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Lai S, Zhang L, Tu X, Ma X, Song Y, Cao K, Li M, Meng J, Shi Y, Wu Q, Yang C, Lan Z, Lau CG, Shi J, Ma W, Li S, Xue YX, Huang Z. Termination of convulsion seizures by destabilizing and perturbing seizure memory engrams. SCIENCE ADVANCES 2024; 10:eadk9484. [PMID: 38507477 PMCID: PMC10954199 DOI: 10.1126/sciadv.adk9484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/13/2024] [Indexed: 03/22/2024]
Abstract
Epileptogenesis, arising from alterations in synaptic strength, shares mechanistic and phenotypic parallels with memory formation. However, direct evidence supporting the existence of seizure memory remains scarce. Leveraging a conditioned seizure memory (CSM) paradigm, we found that CSM enabled the environmental cue to trigger seizure repetitively, and activating cue-responding engram cells could generate CSM artificially. Moreover, cue exposure initiated an analogous process of memory reconsolidation driven by mammalian target of rapamycin-brain-derived neurotrophic factor signaling. Pharmacological targeting of the mammalian target of rapamycin pathway within a limited time window reduced seizures in animals and interictal epileptiform discharges in patients with refractory seizures. Our findings reveal a causal link between seizure memory engrams and seizures, which leads us to a deeper understanding of epileptogenesis and points to a promising direction for epilepsy treatment.
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Affiliation(s)
- Shirong Lai
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
- School of Health Management, Xihua University, Chengdu 610039, China
| | - Libo Zhang
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing 100191, China
- Shenzhen Public Service Platform for Clinical Application of Medical Imaging, Shenzhen Key Laboratory for Drug Addiction and Medication Safety, Department of Ultrasound, Peking University Shenzhen Hospital, Shenzhen-PKU-HKUST Medical Center, Shenzhen 518036, China
| | - Xinyu Tu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Xinyue Ma
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yujing Song
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Kexin Cao
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing 100191, China
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing 100191, China
| | - Miaomiao Li
- Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110022, China
| | - Jihong Meng
- Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110022, China
| | - Yiqiang Shi
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Qing Wu
- School of Health Management, Xihua University, Chengdu 610039, China
| | - Chen Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Zifan Lan
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | | | - Jie Shi
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing 100191, China
| | - Weining Ma
- Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110022, China
| | - Shaoyi Li
- Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110022, China
| | - Yan-Xue Xue
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing 100191, China
- Chinese Institute for Brain Research, Beijing 102206, China
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
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2
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Perversi F, Costa C, Labate A, Lattanzi S, Liguori C, Maschio M, Meletti S, Nobili L, Operto FF, Romigi A, Russo E, Di Bonaventura C. The broad-spectrum activity of perampanel: state of the art and future perspective of AMPA antagonism beyond epilepsy. Front Neurol 2023; 14:1182304. [PMID: 37483446 PMCID: PMC10359664 DOI: 10.3389/fneur.2023.1182304] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 06/07/2023] [Indexed: 07/25/2023] Open
Abstract
Glutamate is the brain's main excitatory neurotransmitter. Glutamatergic neurons primarily compose basic neuronal networks, especially in the cortex. An imbalance of excitatory and inhibitory activities may result in epilepsy or other neurological and psychiatric conditions. Among glutamate receptors, AMPA receptors are the predominant mediator of glutamate-induced excitatory neurotransmission and dictate synaptic efficiency and plasticity by their numbers and/or properties. Therefore, they appear to be a major drug target for modulating several brain functions. Perampanel (PER) is a highly selective, noncompetitive AMPA antagonist approved in several countries worldwide for treating different types of seizures in various epileptic conditions. However, recent data show that PER can potentially address many other conditions within epilepsy and beyond. From this perspective, this review aims to examine the new preclinical and clinical studies-especially those produced from 2017 onwards-on AMPA antagonism and PER in conditions such as mesial temporal lobe epilepsy, idiopathic and genetic generalized epilepsy, brain tumor-related epilepsy, status epilepticus, rare epileptic syndromes, stroke, sleep, epilepsy-related migraine, cognitive impairment, autism, dementia, and other neurodegenerative diseases, as well as provide suggestions on future research agenda aimed at probing the possibility of treating these conditions with PER and/or other AMPA receptor antagonists.
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Affiliation(s)
| | - Cinzia Costa
- Section of Neurology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
- Neurological Clinic, S. Maria Della Misericordia Hospital, Perugia, Italy
| | - Angelo Labate
- Neurophysiopatology and Movement Disorders Clinic, University of Messina, Messina, Italy
| | - Simona Lattanzi
- Neurological Clinic, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Claudio Liguori
- Department of Systems Medicine, University of Rome ‘Tor Vergata”, Rome, Italy
- Epilepsy Center, Neurology Unit, University Hospital “Tor Vergata”, Rome, Italy
| | - Marta Maschio
- Center for Tumor-Related Epilepsy, UOSD Neuro-Oncology, IRCCS Regina Elena National Cancer Institute, Rome, Italy
| | - Stefano Meletti
- Neurology Department, University Hospital of Modena, Modena, Italy
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio-Emilia, Modena, Italy
| | - Lino Nobili
- Child Neuropsychiatry Unit, IRCCS Istituto G. Gaslini, Genova, Italy
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Child and Maternal Health (DINOGMI), University of Genova, Genova, Italy
| | - Francesca Felicia Operto
- Child and Adolescent Neuropsychiatry Unit, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
- Department of Science of Health, School of Medicine, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Andrea Romigi
- Sleep Medicine Center, Neurological Mediterranean Institute IRCCS Neuromed, Pozzilli, Italy
- Psychology Faculty, International Telematic University Uninettuno, Rome, Italy
| | - Emilio Russo
- Department of Science of Health, School of Medicine, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Carlo Di Bonaventura
- Epilepsy Unit, Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
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3
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Kapur J, Long L, Dixon-Salazar T. Consequences: Bench to home. Epilepsia 2022; 63 Suppl 1:S14-S24. [PMID: 35999173 DOI: 10.1111/epi.17342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/08/2022] [Accepted: 06/08/2022] [Indexed: 01/02/2023]
Abstract
Seizure clusters (also referred to as acute repetitive seizures) consist of several seizures interspersed with brief interictal periods. Seizure clusters can break down γ-aminobutyric acidergic (GABAergic) inhibition of dentate granule cells, leading to hyperactivation. Functional changes to GABAA receptors, which play a vital neuroinhibitory role, can include altered GABAA receptor subunit trafficking and cellular localization, intracellular chloride accumulation, and dysregulation of proteins critical to chloride homeostasis. A reduction in neuroinhibition and potentiation of excitatory neurotransmission in CA1 pyramidal neurons represent pathological mechanisms that underlie seizure clusters. Benzodiazepines are well-established treatments for seizure clusters; however, there remain barriers to appropriate care. At the clinical level, there is variability in seizure cluster definitions, such as the number and/or type of seizures associated with a cluster as well as the interictal duration between seizures. This can lead to delays in diagnosis and timely treatment. There are gaps in understanding between clinicians, their patients, and caregivers regarding acute treatment for seizure clusters, such as the use of rescue medications and emergency services. This lack of consensus to define seizure clusters in addition to a lack of education for appropriate treatment can affect quality of life for patients and place a greater burden on patient families and caregivers. For patients with seizure clusters, the sense of unpredictability can lead to continuous traumatic stress, during which patients and families live with a heightened level of anxiety. Clinicians can affect patient quality of life and clinical outcomes through improved seizure cluster education and treatment, such as the development and implementation of a personalized seizure action plan as well as prescriptions for suitable rescue medications indicated for seizure clusters and instructions for their proper use. In all, the combination of targeted therapy along with patient education and support can improve quality of life.
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Affiliation(s)
- Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, Virginia, USA
| | - Lucretia Long
- Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA
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4
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Rosen JB, Schulkin J. Hyperexcitability: From Normal Fear to Pathological Anxiety and Trauma. Front Syst Neurosci 2022; 16:727054. [PMID: 35993088 PMCID: PMC9387392 DOI: 10.3389/fnsys.2022.727054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 06/20/2022] [Indexed: 11/16/2022] Open
Abstract
Hyperexcitability in fear circuits is suggested to be important for development of pathological anxiety and trauma from adaptive mechanisms of fear. Hyperexcitability is proposed to be due to acquired sensitization in fear circuits that progressively becomes more severe over time causing changing symptoms in early and late pathology. We use the metaphor and mechanisms of kindling to examine gains and losses in function of one excitatory and one inhibitory neuropeptide, corticotrophin releasing factor and somatostatin, respectively, to explore this sensitization hypothesis. We suggest amygdala kindling induced hyperexcitability, hyper-inhibition and loss of inhibition provide clues to mechanisms for hyperexcitability and progressive changes in function initiated by stress and trauma.
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Affiliation(s)
- Jeffrey B. Rosen
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
- *Correspondence: Jeffrey B. Rosen,
| | - Jay Schulkin
- School of Medicine, University of Washington, Seattle, WA, United States
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5
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Matamoros-Angles A, Hervera A, Soriano J, Martí E, Carulla P, Llorens F, Nuvolone M, Aguzzi A, Ferrer I, Gruart A, Delgado-García JM, Del Río JA. Analysis of co-isogenic prion protein deficient mice reveals behavioral deficits, learning impairment, and enhanced hippocampal excitability. BMC Biol 2022; 20:17. [PMID: 35027047 PMCID: PMC8759182 DOI: 10.1186/s12915-021-01203-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 12/02/2021] [Indexed: 12/22/2022] Open
Abstract
Background Cellular prion protein (PrPC) is a cell surface GPI-anchored protein, usually known for its role in the pathogenesis of human and animal prionopathies. However, increasing knowledge about the participation of PrPC in prion pathogenesis contrasts with puzzling data regarding its natural physiological role. PrPC is expressed in a number of tissues, including at high levels in the nervous system, especially in neurons and glial cells, and while previous studies have established a neuroprotective role, conflicting evidence for a synaptic function has revealed both reduced and enhanced long-term potentiation, and variable observations on memory, learning, and behavior. Such evidence has been confounded by the absence of an appropriate knock-out mouse model to dissect the biological relevance of PrPC, with some functions recently shown to be misattributed to PrPC due to the presence of genetic artifacts in mouse models. Here we elucidate the role of PrPC in the hippocampal circuitry and its related functions, such as learning and memory, using a recently available strictly co-isogenic Prnp0/0 mouse model (PrnpZH3/ZH3). Results We performed behavioral and operant conditioning tests to evaluate memory and learning capabilities, with results showing decreased motility, impaired operant conditioning learning, and anxiety-related behavior in PrnpZH3/ZH3 animals. We also carried in vivo electrophysiological recordings on CA3-CA1 synapses in living behaving mice and monitored spontaneous neuronal firing and network formation in primary neuronal cultures of PrnpZH3/ZH3 vs wildtype mice. PrPC absence enhanced susceptibility to high-intensity stimulations and kainate-induced seizures. However, long-term potentiation (LTP) was not enhanced in the PrnpZH3/ZH3 hippocampus. In addition, we observed a delay in neuronal maturation and network formation in PrnpZH3/ZH3 cultures. Conclusion Our results demonstrate that PrPC promotes neuronal network formation and connectivity. PrPC mediates synaptic function and protects the synapse from excitotoxic insults. Its deletion may underlie an epileptogenic-susceptible brain that fails to perform highly cognitive-demanding tasks such as associative learning and anxiety-like behaviors. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01203-0.
