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Fonseca-Gomes J, Costa-Coelho T, Ferreira-Manso M, Inteiro-Oliveira S, Vaz SH, Alemãn-Serrano N, Atalaia-Barbacena H, Ribeiro-Rodrigues L, Ramalho RM, Pinto R, Vicente Miranda H, Tanqueiro SR, de Almeida-Borlido C, Ramalho MJ, Miranda-Lourenço C, Belo RF, Ferreira CB, Neves V, Rombo DM, Viais R, Martins IC, Jerónimo-Santos A, Caetano A, Manso N, Mäkinen P, Marttinen M, Takalo M, Bremang M, Pike I, Haapasalo A, Loureiro JA, Pereira MC, Santos NC, Outeiro TF, Castanho MARB, Fernandes A, Hiltunen M, Duarte CB, Castrén E, de Mendonça A, Sebastião AM, Rodrigues TM, Diógenes MJ. A small TAT-TrkB peptide prevents BDNF receptor cleavage and restores synaptic physiology in Alzheimer's disease. Mol Ther 2024; 32:3372-3401. [PMID: 39205389 DOI: 10.1016/j.ymthe.2024.08.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 08/01/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024] Open
Abstract
In Alzheimer's disease (AD), amyloid β (Aβ)-triggered cleavage of TrkB-FL impairs brain-derived neurotrophic factor (BDNF) signaling, thereby compromising neuronal survival, differentiation, and synaptic transmission and plasticity. Using cerebrospinal fluid and postmortem human brain samples, we show that TrkB-FL cleavage occurs from the early stages of the disease and increases as a function of pathology severity. To explore the therapeutic potential of this disease mechanism, we designed small TAT-fused peptides and screened their ability to prevent TrkB-FL receptor cleavage. Among these, a TAT-TrkB peptide with a lysine-lysine linker prevented TrkB-FL cleavage both in vitro and in vivo and rescued synaptic deficits induced by oligomeric Aβ in hippocampal slices. Furthermore, this TAT-TrkB peptide improved the cognitive performance, ameliorated synaptic plasticity deficits and prevented Tau pathology progression in vivo in the 5XFAD mouse model of AD. No evidence of liver or kidney toxicity was found. We provide proof-of-concept evidence for the efficacy and safety of this therapeutic strategy and anticipate that this TAT-TrkB peptide has the potential to be a disease-modifying drug that can prevent and/or reverse cognitive deficits in patients with AD.
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Affiliation(s)
- João Fonseca-Gomes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Tiago Costa-Coelho
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisbon, Portugal
| | - Mafalda Ferreira-Manso
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisbon, Portugal; Department of Pharmaceutical Sciences and Medicines, Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisbon, Portugal
| | - Sara Inteiro-Oliveira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Sandra H Vaz
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Nuno Alemãn-Serrano
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Henrique Atalaia-Barbacena
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Leonor Ribeiro-Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Rita M Ramalho
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Rui Pinto
- Laboratory of Systems Integration Pharmacology, Clinical, and Regulatory Science, Research Institute for Medicines (iMED.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisbon, Portugal; Dr. Joaquim Chaves Laboratório de Análises Clínicas, 2790-224 Carnaxide, Portugal
| | - Hugo Vicente Miranda
- iNOVA4Health, NOVA Medical School, NMS, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal
| | - Sara R Tanqueiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Carolina de Almeida-Borlido
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Maria João Ramalho
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
| | - Catarina Miranda-Lourenço
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Rita F Belo
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Catarina B Ferreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Vera Neves
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Diogo M Rombo
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Ricardo Viais
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Ivo C Martins
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - André Jerónimo-Santos
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - António Caetano
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Nuno Manso
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Petra Mäkinen
- Institute of Biomedicine, School of Medicine, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
| | - Mikael Marttinen
- Institute of Biomedicine, School of Medicine, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland; Structural and Computational Biology, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Mari Takalo
- Institute of Biomedicine, School of Medicine, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
| | - Michael Bremang
- Proteome Sciences, Coveham House, Downside Bridge Road, KT11 3EP Cobham, UK
| | - Ian Pike
- Proteome Sciences, Coveham House, Downside Bridge Road, KT11 3EP Cobham, UK
| | - Annakaisa Haapasalo
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland
| | - Joana A Loureiro
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
| | - Maria Carmo Pereira
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal; ALiCE-Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
| | - Nuno C Santos
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37073 Göttingen, Germany; Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany; Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; German Center for Neurodegenerative Diseases (DZNE), 37075 Göttingen, Germany
| | - Miguel A R B Castanho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Adelaide Fernandes
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisbon, Portugal; Department of Pharmaceutical Sciences and Medicines, Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisbon, Portugal
| | - Mikko Hiltunen
- Institute of Biomedicine, School of Medicine, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
| | - Carlos B Duarte
- CNC - Center for Neuroscience and Cell Biology and Department of Life Sciences, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Eero Castrén
- Neuroscience Center, University of Helsinki, 00014 Helsinki, Finland
| | - Alexandre de Mendonça
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Tiago M Rodrigues
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal.
| | - Maria José Diógenes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal.
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Lopez-Rodriguez AB, Murray CL, Kealy J, Towns C, Roche A, Nazmi A, Doran M, Lowry JP, Cunningham C. Hyperthermia elevates brain temperature and improves behavioural signs in animal models of autism spectrum disorder. Mol Autism 2023; 14:43. [PMID: 37968722 PMCID: PMC10652497 DOI: 10.1186/s13229-023-00569-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 09/25/2023] [Indexed: 11/17/2023] Open
Abstract
BACKGROUND Autism spectrum disorders (ASD) are predominantly neurodevelopmental and largely genetically determined. However, there are human data supporting the idea that fever can improve symptoms in some individuals, but those data are limited and there are almost no data to support this from animal models. We aimed to test the hypothesis that elevated body temperature would improve function in two animal models of ASD. METHODS We used a 4 h whole-body hyperthermia (WBH) protocol and, separately, systemic inflammation induced by bacterial endotoxin (LPS) at 250 µg/kg, to dissociate temperature and inflammatory elements of fever in two ASD animal models: C58/J and Shank3B- mice. We used one- or two-way ANOVA and t-tests with normally distributed data and Kruskal-Wallis or Mann-Whitney with nonparametric data. Post hoc comparisons were made with a level of significance set at p < 0.05. For correlation analyses, data were adjusted by a linear regression model. RESULTS Only LPS induced inflammatory signatures in the brain while only WBH produced fever-range hyperthermia. WBH reduced repetitive behaviours and improved social interaction in C58/J mice and significantly reduced compulsive grooming in Shank3B- mice. LPS significantly suppressed most activities over 5-48 h. LIMITATIONS We show behavioural, cellular and molecular changes, but provide no specific mechanistic explanation for the observed behavioural improvements. CONCLUSIONS The data are the first, to our knowledge, to demonstrate that elevated body temperature can improve behavioural signs in 2 distinct ASD models. Given the developmental nature of ASD, evidence that symptoms may be improved by environmental perturbations indicates possibilities for improving function in these individuals. Since experimental hyperthermia in patients would carry significant risks, it is now essential to pursue molecular mechanisms through which hyperthermia might bring about the observed benefits.
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Affiliation(s)
- Ana Belen Lopez-Rodriguez
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Carol L Murray
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - John Kealy
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Clodagh Towns
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Andrew Roche
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Arshed Nazmi
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland
| | - Michelle Doran
- Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Republic of Ireland
| | - John P Lowry
- Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Republic of Ireland
| | - Colm Cunningham
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Republic of Ireland.
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Kim T, Kadji H, Whalen AJ, Ashourvan A, Freeman E, Fried SI, Tadigadapa S, Schiff SJ. Thermal effects on neurons during stimulation of the brain. J Neural Eng 2022; 19:056029. [PMID: 36126646 PMCID: PMC9855718 DOI: 10.1088/1741-2552/ac9339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/13/2022] [Accepted: 09/20/2022] [Indexed: 01/25/2023]
Abstract
All electric and magnetic stimulation of the brain deposits thermal energy in the brain. This occurs through either Joule heating of the conductors carrying current through electrodes and magnetic coils, or through dissipation of energy in the conductive brain.Objective.Although electrical interaction with brain tissue is inseparable from thermal effects when electrodes are used, magnetic induction enables us to separate Joule heating from induction effects by contrasting AC and DC driving of magnetic coils using the same energy deposition within the conductors. Since mammalian cortical neurons have no known sensitivity to static magnetic fields, and if there is no evidence of effect on spike timing to oscillating magnetic fields, we can presume that the induced electrical currents within the brain are below the molecular shot noise where any interaction with tissue is purely thermal.Approach.In this study, we examined a range of frequencies produced from micromagnetic coils operating below the molecular shot noise threshold for electrical interaction with single neurons.Main results.We found that small temperature increases and decreases of 1∘C caused consistent transient suppression and excitation of neurons during temperature change. Numerical modeling of the biophysics demonstrated that the Na-K pump, and to a lesser extent the Nernst potential, could account for these transient effects. Such effects are dependent upon compartmental ion fluxes and the rate of temperature change.Significance.A new bifurcation is described in the model dynamics that accounts for the transient suppression and excitation; in addition, we note the remarkable similarity of this bifurcation's rate dependency with other thermal rate-dependent tipping points in planetary warming dynamics. These experimental and theoretical findings demonstrate that stimulation of the brain must take into account small thermal effects that are ubiquitously present in electrical and magnetic stimulation. More sophisticated models of electrical current interaction with neurons combined with thermal effects will lead to more accurate modulation of neuronal activity.
