants in rats. Moreover, the putative role of the hippocampal formation in this respect was investigated with the help of c-fos immuncytochemistry to mark local neuronal activity. It was found that fluoxetine (10.0 mg/kg, i.p.) enhanced the proconvulsive effect of pentylenetetrazol (50.0 mg/kg, i.p.), and simultaneously inhibited pentylenetetrazol-stimulated c-Fos expression in some areas of the hippocampus. Fluoxetine pretreatment did not alter pentylenetetrazol brain concentration indicating that this phenomenon was not related to the pharmacokinetic interaction. It is suggested that inhibition by fluoxetine of some neuronal populations contributing to the local feedback mechanism controlling excessive epileptiform discharges within the hippocampus might lead to an increase in epileptic activity. The reported in the present paper fluoxetine versus pentylenetetrazol interaction may, therefore, serve as a model of seizures associated with treatment with antidepressants.
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Affiliation(s)
- Małgorzata Zienowicz
- Department of Experimental and Clinical Pharmacology, Warsaw Medical University, 26/28 Krakowskie Przedmiescie Street, 00-927 Warsaw, Poland
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Nairismägi J, Gröhn OHJ, Kettunen MI, Nissinen J, Kauppinen RA, Pitkänen A. Progression of Brain Damage after Status Epilepticus and Its Association with Epileptogenesis: A Quantitative MRI Study in a Rat Model of Temporal Lobe Epilepsy. Epilepsia 2004; 45:1024-34. [PMID: 15329065 DOI: 10.1111/j.0013-9580.2004.08904.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE This study examined the hypothesis that neurodegeneration continues after status epilepticus (SE) ends and that the severity of damage at the early phase of the epileptogenic process predicts the outcome of epilepsy in a long-term follow-up. METHODS SE was induced in rats by electrical stimulation of the amygdala, and the progression of structural alterations was monitored with multiparametric magnetic resonance imaging (MRI). Absolute T2, T1rho, and diffusion (Dav) images were acquired from amygdala, piriform cortex, thalamus, and hippocampus for < or = 4.5 months after SE. Frequency and type of spontaneous seizures were monitored with video-electroencephalography recordings. Histologic damage was assessed from Nissl, Timm, and Fluoro-Jade B preparations at 8 months. RESULTS At the acute phase (2 days after SE induction), quantitative MRI revealed increased T2, T1rho, and Dav values in the primary focal area (amygdala), reflecting disturbed water homeostasis and possible early structural damage. Pathologic T2 and T1rho were observed in mono- or polysynaptically connected regions, including the piriform cortex, midline thalamus, and hippocampus. The majority of acute MRI abnormalities were reversed by 9 days after SE. In later time points (> 20 days after induction), both the T1rho and diffusion MRI revealed secondarily affected areas, most predominantly in the amygdala and hippocampus. At this time, animals began to have spontaneous seizures. The initial pathology revealed by MRI had a low predictive value for the subsequent severity of epilepsy and tissue damage. CONCLUSIONS The results demonstrate progressive neurodegeneration after SE in the amygdala and the hippocampus and stress the need for continued administration of neuroprotectants in the treatment of SE even after electrographic seizure activity has ceased.
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Affiliation(s)
- Jaak Nairismägi
- National Bio-NMR Facility and Department of Biomedical NMR, University of Kuopio, Kuopio, Finland
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Niittykoski M, Nissinen J, Penttonen M, Pitkänen A. Electrophysiologic changes in the lateral and basal amygdaloid nuclei in temporal lobe epilepsy: an in vitro study in epileptic rats. Neuroscience 2004; 124:269-81. [PMID: 14980378 DOI: 10.1016/j.neuroscience.2003.11.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2003] [Indexed: 10/26/2022]
Abstract
The functional consequences of neuronal loss during epileptogenesis in the lateral and basal amygdaloid nuclei are poorly understood. The present study tested the hypothesis that electrical responsiveness varies in different amygdaloid nuclei in the chronically epileptic amygdala. Further, we examined the amygdaloid region most prone to seizure initiation. Epileptogenesis was triggered in 20 rats by inducing status epilepticus (SE) with electrical stimulation of the lateral nucleus of the amygdala. Electrode-implanted non-stimulated rats served as controls. The occurrence and duration of spontaneous seizures were monitored with video-electroencephalography (EEG) at 8-9 weeks after SE. Thereafter, animals were killed and extracellular recordings were made from slices of both amygdalas. In the lateral nucleus of epileptic animals, the frequency of spontaneous responses was reduced compared with controls (P < 0.05). The amplitudes of evoked field responses were reduced (P < 0.01), whereas paired pulse (PP) facilitation was enhanced (P < or = 0.05). In the basal nucleus of the epileptic animals, PP facilitation was enhanced (P < 0.05) and sensitivity to 4-aminopyridine (4-AP)-induced epileptiform activity was increased compared with controls (P < 0.05). In the epileptic animals, the basal nucleus was also more sensitive than the lateral nucleus to 4-AP-induced epileptiform activity (P < 0.05). Correlation analysis indicated that longer SE duration was associated with longer half widths (P = 0.001) and smaller slopes (P < 0.05) of evoked responses as well as with attenuated PP facilitation (P<0.01). Moreover, a higher frequency of spontaneous seizures was associated with longer half widths (P < 0.05) and smaller slopes (P < 0.05) of evoked responses as well as with enhanced PP facilitation (P < 0.05). These data suggest that there is a reduced release of glutamate and reduced inhibition in the lateral and basal amygdaloid nuclei in epileptic animals. Further, the basal nucleus is more prone to epileptic activity than the lateral nucleus. Finally, the severity of SE and spontaneous seizures in vivo is associated with electrophysiologic alterations in vitro.