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Affiliation(s)
- A Matamoros-Angles
- Molecular and Cellular Neurobiotechnology, Institute of Bioengineering of Catalonia (IBEC), Parc Científic de Barcelona, Barcelona, Spain.,Department of Cell Biology, Physiology, and Immunology, University of Barcelona, Barcelona, Spain.,CIBERNED (Network Centre of Biomedical Research of Neurodegenerative Diseases), Institute of Health Carlos III, Barcelona, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain.,Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - A Hervera
- Molecular and Cellular Neurobiotechnology, Institute of Bioengineering of Catalonia (IBEC), Parc Científic de Barcelona, Barcelona, Spain.,Department of Cell Biology, Physiology, and Immunology, University of Barcelona, Barcelona, Spain.,CIBERNED (Network Centre of Biomedical Research of Neurodegenerative Diseases), Institute of Health Carlos III, Barcelona, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - J Soriano
- Departament de Física de la Materia Condensada, University of Barcelona, Barcelona, Spain.,Institute of Complex Systems (UBICS), University of Barcelona, Barcelona, Spain
| | - E Martí
- Department of Biomedicine, University of Barcelona, Barcelona, Spain.,Bioinformatics and Genomics, Center for Genomic Regulation, Barcelona, Spain
| | - P Carulla
- Molecular and Cellular Neurobiotechnology, Institute of Bioengineering of Catalonia (IBEC), Parc Científic de Barcelona, Barcelona, Spain.,Department of Cell Biology, Physiology, and Immunology, University of Barcelona, Barcelona, Spain.,CIBERNED (Network Centre of Biomedical Research of Neurodegenerative Diseases), Institute of Health Carlos III, Barcelona, Spain
| | - F Llorens
- CIBERNED (Network Centre of Biomedical Research of Neurodegenerative Diseases), Institute of Health Carlos III, Barcelona, Spain.,Department of Neurology, University Medical School, Göttingen, Germany.,Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Catalonia, Spain
| | - M Nuvolone
- Institute of Neuropathology, University Hospital of Zürich, Zürich, Switzerland.,Amyloidosis Center, Foundation IRCCS Policlinico San Matteo, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - A Aguzzi
- Institute of Neuropathology, University Hospital of Zürich, Zürich, Switzerland
| | - I Ferrer
- CIBERNED (Network Centre of Biomedical Research of Neurodegenerative Diseases), Institute of Health Carlos III, Barcelona, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain.,Senior Consultant, Bellvitge University Hospital, IDIBELL (Bellvitge Biomedical Research Centre), L'Hospitalet de Llobregat, Spain.,Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain
| | - A Gruart
- Division of Neurosciences, Pablo de Olavide University, 41013, Seville, Spain
| | - J M Delgado-García
- Division of Neurosciences, Pablo de Olavide University, 41013, Seville, Spain.
| | - J A Del Río
- Molecular and Cellular Neurobiotechnology, Institute of Bioengineering of Catalonia (IBEC), Parc Científic de Barcelona, Barcelona, Spain. .,Department of Cell Biology, Physiology, and Immunology, University of Barcelona, Barcelona, Spain. .,CIBERNED (Network Centre of Biomedical Research of Neurodegenerative Diseases), Institute of Health Carlos III, Barcelona, Spain. .,Institute of Neuroscience, University of Barcelona, Barcelona, Spain.
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6
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Cruz Del Angel Y, Orfila JE, Herson PS, Brooks-Kayal A, González MI. Down-regulation of AMPA receptors and long-term potentiation during early epileptogenesis. Epilepsy Behav 2021; 124:108320. [PMID: 34592633 DOI: 10.1016/j.yebeh.2021.108320] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/24/2021] [Accepted: 08/31/2021] [Indexed: 10/20/2022]
Abstract
Epilepsy is a brain disorder characterized by the occurrence of recurrent spontaneous seizures. Behavioral disorders and altered cognition are frequent comorbidities affecting the quality of life of people with epilepsy. These impairments are undoubtedly multifactorial and the specific mechanisms underlying these comorbidities are largely unknown. Long-lasting alterations in synaptic strength due to changes in expression, phosphorylation, or function of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs) have been associated with alterations in neuronal synaptic plasticity. In particular, alterations in hippocampal long-term potentiation (LTP), a well-accepted model of learning and memory, have been associated with altered cognition in epilepsy. Here, we analyzed the effects of pilocarpine-induced status epilepticus (SE) on AMPARs to determine if alterations in AMPAR signaling might be one of the mechanisms contributing to altered cognition during epilepsy. We found alterations in the phosphorylation and plasma membrane expression of AMPARs. In addition, we detected altered expression of GRIP, a key scaffolding protein involved in the proper distribution of AMPARs at the neuronal cell surface. Interestingly, a functional analysis revealed that these molecular changes are linked to impaired LTP. Together, these observations suggest that seizure-induced alterations in the molecular machinery regulating AMPARs likely impact the neuron's ability to support synaptic plasticity that is required for learning and memory.
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Affiliation(s)
- Yasmin Cruz Del Angel
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - James E Orfila
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Paco S Herson
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Amy Brooks-Kayal
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Children's Hospital Colorado, Aurora, CO 80045, USA
| | - Marco I González
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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7
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Nonperiodic stimulation for the treatment of refractory epilepsy: Applications, mechanisms, and novel insights. Epilepsy Behav 2021; 121:106609. [PMID: 31704250 DOI: 10.1016/j.yebeh.2019.106609] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 10/14/2019] [Accepted: 10/14/2019] [Indexed: 11/21/2022]
Abstract
Electrical stimulation of the central nervous system is a promising alternative for the treatment of pharmacoresistant epilepsy. Successful clinical and experimental stimulation is most usually carried out as continuous trains of current or voltage pulses fired at rates of 100 Hz or above, since lower frequencies yield controversial results. On the other hand, stimulation frequency should be as low as possible, in order to maximize implant safety and battery efficiency. Moreover, the development of stimulation approaches has been largely empirical in general, while they should be engineered with the neurobiology of epilepsy in mind if a more robust, efficient, efficacious, and safe application is intended. In an attempt to reconcile evidence of therapeutic effect with the understanding of the underpinnings of epilepsy, our group has developed a nonstandard form of low-frequency stimulation with randomized interpulse intervals termed nonperiodic stimulation (NPS). The rationale was that an irregular temporal pattern would impair neural hypersynchronization, which is a hallmark of epilepsy. In this review, we start by briefly revisiting the literature on the molecular, cellular, and network level mechanisms of epileptic phenomena in order to highlight this often-overlooked emergent property of cardinal importance in the pathophysiology of the disease. We then review our own studies on the efficacy of NPS against acute and chronic experimental seizures and also on the anatomical and physiological mechanism of the method, paying special attention to the hypothesis that the lack of temporal regularity induces desynchronization. We also put forward a novel insight regarding the temporal structure of NPS that may better encompass the set of findings published by the group: the fact that intervals between stimulation pulses have a distribution that follows a power law and thus may induce natural-like activity that would compete with epileptiform discharge for the recruitment of networks. We end our discussion by mentioning ongoing research and future projects of our lab.
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8
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Sarazin MXB, Victor J, Medernach D, Naudé J, Delord B. Online Learning and Memory of Neural Trajectory Replays for Prefrontal Persistent and Dynamic Representations in the Irregular Asynchronous State. Front Neural Circuits 2021; 15:648538. [PMID: 34305535 PMCID: PMC8298038 DOI: 10.3389/fncir.2021.648538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 05/31/2021] [Indexed: 11/13/2022] Open
Abstract
In the prefrontal cortex (PFC), higher-order cognitive functions and adaptive flexible behaviors rely on continuous dynamical sequences of spiking activity that constitute neural trajectories in the state space of activity. Neural trajectories subserve diverse representations, from explicit mappings in physical spaces to generalized mappings in the task space, and up to complex abstract transformations such as working memory, decision-making and behavioral planning. Computational models have separately assessed learning and replay of neural trajectories, often using unrealistic learning rules or decoupling simulations for learning from replay. Hence, the question remains open of how neural trajectories are learned, memorized and replayed online, with permanently acting biological plasticity rules. The asynchronous irregular regime characterizing cortical dynamics in awake conditions exerts a major source of disorder that may jeopardize plasticity and replay of locally ordered activity. Here, we show that a recurrent model of local PFC circuitry endowed with realistic synaptic spike timing-dependent plasticity and scaling processes can learn, memorize and replay large-size neural trajectories online under asynchronous irregular dynamics, at regular or fast (sped-up) timescale. Presented trajectories are quickly learned (within seconds) as synaptic engrams in the network, and the model is able to chunk overlapping trajectories presented separately. These trajectory engrams last long-term (dozen hours) and trajectory replays can be triggered over an hour. In turn, we show the conditions under which trajectory engrams and replays preserve asynchronous irregular dynamics in the network. Functionally, spiking activity during trajectory replays at regular timescale accounts for both dynamical coding with temporal tuning in individual neurons, persistent activity at the population level, and large levels of variability consistent with observed cognitive-related PFC dynamics. Together, these results offer a consistent theoretical framework accounting for how neural trajectories can be learned, memorized and replayed in PFC networks circuits to subserve flexible dynamic representations and adaptive behaviors.
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Affiliation(s)
- Matthieu X B Sarazin
- Institut des Systèmes Intelligents et de Robotique, CNRS, Inserm, Sorbonne Université, Paris, France
| | - Julie Victor
- CEA Paris-Saclay, CNRS, NeuroSpin, Saclay, France
| | - David Medernach
- Institut des Systèmes Intelligents et de Robotique, CNRS, Inserm, Sorbonne Université, Paris, France
| | - Jérémie Naudé
- Neuroscience Paris Seine - Institut de biologie Paris Seine, CNRS, Inserm, Sorbonne Université, Paris, France
| | - Bruno Delord
- Institut des Systèmes Intelligents et de Robotique, CNRS, Inserm, Sorbonne Université, Paris, France
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9
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Rosiles-Abonce A, Rubio C, Taddei E, Rosiles D, Rubio-Osornio M. Antiepileptogenic Effect of Retinoic Acid. Curr Neuropharmacol 2021; 19:383-391. [PMID: 32351181 PMCID: PMC8033965 DOI: 10.2174/1570159x18666200429232104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/17/2020] [Accepted: 04/24/2020] [Indexed: 11/24/2022] Open
Abstract
Retinoic acid, a metabolite of vitamin A, acts through either genomic or nongenomic actions. The genomic action of retinoids exerts effects on gene transcription through interaction with retinoid receptors such as retinoic acid receptors (RARα, β, and γ) and retinoid X receptors (RXRα, β, and γ) that are primarily concentrated in the amygdala, pre-frontal cortex, and hippocampal areas in the brain. In response to retinoid binding, RAR/RXR heterodimers undergo major conformational changes and orchestrate the transcription of specific gene networks. Previous experimental studies have reported that retinoic acid exerts an antiepileptogenic effect through diverse mechanisms, including the modulation of gap junctions, neurotransmitters, long-term potentiation, calcium channels and some genes. To our knowledge, there are no previous or current clinical trials evaluating the use of retinoic acid for seizure control.