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Affiliation(s)
- TaeKen Kim
- Department of Physics, The Pennsylvania State University, University Park, PA, United States of America
| | - Herve Kadji
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States of America
- Department of Radiation Oncology, Hackensack Meridian Health Mountainside Medical Center, Montclair, NJ, United States of America
| | - Andrew J Whalen
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA, United States of America
- Department of Neurosurgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States of America
| | - Arian Ashourvan
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States of America
| | - Eugene Freeman
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, United States of America
- Honeywell International Aerospace Advanced Technology, Plymouth, MN, United States of America
| | - Shelley I Fried
- Department of Neurosurgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States of America
- Boston VA Healthcare System, Boston 02130, United States of America
| | - Srinivas Tadigadapa
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, United States of America
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, United States of America
| | - Steven J Schiff
- Department of Physics, The Pennsylvania State University, University Park, PA, United States of America
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States of America
- Department of Neurosurgery, Penn State College of Medicine, Hershey, PA 17033, United States of America
- Department of Neurosurgery, Yale University, 333 Cedar Street, TMP 410, New Haven, CT 06510, United States of America
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Lü XY, Meng C, An S, Zhao YF, Wang ZG. Study on influence of external factors on the electrical excitability of PC12 quasi-neuronal networks through Voltage Threshold Measurement Method. PLoS One 2022; 17:e0265078. [PMID: 35263381 PMCID: PMC8906582 DOI: 10.1371/journal.pone.0265078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/22/2022] [Indexed: 11/18/2022] Open
Abstract
The aim of this paper was to investigate the influence of four different external factors (acetylcholine, ethanol, temperature and lidocaine hydrochloride) on PC12 quasi-neuronal networks by multielectrode-array-based Voltage Threshold Measurement Method (VTMM). At first, VTMM was employed to measure the lowest amplitude of the voltage stimulating pulses that could just trigger the action potential from PC12 quasi-neuronal networks under normal conditions, and the amplitude was defined as the normal voltage threshold (VTh). Then the changes of the VTh of PC12 quasi-neuronal networks treated by the four external factors were tested respectively. The results showed the normal VTh of PC12 quasi-neuronal networks was 36 mV. The VTh has negative correlation with the concentration of acetylcholine and has positive correlation with the concentration of ethanol. The curves of the correlation of the VTh with temperature and the concentration of lidocaine hydrochloride were U-shaped and Λ-shaped respectively. Comparing with our earlier studies on hippocampal neuronal networks and hippocampal slices, PC12 quasi-neuronal networks not only had the same typical voltage threshold characteristic, but also had similar changes on electrical excitability when treated by the four external factors mentioned above. Therefore, the rapid-formed PC12 quasi-neuronal networks could replace neuronal networks in proper conditions, and VTMM could be used to analyze the influence of external factors on the electrical excitability of PC12 quasi-neuronal networks.
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Affiliation(s)
- Xiao-Ying Lü
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, Jiangsu Province, China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
- * E-mail: (XYL); (ZGW)
| | - Chen Meng
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, Jiangsu Province, China
| | - Shuai An
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, Jiangsu Province, China
| | - Yong-Fang Zhao
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, Jiangsu Province, China
| | - Zhi-Gong Wang
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
- Institute of RF- & OE-ICs, Southeast University, Nanjing, Jiangsu Province, China
- * E-mail: (XYL); (ZGW)
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Saccher M, Kawasaki S, Onori MP, van Woerden GM, Giagka V, Dekker R. Focused ultrasound neuromodulation on a multiwell MEA. Bioelectron Med 2022; 8:2. [PMID: 35081966 PMCID: PMC8793260 DOI: 10.1186/s42234-021-00083-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/06/2021] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Microelectrode arrays (MEA) enable the measurement and stimulation of the electrical activity of cultured cells. The integration of other neuromodulation methods will significantly enhance the application range of MEAs to study their effects on neurons. A neuromodulation method that is recently gaining more attention is focused ultrasound neuromodulation (FUS), which has the potential to treat neurological disorders reversibly and precisely. METHODS In this work, we present the integration of a focused ultrasound delivery system with a multiwell MEA plate. RESULTS The ultrasound delivery system was characterised by ultrasound pressure measurements, and the integration with the MEA plate was modelled with finite-element simulations of acoustic field parameters. The results of the simulations were validated with experimental visualisation of the ultrasound field with Schlieren imaging. In addition, the system was tested on a murine primary hippocampal neuron culture, showing that ultrasound can influence the activity of the neurons. CONCLUSIONS Our system was demonstrated to be suitable for studying the effect of focused ultrasound on neuronal cultures. The system allows reproducible experiments across the wells due to its robustness and simplicity of operation.
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Affiliation(s)
- Marta Saccher
- Department of Microelectronics, Delft University of Technology, Delft, Netherlands
| | - Shinnosuke Kawasaki
- Department of Microelectronics, Delft University of Technology, Delft, Netherlands
| | | | - Geeske M. van Woerden
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Vasiliki Giagka
- Department of Microelectronics, Delft University of Technology, Delft, Netherlands
- Fraunhofer Institute for Reliability and Microintegration IZM, Berlin, Germany
| | - Ronald Dekker
- Department of Microelectronics, Delft University of Technology, Delft, Netherlands
- Philips Research, Eindhoven, Netherlands
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Locus Coeruleus in Non-Mammalian Vertebrates. Brain Sci 2022; 12:brainsci12020134. [PMID: 35203898 PMCID: PMC8870555 DOI: 10.3390/brainsci12020134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/08/2022] [Accepted: 01/15/2022] [Indexed: 11/30/2022] Open
Abstract
The locus coeruleus (LC) is a vertebrate-specific nucleus and the primary source of norepinephrine (NE) in the brain. This nucleus has conserved properties across species: highly homogeneous cell types, a small number of cells but extensive axonal projections, and potent influence on brain states. Comparative studies on LC benefit greatly from its homogeneity in cell types and modularity in projection patterns, and thoroughly understanding the LC-NE system could shed new light on the organization principles of other more complex modulatory systems. Although studies on LC are mainly focused on mammals, many of the fundamental properties and functions of LC are readily observable in other vertebrate models and could inform mammalian studies. Here, we summarize anatomical and functional studies of LC in non-mammalian vertebrate classes, fish, amphibians, reptiles, and birds, on topics including axonal projections, gene expressions, homeostatic control, and modulation of sensorimotor transformation. Thus, this review complements mammalian studies on the role of LC in the brain.
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Serotonin Discharge Regulation by Additional Neurotransmitters of Rat Hippocampus Associated With the Continence Central Circuit. Int Neurourol J 2021; 25:S106-113. [PMID: 34844393 PMCID: PMC8654317 DOI: 10.5213/inj.2142348.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 11/18/2021] [Indexed: 11/16/2022] Open
Abstract
Purpose The lower urinary tract is believed to be centrally regulated with the involvement of a range of neurotransmitters. The parasympathetic excitatory input to the urinary bladder is suppressed when the serotonergic system is activated, and thereby voiding is blocked. In healthy people, continence is usually underpinned by hippocampal formation (circuit 3). In order to advance knowledge of how serotoninergic neurons and additional nerve fibers were correlated, the purpose of the present work was to research how the discharge of serotonin from hippocampal slices was affected by different neurotransmitters in rat models. Methods The adopted procedure involved administration of the central neurotransmitters acetylcholine, norepinephrine, dopamine, N-methyl-D-aspartate (NMDA), gamma-aminobutyric acid (GABA), glycine, and neuropeptide Y as well as monitoring of the alterations in the discharge of [3H]5-hydroxytryptamine (5-HT). Furthermore, to determine whether the effect of the neurotransmitters was influenced by interneuron, tetrodotoxin was also employed. Results Acetylcholine (10-5M) did not alter [3H]5-HT discharge, whereas more 5-HT was discharged from the hippocampal slices of rats under stimulation by norepinephrine (10-5M) as well as dopamine (10-5M) and tetrodotoxin (10-6M) did not inhibit the discharge. By contrast, tetrodotoxin inhibited the discharge of [3H]5-HT that was exacerbated by NMDA (10-4M). Meanwhile, compared to control, GABA (10-5M), glycine (10-5M), or neuropeptide Y (10-6M) did not alter the [³H]5-HT discharge. Conclusions From the research findings, it can be concluded that 5-HT discharge from rat hippocampus is enhanced by norepinephrine and dopamine through direct effect on the 5-HT neuronal terminal. By contrast, 5-HT discharge is intensified by NMDA by activating interneurons.
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Emerging Applications of Optical Fiber-Based Devices for Brain Research. ADVANCED FIBER MATERIALS 2021. [DOI: 10.1007/s42765-021-00092-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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9
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Chen YS, Shu K, Kang HC. Deep Brain Stimulation in Alzheimer's Disease: Targeting the Nucleus Basalis of Meynert. J Alzheimers Dis 2021; 80:53-70. [PMID: 33492288 DOI: 10.3233/jad-201141] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Alzheimer's disease (AD) is becoming a prevalent disease in the elderly population. Past decades have witnessed the development of drug therapies with varying targets. However, all drugs with a single molecular target fail to reverse or ameliorate AD progression, which ultimately results in cortical and subcortical network dysregulation. Deep brain stimulation (DBS) has been proven effective for the treatment of Parkinson's disease, essential tremor, and other neurological diseases. As such, DBS has also been gradually acknowledged as a potential therapy for AD. The current review focuses on DBS of the nucleus basalis of Meynert (NBM). As a critical component of the cerebral cholinergic system and the Papez circuit in the basal ganglia, the NBM plays an indispensable role in the subcortical regulation of memory, attention, and arousal state, which makes the NBM a promising target for modulation of neural network dysfunction and AD treatment. We summarized the intricate projection relations and functionality of the NBM, current approaches for stereotactic localization and evaluation of the NBM, and the therapeutic effects of NBM-DBS both in patients and animal models. Furthermore, the current shortcomings of NBM-DBS, such as variations in cortical blood flow, increased temperature in the target area, and stimulation-related neural damage, were presented.
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Affiliation(s)
- Yu-Si Chen
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Kai Shu
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hui-Cong Kang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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da Silva AJ, Dos Santos ES. Energetic and thermodynamical aspects of the cyclodextrins-cannabidiol complex in aqueous solution: a molecular-dynamics study. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2020; 49:571-589. [PMID: 32939610 DOI: 10.1007/s00249-020-01463-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/23/2020] [Accepted: 09/04/2020] [Indexed: 12/19/2022]
Abstract
Cyclodextrins (CDs) are well-known carriers for encapsulating hydrophobic molecules, while among cannabinoids, cannabidiol (CBD) has attracted considerable attention due to its therapeutic capability. In this framework, we employed molecular dynamics and docking techniques for investigating the interaction energy and thermodynamical issues between different CDs (α, β, and γ type) and CBD immersed in water and a solution mimicking a physiological environment. We quantified the energetic aspects, for different thermal conditions, in which both aqueous solutions interact with CBDs and CDs and the CBD-CDs complex itself. In order to approximate the physiological conditions, our simulations also included the mammalian temperature. The calculations revealed significant interaction energy between lactate and the CD surface and a movement of lactate toward CD as well. We observed an almost constant number of lactate molecules forming clusters without exhibiting a temperature dependence. Next, the degree of CBD-CDs complexation at four different temperatures was analyzed. The results showed that the complexation depends on the medium, becoming weaker with the temperature increment. Our findings highlighted that the entropy contribution is relevant for CBD-α-CD and CBD-β-CD, while CBD-γ-CD is practically insensitive to temperature changes for both solutions. In both water and artificial physiological solutions, the γ-CD appears more stable than the other complexes. Overall, CBD achieved partial encapsulation considering α-CD and β-CD, showing a temperature dependence, while γ-CD remained fully immersed no matter the thermal level assumed. We also discuss the pharmacological relevance and physiological implications of these findings.