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Affiliation(s)
- M Niittykoski
- Epilepsy Research Laboratory, Department of Neurobiology, A.I. Virtanen Institute for Molecular Sciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland
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Schindler CK, Shinoda S, Simon RP, Henshall DC. Subcellular distribution of Bcl-2 family proteins and 14-3-3 within the hippocampus during seizure-induced neuronal death in the rat. Neurosci Lett 2004; 356:163-6. [PMID: 15036620 DOI: 10.1016/j.neulet.2003.11.048] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2003] [Revised: 11/12/2003] [Accepted: 11/16/2003] [Indexed: 11/17/2022]
Abstract
The molecular regulation of seizure-induced neuronal death may involve interactions between proteins of the Bcl-2 and 14-3-3 families. To further examine these pathways we performed subcellular fractionation on hippocampi obtained following a brief period of status epilepticus in the rat. Western blotting determined seizures induced caspase-8 cleavage and increased Bcl-w levels within the cytoplasm. Bax, Bad and Bid were largely present within the cytoplasm before and after seizures, although some Bax and, following seizures, truncated Bid was detected in mitochondria. Levels of 14-3-3 were significantly reduced in the cytoplasm and microsomal fractions. These data establish the expression and distribution profile of key Bcl-2 family proteins and the signaling chaperone 14-3-3 in the rat and provide additional evidence for the activation of programmed cell death pathways by seizures.
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Affiliation(s)
- Clara K Schindler
- Robert S. Dow Neurobiology Laboratories, Legacy Clinical Research and Technology Center, 1225 NE 2nd Avenue, Portland, OR 97232, USA
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Akhtar RS, Ness JM, Roth KA. Bcl-2 family regulation of neuronal development and neurodegeneration. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2004; 1644:189-203. [PMID: 14996503 DOI: 10.1016/j.bbamcr.2003.10.013] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2003] [Accepted: 10/27/2003] [Indexed: 01/03/2023]
Abstract
Neuronal cell death is a key feature of both normal nervous system development and neuropathological conditions. The Bcl-2 family, via its regulation of both caspase-dependent and caspase-independent cell death pathways, is uniquely positioned to critically control neuronal cell survival. Targeted gene disruptions of specific bcl-2 family members and the generation of transgenic mice overexpressing anti- or pro-apoptotic Bcl-2 family members have confirmed the importance of the Bcl-2 family in the nervous system. Data from studies of human brain tissue and experimental animal models of neuropathological conditions support the hypothesis that the Bcl-2 family regulates cell death in the mature nervous system and suggest that pharmacological manipulation of Bcl-2 family action could prove beneficial in the treatment of human neurological conditions such as stroke and neurodegenerative diseases.
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Affiliation(s)
- Rizwan S Akhtar
- Division of Pediatric Neurology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Kemppainen S, Pitkänen A. Damage to the amygdalo-hippocampal projection in temporal lobe epilepsy: A tract-tracing study in chronic epileptic rats. Neuroscience 2004; 126:485-501. [PMID: 15207366 DOI: 10.1016/j.neuroscience.2004.03.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2004] [Indexed: 10/26/2022]
Abstract
Both the amygdala and hippocampus are damaged in drug-resistant temporal lobe epilepsy (TLE), suggesting that amygdalo-hippocampal interconnectivity is compromised in TLE. Therefore, we examined one of the major projections from the amygdala to the hippocampus, the projection from the amygdala to the CA1 subfield of the hippocampus/subiculum border region, and assessed whether it is preserved in rats with spontaneous seizures. Male Wistar rats were injected with kainic acid (9 mg/kg, i.p.) to induce chronic epilepsy. The occurrence of spontaneous seizures was monitored 5 or 15 weeks later by video-recording the rats for up to 5 days. Saline-injected animals served as controls. Thereafter, the retrograde tracer Fluoro-gold was injected into the border region of the temporal CA1/subiculum. Rats were perfused for histology 1-2 weeks later and sections were immunohistochemically processed to detect Fluoro-gold-positive cells. Comparison of the labeling in control and epileptic tissue indicated that a large cluster of retrogradely labeled cells in the parvicellular division of the basal nucleus was well preserved in epilepsy, even when the neuronal damage in the amygdala was substantial. Another large cluster of retrogradely labeled cells in the lateral division of the amygdalo-hippocampal area, the posterior cortical nucleus (part of the vomeronasal amygdala), and the periamygdaloid cortex (part of the olfactory amygdala), however, had disappeared in epileptic brain in parallel to severe neuronal loss in these nuclei. These data demonstrate that a projection from the parvicellular division of the basal nucleus to the temporal CA1/subiculum region is resistant to status epilepticus-induced neuronal damage and provides a candidate pathway by which seizure activity can spread and propagate from the amygdala to the hippocampal formation.