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Affiliation(s)
| | | | | | | | - Moisés Rubio-Osornio
- Address correspondence to this author at the Laboratorio Experimental de Enfermedades Neurodegenerativas, Instituto Nacional de Neurología y Neurocirugía, Ciudad de Mexico; E-mail:
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10
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Ellrich J. Cortical stimulation in pharmacoresistant focal epilepsies. Bioelectron Med 2020; 6:19. [PMID: 32984441 PMCID: PMC7517676 DOI: 10.1186/s42234-020-00054-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/25/2020] [Indexed: 12/30/2022] Open
Abstract
Pharmacoresistance and adverse drug events designate a considerable group of patients with focal epilepsies that require alternative treatments such as neurosurgical intervention and neurostimulation. Electrical or magnetic stimulations of cortical brain areas for the treatment of pharmacoresistant focal epilepsies emerged from preclinical studies and experience through intraoperative neurophysiological monitoring in patients. Direct neurostimulation of seizure onset zones in neocortical brain areas may specifically affect neuronal networks involved in epileptiform activity without remarkable adverse influence on physiological cortical processing in immediate vicinity. Noninvasive low-frequency transcranial magnetic stimulation and cathodal transcranial direct current stimulation are suggested to be anticonvulsant; however, potential effects are ephemeral and require effect maintenance by ongoing stimulation. Invasive responsive neurostimulation, chronic subthreshold cortical stimulation, and epicranial cortical stimulation cover a broad range of different emerging technologies with intracranial and epicranial approaches that still have limited market access partly due to ongoing clinical development. Despite significant differences, the present bioelectronic technologies share common mode of actions with acute seizure termination by high-frequency stimulation and long-term depression induced by low-frequency magnetic or electrical stimulation or transcranial direct current stimulation.
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Affiliation(s)
- Jens Ellrich
- Medical Faculty, University of Erlangen-Nuremberg, Erlangen, Germany.,Precisis AG, Heidelberg, Germany
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11
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Denoyer Y, Merlet I, Wendling F, Benquet P. Modelling acute and lasting effects of tDCS on epileptic activity. J Comput Neurosci 2020; 48:161-176. [DOI: 10.1007/s10827-020-00745-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 02/10/2020] [Accepted: 04/04/2020] [Indexed: 12/11/2022]
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12
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Chauvière L. Update on temporal lobe‐dependent information processing, in health and disease. Eur J Neurosci 2019; 51:2159-2204. [DOI: 10.1111/ejn.14594] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/06/2019] [Accepted: 09/27/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Laëtitia Chauvière
- INSERM U1266 Institut de Psychiatrie et de Neurosciences de Paris (IPNP) Paris France
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13
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Pannangrong W, Sirichoat A, Wongsiri T, Wigmore P, Welbat JU. Valproic acid withdrawal ameliorates impairments of hippocampal-spatial working memory and neurogenesis. J Zhejiang Univ Sci B 2019; 20:253-263. [PMID: 30829012 DOI: 10.1631/jzus.b1800340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Valproic acid (VPA), an agent that is used to treat epileptic seizures, can cause spatial memory impairment in adults and children. This effect is thought to be due to the ability of VPA to inhibit neurogenesis in the hippocampus, which is required for learning. We have previously used an animal model to show that VPA significantly impairs hippocampal-spatial working memory and inhibits neuronal generation in the sub-granular zone of the dentate gyrus. As there are patient reports of improvements in memory after discontinuing VPA treatment, the present study investigated the recovery of both spatial memory and hippocampal neurogenesis at two time points after withdrawal of VPA. Male Wistar rats were given intraperitoneal injections of 0.9% normal saline or VPA (300 mg/kg) twice a day for 10 d. At 1, 30, or 45 d after the drug treatment, the novel object location (NOL) test was used to examine spatial memory; hippocampal cell division was counted using Ki67 immunohistochemistry, and levels of brain-derived neurotrophic factor (BDNF) and Notch1 were measured using western immunoblotting. Spatial working memory was impaired 1 and 30 d after the final administration, but was restored to control levels by 45 d. Cell proliferation had increased to control levels at 30 and 45 d. Both markers of neurogenesis (BDNF and Notch1 levels) had returned to control levels at 45 d. These results demonstrate that memory recovery occurs over a period of six weeks after discontinuing VPA treatment and is preceded by a return of hippocampal neurogenesis to control levels.
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Affiliation(s)
- Wanassanun Pannangrong
- Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Apiwat Sirichoat
- Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Trai Wongsiri
- Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Peter Wigmore
- School of Life Sciences, Medical School, Queen's Medical Centre, Nottingham University, Nottingham NG7 2UH, UK
| | - Jariya Umka Welbat
- Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.,Neuroscience Research and Development Group, Khon Kaen University, Khon Kaen 40002, Thailand
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14
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Celli R, Santolini I, Van Luijtelaar G, Ngomba RT, Bruno V, Nicoletti F. Targeting metabotropic glutamate receptors in the treatment of epilepsy: rationale and current status. Expert Opin Ther Targets 2019; 23:341-351. [PMID: 30801204 DOI: 10.1080/14728222.2019.1586885] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Several drugs targeting the GABAergic system are used in the treatment of epilepsy, but only one drug targeting glutamate receptors is on the market. This is surprising because an imbalance between excitatory and inhibitory neurotransmission lies at the core of the pathophysiology of epilepsy. One possible explanation is that drug development has been directed towards the synthesis of molecules that inhibit the activity of ionotropic glutamate receptors. These receptors mediate fast excitatory synaptic transmission in the central nervous system (CNS) and their blockade may cause severe adverse effects such as sedation, cognitive impairment, and psychotomimetic effects. Metabotropic glutamate (mGlu) receptors are more promising drug targets because these receptors modulate synaptic transmission rather than mediate it. Areas covered: We review the current evidence that links mGlu receptor subtypes to the pathophysiology and experimental treatment of convulsive and absence seizures. Expert opinion: While mGlu5 receptor negative allosteric modulators have the potential to be protective against convulsive seizures and hyperactivity-induced neurodegeneration, drugs that enhance mGlu5 and mGlu7 receptor function may have beneficial effects in the treatment of absence epilepsy. Evidence related to the other mGlu receptor subtypes is more fragmentary; further investigations are required for an improved understanding of their role in the generation and propagation of seizures.
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Affiliation(s)
| | | | | | | | - Valeria Bruno
- a IRCCS NEUROMED , Pozzilli , Italy.,d Departments of Physiology and Pharmacology , University Sapienza , Rome , Italy
| | - Ferdinando Nicoletti
- a IRCCS NEUROMED , Pozzilli , Italy.,d Departments of Physiology and Pharmacology , University Sapienza , Rome , Italy
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15
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Gisquet-Verrier P, Riccio DC. Memory Integration as a Challenge to the Consolidation/Reconsolidation Hypothesis: Similarities, Differences and Perspectives. Front Syst Neurosci 2019; 12:71. [PMID: 30687031 PMCID: PMC6337075 DOI: 10.3389/fnsys.2018.00071] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 12/18/2018] [Indexed: 01/04/2023] Open
Abstract
We recently proposed that retrograde amnesia does not result from a disruption of the consolidation/reconsolidation processes but rather to the integration of the internal state induced by the amnesic treatment within the initial memory. Accordingly, the performance disruption induced by an amnesic agent does not result from a disruption of the memory fixation process, but from a difference in the internal state present during the learning phase (or reactivation) and at the later retention test: a case of state-dependency. In the present article, we will review similarities and differences these two competing views may have on memory processing. We will also consider the consequences the integration concept may have on the way memory is built, maintained and retrieved, as well as future research perspectives that such a new view may generate.
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Affiliation(s)
- Pascale Gisquet-Verrier
- Institut des Neurosciences Paris-Saclay (Neuro-PSI), Université Paris-Sud, CNRS UMR 9197, Université Paris-Saclay, Orsay, France
| | - David C Riccio
- Department of Psychological Sciences, Kent State University, Kent, OH, United States
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16
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Gisquet-Verrier P, Riccio DC. Memory integration: An alternative to the consolidation/reconsolidation hypothesis. Prog Neurobiol 2018; 171:15-31. [PMID: 30343034 DOI: 10.1016/j.pneurobio.2018.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 09/11/2018] [Accepted: 10/13/2018] [Indexed: 10/28/2022]
Abstract
The original concept of consolidation considers that memory requires time to be fixed. Since 2000, a comparable protein-dependent re-stabilization phase, called reconsolidation, has been assumed to take place after memory retrieval. This consolidation/reconsolidation hypothesis, has dominated the literature for more than 50 years, despite compelling evidence that is inconsistent with it. In this review, we present an historical overview and explain how, despite serious criticisms, this hypothesis has persisted for decades and become accepted as a dogma. Based on both older and more recent evidence, we next propose the concept of memory integration which involves the linkage or embedding of new material into an already existing representation. We believe integration provides a viable explanation for retrograde amnesia in place of the consolidation/reconsolidation hypothesis. Integration can further be the basis for several major cases of memory alteration such as time dependent memory enhancement, interference, counter-conditioning, updating and other instances of memory malleability. In a final section we consider the implications this new concept may have for memory processes and its translational applications.
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Affiliation(s)
- Pascale Gisquet-Verrier
- Neuro-PSI, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Bât 446, Orsay, F-91405, France.
| | - David C Riccio
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA
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17
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Reyes-Garcia SZ, de Almeida ACG, Ortiz-Villatoro NN, Scorza FA, Cavalheiro EA, Scorza CA. Robust Network Inhibition and Decay of Early-Phase LTP in the Hippocampal CA1 Subfield of the Amazon Rodent Proechimys. Front Neural Circuits 2018; 12:81. [PMID: 30337859 PMCID: PMC6180286 DOI: 10.3389/fncir.2018.00081] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 09/13/2018] [Indexed: 01/28/2023] Open
Abstract
Background: Diverse forms of long-term potentiation (LTP) have been described, but one of the most investigated is encountered in the glutamatergic synapses of the hippocampal cornu Ammonis (CA1) subfield. However, little is known about synaptic plasticity in wildlife populations. Laboratory animals are extremely inbred populations that have been disconnected from their natural environment and so their essential ecological aspects are entirely absent. Proechimys are small rodents from Brazil’s Amazon rainforest and their nervous systems have evolved to carry out specific tasks of their unique ecological environment. It has also been shown that long-term memory duration did not persist for 24-h in Proechimys, in contrast to Wistar rats, when both animal species were assessed by the plus-maze discrimination avoidance task and object recognition test. Methods: In this work, different protocols, such as theta burst, single tetanic burst or multiple trains of high frequency stimulation (HFS), were used to induce LTP in hippocampal brain slices of Proechimys and Wistar rats. Results: A protocol-independent fast decay of early-phase LTP at glutamatergic synapses of the CA1 subfield was encountered in Proechimys. Long-term depression (LTD) and baseline paired-pulse facilitation (PPF) were investigated but no differences were found between animal species. Input/output (I/O) relationships suggested lower excitability in Proechimys in comparison to Wistar rats. Bath application of d-(-)-2-amino-5-phosphonopentanoicacid (D-AP5) and CNQX prevented the induction of LTP in both Proechimys and Wistar. However, in marked contrast to Wistar rats, LTP induction was not facilitated by the GABAA antagonist in the Amazon rodents, even higher concentrations failed to facilitate LTP in Proechimys. Next, the effects of GABAA inhibition on spontaneous activity as well as evoked field potentials (FPs) were evaluated in CA1 pyramidal cells. Likewise, much lower activity was detected in Proechimys brain slices in comparison to those of the Wistar rats. Conclusions: These findings suggest a possible high inhibitory tone in the CA1 network mediated by GABAA receptors in the Amazon rodents. Currently, neuroscience research still seeks to reveal molecular pathways that control learning and memory processes, Proechimys may prove useful in identifying such mechanisms in complement to traditional animal models.