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Affiliation(s)
- A J da Silva
- Instituto de Humanidades, Artes e Ciências, Universidade Federal do Sul da Bahia, Itabuna, Bahia, 45613-204, Brazil.
| | - E S Dos Santos
- Instituto de Física, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, Bahia, 40210-340, Brazil
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Moradi K, Ascoli GA. A comprehensive knowledge base of synaptic electrophysiology in the rodent hippocampal formation. Hippocampus 2020; 30:314-331. [PMID: 31472001 PMCID: PMC7875289 DOI: 10.1002/hipo.23148] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/16/2019] [Accepted: 08/06/2019] [Indexed: 01/14/2023]
Abstract
The cellular and synaptic architecture of the rodent hippocampus has been described in thousands of peer-reviewed publications. However, no human- or machine-readable public catalog of synaptic electrophysiology data exists for this or any other neural system. Harnessing state-of-the-art information technology, we have developed a cloud-based toolset for identifying empirical evidence from the scientific literature pertaining to synaptic electrophysiology, for extracting the experimental data of interest, and for linking each entry to relevant text or figure excerpts. Mining more than 1,200 published journal articles, we have identified eight different signal modalities quantified by 90 different methods to measure synaptic amplitude, kinetics, and plasticity in hippocampal neurons. We have designed a data structure that both reflects the differences and maintains the existing relations among experimental modalities. Moreover, we mapped every annotated experiment to identified potential connections, that is, specific pairs of presynaptic and postsynaptic neuron types. To this aim, we leveraged Hippocampome.org, an open-access knowledge base of morphologically, electrophysiologically, and molecularly characterized neuron types in the rodent hippocampal formation. Specifically, we have implemented a computational pipeline to systematically translate neuron type properties into formal queries in order to find all compatible potential connections. With this system, we have collected nearly 40,000 synaptic data entities covering 88% of the 3,120 potential connections in Hippocampome.org. Correcting membrane potentials with respect to liquid junction potentials significantly reduced the difference between theoretical and experimental reversal potentials, thereby enabling the accurate conversion of all synaptic amplitudes to conductance. This data set allows for large-scale hypothesis testing of the general rules governing synaptic signals. To illustrate these applications, we confirmed several expected correlations between synaptic measurements and their covariates while suggesting previously unreported ones. We release all data open-source at Hippocampome.org in order to further research across disciplines.
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Affiliation(s)
- Keivan Moradi
- Neuroscience Program, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA (USA)
| | - Giorgio A. Ascoli
- Neuroscience Program, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA (USA)
- Bioengineering Department, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA (USA)
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12
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Temperature elevation in epileptogenic foci exacerbates epileptic discharge through TRPV4 activation. J Transl Med 2020; 100:274-284. [PMID: 31641226 DOI: 10.1038/s41374-019-0335-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/10/2019] [Accepted: 09/20/2019] [Indexed: 12/15/2022] Open
Abstract
Physiological brain temperature is an important determinant of brain function, and it is well established that changes in brain temperature dynamically influence hippocampal neuronal activity. We previously demonstrated that the thermosensor TRPV4 is activated at physiological brain temperature in hippocampal neurons thereby controlling neuronal excitability in vitro. Here, we examined whether TRPV4 regulates neuronal excitability through its activation by brain temperature in vivo. We locally cooled the hippocampus using our novel electrical device and demonstrated constitutive TRPV4 activation in normal mouse brain. We generated a model of partial epilepsy by utilizing kindling stimuli in the ventral hippocampus of wild type (WT) or TRPV4-deficient (TRPV4KO) mice and obtained electroencephalograms (EEG). The frequencies of epileptic EEG in WT mice were significantly larger than those in TRPV4KO mice. These results indicate that TRPV4 activation is involved in disease progression of epilepsy. We expected that disease progression would enhance hyperexcitability and lead to hyperthermia in the epileptogenic foci. To confirm this hypothesis, we developed a new device to measure exact brain temperature only in a restricted local area. From the recording results by the new device, we found that the brain temperatures in epileptogenic zones were dramatically elevated compared with normal regions. Furthermore, we demonstrated that the temperature elevation was critical for disease progression. Based on these results, we speculate that brain cooling treatment at epileptogenic foci would effectively suppress epileptic discharges through inhibition of TRPV4. Notably, the cooling treatment drastically suppressed neuronal discharges dependent on the inactivation of TRPV4.
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13
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Sonntag M, Arendt T. Neuronal Activity in the Hibernating Brain. Front Neuroanat 2019; 13:71. [PMID: 31338028 PMCID: PMC6629779 DOI: 10.3389/fnana.2019.00071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/26/2019] [Indexed: 11/13/2022] Open
Abstract
Hibernation is a natural phenomenon in many species which helps them to survive under extreme ambient conditions, such as cold temperatures and reduced availability of food in the winter months. It is characterized by a dramatic and regulated drop of body temperature, which in some cases can be near 0°C. Additionally, neural control of hibernation is maintained over all phases of a hibernation bout, including entrance into, during and arousal from torpor, despite a marked decrease in overall neural activity in torpor. In the present review, we provide an overview on what we know about neuronal activity in the hibernating brain focusing on cold-induced adaptations. We discuss pioneer and more recent in vitro and in vivo electrophysiological data and molecular analyses of activity markers which strikingly contributed to our understanding of the brain's sensitivity to dramatic changes in temperature across the hibernation cycle. Neuronal activity is markedly reduced with decreasing body temperature, and many neurons may fire infrequently in torpor at low brain temperatures. Still, there is convincing evidence that specific regions maintain their ability to generate action potentials in deep torpor, at least in response to adequate stimuli. Those regions include the peripheral system and primary central regions. However, further experiments on neuronal activity are needed to more precisely determine temperature effects on neuronal activity in specific cell types and specific brain nuclei.
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Affiliation(s)
- Mandy Sonntag
- Paul-Flechsig-Institute of Brain Research, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Thomas Arendt
- Paul-Flechsig-Institute of Brain Research, Medical Faculty, University of Leipzig, Leipzig, Germany
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14
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Abstract
Patients with prolonged seizures that do not respond to intravenous benzodiazepines and a second-line anticonvulsant suffer from refractory status epilepticus and those with seizures that do not respond to continuous intravenous anesthetic anticonvulsants suffer from super-refractory status epilepticus. Both conditions are associated with significant morbidity and mortality. A strict pharmacological treatment regimen is urgently required, but the level of evidence for the available drugs is very low. Refractory complex focal status epilepticus generally does not require anesthetics, but all intravenous non-anesthetizing anticonvulsants may be used. Most descriptive data are available for levetiracetam, phenytoin and valproate. Refractory generalized convulsive status epilepticus is a life-threatening emergency, and long-term clinical consequences are eminent. Administration of intravenous anesthetics is mandatory, and drugs acting at the inhibitory gamma-aminobutyric acid (GABA)A receptor such as midazolam, propofol and thiopental/pentobarbital are recommended without preference for one of those. One in five patients with anesthetic treatment does not respond and has super-refractory status epilepticus. With sustained seizure activity, excitatory N-methyl-d-aspartate (NMDA) receptors are increasingly expressed post-synaptically. Ketamine is an antagonist at this receptor and may prove efficient in some patients at later stages. Neurosteroids such as allopregnanolone increase sensitivity at GABAA receptors; a Phase 1/2 trial demonstrated safety and tolerability, but randomized controlled data failed to demonstrate efficacy. Adjunct ketogenic diet may contribute to termination of difficult-to-treat status epilepticus. Randomized controlled trials are needed to increase evidence for treatment of refractory and super-refractory status epilepticus, but there are multiple obstacles for realization. Hitherto, prospective multicenter registries for pharmacological treatment may help to improve our knowledge.
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Affiliation(s)
- Martin Holtkamp
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany.
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15
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Musolino ST, Schartner EP, Hutchinson MR, Salem A. Improved method for optical fiber temperature probe implantation in brains of free-moving rats. J Neurosci Methods 2019; 313:24-28. [DOI: 10.1016/j.jneumeth.2018.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/18/2018] [Accepted: 12/18/2018] [Indexed: 11/30/2022]
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16
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Dimpfel W, Franklin R, Gericke N, Schombert L. Effect of Zembrin ® and four of its alkaloid constituents on electric excitability of the rat hippocampus. JOURNAL OF ETHNOPHARMACOLOGY 2018; 223:135-141. [PMID: 29758341 DOI: 10.1016/j.jep.2018.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/10/2018] [Indexed: 06/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Sceletium tortuosum (Mesembryanthemaceae), a succulent plant indigenous to South Africa. is consumed in the form of teas, decoctions and tinctures and is sometimes smoked and used as snuff. In recent years, Sceletium has received a great deal of commercial interest for relieving stress in healthy people, and for treating a broad range of psychological, psychiatric and inflammatory conditions. MATERIAL AND METHODS The whole extract (Zembrin®) was tested ex vivo in the hippocampus slice preparation after one week of daily oral administration of 5 and 10 mg/kg. Four alkaloids - mesembrine, mesembranol, mesembrenol and mesembrenone - were tested directly in vitro. All four were also tested in the presence of different glutamate receptor agonists. RESULTS Zembrin® ex vivo as well as all alkaloids in vitro attenuated the amplitude of the population spike during electric stimulation as single shock as well as theta burst stimulation. Only Mesembranol and Mesembrenol having a hydroxyl group at position C6 instead of carbonyl group as in mesembrine and mesembrenone acted by attenuation of AMPA receptor mediated transmission as documented for the whole extract. DISCUSSION The current experimental series revealed a new physiological effect of Zembrin® on the electric activity of the hippocampus. Attenuation of AMPA mediated transmission has been related to successful adjunctive treatment of epileptic patients. Administered doses of 5 and 10 mg/kg are in line with a dosage of 50 mg/subject as tested clinically. CONCLUSION We have discovered a new structure activity relationship for Sceletium alkaloids. Since attenuation of AMPA mediated transmission has been related to successful adjunctive treatment of epileptic patients), Mesembrenol and Mesembranol may serve as new chemical leads for the development of new drugs for the treatment of epilepsy.