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Affiliation(s)
- S Kemppainen
- Epilepsy Research Laboratory, A. I. Virtanen Institute for Molecular Sciences, University of Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland
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Benini R, D'Antuono M, Pralong E, Avoli M. Involvement of amygdala networks in epileptiform synchronization in vitro. Neuroscience 2003; 120:75-84. [PMID: 12849742 DOI: 10.1016/s0306-4522(03)00262-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We used field potential and intracellular recordings in rat brain slices that included the hippocampus, a portion of the basolateral/lateral nuclei of the amygdala (BLA) and the entorhinal cortex (EC). Bath application of the convulsant 4-aminopyridine (50 microM) to slices (n=12) with reciprocally connected areas, induced short-lasting interictal-like epileptiform discharges that (i) occurred at intervals of 1.2-2.8 s, (ii) originated in CA3, and (iii) spread to EC and BLA. Cutting the Schaffer collaterals abolished them in both parahippocampal areas where slower interictal-like (interval of occurrence=4-17 s) and prolonged ictal-like discharges (duration=15+/-6.9 s, mean+/-S.D., n=7) appeared. These new types of epileptiform activity originated in either EC or BLA. Similar findings were obtained in slices (n=19) in which the hippocampus outputs were not connected with the EC and BLA under control conditions. Cutting the EC-BLA connections made independent slow interictal- and ictal-like activities appear in both areas (n=5). NMDA receptor antagonism (n=6) abolished ictal-like discharges and reduced the duration of the slow interictal-like events. Repetitive stimulation of BLA at 0.5-1 Hz in Schaffer collateral cut slices, induced interictal-like epileptiform depolarizations in EC and reversibly blocked ictal-like activity (n=14). Thus, CA3 outputs in intact slices entrain EC and BLA networks into an interictal-like pattern that inhibits the propensity of these parahippocampal areas to generate prolonged ictal-like paroxysms. Accordingly, NMDA receptor-dependent ictal-like events are initiated in BLA or EC once the propagation of CA3-driven interictal-like discharges to these areas is abated by cutting the Schaffer collaterals. Similar inhibitory effects also occur by activating BLA outputs directed to EC at rates that mimic the CA3-driven interictal-like pattern.
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Affiliation(s)
- R Benini
- Montreal Neurological Institute and Departments of Neurology and Neurosurgery, and of Physiology, McGill University, Montreal, QC, H3A 2B4, Canada
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Condorelli DF, Trovato-Salinaro A, Mudò G, Mirone MB, Belluardo N. Cellular expression of connexins in the rat brain: neuronal localization, effects of kainate-induced seizures and expression in apoptotic neuronal cells. Eur J Neurosci 2003; 18:1807-27. [PMID: 14622215 DOI: 10.1046/j.1460-9568.2003.02910.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The identification of connexins (Cxs) expressed in neuronal cells represents a crucial step for understanding the direct communication between neurons and between neuron and glia. In the present work, using a double-labelling method combining in situ hybridization for Cx mRNAs with immunohistochemical detection for neuronal markers, we provide evidence that, among cerebral connexins (Cx26, Cx32, Cx36, Cx37, Cx40, Cx43, Cx45 and Cx47), only Cx45 and Cx36 mRNAs are localized in neuronal cells in both developing and adult rat brain. In order to establish whether connexin expression is influenced in vivo by abnormal neuronal activity, we examined the short-term effects of kainate-induced seizures. The results revealed an unexpected expression of Cx26 and Cx45 mRNA in neuronal cells undergoing apoptotic cell death in the CA3-CA4, in the hilus of the hippocampus and in other brain regions involved in seizure-induced lesion. However, the expression of Cx26 and Cx45 mRNAs was not associated with detectable expression of corresponding proteins as evaluated by immunohistochemistry with specific antibodies. Moreover, in the same brain regions Cx32 and Cx43 were up-regulated in non-neruronal cells whereas the neuronal Cx36 was down-regulated. Taken together the present results provide novel information regarding the specific subpopulation of neurons expressing Cx45 and raise the question of the meaning of connexin mRNA expression in the neuronal apoptotic process.
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Affiliation(s)
- Daniele F Condorelli
- Department of Chemical Sciences, Section of Biochemistry and Molecular Biology, University of Catania, Catania, Italy
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