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Affiliation(s)
- Selvin Z Reyes-Garcia
- Disciplina de Neurociência, Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.,Departamento de Ciencias Morfológicas, Facultad de Ciencias Médicas, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Antônio-Carlos Guimarães de Almeida
- Laboratório de Neurociência Experimental e Computacional, Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei, São João del-Rei, Brazil
| | - Nancy N Ortiz-Villatoro
- Disciplina de Neurociência, Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Fulvio A Scorza
- Disciplina de Neurociência, Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Esper A Cavalheiro
- Disciplina de Neurociência, Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Carla A Scorza
- Disciplina de Neurociência, Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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18
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Aroniadou-Anderjaska V, Pidoplichko VI, Figueiredo TH, Braga MFM. Oscillatory Synchronous Inhibition in the Basolateral Amygdala and its Primary Dependence on NR2A-containing NMDA Receptors. Neuroscience 2018; 373:145-158. [PMID: 29339324 DOI: 10.1016/j.neuroscience.2018.01.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/20/2017] [Accepted: 01/07/2018] [Indexed: 12/18/2022]
Abstract
Synchronous, rhythmic firing of GABAergic interneurons is a fundamental mechanism underlying the generation of brain oscillations, and evidence suggests that NMDA receptors (NMDARs) play a key role in oscillatory activity by regulating the activity of interneurons. Consistent with this, derangement of brain rhythms in certain neuropsychiatric disorders, notably schizophrenia and autism, is associated with NMDAR hypofunction and loss of inhibitory interneurons. In the basolateral amygdala (BLA)-dysfunction of which is involved in a host of neuropsychiatric diseases-, principal neurons display spontaneous, rhythmic "bursts" of inhibitory activity, which could potentially be involved in the orchestration of oscillations in the BLA network; here, we investigated the role of NMDARs in these inhibitory oscillations. Rhythmic bursts of spontaneous IPSCs (0.5 Hz average burst frequency) recorded from rat BLA principal cells were blocked or significantly suppressed by D-AP5, and could be driven by NMDAR activation alone. BLA interneurons generated spontaneous bursts of suprathreshold EPSCs at a similar frequency, which were also blocked or reduced by D-AP5. PEAQX (GluN2A-NMDAR antagonist; 0.4 μM) or Ro-25-6981 (GluN2B-NMDAR antagonist; 5 μM) suppressed the IPSC and EPSC bursts; suppression by PEAQX was significantly greater than that by Ro-25-6981. Immunohistochemical labeling revealed the presence of both GluN2A- and GluN2B-NMDARs on GABAergic BLA interneurons, while, functionally, GluN2A-NMDARs have the dominant role, as suggested by a greater reduction of NMDA-evoked currents by PEAQX versus Ro-25-6981. Entrainment of BLA principal neurons in an oscillatory generation of inhibitory activity depends primarily on activation of GluN2A-NMDARs, and interneuronal GluN2A-NMDARs may play a significant role.
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Affiliation(s)
- Vassiliki Aroniadou-Anderjaska
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - Volodymyr I Pidoplichko
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - Maria F M Braga
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
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19
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Remigio GJ, Loewen JL, Heuston S, Helgeson C, White HS, Wilcox KS, West PJ. Corneal kindled C57BL/6 mice exhibit saturated dentate gyrus long-term potentiation and associated memory deficits in the absence of overt neuron loss. Neurobiol Dis 2017; 105:221-234. [PMID: 28624414 PMCID: PMC5538573 DOI: 10.1016/j.nbd.2017.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 06/09/2017] [Indexed: 12/25/2022] Open
Abstract
Memory deficits have a significant impact on the quality of life of patients with epilepsy and currently no effective treatments exist to mitigate this comorbidity. While these cognitive comorbidities can be associated with varying degrees of hippocampal cell death and hippocampal sclerosis, more subtle changes in hippocampal physiology independent of cell loss may underlie memory dysfunction in many epilepsy patients. Accordingly, animal models of epilepsy or epileptic processes exhibiting memory deficits in the absence of cell loss could facilitate novel therapy discovery. Mouse corneal kindling is a cost-effective and non-invasive model of focal to bilateral tonic-clonic seizures that may exhibit memory deficits in the absence of cell loss. Therefore, we tested the hypothesis that corneal kindled C57BL/6 mice exhibit spatial pattern processing and memory deficits in a task reliant on DG function and that these impairments would be concurrent with physiological remodeling of the DG as opposed to overt neuron loss. Following corneal kindling, C57BL/6 mice exhibited deficits in a DG-associated spatial memory test - the metric task. Compatible with this finding, we also discovered saturated, and subsequently impaired, LTP of excitatory synaptic transmission at the perforant path to DGC synapse. This saturation of LTP was consistent with evidence suggesting that perforant path to DGC synapses in kindled mice had previously experienced LTP-like changes to their synaptic weights: increased postsynaptic depolarizations in response to equivalent presynaptic input and significantly larger amplitude AMPA receptor mediated spontaneous EPSCs. Additionally, there was evidence for kindling-induced changes in the intrinsic excitability of DGCs: reduced threshold to population spikes under extracellular recording conditions and significantly increased membrane resistances observed in DGCs. Importantly, quantitative immunohistochemical analysis revealed hippocampal astrogliosis in the absence of overt neuron loss. These changes in spatial pattern processing and memory deficits in corneal kindled mice represent a novel model of seizure-induced cognitive dysfunction associated with pathophysiological remodeling of excitatory synaptic transmission and granule cell excitability in the absence of overt cell loss.
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Affiliation(s)
- Gregory J Remigio
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84108-1210, USA; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84108-1210, USA
| | - Jaycie L Loewen
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84108-1210, USA; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84108-1210, USA
| | | | - Colin Helgeson
- Juan Diego Catholic High School, Draper, UT 84020-9035, USA
| | - H Steve White
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84108-1210, USA; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84108-1210, USA; Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT 84108-1210, USA
| | - Karen S Wilcox
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84108-1210, USA; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84108-1210, USA; Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT 84108-1210, USA
| | - Peter J West
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84108-1210, USA; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84108-1210, USA; Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT 84108-1210, USA.
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20
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Łukawski K, Andres-Mach M, Czuczwar M, Łuszczki JJ, Kruszyński K, Czuczwar SJ. Mechanisms of epileptogenesis and preclinical approach to antiepileptogenic therapies. Pharmacol Rep 2017; 70:284-293. [PMID: 29477036 DOI: 10.1016/j.pharep.2017.07.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/17/2017] [Accepted: 07/12/2017] [Indexed: 12/30/2022]
Abstract
The prevalence of epilepsy is estimated 5-10 per 1000 population and around 70% of patients with epilepsy can be sufficiently controlled by antiepileptic drugs (AEDs). Epileptogenesis is the process responsible for converting normal into an epileptic brain and mechanisms responsible include among others: inflammation, neurodegeneration, neurogenesis, neural reorganization and plasticity. Some AEDs may be antiepileptiogenic (diazepam, eslicarbazepine) but the correlation between neuroprotection and inhibition of epileptogenesis is not evident. Antiepileptogenic activity has been postulated for mTOR ligands, resveratrol and losartan. So far, clinical evidence gives some hope for levetiracetam as an AED inhibiting epileptogenesis in neurosurgical patients. Biomarkers for epileptogenesis are needed for the proper selection of patients for evaluation of potential antiepileptogenic compounds.
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Affiliation(s)
- Krzysztof Łukawski
- Department of Physiopathology, Institute of Rural Health, Lublin, Poland; Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| | - Marta Andres-Mach
- Isobolographic Analysis Laboratory, Institute of Rural Health, Lublin, Poland
| | - Mirosław Czuczwar
- 2nd Department of Anesthesiology and Intensive Care, Medical University of Lublin, Lublin, Poland
| | - Jarogniew J Łuszczki
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland; Isobolographic Analysis Laboratory, Institute of Rural Health, Lublin, Poland
| | | | - Stanisław J Czuczwar
- Department of Physiopathology, Institute of Rural Health, Lublin, Poland; Department of Pathophysiology, Medical University of Lublin, Lublin, Poland.
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21
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Boly M, Jones B, Findlay G, Plumley E, Mensen A, Hermann B, Tononi G, Maganti R. Altered sleep homeostasis correlates with cognitive impairment in patients with focal epilepsy. Brain 2017; 140:1026-1040. [PMID: 28334879 DOI: 10.1093/brain/awx017] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 12/20/2016] [Indexed: 11/13/2022] Open
Abstract
In animal studies, both seizures and interictal spikes induce synaptic potentiation. Recent evidence suggests that electroencephalogram slow wave activity during sleep reflects synaptic potentiation during wake, and that its homeostatic decrease during the night is associated with synaptic renormalization and its beneficial effects. Here we asked whether epileptic activity induces plastic changes that can be revealed by high-density electroencephalography recordings during sleep in 15 patients with focal epilepsy and 15 control subjects. Compared to controls, patients with epilepsy displayed increased slow wave activity power during non-rapid eye movement sleep over widespread, bilateral scalp regions. This global increase in slow wave activity power was positively correlated with the frequency of secondarily generalized seizures in the 3-5 days preceding the recordings. Individual patients also showed local increases in sleep slow wave activity power at scalp locations matching their seizure focus. This local increase in slow wave activity power was positively correlated with the frequency of interictal spikes during the last hour of wakefulness preceding sleep. By contrast, frequent interictal spikes during non-rapid eye movement sleep predicted a reduced homeostatic decrease in the slope of sleep slow waves during the night, which in turn predicted reduced daytime learning. Patients also showed an increase in sleep spindle power, which was negatively correlated with intelligence quotient. Altogether, these findings suggest that both seizures and interictal spikes may induce long-lasting changes in the human brain that can be sensitively detected by electroencephalographic markers of sleep homeostasis. Furthermore, abnormalities in sleep markers are correlated with cognitive impairment, suggesting that not only seizures, but also interictal spikes can have negative consequences.
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Affiliation(s)
- Melanie Boly
- Department of Neurology, University of Wisconsin, Madison, USA.,Department of Psychiatry, University of Wisconsin, Madison, USA
| | - Benjamin Jones
- Department of Neurology, University of Wisconsin, Madison, USA.,Department of Psychiatry, University of Wisconsin, Madison, USA
| | - Graham Findlay
- Department of Neurology, University of Wisconsin, Madison, USA.,Department of Psychiatry, University of Wisconsin, Madison, USA
| | - Erin Plumley
- Department of Neurology, University of Wisconsin, Madison, USA
| | - Armand Mensen
- Department of Psychiatry, University of Wisconsin, Madison, USA
| | - Bruce Hermann
- Department of Neurology, University of Wisconsin, Madison, USA
| | - Guilio Tononi
- Department of Psychiatry, University of Wisconsin, Madison, USA
| | - Rama Maganti
- Department of Neurology, University of Wisconsin, Madison, USA
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22
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Stafstrom CE, Staedtke V, Comi AM. Epilepsy Mechanisms in Neurocutaneous Disorders: Tuberous Sclerosis Complex, Neurofibromatosis Type 1, and Sturge-Weber Syndrome. Front Neurol 2017; 8:87. [PMID: 28367137 PMCID: PMC5355446 DOI: 10.3389/fneur.2017.00087] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 02/24/2017] [Indexed: 01/27/2023] Open
Abstract
Neurocutaneous disorders are multisystem diseases affecting skin, brain, and other organs. Epilepsy is very common in the neurocutaneous disorders, affecting up to 90% of patients with tuberous sclerosis complex (TSC) and Sturge–Weber syndrome (SWS), for example. The mechanisms underlying the increased predisposition to brain hyperexcitability differ between disorders, yet some molecular pathways overlap. For instance, the mechanistic target of rapamycin (mTOR) signaling cascade plays a central role in seizures and epileptogenesis in numerous acquired and genetic disorders, including several neurocutaneous disorders. Potential routes for target-specific treatments are emerging as the genetic and molecular pathways involved in neurocutaneous disorders become increasingly understood. This review explores the clinical features and mechanisms of epilepsy in three common neurocutaneous disorders—TSC, neurofibromatosis type 1, and SWS.