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17
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Dimpfel W, Schombert L, Panossian AG. Assessing the Quality and Potential Efficacy of Commercial Extracts of Rhodiola rosea L. by Analyzing the Salidroside and Rosavin Content and the Electrophysiological Activity in Hippocampal Long-Term Potentiation, a Synaptic Model of Memory. Front Pharmacol 2018; 9:425. [PMID: 29881348 PMCID: PMC5976749 DOI: 10.3389/fphar.2018.00425] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/11/2018] [Indexed: 12/20/2022] Open
Abstract
Rhodiola rosea L. roots and rhizome extracts are active ingredients in adaptogenic herbal medicinal products (HMP) and dietary supplements for temporary relief of symptoms of stress, such as fatigue and weakness. R. rosea extract has a stimulating effect on the CNS, suggesting potential benefits on cognitive functions, memory, learning, and attention. The reproducible efficacy and quality of preparations of the underground parts of R. rosea depend on the highly variable content of the active markers, salidroside and rosavin, which affect the quality of HMP and dietary supplements. However, it is not clear which analytical markers are important for assessing the efficacy of R. rosea preparations intended for use in aging-induced mild cognitive disorders, such as attenuated memory, attention, and learning. Furthermore, the activity of various commercial R. rosea extracts has not been correlated with their content. Here, the biological activities of salidroside, rosavin, and seven commercial extracts of underground parts of R. rosea were assessed using a synaptic model of memory: long-term potentiation (LTP) of synaptic transmission in hippocampus slices. A high degree of variation in the content of all active markers was observed. One extract from China lacked rosavin, and there was even variation in the extracts from the Altai geographic region. In vitro, rosavin, salidroside and all tested R. rosea extracts potentiated electric stimulation of an intra-hippocampal electric circuit, which resulted in higher responses of the pyramidal cells in isolated hippocampus slices. Rosavin was more active at higher concentrations than salidroside; while, salidroside was more effective at lower concentrations. The highest content of both active markers was found in the extracts that were active at the lowest concentrations tested; while, some extracts contained some other compounds that presumably reduced the efficacy due to antagonistic interactions. Standardized content of active markers is necessary for the quality control of herbal preparations containing R. rosea extracts, but insufficient for assessment of their potential efficacy. Additional bioassays are needed to assure the reproducible pharmacological activity of R. rosea extracts; therefore, the LTP of synaptic transmission in hippocampus slices may serve as a validation tool for the quality control of R. rosea extracts.
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Affiliation(s)
- Wilfried Dimpfel
- Department of Pharmacology, Justus Liebig University Giessen, Giessen, Germany
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18
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Ischemic Brain Injury Leads to Brain Edema via Hyperthermia-Induced TRPV4 Activation. J Neurosci 2018; 38:5700-5709. [PMID: 29793978 DOI: 10.1523/jneurosci.2888-17.2018] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 04/26/2018] [Accepted: 05/03/2018] [Indexed: 01/27/2023] Open
Abstract
Brain edema is characterized by an increase in net brain water content, which results in an increase in brain volume. Although brain edema is associated with a high fatality rate, the cellular and molecular processes of edema remain largely unclear. Here, we developed an in vitro model of ischemic stroke-induced edema in which male mouse brain slices were treated with oxygen-glucose deprivation (OGD) to mimic ischemia. We continuously measured the cross-sectional area of the brain slice for 150 min under macroscopic microscopy, finding that OGD induces swelling of brain slices. OGD-induced swelling was prevented by pharmacologically blocking or genetically knocking out the transient receptor potential vanilloid 4 (TRPV4), a member of the thermosensitive TRP channel family. Because TRPV4 is activated at around body temperature and its activation is enhanced by heating, we next elevated the temperature of the perfusate in the recording chamber, finding that hyperthermia induces swelling via TRPV4 activation. Furthermore, using the temperature-dependent fluorescence lifetime of a fluorescent-thermosensitive probe, we confirmed that OGD treatment increases the temperature of brain slices through the activation of glutamate receptors. Finally, we found that brain edema following traumatic brain injury was suppressed in TRPV4-deficient male mice in vivo Thus, our study proposes a novel mechanism: hyperthermia activates TRPV4 and induces brain edema after ischemia.SIGNIFICANCE STATEMENT Brain edema is characterized by an increase in net brain water content, which results in an increase in brain volume. Although brain edema is associated with a high fatality rate, the cellular and molecular processes of edema remain unclear. Here, we developed an in vitro model of ischemic stroke-induced edema in which mouse brain slices were treated with oxygen-glucose deprivation. Using this system, we showed that the increase in brain temperature and the following activation of the thermosensitive cation channel TRPV4 (transient receptor potential vanilloid 4) are involved in the pathology of edema. Finally, we confirmed that TRPV4 is involved in brain edema in vivo using TRPV4-deficient mice, concluding that hyperthermia activates TRPV4 and induces brain edema after ischemia.
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Analytical modelling of temperature effects on an AMPA-type synapse. J Comput Neurosci 2018; 44:379-391. [PMID: 29752691 PMCID: PMC5973960 DOI: 10.1007/s10827-018-0684-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 03/28/2018] [Accepted: 04/09/2018] [Indexed: 01/28/2023]
Abstract
It was previously reported, that temperature may significantly influence neural dynamics on the different levels of brain function. Thus, in computational neuroscience, it would be useful to make models scalable for a wide range of various brain temperatures. However, lack of experimental data and an absence of temperature-dependent analytical models of synaptic conductance does not allow to include temperature effects at the multi-neuron modeling level. In this paper, we propose a first step to deal with this problem: A new analytical model of AMPA-type synaptic conductance, which is able to incorporate temperature effects in low-frequency stimulations. It was constructed based on Markov model description of AMPA receptor kinetics using the set of coupled ODEs. The closed-form solution for the set of differential equations was found using uncoupling assumption (introduced in the paper) with few simplifications motivated both from experimental data and from Monte Carlo simulation of synaptic transmission. The model may be used for computationally efficient and biologically accurate implementation of temperature effects on AMPA receptor conductance in large-scale neural network simulations. As a result, it may open a wide range of new possibilities for researching the influence of temperature on certain aspects of brain functioning.
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20
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An S, Zhao YF, Lü XY, Wang ZG. Quantitative evaluation of extrinsic factors influencing electrical excitability in neuronal networks: Voltage Threshold Measurement Method (VTMM). Neural Regen Res 2018; 13:1026-1035. [PMID: 29926830 PMCID: PMC6022462 DOI: 10.4103/1673-5374.233446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The electrical excitability of neural networks is influenced by different environmental factors. Effective and simple methods are required to objectively and quantitatively evaluate the influence of such factors, including variations in temperature and pharmaceutical dosage. The aim of this paper was to introduce ‘the voltage threshold measurement method’, which is a new method using microelectrode arrays that can quantitatively evaluate the influence of different factors on the electrical excitability of neural networks. We sought to verify the feasibility and efficacy of the method by studying the effects of acetylcholine, ethanol, and temperature on hippocampal neuronal networks and hippocampal brain slices. First, we determined the voltage of the stimulation pulse signal that elicited action potentials in the two types of neural networks under normal conditions. Second, we obtained the voltage thresholds for the two types of neural networks under different concentrations of acetylcholine, ethanol, and different temperatures. Finally, we obtained the relationship between voltage threshold and the three influential factors. Our results indicated that the normal voltage thresholds of the hippocampal neuronal network and hippocampal slice preparation were 56 and 31 mV, respectively. The voltage thresholds of the two types of neural networks were inversely proportional to acetylcholine concentration, and had an exponential dependency on ethanol concentration. The curves of the voltage threshold and the temperature of the medium for the two types of neural networks were U-shaped. The hippocampal neuronal network and hippocampal slice preparations lost their excitability when the temperature of the medium decreased below 34 and 33°C or increased above 42 and 43°C, respectively. These results demonstrate that the voltage threshold measurement method is effective and simple for examining the performance/excitability of neuronal networks.
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Affiliation(s)
- Shuai An
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, Jiangsu Province, China
| | - Yong-Fang Zhao
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, Jiangsu Province, China
| | - Xiao-Ying Lü
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Zhi-Gong Wang
- Institute of RF- & OE-ICs, Southeast University, Nanjing; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
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21
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Gulick DW, Li T, Kleim JA, Towe BC. Comparison of Electrical and Ultrasound Neurostimulation in Rat Motor Cortex. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:2824-2833. [PMID: 28964613 DOI: 10.1016/j.ultrasmedbio.2017.08.937] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 08/16/2017] [Accepted: 08/17/2017] [Indexed: 06/07/2023]
Abstract
Ultrasound (US) is known to non-invasively stimulate and modulate brain function; however, the mechanism of action is poorly understood. This study tested US stimulation of rat motor cortex (100 W/cm2, 200 kHz) in combination with epidural cortical stimulation. US directly evoked hindlimb movement. This response occurred even with short US bursts (3 ms) and had short latency (10 ms) and long refractory (3 s) periods. Unexpectedly, the epidural cortical stimulation hindlimb response was not altered during the 3-s refractory period of the US hindlimb response. This finding suggests that the US refractory period is not a general suppression of motor cortex, but rather the recovery time of a US-specific mechanism.
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Affiliation(s)
- Daniel W Gulick
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA.
| | - Tao Li
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jeffrey A Kleim
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA
| | - Bruce C Towe
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA
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22
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Vicente Miranda H, Szego ÉM, Oliveira LMA, Breda C, Darendelioglu E, de Oliveira RM, Ferreira DG, Gomes MA, Rott R, Oliveira M, Munari F, Enguita FJ, Simões T, Rodrigues EF, Heinrich M, Martins IC, Zamolo I, Riess O, Cordeiro C, Ponces-Freire A, Lashuel HA, Santos NC, Lopes LV, Xiang W, Jovin TM, Penque D, Engelender S, Zweckstetter M, Klucken J, Giorgini F, Quintas A, Outeiro TF. Glycation potentiates α-synuclein-associated neurodegeneration in synucleinopathies. Brain 2017; 140:1399-1419. [PMID: 28398476 DOI: 10.1093/brain/awx056] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 01/20/2017] [Indexed: 12/15/2022] Open
Abstract
α-Synuclein misfolding and aggregation is a hallmark in Parkinson's disease and in several other neurodegenerative diseases known as synucleinopathies. The toxic properties of α-synuclein are conserved from yeast to man, but the precise underpinnings of the cellular pathologies associated are still elusive, complicating the development of effective therapeutic strategies. Combining molecular genetics with target-based approaches, we established that glycation, an unavoidable age-associated post-translational modification, enhanced α-synuclein toxicity in vitro and in vivo, in Drosophila and in mice. Glycation affected primarily the N-terminal region of α-synuclein, reducing membrane binding, impaired the clearance of α-synuclein, and promoted the accumulation of toxic oligomers that impaired neuronal synaptic transmission. Strikingly, using glycation inhibitors, we demonstrated that normal clearance of α-synuclein was re-established, aggregation was reduced, and motor phenotypes in Drosophila were alleviated. Altogether, our study demonstrates glycation constitutes a novel drug target that can be explored in synucleinopathies as well as in other neurodegenerative conditions.