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Affiliation(s)
- Carl E Stafstrom
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Verena Staedtke
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Anne M Comi
- Department of Neurology, Kennedy Krieger Institute, Johns Hopkins University School of Medicine , Baltimore, MD , USA
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23
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Postnikova TY, Zubareva OE, Kovalenko AA, Kim KK, Magazanik LG, Zaitsev AV. Status epilepticus impairs synaptic plasticity in rat hippocampus and is followed by changes in expression of NMDA receptors. BIOCHEMISTRY (MOSCOW) 2017; 82:282-290. [DOI: 10.1134/s0006297917030063] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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24
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Vose LR, Stanton PK. Synaptic Plasticity, Metaplasticity and Depression. Curr Neuropharmacol 2017; 15:71-86. [PMID: 26830964 PMCID: PMC5327460 DOI: 10.2174/1570159x14666160202121111] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 08/13/2015] [Accepted: 01/30/2016] [Indexed: 01/30/2023] Open
Abstract
The development of a persistent depressive affective state has for some time been thought to result from persistent alterations in neurotransmitter-mediated synaptic transmission. While the identity of those transmitters has changed over the years, the literature has lacked mechanistic connections between the neurophysiological mechanisms they regulate, and how these mechanisms alter neuronal function, and, hence, affective homeostasis. This review will examine recent work that suggests that both long-term activity-dependent changes in synaptic strength (“plasticity”), and shifting set points for the ease of induction of future long-term changes (“metaplasticity”), may be critical to establishing and reversing a depressive behavioral state. Activity-dependent long-term synaptic plasticity involves both strengthening and weakening of synaptic connections associated with a dizzying array of neurochemical alterations that include synaptic insertion and removal of a number of subtypes of AMPA, NMDA and metabotropic glutamate receptors, changes in presynaptic glutamate release, and structural changes in dendritic spines. Cellular mechanisms of metaplasticity are far less well understood. Here, we will review the growing evidence that long-term synaptic changes in glutamatergic transmission, in brain regions that regulate mood, are key determinants of affective homeostasis and therapeutic targets with immense potential for drug development.
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Affiliation(s)
| | - Patric K Stanton
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, 10595, USA
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25
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Cota VR, Drabowski BMB, de Oliveira JC, Moraes MFD. The epileptic amygdala: Toward the development of a neural prosthesis by temporally coded electrical stimulation. J Neurosci Res 2017; 94:463-85. [PMID: 27091311 DOI: 10.1002/jnr.23741] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 03/09/2016] [Accepted: 03/09/2016] [Indexed: 02/06/2023]
Abstract
Many patients with epilepsy do not obtain proper control of their seizures through conventional treatment. We review aspects of the pathophysiology underlying epileptic phenomena, with a special interest in the role of the amygdala, stressing the importance of hypersynchronism in both ictogenesis and epileptogenesis. We then review experimental studies on electrical stimulation of mesiotemporal epileptogenic areas, the amygdala included, as a means to treat medically refractory epilepsy. Regular high-frequency stimulation (HFS) commonly has anticonvulsant effects and sparse antiepileptogenic properties. On the other hand, HFS is related to acute and long-term increases in excitability related to direct neuronal activation, long-term potentiation, and kindling, raising concerns regarding its safety and jeopardizing in-depth understanding of its mechanisms. In turn, the safer regular low-frequency stimulation (LFS) has a robust antiepileptogenic effect, but its pro- or anticonvulsant effect seems to vary at random among studies. As an alternative, studies by our group on the development and investigation of temporally unstructured electrical stimulation applied to the amygdala have shown that nonperiodic stimulation (NPS), which is a nonstandard form of LFS, is capable of suppressing both acute and chronic spontaneous seizures. We hypothesize two noncompetitive mechanisms for the therapeutic role of amygdala in NPS, 1) a direct desynchronization of epileptic circuitry in the forebrain and brainstem and 2) an indirect desynchronization/inhibition through nucleus accumbens activation. We conclude by reintroducing the idea that hypersynchronism, rather than hyperexcitability, may be the key for epileptic phenomena and epilepsy treatment.
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Affiliation(s)
- Vinícius Rosa Cota
- Laboratório Interdisciplinar de Neuroengenharia e Neurociências, Departamento de Engenharia Elétrica (DEPEL), Universidade Federal de São João Del-Rei, São João Del-Rei, Minas Gerais, Brazil
| | - Bruna Marcela Bacellar Drabowski
- Laboratório Interdisciplinar de Neuroengenharia e Neurociências, Departamento de Engenharia Elétrica (DEPEL), Universidade Federal de São João Del-Rei, São João Del-Rei, Minas Gerais, Brazil
| | - Jasiara Carla de Oliveira
- Laboratório Interdisciplinar de Neuroengenharia e Neurociências, Departamento de Engenharia Elétrica (DEPEL), Universidade Federal de São João Del-Rei, São João Del-Rei, Minas Gerais, Brazil
| | - Márcio Flávio Dutra Moraes
- Núcleo de Neurociências, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Expression of TRPV1 Receptors Increased in Hippocampus Following Pentylenetetrazole-Induced Kindling in Male Rats. ARCHIVES OF NEUROSCIENCE 2016. [DOI: 10.5812/archneurosci.35459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Plasticity of Hippocampal Excitatory-Inhibitory Balance: Missing the Synaptic Control in the Epileptic Brain. Neural Plast 2016; 2016:8607038. [PMID: 27006834 PMCID: PMC4783563 DOI: 10.1155/2016/8607038] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/20/2016] [Accepted: 01/31/2016] [Indexed: 11/24/2022] Open
Abstract
Synaptic plasticity is the capacity generated by experience to modify the neural function and, thereby, adapt our behaviour. Long-term plasticity of glutamatergic and GABAergic transmission occurs in a concerted manner, finely adjusting the excitatory-inhibitory (E/I) balance. Imbalances of E/I function are related to several neurological diseases including epilepsy. Several evidences have demonstrated that astrocytes are able to control the synaptic plasticity, with astrocytes being active partners in synaptic physiology and E/I balance. Here, we revise molecular evidences showing the epileptic stage as an abnormal form of long-term brain plasticity and propose the possible participation of astrocytes to the abnormal increase of glutamatergic and decrease of GABAergic neurotransmission in epileptic networks.
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Takano T. Interneuron Dysfunction in Syndromic Autism: Recent Advances. Dev Neurosci 2015; 37:467-75. [PMID: 26183392 DOI: 10.1159/000434638] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 05/27/2015] [Indexed: 11/19/2022] Open
Abstract
Autism is an extremely heterogeneous disorder, but its frequent cooccurrence with epilepsy leads to speculation that there may be common mechanisms associated with these disorders. Inhibitory interneurons are considered to be the main cellular elements that control hyperexcitability in the brain, and interneuron dysfunction can cause pathological hyperexcitability linked to seizure susceptibility or epilepsy. This review summarizes some of the recent advances that support the relationship between interneuron dysfunction and cognitive impairment in human syndromic autism, with particular reference to the pathophysiological findings of murine experimental models of autism. Alterations in x03B3;-aminobutyric acid (GABA)ergic circuits include a wide variety of neurobiological dysfunctions and do not simply involve the loss or gain of any given type of inhibitory mechanism. The characteristics of interneuron dysfunction in each murine model of autism differ for each syndrome, and these diversities may be due to differences in genetic backgrounds or some other currently unknown variances. Future studies should give us a greater understanding of the involvement of different classes of GABAergic interneurons and allow us to define the relationship between the precise pathophysiological mechanisms and the corresponding clinical phenotypes in autism.
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Affiliation(s)
- Tomoyuki Takano
- Department of Pediatrics, Shiga University of Medical Science, Otsu, Japan
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Saffarzadeh F, Eslamizade MJ, Ghadiri T, Modarres Mousavi SM, Hadjighassem M, Gorji A. Effects of TRPV1 on the hippocampal synaptic plasticity in the epileptic rat brain. Synapse 2015; 69:375-83. [PMID: 25967571 DOI: 10.1002/syn.21825] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/04/2015] [Accepted: 04/20/2015] [Indexed: 12/27/2022]
Abstract
Temporal lobe epilepsy is often presented by medically intractable recurrent seizures due to dysfunction of temporal lobe structures, mostly the temporomesial structures. The role of transient receptor potential vaniloid 1 (TRPV1) activity on synaptic plasticity of the epileptic brain tissues was investigated. We studied hippocampal TRPV1 protein content and distribution in the hippocampus of epileptic rats. Furthermore, the effects of pharmacologic modulation of TRPV1 receptors on field excitatory postsynaptic potentials have been analyzed after induction of long term potentiation (LTP) in the hippocampal CA1 and CA3 areas after 1 day (acute phase) and 3 months (chronic phase) of pilocarpine-induced status epilepticus (SE). A higher expression of TRPV1 protein in the hippocampus as well as a higher distribution of this channel in CA1 and CA3 areas in both acute and chronic phases of pilocarpine-induced SE was observed. Activation of TRPV1 using capsaicin (1 µM) enhanced LTP induction in CA1 region in non-epileptic rats. Inhibition of TRPV1 by capsazepine (10 µM) did not affect LTP induction in non-epileptic rats. In acute phase of SE, activation of TRPV1 enhanced LTP in both CA1 and CA3 areas but TRPV1 inhibition did not affect LTP. In chronic phase of SE, application of TRPV1 antagonist enhanced LTP induction in CA1 and CA3 regions but TRPV1 activation had no effect on LTP. These findings indicate that a higher expression of TRPV1 in epileptic conditions is accompanied by a functional impact on the synaptic plasticity in the hippocampus. This suggests TRPV1 as a potential target in treatment of seizure attacks.
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Affiliation(s)
- Fatemeh Saffarzadeh
- Department of Neuroscience, School of Medical Advanced Studies, Iran University of Medical Sciences, Tehran, Iran.,Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran
| | - Mohammad J Eslamizade
- Department of Neuroscience, School of Medical Advanced Studies, Iran University of Medical Sciences, Tehran, Iran.,Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran.,Department of Physiology and Neurophysiology Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Tahereh Ghadiri
- Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran
| | | | - Mahmoudreza Hadjighassem
- Department of Neuroscience, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Gorji
- Shefa Neuroscience Research Center, Khatam-Al-Anbia Hospital, Tehran, Iran.,Klinik Und Poliklinik Für Neurochirurgie, Department of Neurology, Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Germany
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Braida D, Guerini FR, Ponzoni L, Corradini I, De Astis S, Pattini L, Bolognesi E, Benfante R, Fornasari D, Chiappedi M, Ghezzo A, Clerici M, Matteoli M, Sala M. Association between SNAP-25 gene polymorphisms and cognition in autism: functional consequences and potential therapeutic strategies. Transl Psychiatry 2015; 5:e500. [PMID: 25629685 PMCID: PMC4312830 DOI: 10.1038/tp.2014.136] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 11/19/2014] [Indexed: 12/27/2022] Open
Abstract
Synaptosomal-associated protein of 25 kDa (SNAP-25) is involved in different neuropsychiatric disorders, including schizophrenia and attention-deficit/hyperactivity disorder. Consistently, SNAP-25 polymorphisms in humans are associated with hyperactivity and/or with low cognitive scores. We analysed five SNAP-25 gene polymorphisms (rs363050, rs363039, rs363043, rs3746544 and rs1051312) in 46 autistic children trying to correlate them with Childhood Autism Rating Scale and electroencephalogram (EEG) abnormalities. The functional effects of rs363050 single-nucleotide polymorphism (SNP) on the gene transcriptional activity, by means of the luciferase reporter gene, were evaluated. To investigate the functional consequences that SNAP-25 reduction may have in children, the behaviour and EEG of SNAP-25(+/-) adolescent mice (SNAP-25(+/+)) were studied. Significant association of SNAP-25 polymorphism with decreasing cognitive scores was observed. Analysis of transcriptional activity revealed that SNP rs363050 encompasses a regulatory element, leading to protein expression decrease. Reduction of SNAP-25 levels in adolescent mice was associated with hyperactivity, cognitive and social impairment and an abnormal EEG, characterized by the occurrence of frequent spikes. Both EEG abnormalities and behavioural deficits were rescued by repeated exposure for 21 days to sodium salt valproate (VLP). A partial recovery of SNAP-25 expression content in SNAP-25(+/-) hippocampi was also observed by means of western blotting. A reduced expression of SNAP-25 is responsible for the cognitive deficits in children affected by autism spectrum disorders, as presumably occurring in the presence of rs363050(G) allele, and for behavioural and EEG alterations in adolescent mice. VLP treatment could result in novel therapeutic strategies.
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Affiliation(s)
- D Braida
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,Fondazione IRCCS Don Gnocchi, Milan, Italy
| | | | - L Ponzoni
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,Fondazione Fratelli Confalonieri, Milan, Italy
| | | | - S De Astis
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy
| | - L Pattini
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | | | - R Benfante
- CNR—Neuroscience Institute, Milan, Italy
| | - D Fornasari
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,CNR—Neuroscience Institute, Milan, Italy
| | - M Chiappedi
- Child Neuropsychiatry Unit, National Neurological Institute C. Mondino, Pavia, Italy
| | - A Ghezzo
- Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy,Associazione Nazionale Famiglie di Persone con Disabilitá Affettiva e/o Relazionale (ANFFAS), Macerata, Italy
| | - M Clerici
- Fondazione IRCCS Don Gnocchi, Milan, Italy,Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - M Matteoli
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,Humanitas Clinical and Research Center, Rozzano, Italy
| | - M Sala
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,CNR—Neuroscience Institute, Milan, Italy,Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Via Vanvitelli 32, Milan 20129, Italy. E-mail:
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31
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Lasarge CL, Danzer SC. Mechanisms regulating neuronal excitability and seizure development following mTOR pathway hyperactivation. Front Mol Neurosci 2014; 7:18. [PMID: 24672426 PMCID: PMC3953715 DOI: 10.3389/fnmol.2014.00018] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/27/2014] [Indexed: 01/19/2023] Open
Abstract
The phosphatidylinositol-3-kinase/phosphatase and tensin homolog (PTEN)-mammalian target of rapamycin (mTOR) pathway regulates a variety of neuronal functions, including cell proliferation, survival, growth, and plasticity. Dysregulation of the pathway is implicated in the development of both genetic and acquired epilepsies. Indeed, several causal mutations have been identified in patients with epilepsy, the most prominent of these being mutations in PTEN and tuberous sclerosis complexes 1 and 2 (TSC1, TSC2). These genes act as negative regulators of mTOR signaling, and mutations lead to hyperactivation of the pathway. Animal models deleting PTEN, TSC1, and TSC2 consistently produce epilepsy phenotypes, demonstrating that increased mTOR signaling can provoke neuronal hyperexcitability. Given the broad range of changes induced by altered mTOR signaling, however, the mechanisms underlying seizure development in these animals remain uncertain. In transgenic mice, cell populations with hyperactive mTOR have many structural abnormalities that support recurrent circuit formation, including somatic and dendritic hypertrophy, aberrant basal dendrites, and enlargement of axon tracts. At the functional level, mTOR hyperactivation is commonly, but not always, associated with enhanced synaptic transmission and plasticity. Moreover, these populations of abnormal neurons can affect the larger network, inducing secondary changes that may explain paradoxical findings reported between cell and network functioning in different models or at different developmental time points. Here, we review the animal literature examining the link between mTOR hyperactivation and epileptogenesis, emphasizing the impact of enhanced mTOR signaling on neuronal form and function.
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Affiliation(s)
- Candi L Lasarge
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA ; Department of Anesthesia, University of Cincinnati Cincinnati, OH, USA ; Department of Pediatrics, University of Cincinnati Cincinnati, OH, USA
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32
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Goh JJ, Manahan-Vaughan D. Role of inhibitory autophosphorylation of calcium/calmodulin-dependent kinase II (αCAMKII) in persistent (>24 h) hippocampal LTP and in LTD facilitated by novel object-place learning and recognition in mice. Behav Brain Res 2014; 285:79-88. [PMID: 24480420 DOI: 10.1016/j.bbr.2014.01.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/07/2014] [Accepted: 01/17/2014] [Indexed: 11/16/2022]
Abstract
Experience-dependent synaptic plasticity is widely expressed in the mammalian brain and is believed to underlie memory formation. Persistent forms of synaptic plasticity in the hippocampus, such as long-term potentiation (LTP) and long-term depression (LTD) are particularly of interest, as evidence is accumulating that they are expressed as a consequence of, or at the very least in association with, hippocampus-dependent novel learning events. Learning-facilitated plasticity describes the property of hippocampal synapses to express persistent synaptic plasticity when novel spatial learning is combined with afferent stimulation that is subthreshold for induction of changes in synaptic strength. In mice it occurs following novel object recognition and novel object-place recognition. Calmodulin-dependent kinase II (CAMKII) is strongly expressed in synapses and has been shown to be required for hippocampal LTP in vitro and for spatial learning in the water maze. Here, we show that in mice that undergo persistent inhibitory autophosphorylation of αCAMKII, object-place learning is intact. Furthermore, these animals demonstrate a higher threshold for induction of persistent (>24 h) hippocampal LTP in the hippocampal CA1 region during unrestrained behaviour. The transgenic mice also express short-term depression in response to afferent stimulation frequencies that are ineffective in controls. Furthermore, they express stronger LTD in response to novel learning of spatial configurations compared to controls. These findings support that modulation of αCAMKII activity via autophosphorylation at the Thr305/306 site comprises a key mechanism for the maintenance of synaptic plasticity within a dynamic range. They also indicate that a functional differentiation occurs in the way spatial information is encoded: whereas LTP is likely to be critically involved in the encoding of space per se, LTD appears to play a special role in the encoding of the content or features of space.
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Affiliation(s)
- Jinzhong Jeremy Goh
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Universitaetsstr. 150, MA 4/150, 44780 Bochum, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Universitaetsstr. 150, MA 4/150, 44780 Bochum, Germany.
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33
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Bateup HS, Johnson CA, Denefrio CL, Saulnier JL, Kornacker K, Sabatini BL. Excitatory/inhibitory synaptic imbalance leads to hippocampal hyperexcitability in mouse models of tuberous sclerosis. Neuron 2013; 78:510-22. [PMID: 23664616 DOI: 10.1016/j.neuron.2013.03.017] [Citation(s) in RCA: 250] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2013] [Indexed: 11/27/2022]
Abstract
Neural circuits are regulated by activity-dependent feedback systems that tightly control network excitability and which are thought to be crucial for proper brain development. Defects in the ability to establish and maintain network homeostasis may be central to the pathogenesis of neurodevelopmental disorders. Here, we examine the function of the tuberous sclerosis complex (TSC)-mTOR signaling pathway, a common target of mutations associated with epilepsy and autism spectrum disorder, in regulating activity-dependent processes in the mouse hippocampus. We find that the TSC-mTOR pathway is a central component of a positive feedback loop that promotes network activity by repressing inhibitory synapses onto excitatory neurons. In Tsc1 KO neurons, weakened inhibition caused by deregulated mTOR alters the balance of excitatory and inhibitory synaptic transmission, leading to hippocampal hyperexcitability. These findings identify the TSC-mTOR pathway as a regulator of neural network activity and have implications for the neurological dysfunction in disorders exhibiting deregulated mTOR signaling.
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Affiliation(s)
- Helen S Bateup
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
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Vezzani A, Friedman A, Dingledine RJ. The role of inflammation in epileptogenesis. Neuropharmacology 2013; 69:16-24. [PMID: 22521336 PMCID: PMC3447120 DOI: 10.1016/j.neuropharm.2012.04.004] [Citation(s) in RCA: 353] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 03/19/2012] [Accepted: 04/02/2012] [Indexed: 12/20/2022]
Abstract
One compelling challenge in the therapy of epilepsy is to develop anti-epileptogenic drugs with an impact on the disease progression. The search for novel targets has focused recently on brain inflammation since this phenomenon appears to be an integral part of the diseased hyperexcitable brain tissue from which spontaneous and recurrent seizures originate. Although the contribution of specific proinflammatory pathways to the mechanism of ictogenesis in epileptic tissue has been demonstrated in experimental models, the role of these pathways in epileptogenesis is still under evaluation. We review the evidence conceptually supporting the involvement of brain inflammation and the associated blood-brain barrier damage in epileptogenesis, and describe the available pharmacological evidence where post-injury intervention with anti-inflammatory drugs has been attempted. Our review will focus on three main inflammatory pathways, namely the IL-1 receptor/Toll-like receptor signaling, COX-2 and the TGF-β signaling. The mechanisms underlying neuronal-glia network dysfunctions induced by brain inflammation are also discussed, highlighting novel neuromodulatory effects of classical inflammatory mediators such as cytokines and prostaglandins. The increase in knowledge about a role of inflammation in disease progression, may prompt the use of specific anti-inflammatory drugs for developing disease-modifying treatments. This article is part of the Special Issue entitled 'New Targets and Approaches to the Treatment of Epilepsy'.
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Affiliation(s)
- Annamaria Vezzani
- Laboratory Experimental Neurology, Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via G. La Masa 19, 20156 Milano, Italy.
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Karson A, Utkan T, Balcı F, Arıcıoğlu F, Ateş N. Age-dependent decline in learning and memory performances of WAG/Rij rat model of absence epilepsy. Behav Brain Funct 2012; 8:51. [PMID: 22998946 PMCID: PMC3514399 DOI: 10.1186/1744-9081-8-51] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2012] [Accepted: 09/19/2012] [Indexed: 12/11/2022] Open
Abstract
Recent clinical studies revealed emotional and cognitive impairments associated with absence epilepsy. Preclinical research with genetic models of absence epilepsy however have primarily focused on dysfunctional emotional processes and paid relatively less attention to cognitive impairment. In order to bridge this gap, we investigated age-dependent changes in learning and memory performance, anxiety-like behavior, and locomotor activity of WAG/Rij rats (a valid model of generalized absence epilepsy) using passive avoidance, Morris water maze, elevated plus maze, and locomotor activity cage. We tested 5 month-old and 13 month-old WAG/Rij rats and compared their performance to age-matched Wistar rats. Results revealed a decline in emotional and spatial memory of WAG/Rij rats compared to age-matched Wistar rats only at 13 months of age. Importantly, there were no significant differences between WAG/Rij and Wistar rats in terms of anxiety-like behavior and locomotor activity at either age. Results pointed at age-dependent learning and memory deficits in the WAG/Rij rat model of absence epilepsy.
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Affiliation(s)
- Ayşe Karson
- Medical School, Department of Physiology, Kocaeli University, Umuttepe, Kocaeli, 41380, Turkey.