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Affiliation(s)
- Hugo Vicente Miranda
- CEDOC, Chronic Diseases Research Centre, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal.,Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Éva M Szego
- Department of Neurodegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Waldweg 33, 37073 Göttingen, Germany
| | - Luís M A Oliveira
- Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2829-511 Monte de Caparica, Caparica, Portugal.,Laboratory of Cellular Dynamics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Carlo Breda
- Department of Genetics, University of Leicester, Leicester LE1 7RH, UK
| | - Ekrem Darendelioglu
- Department of Genetics, University of Leicester, Leicester LE1 7RH, UK.,Bingol University, Science and Letters Faculty, Molecular Biology and Genetics Department, 12000, Bingol, Turkey
| | - Rita M de Oliveira
- CEDOC, Chronic Diseases Research Centre, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal.,Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Diana G Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Department of Neurodegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Waldweg 33, 37073 Göttingen, Germany
| | - Marcos A Gomes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Ruth Rott
- Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Márcia Oliveira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Francesca Munari
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), 37077 Göttingen, Germany
| | - Francisco J Enguita
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Tânia Simões
- Laboratório de Proteómica, Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, 1649-016 Lisboa, Portugal
| | - Eva F Rodrigues
- Department of Neurodegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Waldweg 33, 37073 Göttingen, Germany
| | - Michael Heinrich
- Department of Molecular Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany
| | - Ivo C Martins
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Irina Zamolo
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, 72074 Tuebingen, Germany
| | - Olaf Riess
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, 72074 Tuebingen, Germany
| | - Carlos Cordeiro
- Enzymology Group, Departamento de Quimica e Bioquimica, Centro de Quimica e Bioquimica, Faculdade de Ciencias da Universidade de Lisboa, Campo Grande, Edificio C8, 1749-016, Lisboa, Portugal
| | - Ana Ponces-Freire
- Enzymology Group, Departamento de Quimica e Bioquimica, Centro de Quimica e Bioquimica, Faculdade de Ciencias da Universidade de Lisboa, Campo Grande, Edificio C8, 1749-016, Lisboa, Portugal
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Swiss Federal Institute of Technology Lausanne (EPFL), FSV-BMI AI 2137.1, Station 15, CH-1015 Lausanne, Switzerland
| | - Nuno C Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Luisa V Lopes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Wei Xiang
- Institute for Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Thomas M Jovin
- Laboratory of Cellular Dynamics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Deborah Penque
- Laboratório de Proteómica, Departamento de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, 1649-016 Lisboa, Portugal
| | - Simone Engelender
- Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Markus Zweckstetter
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), 37077 Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center, 37075 Göttingen, Germany
| | - Jochen Klucken
- Department of Molecular Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany
| | - Flaviano Giorgini
- Department of Genetics, University of Leicester, Leicester LE1 7RH, UK
| | - Alexandre Quintas
- Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz, 2829-511 Monte de Caparica, Caparica, Portugal
| | - Tiago F Outeiro
- CEDOC, Chronic Diseases Research Centre, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal.,Department of Neurodegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Waldweg 33, 37073 Göttingen, Germany.,Max Plank Institute for Experimental Medicine, Goettingen, Germany
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23
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Musolino S, Schartner EP, Tsiminis G, Salem A, Monro TM, Hutchinson MR. Portable optical fiber probe for in vivo brain temperature measurements. BIOMEDICAL OPTICS EXPRESS 2016; 7:3069-3077. [PMID: 27570698 PMCID: PMC4986814 DOI: 10.1364/boe.7.003069] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/10/2016] [Accepted: 06/23/2016] [Indexed: 06/06/2023]
Abstract
This work reports on the development of an optical fiber based probe for in vivo measurements of brain temperature. By utilizing a thin layer of rare-earth doped tellurite glass on the tip of a conventional silica optical fiber a robust probe, suitable for long-term in vivo measurements of temperature can be fabricated. This probe can be interrogated using a portable optical measurement setup, allowing for measurements to be performed outside of standard optical laboratories.
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Affiliation(s)
- Stefan Musolino
- ARC Centre of Excellence for Nanoscale BioPhotonics and Institute for Photonics and Advanced Sensing, Adelaide, SA 5005, Australia
- School of Medicine, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Erik P. Schartner
- ARC Centre of Excellence for Nanoscale BioPhotonics and Institute for Photonics and Advanced Sensing, Adelaide, SA 5005, Australia
- School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Georgios Tsiminis
- ARC Centre of Excellence for Nanoscale BioPhotonics and Institute for Photonics and Advanced Sensing, Adelaide, SA 5005, Australia
- School of Medicine, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Abdallah Salem
- School of Medicine, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Tanya M. Monro
- ARC Centre of Excellence for Nanoscale BioPhotonics and Institute for Photonics and Advanced Sensing, Adelaide, SA 5005, Australia
- The University of South Australia, Adelaide, SA 5001, Australia
| | - Mark R. Hutchinson
- ARC Centre of Excellence for Nanoscale BioPhotonics and Institute for Photonics and Advanced Sensing, Adelaide, SA 5005, Australia
- School of Medicine, The University of Adelaide, Adelaide, SA 5005, Australia
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24
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Shibasaki K, Sugio S, Takao K, Yamanaka A, Miyakawa T, Tominaga M, Ishizaki Y. TRPV4 activation at the physiological temperature is a critical determinant of neuronal excitability and behavior. Pflugers Arch 2015; 467:2495-507. [PMID: 26250433 DOI: 10.1007/s00424-015-1726-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/26/2015] [Accepted: 07/28/2015] [Indexed: 11/25/2022]
Abstract
For homeothermic animals, constant body temperature is an important determinant of brain function. It is well established that changes in brain temperature dynamically influence hippocampal activity. We previously reported that the thermosensor TRPV4 (activated above 34 °C) is activated at the physiological temperature in hippocampal neurons and controls neuronal excitability in vitro. Here, we examined if TRPV4 regulates neuronal excitability through its activation at the physiological temperature in vivo. We found that TRPV4-deficient (TRPV4KO) mice exhibit reduced depression-like and social behaviors compared to wild-type (WT) mice, and the number of c-fos positive cells in the dentate gyrus was significantly reduced upon the depression-like behaviors. We measured resting membrane potentials (RMPs) in the hippocampal granule cells from slice preparations at 35 °C and found that TRPV4-positive neurons significantly depolarized the RMPs through TRPV4 activation at the physiological temperature. The depolarization increased the spike numbers depending on the enhancement of TRPV4 activation. We also found that theta-frequency electroencephalogram (EEG) activities in TRPV4KO mice during wake periods were significantly reduced compared with those in WT mice. Taken together, we report for the first time that TRPV4 activation at the physiological temperature is important to regulate neuronal excitability and behaviors in mammals.
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Affiliation(s)
- Koji Shibasaki
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine, Maebashi, 371-8511, Japan.
| | - Shouta Sugio
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine, Maebashi, 371-8511, Japan
| | - Keizo Takao
- Section of Behavior Patterns, Maebashi, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), Tokyo, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan
| | - Tsuyoshi Miyakawa
- Section of Behavior Patterns, Maebashi, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), Tokyo, Japan
- Division of Systems Medicine, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, 470-7792, Japan
| | - Makoto Tominaga
- Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
- Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki, 444-8585, Japan
| | - Yasuki Ishizaki
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine, Maebashi, 371-8511, Japan
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25
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Abstract
In a rat model of status epilepticus (SE) induced by lithium and pilocarpine and refractory to midazolam, deep hypothermia (20 °C for 30 min) reduced EEG power over 50-fold, stopped SE within 12 min, and reduced EEG spikes by 87%. Hypothermia deserves further investigation as a treatment of last resort for refractory SE. This article is part of a Special Issue entitled "Status Epilepticus".
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Affiliation(s)
- Jerome Niquet
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA.
| | - Roger Baldwin
- Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA
| | - Michael Gezalian
- Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA
| | - Claude G. Wasterlain
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA,Epilepsy Research Laboratory (151), Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA,Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA
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26
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Newmyer R, Mendelson J, Pang D, Fink EL. Targeted Temperature Management in Pediatric Central Nervous System Disease. CURRENT TREATMENT OPTIONS IN PEDIATRICS 2015; 1:38-47. [PMID: 26042193 PMCID: PMC4450147 DOI: 10.1007/s40746-014-0008-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Acute central nervous system conditions due to hypoxic-ischemic encephalopathy, traumatic brain injury (TBI), status epilepticus, and central nervous system infection/inflammation, are a leading cause of death and disability in childhood. There is a critical need for effective neuroprotective therapies to improve outcome targeting distinct disease pathology. Fever, defined as patient temperature > 38°C, has been clearly shown to exacerbate brain injury. Therapeutic hypothermia (HT) is an intervention using targeted temperature management that has multiple mechanisms of action and robust evidence of efficacy in multiple experimental models of brain injury. Prospective clinical evidence for its neuroprotective efficacy exists in narrowly-defined populations with hypoxic-ischemic injury outside of the pediatric age range while trials comparing hypothermia to normothermia after TBI have failed to demonstrate a benefit on outcome but consistently demonstrate potential use in decreasing refractory intracranial pressure. Data in children from prospective, randomized controlled trials using different strategies of targeted temperature management for various outcomes are few but a large study examining HT versus controlled normothermia to improve neurological outcome in cardiac arrest is underway.
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Affiliation(s)
- Robert Newmyer
- Children's Hospital of Pittsburgh of UPMC (Pittsburgh, PA USA)
| | - Jenny Mendelson
- Children's Hospital of Pittsburgh of UPMC (Pittsburgh, PA USA)
| | - Diana Pang
- Children's Hospital of Pittsburgh of UPMC (Pittsburgh, PA USA)
| | - Ericka L Fink
- Children's Hospital of Pittsburgh of UPMC (Pittsburgh, PA USA)
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27
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Shibasaki K, Tominaga M, Ishizaki Y. Hippocampal neuronal maturation triggers post-synaptic clustering of brain temperature-sensor TRPV4. Biochem Biophys Res Commun 2015; 458:168-73. [PMID: 25637662 DOI: 10.1016/j.bbrc.2015.01.087] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 01/19/2015] [Indexed: 01/16/2023]
Abstract
Compartmentalization of neuronal function is achieved via specifically localized clustering of ion channels in discrete subcellular membrane domains. Transient receptor potential (TRP) channels exhibit highly variable cellular and subcellular patterns of expression. We previously revealed that the thermo-sensor TRPV4 (activated above 34 °C) is gated by physiological brain temperatures in hippocampal neurons and thereby controls their excitability. Here, we examined synaptic clustering of TRPV4 in developing hippocampal neurons. We found that TRPV4 accumulated in the soma of immature hippocampal neurons, and did not localize to post-synaptic locations although PSD-95-labeled post-synaptic structures were evident. During the maturation of neurons, TRPV4 was targeted to dendrites and also clustered at post-synaptic locations. Taken together, we reveal that TRPV4 localizes to post-synaptic sites and the post-synaptic targeting is strictly regulated in a neuronal maturation-dependent manner.