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36
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Sun FJ, Guo W, Zheng DH, Zhang CQ, Li S, Liu SY, Yin Q, Yang H, Shu HF. Increased expression of TRPV1 in the cortex and hippocampus from patients with mesial temporal lobe epilepsy. J Mol Neurosci 2012; 49:182-93. [PMID: 22936245 DOI: 10.1007/s12031-012-9878-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Accepted: 08/14/2012] [Indexed: 12/30/2022]
Abstract
Transient receptor potential vanilloid type-1 (TRPV1) is a ligand-gated nonselective cation channel that has been well characterized in peripheral pain pathway. Recent evidence from animal models of temporal lobe epilepsy (TLE) has supported the important role of TRPV1 in epileptogenesis. In this study, we investigated the expression and cellular distribution of TRPV1 in the temporal cortex (CTX) and hippocampus (HPC) from 26 patients with mesial TLE (MTLE) compared with 12 histologically normal samples. Reverse transcription-PCR and Western blotting revealed up-regulated mRNA and protein levels of TRPV1 in the MTLE group versus the control group. Immunohistochemistry data demonstrated that TRPV1 was mainly distributed in the cell bodies and dendrites of neurons. Double-labeled immunofluorescence further revealed that TRPV1 was localized on NeuN-positive neurons and GFAP-positive astrocytes, but not on HLA-positive microglia. In addition, its co-localization with glutamate and gamma-aminobutyric acid (GABA) indicated that TRPV1 was distributed on both glutamatergic and GABAergic neurons. Moreover, nerve growth factor, a sensitizing factor for TRPV1, was showed a higher expression pattern in MTLE patients. Taken together, our findings suggest that the overexpression and distribution patterns of TRPV1 might be involved in the pathogenesis and epileptogenesis of human MTLE.
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Affiliation(s)
- Fei-Ji Sun
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 2-V Xinqiao Street, Chongqing 400037, China
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37
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Gulati V, Wallace R. Rafts, Nanoparticles and Neural Disease. NANOMATERIALS (BASEL, SWITZERLAND) 2012; 2:217-250. [PMID: 28348305 PMCID: PMC5304588 DOI: 10.3390/nano2030217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 07/19/2012] [Accepted: 07/20/2012] [Indexed: 11/17/2022]
Abstract
This review examines the role of membrane rafts in neural disease as a rationale for drug targeting utilizing lipid-based nanoparticles. The article begins with an overview of methodological issues involving the existence, sizes, and lifetimes of rafts, and then examines raft function in the etiologies of three major neural diseases-epilepsy, Parkinson's disease, and Alzheimer's disease-selected as promising candidates for raft-based therapeutics. Raft-targeting drug delivery systems involving liposomes and solid lipid nanoparticles are then examined in detail.
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Affiliation(s)
- Vishal Gulati
- Ross University School of Medicine, Miami Beach Community Health Center, 11645 Biscayne Boulevard, North Miami, FL 33181, USA.
| | - Ron Wallace
- Department of Anthropology, University of Central Florida, Orlando, FL 32816, USA.
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38
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Involvement of transient receptor potential vanilloid type 1 channels in the pro-convulsant effect of anandamide in pentylenetetrazole-induced seizures. Epilepsy Res 2012; 100:113-24. [PMID: 22386872 DOI: 10.1016/j.eplepsyres.2012.02.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 02/01/2012] [Accepted: 02/04/2012] [Indexed: 01/31/2023]
Abstract
Anandamide, an endogenous agonist of CB(1) receptors, also activates TRPV1 but at a higher concentration. Studies demonstrate the anticonvulsant activity of anandamide via CB(1) receptors, while its action through TRPV1 is still ambiguous. Thus, the present study investigated the influence of anandamide on pentylenetetrazole-induced seizures in mice pretreated with TRPV1 or CB(1) receptor antagonists. Acute intracerebroventricular administration of low doses of anandamide (10, 20, or 40μg/mouse) produced anticonvulsant effect, while the pro-convulsant effect was evident at high doses (80 or 100μg/mouse). Interestingly, AM251 (2μg/mouse), a CB(1) antagonist pretreatment blocked the anticonvulsant effect, but augmented the pro-convulsant effect. Conversely, in the presence of inactive dose of capsazepine (1μg/mouse), a TRPV1 antagonist, anandamide exhibited significant anticonvulsant effect even at high doses with no change in its anticonvulsant effect. Moreover, mice treated with capsaicin, a TRPV1 agonist (10, or 100μg/mouse) exhibited pro-convulsant activity that was blocked by capsazepine pretreatment. However, capsazepine, per se at doses 10 or 100μg/mouse exhibited anticonvulsant effect. Like anandamide, the agents (AM404 and URB597), which increase its synaptic concentrations produced similar biphasic effects. Thus, these results indicate that anandamide exhibits both pro- and anticonvulsant activities by activating TRPV1 and CB(1) receptor respectively.
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O'Neill J, Piacentini JC, Chang S, Levitt JG, Rozenman M, Bergman L, Salamon N, Alger JR, McCracken JT. MRSI correlates of cognitive-behavioral therapy in pediatric obsessive-compulsive disorder. Prog Neuropsychopharmacol Biol Psychiatry 2012; 36:161-8. [PMID: 21983143 PMCID: PMC4344316 DOI: 10.1016/j.pnpbp.2011.09.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 09/02/2011] [Accepted: 09/08/2011] [Indexed: 01/01/2023]
Abstract
BACKGROUND The brain mechanisms of cognitive-behavioral therapy (CBT), a highly effective treatment for pediatric obsessive-compulsive disorder (OCD), are unknown. Neuroimaging in adult OCD indicates that CBT is associated with metabolic changes in striatum, thalamus, and anterior cingulate cortex. We therefore probed putative metabolic effects of CBT on these brain structures in pediatric OCD using proton magnetic resonance spectroscopic imaging (1H MRSI). METHOD Five unmedicated OCD patients (4 ♀, 13.5±2.8) and 9 healthy controls (7 ♀, 13.0±2.5) underwent MRSI (1.5 T, repetition-time/echo-time=1500/30 ms) of bilateral putamen, thalamus and pregenual anterior cingulate cortex (pACC). Patients were rescanned after 12 weeks of exposure-based CBT. The Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) of OCD symptoms was administered before and after CBT. RESULTS Four of 5 patients responded to CBT (mean 32.8% CY-BOCS reduction). Multiple metabolite effects emerged. Pre-CBT, N-acetyl-aspartate+N-acetyl-aspartyl-glutamate (tNAA) in left pregenual anterior cingulate cortex (pACC) was 55.5% higher in patients than controls. Post-CBT, tNAA (15.0%) and Cr (23.9%) in left pACC decreased and choline compounds (Cho) in right thalamus increased (10.6%) in all 5 patients. In left thalamus, lower pre-CBT tNAA, glutamate+glutamine (Glx), and myo-inositol (mI) predicted greater post-CBT drop in CY-BOCS (r=0.98) and CY-BOCS decrease correlated with increased Cho. CONCLUSIONS Interpretations are offered in terms of the Glutamatergic Hypothesis of Pediatric OCD. Similar to 18FDG-PET in adults, objectively measurable regional MRSI metabolites may indicate pediatric OCD and predict its response to CBT.
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Affiliation(s)
- Joseph O'Neill
- Division of Child & Adolescent Psychiatry, Semel Institute for Neurosciences, Department of Radiological Sciences, UCLA School of Medicine, Los Angeles, CA 90024-1759, United States.
| | - John C. Piacentini
- Division of Child & Adolescent Psychiatry, Semel Institute for Neurosciences, UCLA School of Medicine, Los Angeles, California
| | - Susanna Chang
- Division of Child & Adolescent Psychiatry, Semel Institute for Neurosciences, UCLA School of Medicine, Los Angeles, California
| | - Jennifer G. Levitt
- Division of Child & Adolescent Psychiatry, Semel Institute for Neurosciences, UCLA School of Medicine, Los Angeles, California
| | - Michelle Rozenman
- Division of Child & Adolescent Psychiatry, Semel Institute for Neurosciences, UCLA School of Medicine, Los Angeles, California
| | - Lindsey Bergman
- Division of Child & Adolescent Psychiatry, Semel Institute for Neurosciences, UCLA School of Medicine, Los Angeles, California
| | - Noriko Salamon
- Department of Radiological Sciences, UCLA School of Medicine, Los Angeles, California
| | - Jeffry R. Alger
- Department of Neurology, UCLA School of Medicine, Los Angeles, California
| | - James T. McCracken
- Division of Child & Adolescent Psychiatry, Semel Institute for Neurosciences, UCLA School of Medicine, Los Angeles, California
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Maroso M, Balosso S, Ravizza T, Liu J, Bianchi ME, Vezzani A. Interleukin-1 type 1 receptor/Toll-like receptor signalling in epilepsy: the importance of IL-1beta and high-mobility group box 1. J Intern Med 2011; 270:319-26. [PMID: 21793950 DOI: 10.1111/j.1365-2796.2011.02431.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Inflammatory processes in brain tissue have been described in human epilepsy of various aetiologies and in experimental models of seizures. This, together with the anticonvulsant properties of anti-inflammatory therapies both in clinical and in experimental settings, highlights the important role of brain inflammation in the aetiopathogenesis of seizures. Preclinical investigations in experimental models using pharmacological and genetic tools have identified a significant contribution of interleukin-1 (IL-1) type 1 receptor/Toll-like receptor (IL-1R/TLR) signalling to seizure activity. This signalling can be activated by ligands associated with infections (pathogen-associated molecular patterns) or by endogenous molecules, such as proinflammatory cytokines (e.g. IL-1beta) or danger signals [damage-associated molecular patterns, e.g. high-mobility group box 1 (HMGB1)]. IL-1beta and HMGB1 are synthesized and released by astrocytes and microglia in the rodent brain during seizures. Notably, a rapid release of HMGB1 from neurons appears to be triggered by proconvulsant drugs even before seizure occurrence and is involved in their precipitation of seizures. The activation of IL-1R/TLR signalling mediates rapid post-translational changes in N-methyl-d-aspartate-gated ion channels in neurons. A long-term decrease in seizure threshold has also been observed, possibly mediated by transcriptional activation of genes contributing to molecular and cellular plasticity. This emerging evidence identifies specific targets with potential anticonvulsant effects in drug-resistant forms of epilepsy.
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Affiliation(s)
- M Maroso
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via G. La Masa 19, Milan, Italy
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Striatum–hippocampus balance: From physiological behavior to interneuronal pathology. Prog Neurobiol 2011; 94:102-14. [DOI: 10.1016/j.pneurobio.2011.04.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 03/28/2011] [Accepted: 04/06/2011] [Indexed: 11/20/2022]
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Kivelev J, Niemelä M, Blomstedt G, Roivainen R, Lehecka M, Hernesniemi J. Microsurgical treatment of temporal lobe cavernomas. Acta Neurochir (Wien) 2011; 153:261-70. [PMID: 20872256 DOI: 10.1007/s00701-010-0812-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Accepted: 09/16/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND Cavernomas of the temporal lobe occur in 10-20% of patients with cerebral cavernomas. They frequently cause epileptic seizures, some of which tend to become refractory to medical therapy. Surgical removal of safely achievable symptomatic lesions has been frequently consistent with good long-term outcome. In the present study, a postoperative outcome is assessed. METHODS Of our 360 consecutive patients with cerebral cavernomas, 53 (15%) had a single cavernoma in the temporal lobe. Forty-nine patients were treated surgically and were included in the study. All data were analyzed retrospectively. The cavernomas were allocated into three groups based on the temporal lobe site: medial, anterolateral, and posterolateral. To collect follow-up data, all available patients were interviewed by phone. Seizure outcome was assessed using the Engel classification and general outcome using the Glasgow Outcome Scale (GOS). RESULTS Patients' median age at presentation was 37 (range, 7-64) years, with a female/male ratio of 2.5:1. Epileptic seizures occurred in 40 patients (82%). Median duration of seizures preoperatively was 3 (range, 0.1-23) years. In addition, four patients (10%) had memory disorder. Three patients without history of seizures (6%) complained of headache and two (4%) had memory problems. Three patients (6%) had an incidental cavernoma. Hemorrhage occurred in nine patients (18%) preoperatively. Median postoperative follow-up time was 6 (range, 0.2-26) years. Favorable seizure outcome (Engel class I and II) was registered in 35 patients (90%). Ten patients (25%) who had only a single seizure before surgery were seizure free during postoperative follow-up. Good general outcome (GOS, 4.5) was detected in 46 patients (96%). Two patients (4%) developed a new mild memory deficit after surgery, and in two patients existing memory deficits worsened. CONCLUSIONS Microsurgical removal of temporal lobe cavernomas is a safe and effective method to improve seizure outcome in patients with medically intractable epilepsy and to prevent deterioration caused by hemorrhage.