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Affiliation(s)
- Koji Shibasaki
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan.
| | - Makoto Tominaga
- Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki 444-8787, Japan; Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787, Japan; Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan
| | - Yasuki Ishizaki
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan
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28
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Mokrushin AA, Pavlinova LI, Borovikov SE. Influence of cooling rate on activity of ionotropic glutamate receptors in brain slices at hypothermia. J Therm Biol 2014; 44:5-13. [PMID: 25086967 DOI: 10.1016/j.jtherbio.2014.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 10/25/2022]
Abstract
Hypothermia is a known approach in the treatment of neurological pathologies. Mild hypothermia enhances the therapeutic window for application of medicines, while deep hypothermia is often accompanied by complications, including problems in the recovery of brain functions. The purpose of present study was to investigate the functioning of glutamate ionotropic receptors in brain slices cooled with different rates during mild, moderate and deep hypothermia. Using a system of gradual cooling combined with electrophysiological recordings in slices, we have shown that synaptic activity mediated by the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and N-methyl-D-aspartate receptors in rat olfactory cortex was strongly dependent on the rate of lowering the temperature. High cooling rate caused a progressive decrease in glutamate receptor activity in brain slices during gradual cooling from mild to deep hypothermia. On the contrary, low cooling rate slightly changed the synaptic responses in deep hypothermia. The short-term potentiation may be induced in slices by electric tetanization at 16 °C in this case. Hence, low cooling rate promoted preservation of neuronal activity and plasticity in the brain tissue.
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Affiliation(s)
- Anatoly A Mokrushin
- I.P. Pavlov Institute of Physiology, Russian Academy of Science, 199034, Nab. Makarova, 6, Saint-Petersburg, Russia
| | - Larisa I Pavlinova
- I.P. Pavlov Institute of Physiology, Russian Academy of Science, 199034, Nab. Makarova, 6, Saint-Petersburg, Russia; Institute of Experimental Medicine, Russian Academy of Science, 197376, Ul.Akad. Pavlova, 12, Saint-Petersburg, Russia.
| | - Sergey E Borovikov
- Science Center "Bio", 197376 Street L. Tolstoy, Building 7, 5-H (9), Saint-Petersburg, Russia
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29
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Steinbrenner M, Kowski AB, Schmitt FC, Holtkamp M. Hypothermia did not prevent epilepsy following experimental status epilepticus. Brain Res 2014; 1572:50-8. [PMID: 24854118 DOI: 10.1016/j.brainres.2014.05.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/25/2014] [Accepted: 05/12/2014] [Indexed: 11/29/2022]
Abstract
In epilepsy research, one of the major challenges is to prevent or at least mitigate development of epilepsy following acquired brain insult by early therapeutic interventions. So far, all pharmacological antiepileptogenic treatment approaches were largely unsuccessful in clinical trials and in experimental animal studies. In a well-established rat model of chronic epilepsy following self-sustaining status epilepticus (SSSE), we assessed the antiepileptogenic properties of 3-h-cooling induced directly after the end of SSSE. Occurrence of spontaneous seizures and seizure severity up to 8 weeks after SSSE were compared with normothermic SSSE controls. Furthermore, electrophysiological parameters assessing inhibition and excitation in the dentate gyrus were assessed at multiple time points. Post SSSE hypothermia did not prevent the occurrence of seizures in any animal. Eight weeks after SSSE, Racine motor seizures trended to be less severe following cooling (4.0±0.6) compared with normothermic controls (4.8±0.2) but the difference was not significant when testing for multiple comparisons. Early loss of inhibition that is typically seen following SSSE was somewhat attenuated in cooled animals 3h after SSSE as expressed by smaller paired-pulse ratios (PPR; 0.16±0.21) compared with normothermic controls (0.54±0.21) but difference was not significant either. Latency between stimulus artefact and excitatory post-synaptic potential 3h after SSSE, reciprocally reflecting neuronal excitation, was higher in animals that underwent hypothermia (8.29±2.45 ms) compared with controls (4.82±0.66 ms), difference was not significant after correction for multiple comparisons. In summary, the current experiments were not able to demonstrate prevention or mitigation of epileptogenesis with immediate short-term cooling following SSSE.
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Affiliation(s)
- Mirja Steinbrenner
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
| | - Alexander B Kowski
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
| | - Friedhelm C Schmitt
- Department of Neurology, Universitätsklinik Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany.
| | - Martin Holtkamp
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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30
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Gu F, Hazra A, Aulakh A, Žiburkus J. Purinergic control of hippocampal circuit hyperexcitability in Dravet syndrome. Epilepsia 2014; 55:245-55. [PMID: 24417577 DOI: 10.1111/epi.12487] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2013] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Severe myoclonic epilepsy in infancy (SMEI) or Dravet syndrome is one of the most devastating childhood epilepsies. Children with SMEI have febrile and afebrile seizures (FS and aFS), ataxia, and social and cognitive dysfunctions. SMEI is pharmacologically intractable and can be fatal in 10-20% of patients. It remains to be elucidated how channelopathies that cause SMEI impact synaptic activities in key neural circuits, and there is an ongoing critical need for alternative methods of controlling seizures in SMEI. Using the SCN1A gene knock-in mouse model of SMEI (mSMEI), we studied hippocampal cell and circuit excitability, particularly during hyperthermia, and tested whether an adenosine A1 receptor (A1R) agonist can reliably control hippocampal circuit hyperexcitability. METHODS Using a combination of electrophysiology (extracellular and whole-cell voltage clamp) and fast voltage-sensitive dye imaging (VSDI), we quantified synaptic excitation and inhibition, spatiotemporal characteristics of neural circuit activity, and hyperthermia-induced febrile seizure-like events (FSLEs) in juvenile mouse hippocampal slices. We used hyperthermia to elicit FSLEs in hippocampal slices, while making use of adenosine A1R agonist N6-cyclopentyladenosine (CPA) to control abnormally widespread neural activity and FSLEs. RESULTS We discovered a significant excitation/inhibition (E/I) imbalance in mSMEI hippocampi, in which inhibition was decreased and excitation increased. This imbalance was associated with an increased spatial extent of evoked neural circuit activation and a lowered FSLE threshold. We found that a low concentration (50 nm) of CPA blocked FSLEs and reduced the spatial extent of abnormal neural activity spread while preserving basal levels of excitatory synaptic transmission. SIGNIFICANCE Our study reveals significant hippocampal synapse and circuit dysfunctions in mSMEI and demonstrates that the A1R agonist CPA can reliably control hippocampal hyperexcitability and FSLEs in vitro. These findings may warrant further investigations of purinergic agonists as part of the development of new therapeutic approaches for Dravet syndrome.
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Affiliation(s)
- Feng Gu
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, U.S.A
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31
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Extracellular alpha-synuclein oligomers modulate synaptic transmission and impair LTP via NMDA-receptor activation. J Neurosci 2012; 32:11750-62. [PMID: 22915117 DOI: 10.1523/jneurosci.0234-12.2012] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Parkinson's disease (PD) is the most common representative of a group of disorders known as synucleinopathies, in which misfolding and aggregation of α-synuclein (a-syn) in various brain regions is the major pathological hallmark. Indeed, the motor symptoms in PD are caused by a heterogeneous degeneration of brain neurons not only in substantia nigra pars compacta but also in other extrastriatal areas of the brain. In addition to the well known motor dysfunction in PD patients, cognitive deficits and memory impairment are also an important part of the disorder, probably due to disruption of synaptic transmission and plasticity in extrastriatal areas, including the hippocampus. Here, we investigated the impact of a-syn aggregation on AMPA and NMDA receptor-mediated rat hippocampal (CA3-CA1) synaptic transmission and long-term potentiation (LTP), the neurophysiological basis for learning and memory. Our data show that prolonged exposure to a-syn oligomers, but not monomers or fibrils, increases basal synaptic transmission through NMDA receptor activation, triggering enhanced contribution of calcium-permeable AMPA receptors. Slices treated with a-syn oligomers were unable to respond with further potentiation to theta-burst stimulation, leading to impaired LTP. Prior delivery of a low-frequency train reinstated the ability to express LTP, implying that exposure to a-syn oligomers drives the increase of glutamatergic synaptic transmission, preventing further potentiation by physiological stimuli. Our novel findings provide mechanistic insight on how a-syn oligomers may trigger neuronal dysfunction and toxicity in PD and other synucleinopathies.
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32
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Elwassif MM, Datta A, Rahman A, Bikson M. Temperature control at DBS electrodes using a heat sink: experimentally validated FEM model of DBS lead architecture. J Neural Eng 2012; 9:046009. [PMID: 22764359 PMCID: PMC3406231 DOI: 10.1088/1741-2560/9/4/046009] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
There is a growing interest in the use of deep brain stimulation (DBS) for the treatment of medically refractory movement disorders and other neurological and psychiatric conditions. The extent of temperature increases around DBS electrodes during normal operation (joule heating and increased metabolic activity) or coupling with an external source (e.g. magnetic resonance imaging) remains poorly understood and methods to mitigate temperature increases are being actively investigated. We developed a heat transfer finite element method (FEM) simulation of DBS incorporating the realistic architecture of Medtronic 3389 leads. The temperature changes were analyzed considering different electrode configurations, stimulation protocols and tissue properties. The heat-transfer model results were then validated using micro-thermocouple measurements during DBS lead stimulation in a saline bath. FEM results indicate that lead design (materials and geometry) may have a central role in controlling temperature rise by conducting heat. We show how modifying lead design can effectively control temperature increases. The robustness of this heat-sink approach over complimentary heat-mitigation technologies follows from several features: (1) it is insensitive to the mechanisms of heating (e.g. nature of magnetic coupling); (2) it does not interfere with device efficacy; and (3) can be practically implemented in a broad range of implanted devices without modifying the normal device operations or the implant procedure.
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Affiliation(s)
- Maged M Elwassif
- Department of Biomedical Engineering, The City College of New York of The City University of New York, NY, USA
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33
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Kim JA, Connors BW. High temperatures alter physiological properties of pyramidal cells and inhibitory interneurons in hippocampus. Front Cell Neurosci 2012; 6:27. [PMID: 22783167 PMCID: PMC3390787 DOI: 10.3389/fncel.2012.00027] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/13/2012] [Indexed: 01/14/2023] Open
Abstract
Temperature has multiple effects on neurons, yet little is known about the effects of high temperature on the physiology of mammalian central neurons. Hyperthermia can influence behavior and cause febrile seizures. We studied the effects of acute hyperthermia on the immature hippocampus in vitro by recording from pyramidal neurons and inhibitory oriens-lacunosum moleculare (O-LM) interneurons (identified by green fluorescent protein (GFP) expression in the GIN mouse line). Warming to 41°C caused depolarization, spontaneous action potentials, reduced input resistance and membrane time constant, and increased spontaneous synaptic activity of most pyramidal cells and O-LM interneurons. Pyramidal neurons of area CA3 were more strongly excited by hyperthermia than those of area CA1. About 90% of O-LM interneurons in both CA1 and CA3 increased their firing rates at hyperthermic temperatures; interneurons in CA3 fired faster than those in CA1 on average. Blockade of fast synaptic transmission did not abolish the effect of hyperthermia on neuronal excitability. Our results suggest that hyperthermia increases hippocampal excitability, particularly in seizure-prone area CA3, by altering the intrinsic membrane properties of pyramidal cells and interneurons.