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Epilepsy secondary to tuberous sclerosis: lessons learned and current challenges. Childs Nerv Syst 2010; 26:1495-504. [PMID: 20358377 DOI: 10.1007/s00381-010-1128-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Accepted: 03/10/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND In tuberous sclerosis complex (TSC), a substantially increased risk of developing epilepsy is present as a result of a disruption of a TSC gene expression in the brain and secondary abnormal cellular differentiation, migration, and proliferation. Dysregulated excitation probably has its roots in the disruption of GABAergic interneuron development. There is an age-dependent electroclinical expression of seizures, and epilepsy is often quite severe and unremitting. DISCUSSION The majority of patients (>60%) who are candidates for surgery remain seizure-free after tuberectomy. During the recent years technical advances in the localization of the epileptogenic zone during the recent years have lead to a 63% of Engel class I status after surgery compared with a previous 52%. In medically refractory patients not suitable for surgery, vagus nerve stimulation has proved efficacy in significantly reducing seizure frequency in more than 50% of cases. New evidence suggests that mTOR inhibitors may be helpful in the management of intractable epilepsy for individuals with TSC.
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Auvin S, Shin D, Mazarati A, Sankar R. Inflammation induced by LPS enhances epileptogenesis in immature rat and may be partially reversed by IL1RA. Epilepsia 2010; 51 Suppl 3:34-8. [PMID: 20618397 DOI: 10.1111/j.1528-1167.2010.02606.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Inflammatory signaling in the central nervous system (CNS) has been shown to exacerbate both seizure activity and seizure-induced neuronal injury. However, it has not been firmly established whether neurodegeneration is a prerequisite of proconvulsant effect of neuroinflammation, or whether the latter may facilitate seizures without involving neuronal injury. We examined effects of inflammation in the rapid kindling model, where seizure progression occurs in the absence of neurodegeneration. P14 male Wistar rats were subjected to a rapid kindling procedure: 60 electrical stimulations of the hippocampus delivered every 5 min at the current that had been established to induce afterdischarge. Lipopolysaccharide (LPS) was injected (50 microg/kg, i.p., 2 h prior to the rapid kindling protocol [RKP]); IL-1Ra was injected (25 mg/kg, i.p., 2 h prior to the RKP). The effects of treatments were examined on baseline hippocampal excitability, on the progression of rapid kindling, and on the retention of rapid kindling. LPS increased baseline hippocampal excitability, evident as the decrease of hippocampal ADT. LPS also increased kindling progression. Twenty-four hours after the completion of kindling procedure, LPS-treated animals exhibited increased excitability as compared with saline-treated kindling controls. The kindling progression was blocked by IL1RA when given in combination with LPS. IL1RA was able to reverse the effect of LPS on afterdischarge duration (ADD) while IL1RA alone decreased ADT. We showed that inflammation provoked by LPS enhanced rapid kindling epileptogenesis in immature rat brains. IL1RA was also able to mitigate this augmentation of epileptogenesis enhanced by LPS.
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Affiliation(s)
- Stéphane Auvin
- Department of Pediatrics, David Geffen School of Medicine, UCLA, Los Angeles, California, USA.
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Time-dependent changes in learning ability and induction of long-term potentiation in the lithium-pilocarpine-induced epileptic mouse model. Epilepsy Behav 2010; 17:448-54. [PMID: 20332069 DOI: 10.1016/j.yebeh.2010.02.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 02/12/2010] [Accepted: 02/13/2010] [Indexed: 11/23/2022]
Abstract
To explore the mechanism underlying the development of learning deficits in patients with epilepsy, we generated a mouse model for temporal lobe epilepsy by intraperitoneally injecting mice with pilocarpine with lithium chloride, and investigated time-dependent changes in both contextual fear memory of those model mice and long-term potentiation (LTP) in hippocampal CA1 neurons 1 day, 2 weeks, and 6 weeks after the onset of status epilepticus (SE). Fear memory formation did not change 1 day and 2 weeks after the onset of SE, but was significantly reduced after 6 weeks. Induction of LTP was enhanced 1 day after the onset of SE, but returned to the normal level 2 weeks later, and was almost completely attenuated after 6 weeks. The enhancement of LTP was accompanied by an increase in output responses of excitatory postsynaptic potentials, whereas suppression of LTP was accompanied by alteration of the ratio of paired pulse facilitation. These results indicate that time-dependent changes of LTP induction have a causal role in the development of learning deficits of epilepsy patients.
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Sgobio C, Ghiglieri V, Costa C, Bagetta V, Siliquini S, Barone I, Di Filippo M, Gardoni F, Gundelfinger ED, Di Luca M, Picconi B, Calabresi P. Hippocampal synaptic plasticity, memory, and epilepsy: effects of long-term valproic acid treatment. Biol Psychiatry 2010; 67:567-74. [PMID: 20074705 DOI: 10.1016/j.biopsych.2009.11.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 11/05/2009] [Accepted: 11/07/2009] [Indexed: 11/26/2022]
Abstract
BACKGROUND Memory impairment is commonly associated with epilepsy, and the use of antiepileptic drugs (AEDs) causes additional neuropsychologic deficits that are of particular concern in learning-age children and elderly patients. The aim of this study was to investigate hippocampal synaptic plasticity and morphology as well as hippocampal-dependent memory in physiologic conditions and in a genetic model of epilepsy following chronic treatment with the widely used AED valproic acid (VPA). METHODS Mice lacking the presynaptic scaffolding protein Bassoon were used as a model of epilepsy. Electrophysiologic recordings were used to analyze basal glutamatergic synaptic transmission, paired-pulse facilitation, and activity-dependent long-term potentiation (LTP) in the CA1 area. Dendritic morphology and spine density were analyzed, and glutamate-related signaling was investigated by Western blot analysis. Social transmission of food preference test was used to investigate nonspatial hippocampal memory. RESULTS VPA treatment significantly reduced seizures frequency and mortality in epileptic mice. Long-term potentiation was absent at CA1 synapses of untreated epileptic mutant mice that also showed significant dendritic abnormalities. Treatment with VPA rescued physiologic LTP but did not reverse morphological abnormalities and deficits in nonspatial hippocampal memory observed in mutant epileptic mice. Moreover, VPA was found to induce per se dendritic abnormalities and memory dysfunction in normal animals. CONCLUSIONS The impairment of hippocampal synaptic plasticity in epileptic mice, rescued by VPA treatment, might represent the mechanism underlying epilepsy-induced memory deficits. Moreover, the demonstration that VPA induces morphologic alterations and impairment in specific hippocampal-dependent memory task might explain the detrimental effects of antiepileptic treatment on cognition in human subjects.
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Affiliation(s)
- Carmelo Sgobio
- Fondazione Santa Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
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Abnormal parieto-motor connectivity in Tuberous Sclerosis Complex. Epilepsy Res 2009; 87:102-5. [DOI: 10.1016/j.eplepsyres.2009.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 06/19/2009] [Accepted: 07/24/2009] [Indexed: 11/18/2022]
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Malkowicz D, Martinez D. Role of Quantitative Electroencephalography, Neurotherapy, and Neuroplasticity in Recovery from Neurological and Psychiatric Disorders. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/10874200903127049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Chauvière L, Rafrafi N, Thinus-Blanc C, Bartolomei F, Esclapez M, Bernard C. Early deficits in spatial memory and theta rhythm in experimental temporal lobe epilepsy. J Neurosci 2009; 29:5402-10. [PMID: 19403808 PMCID: PMC6665868 DOI: 10.1523/jneurosci.4699-08.2009] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 02/23/2009] [Accepted: 02/27/2009] [Indexed: 11/21/2022] Open
Abstract
Patients with temporal lobe epilepsy (TLE), the most common form of epilepsy in adults, often display cognitive deficits. The time course and underlying mechanisms of cognitive decline remain unknown during epileptogenesis (the process leading to epilepsy). Using the rat pilocarpine model of TLE, we performed a longitudinal study to assess spatial and nonspatial cognitive performance during epileptogenesis. In parallel, we monitored interictal-like activity (ILA) in the hippocampal CA1 region, as well as theta oscillations, a brain rhythm central to numerous cognitive processes. Here, we report that spatial memory was altered soon after pilocarpine-induced status epilepticus, i.e., already during the seizure-free, latent period. Spatial deficits correlated with a decrease in the power of theta oscillations but not with the frequency of ILA. Spatial deficits persisted when animals had spontaneous seizures (chronic stage) without further modification. In contrast, nonspatial memory performances remained unaffected throughout. We conclude that the reorganization of hippocampal circuitry that immediately follows the initial insult can affect theta oscillation mechanisms, in turn, resulting in deficits in hippocampus-dependent memory tasks. These deficits may be dissociated from the process that leads to epilepsy itself but could instead constitute, as ILA, early markers in at-risk patients and/or provide beneficial therapeutic targets.
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Fu M, Xie Z, Zuo H. TRPV1: a potential target for antiepileptogenesis. Med Hypotheses 2009; 73:100-2. [PMID: 19328632 DOI: 10.1016/j.mehy.2009.01.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2008] [Revised: 11/23/2008] [Accepted: 01/06/2009] [Indexed: 10/21/2022]
Abstract
Epilepsy is one of the most common diseases in neurology department. It is caused by many different kinds of perturbances of normal balance of excitation and inhibition within the central nervous system. Current clinical antiepileptic drugs (AEDs) targets include ion channels, neurotransmitter transporters and neurotransmitter metabolic enzymes. They could control about 70-80% of the patients' symptoms; 20-30% patients develop to be intractable epilepsy sufferers. Moreover, antiepileptic drugs could not prevent formation of foci and disease process, but only alleviate symptoms of seizures at risk of different adverse effects as the consequences of large doses. Recently, impressive data on the actions of transient receptor potential vanilloid receptor 1 (TRPV1) prove it to be an inspiring antiepileptogenic target. TRPV1 activation modulates activity-dependent synaptic efficacy: (i) facilitating long-term potentiation (LTP) and suppressing long-term depression (LTD) of hippocampal neurons (ii) selectively inhibiting excitatory synapses onto hippocampal interneurons, which is expected to increase the excitability of innervated pyramidal cells. Nerve growth factor (NGF) can acutely and chronically upregulates TRPV1 expression, suggesting that TRPV1 channels would play an important role in the course of NGF regulated epileptogenesis. Endocannabinoid anandamide (AEA) is one of the TRPV1 endogenous agonists. It has been proved that, in the course of epilepsy, AEA levels increases due to enhanced formation and both exogenously administered and endogenously produced AEA display proconvulsant activity. Moreover, TRPV1 activation triggers apoptotic neuronal death of rat cortical cultures, which may be responsible, at least in part, for the volume loss of neocortex in chronic epilepsy. Our hypothesis may broaden the drug screening and designing for clinical strategies for epilepsy treatment.
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Affiliation(s)
- Min Fu
- Medical College, Tsinghua University, Beijing 100084, China
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