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Affiliation(s)
- Jennifer A Kim
- Department of Neuroscience, Brown University, Providence RI, USA
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34
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Babiec WE, Faull KF, Feldman JL. Cyclothiazide-induced persistent increase in respiratory-related activity in vitro. J Physiol 2012; 590:4897-915. [PMID: 22753547 DOI: 10.1113/jphysiol.2012.232421] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Hypoglossal (XII) motoneurons (MNs) innervate the genioglossus muscle of the tongue, which plays an important role in maintaining upper airway patency, particularly during sleep, and modulating upper airway resistance. Discovering methods for inducing long-term increases in genioglossal motoneuronal excitability to AMPA-mediated drive may help in the development of therapeutics for upper airway motor disorders such as obstructive sleep apnoea. We show that the diuretic, anti-hypertensive, AMPA receptor modulator cyclothiazide (CTZ) induces a profound and long-lasting increase in the amplitude of respiratory-related XII nerve activity in rhythmically active neonatal rat medullary slices. Treatment of the slice with CTZ (90 μM) for 1 h increased the integrated XII ( XII) nerve burst amplitude to 262 ± 23% of pre-treatment control at 1 h post-treatment;much of this increase lasted at least 12 h. The amount of CTZ-induced facilitation (CIF) was dependent upon both CTZ dose and exposure time and was accompanied by a long-lasting increase in endogenous AMPA-mediated drive currents to XII MNs. CIF, however, is not a form of plasticity and does not depend on AMPA or NMDA receptor activation for its induction. Nor does it depend on coincident protein kinase A or C activity. Rather, measurement of mEPSCs along with mass spectrometric analysis of CTZ-treated slices indicates that the cause is prolonged bioavailability of CTZ. These results illustrate a latent residual capacity for potentiating AMPA-mediated inspiratory drive to XII MNs that might be applied to the treatment of upper airway motor deficits.
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Affiliation(s)
- Walter E Babiec
- Department of Physiology, David Geffen School of Medicine, UCLA, Box 951751, C8-161 NPI, Los Angeles,CA 90095-1751, USA.
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Kowski AB, Kanaan H, Schmitt FC, Holtkamp M. Deep hypothermia terminates status epilepticus--an experimental study. Brain Res 2012; 1446:119-26. [PMID: 22365745 DOI: 10.1016/j.brainres.2012.01.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 01/02/2012] [Accepted: 01/11/2012] [Indexed: 11/18/2022]
Abstract
In search for novel treatment approaches in status epilepticus, the anticonvulsant effect of moderate and deep hypothermia was assessed in a rodent model. Self-sustaining status epilepticus (SSSE) characterized by spontaneous high-amplitude discharges recorded from the dentate gyrus was induced in male adult rats by electrical stimulation of the perforant path. After the end of stimulation, rats underwent cooling to 30 °C (n=7) and 20 °C (n=10) for 120 min and rewarming to 37 °C for another 60 min. Control SSSE animals (n=6) remained untreated for 180 min. Frequency of epileptiform discharges was assessed every 10 min. At the target temperature of 20 °C, SSSE was completely suppressed in four rats, this effect was not observed in any animal of the other two groups (p=0.043). On rewarming, seizure activity did not reoccur. Discharge frequency was significantly lower in the 20 °C group at most time points after 60 min of cooling. Following deep hypothermia, eight animals were rewarmed, all survived and moved spontaneously at 37 °C. These experimental data indicate the strong and enduring anticonvulsant and obviously safe properties of cooling down to 20 °C. Patients with status epilepticus refractory to first- and second-line anticonvulsants may benefit from deep cooling as an effective non-pharmacological adjunct to anesthetic anticonvulsants.
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Motamedi GK, Gonzalez-Sulser A, Dzakpasu R, Vicini S. Cellular mechanisms of desynchronizing effects of hypothermia in an in vitro epilepsy model. Neurotherapeutics 2012; 9:199-209. [PMID: 21913006 PMCID: PMC3271159 DOI: 10.1007/s13311-011-0078-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Hypothermia can terminate epileptiform discharges in vitro and in vivo epilepsy models. Hypothermia is becoming a standard treatment for brain injury in infants with perinatal hypoxic ischemic encephalopathy, and it is gaining ground as a potential treatment in patients with drug resistant epilepsy. However, the exact mechanism of action of cooling the brain tissue is unclear. We have studied the 4-aminopyridine model of epilepsy in mice using single- and dual-patch clamp and perforated multi-electrode array recordings from the hippocampus and cortex. Cooling consistently terminated 4-aminopyridine induced epileptiform-like discharges in hippocampal neurons and increased input resistance that was not mimicked by transient receptor potential channel antagonists. Dual-patch clamp recordings showed significant synchrony between distant CA1 and CA3 pyramidal neurons, but less so between the pyramidal neurons and interneurons. In CA1 and CA3 neurons, hypothermia blocked rhythmic action potential discharges and disrupted their synchrony; however, in interneurons, hypothermia blocked rhythmic discharges without abolishing action potentials. In parallel, multi-electrode array recordings showed that synchronized discharges were disrupted by hypothermia, whereas multi-unit activity was unaffected. The differential effect of cooling on transmitting or secreting γ-aminobutyric acid interneurons might disrupt normal network synchrony, aborting the epileptiform discharges. Moreover, the persistence of action potential firing in interneurons would have additional antiepileptic effects through tonic γ-aminobutyric acid release.
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Affiliation(s)
- Gholam K Motamedi
- Department of Neurology, Georgetown University Hospital, Washington, DC 20007, USA.
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Bouthour W, Leroy F, Emmanuelli C, Carnaud M, Dahan M, Poncer JC, Lévi S. A human mutation in Gabrg2 associated with generalized epilepsy alters the membrane dynamics of GABAA receptors. Cereb Cortex 2011; 22:1542-53. [PMID: 21908847 DOI: 10.1093/cercor/bhr225] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Neuronal activity modulates the membrane diffusion of postsynaptic γ-aminobutyric acid (GABA)(A) receptors (GABA(A)Rs), thereby regulating the efficacy of GABAergic synapses. The K289M mutation in GABA(A)Rs subunit γ2 has been associated with the generalized epilepsy with febrile seizures plus (GEFS+) syndrome. This mutation accelerates receptor deactivation and therefore reduces inhibitory synaptic transmission. Yet, it is not clear why this mutation specifically promotes febrile seizures. We show that upon raising temperature both the number of GABA(A)Rs clusters and the frequency of miniature inhibitory postsynaptic currents decreased in neurons expressing the K289M mutant but not wild-type (WT) recombinant γ2. Single-particle tracking experiments revealed that raising temperature increases the membrane diffusion of synaptic GABA(A)Rs containing the K289M mutant but not WT recombinant γ2. This effect was mediated by enhanced neuronal activity as it was blocked by glutamate receptor antagonists and was mimicked by the convulsant 4-aminopyridine. Our data suggest the K289M mutation in γ2 confers GABA(A)Rs with enhanced sensitivity of their membrane diffusion to neuronal activity. Enhanced activity during hyperthermia may then trigger the escape of receptors from synapses and thereby further reduce the efficacy of GABAergic inhibition. Alteration of the membrane diffusion of neurotransmitter receptors therefore represents a new mechanism in human epilepsy.
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Affiliation(s)
- Walid Bouthour
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche en Santé 839, 75005 Paris, France
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Abstract
Abstract
Neuromodulation strategies have been proposed to treat a variety of neurological disorders, including medication-resistant epilepsy. Electrical stimulation of both central and peripheral nervous systems has emerged as a possible alternative for patients who are not deemed to be good candidates for resective procedures. In addition to well-established treatments such as vagus nerve stimulation, epilepsy centers around the world are investigating the safety and efficacy of neurostimulation at different brain targets, including the hippocampus, thalamus, and subthalamic nucleus. Also promising are the preliminary results of responsive neuromodulation studies, which involve the delivery of stimulation to the brain in response to detected epileptiform or preepileptiform activity. In addition to electrical stimulation, novel therapeutic methods that may open new horizons in the management of epilepsy include transcranial magnetic stimulation, focal drug delivery, cellular transplantation, and gene therapy. We review the current strategies and future applications of neuromodulation in epilepsy.
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Affiliation(s)
- Faisal A Al-Otaibi
- King Faisal Specialist Hospital & Research Centre, Neurosciences Department, Riyadh, Saudi Arabia
| | - Clement Hamani
- Division of Neurosurgery, Toronto Western Hospital, Toronto Western Research Institute, Ontario, Canada
| | - Andres M Lozano
- Division of Neurosurgery, Toronto Western Hospital, Toronto Western Research Institute, Ontario, Canada
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Dimpfel W, Hoffmann JA. Effects of rasagiline, its metabolite aminoindan and selegiline on glutamate receptor mediated signalling in the rat hippocampus slice in vitro. BMC Pharmacol 2011; 11:2. [PMID: 21338509 PMCID: PMC3051903 DOI: 10.1186/1471-2210-11-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 02/21/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rasagiline, a new drug developed to treat Parkinson's disease, is known to inhibit monoamine oxidase B. However, its metabolite R-(-)-aminoindan does not show this kind of activity. The present series of in vitro experiments using the rat hippocampal slice preparation deals with effects of both compounds on the pyramidal cell response after electric stimulation of the Schaffer Collaterals in comparison to selegiline, another MAO B inhibitor. METHOD Stimulation of the Schaffer Collaterals by single stimuli (SS) or theta burst stimulation (TBS) resulted in stable responses of pyramidal cells measured as population spike amplitude (about 1 mV under control SS conditions or about 2 mV after TBS). RESULTS During the first series, this response was attenuated in the presence of rasagiline and aminoindan-to a lesser degree of selegiline-in a concentration dependent manner (5-50 μM) after single stimuli as well as under TBS. During oxygen/glucose deprivation for 10 min the amplitude of the population spike breaks down by 75%. The presence of rasagiline and aminoindan, but rarely the presence of selegiline, prevented this break down. Following glutamate receptor mediated enhancements of neuronal transmission in a second series of experiments very clear differences could be observed in comparison to the action of selegiline: NMDA receptor, AMPA receptor as well as metabotropic glutamate receptor mediated increases of transmission were concentration dependently (0,3 - 2 μM) antagonized by rasagiline and aminoindan, but not by selegiline. On the opposite, only selegiline attenuated kainate receptor mediated increases of excitability. Thus, both monoamino oxidase (MAO) B inhibitors show attenuation of glutamatergic transmission in the hippocampus but interfere with different receptor mediated excitatory modulations at low concentrations. CONCLUSIONS Since aminoindan does not induce MAO B inhibition, these effects must be regarded as being independent from MAO B inhibition. The results provide strong evidence for a neuroprotective activity of rasagiline and aminoindan in concert with an extended clinical indication into the direction of other diseases like Alzheimer's disease or stroke.
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Affiliation(s)
- W Dimpfel
- Justus Liebig University Giessen, c/o NeuroCode AG, Sportparkstr. 9, D 35578 Wetzlar, Germany
| | - JA Hoffmann
- TEVA Pharma GmbH, Waldecker Str. 7, D 64546 Moerfelden-Walldorf, Germany
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Dimpfel W, Kler A, Kriesl E, Lehnfeld R. Theogallin and L-theanine as active ingredients in decaffeinated green tea extract: I. electrophysiological characterization in the rat hippocampus in-vitro. J Pharm Pharmacol 2010; 59:1131-6. [PMID: 17725856 DOI: 10.1211/jpp.59.8.0011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The in-vitro hippocampus slice preparation was used to mimic a physiological situation where nervous tissue is exposed directly to the water soluble extract of green tea and some of its constituents. This investigation provides evidence that L-theanine- and theogallin-enriched decaffeinated green tea extract is able to change the physiological pattern of electrical hippocampus activity in a concentration dependent manner (EC50 3 mg L−1). Of the seven fractions or single components tested (fraction containing all amino acids without L-theanine, fractions containing all amino acids plus L-theanine, glutamic acid, theogallin, its metabolites quinic acid and gallic acid, and L-theanine alone), glutamic acid produced the strongest changes in terms of increased population spike amplitude after single stimuli and increased long-term potentiation, commonly taken as representative for enhancement of spatial and time dependent memory. The presence of theogallin alone shifted the activity in the same direction. Similar results as with theogallin were obtained in the presence of quinic acid. No effect was seen with gallic acid. Opposite changes (decrease of population spike amplitude and attenuated long-term potentiation) were observed in the presence of L-theanine alone. No effects were detected during the addition of the amino acid mixture unless L-theanine was added, leading to a decrease of the responses as observed for the action of L-theanine alone. The results provide evidence for the involvement of several active principles in the action of enriched green tea extract on electrical brain activity. The overall enhancement of hippocampal pyramidal cell responses as observed for the crude extract seems to be due to the combined action of glutamic acid and theogallin (or its presumable metabolite quinic acid), whereas L-theanine seems to have an opposite effect. However, this action was not strong enough to antagonize the effects of glutamic acid and theogallin. The results are in line with the observation that the tested green tea extract improves cognition at concomitant mental relaxation in man.
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Affiliation(s)
- Wilfried Dimpfel
- University of Giessen c/o NeuroCode AG D 35578 Wetzlar, Sportpark-Str. 9, Germany.
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FUJII M, FUJIOKA H, OKU T, TANAKA N, IMOTO H, MARUTA Y, NOMURA S, KAJIWARA K, SAITO T, YAMAKAWA T, YAMAKAWA T, SUZUKI M. Application of Focal Cerebral Cooling for the Treatment of Intractable Epilepsy. Neurol Med Chir (Tokyo) 2010; 50:839-44. [DOI: 10.2176/nmc.50.839] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Masami FUJII
- Department of Neurosurgery, Graduate School of Medicine Yamaguchi University
- Consortium of Advanced Epilepsy Treatment (CADET)
| | - Hiroshi FUJIOKA
- Department of Neurosurgery, Graduate School of Medicine Yamaguchi University
- Consortium of Advanced Epilepsy Treatment (CADET)
| | - Takayuki OKU
- Department of Neurosurgery, Graduate School of Medicine Yamaguchi University
| | - Nobuhiro TANAKA
- Department of Neurosurgery, Graduate School of Medicine Yamaguchi University
| | - Hirochika IMOTO
- Department of Neurosurgery, Graduate School of Medicine Yamaguchi University
- Consortium of Advanced Epilepsy Treatment (CADET)
| | - Yuichi MARUTA
- Department of Neurosurgery, Graduate School of Medicine Yamaguchi University
- Consortium of Advanced Epilepsy Treatment (CADET)
| | - Sadahiro NOMURA
- Department of Neurosurgery, Graduate School of Medicine Yamaguchi University
- Consortium of Advanced Epilepsy Treatment (CADET)
| | - Koji KAJIWARA
- Department of Neurosurgery, Graduate School of Medicine Yamaguchi University
| | - Takashi SAITO
- Applied Medical Engineering Science, Graduate School of Medicine Yamaguchi University
| | - Toshitaka YAMAKAWA
- Kyushu Institute of Technology, Graduate School of Life Science and Systems Engineering
- Consortium of Advanced Epilepsy Treatment (CADET)
| | - Takeshi YAMAKAWA
- Applied Medical Engineering Science, Graduate School of Medicine Yamaguchi University
- Consortium of Advanced Epilepsy Treatment (CADET)
| | - Michiyasu SUZUKI
- Department of Neurosurgery, Graduate School of Medicine Yamaguchi University
- Consortium of Advanced Epilepsy Treatment (CADET)
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Badawy RAB, Harvey AS, Macdonell RAL. Cortical hyperexcitability and epileptogenesis: Understanding the mechanisms of epilepsy - part 2. J Clin Neurosci 2009; 16:485-500. [PMID: 19230676 DOI: 10.1016/j.jocn.2008.10.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Accepted: 10/03/2008] [Indexed: 12/19/2022]
Abstract
Epilepsy encompasses a diverse group of seizure disorders caused by a variety of structural, cellular and molecular alterations of the brain primarily affecting the cerebral cortex, leading to recurrent unprovoked epileptic seizures. In this two-part review we examine the mechanisms underlying normal neuronal function and those predisposing to recurrent epileptic seizures starting at the most basic cellular derangements (Part 1, Volume 16, Issue 3) and working up to the highly complex epileptic networks and factors that modulate the predisposition to seizures (Part 2). We attempt to show that multiple factors can modify the epileptic process and that different mechanisms underlie different types of epilepsy, and in most situations there is an interplay between multiple genetic and environmental factors.
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Affiliation(s)
- Radwa A B Badawy
- Department of Neurology, Austin Health, Heidelberg, Victoria, Australia
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Hrncić D, Vucević D, Rasić A, Radosavljević T, Mladenović D, Susić V, Djurić D, Stanojlović O. Moderate body hypothermia alleviates behavioral and EEG manifestations of audiogenic seizures in metaphit-treated rats. Can J Physiol Pharmacol 2007; 85:1032-7. [PMID: 18066104 DOI: 10.1139/y07-094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We investigated the effects of hypothermia on the incidence and EEG signs of audiogenic seizures in rats treated with metaphit (1-[1(3isothiocyanatophenyl)-cyclohexyl] piperidine), an experimental model of generalized reflex epilepsy. After i.p. injection with metaphit (10 mg/kg) Wistar rats were exposed to audiogenic stimulation at hourly intervals during the time course of the experiment. After intermittent use of an ice pack 8 h after the metaphit treatment, when seizure was fully developed, the body temperature was reduced to 30 +/- 0.5 degrees C in one half of the rats, and maintained at 37 +/- 0.5 degrees C in the other half. Saline-injected rats served as a control group. In the hypothermia group, the incidence of audiogenic seizures induced by metaphit was completely suppressed during the 3 consecutive testing times, while no signs of epileptiform activity were noted in EEG tracings. The termination of hypothermic treatment resulted in the recovery of seizure susceptibility, and during audiogenic stimulation, bursts of spiking activity were recorded in the EEGs of metaphit-treated rats. These findings indicate that moderate body hypothermia is an effective anticonvulsant treatment for audiogenic seizures in metaphit-treated rats.
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Affiliation(s)
- Dragan Hrncić
- Laboratory of Neurophysiology, Department of Physiology, School of Medicine, University of Belgrade, Dr Subotića 9, Belgrade 11000, Serbia
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Shibasaki K, Suzuki M, Mizuno A, Tominaga M. Effects of body temperature on neural activity in the hippocampus: regulation of resting membrane potentials by transient receptor potential vanilloid 4. J Neurosci 2007; 27:1566-75. [PMID: 17301165 PMCID: PMC6673744 DOI: 10.1523/jneurosci.4284-06.2007] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Physiological body temperature is an important determinant for neural functions, and it is well established that changes in temperature have dynamic influences on hippocampal neural activities. However, the detailed molecular mechanisms have never been clarified. Here, we show that hippocampal neurons express functional transient receptor potential vanilloid 4 (TRPV4), one of the thermosensitive TRP (transient receptor potential) channels, and that TRPV4 is constitutively active at physiological temperature. Activation of TRPV4 at 37 degrees C depolarized the resting membrane potential in hippocampal neurons by allowing cation influx, which was observed in wild-type (WT) neurons, but not in TRPV4-deficient (TRPV4KO) cells, although dendritic morphology, synaptic marker clustering, and synaptic currents were indistinguishable between the two genotypes. Furthermore, current injection studies revealed that TRPV4KO neurons required larger depolarization to evoke firing, equivalent to WT neurons, indicating that TRPV4 is a key regulator for hippocampal neural excitabilities. We conclude that TRPV4 is activated by physiological temperature in hippocampal neurons and thereby controls their excitability.
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Affiliation(s)
- Koji Shibasaki
- Section of Cell Signaling, Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787, Japan
- Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan, and
| | - Makoto Suzuki
- Department of Pharmacology, Jichi Medical School, Minamikawachi, Tochigi 329-0498, Japan
| | - Atsuko Mizuno
- Department of Pharmacology, Jichi Medical School, Minamikawachi, Tochigi 329-0498, Japan
| | - Makoto Tominaga
- Section of Cell Signaling, Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787, Japan
- Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan, and
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Elwassif MM, Kong Q, Vazquez M, Bikson M. Bio-heat transfer model of deep brain stimulation-induced temperature changes. J Neural Eng 2006; 3:306-15. [PMID: 17124335 DOI: 10.1088/1741-2560/3/4/008] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
There is a growing interest in the use of chronic deep brain stimulation (DBS) for the treatment of medically refractory movement disorders and other neurological and psychiatric conditions. Fundamental questions remain about the physiologic effects of DBS. Previous basic research studies have focused on the direct polarization of neuronal membranes by electrical stimulation. The goal of this paper is to provide information on the thermal effects of DBS using finite element models to investigate the magnitude and spatial distribution of DBS-induced temperature changes. The parameters investigated include stimulation waveform, lead selection, brain tissue electrical and thermal conductivities, blood perfusion, metabolic heat generation during the stimulation and lead thermal conductivity/heat dissipation through the electrode. Our results show that clinical DBS protocols will increase the temperature of surrounding tissue by up to 0.8 degrees C depending on stimulation/tissue parameters.
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Affiliation(s)
- Maged M Elwassif
- Department of Biomedical Engineering, The City College of New York of The City University of New York, NY 10031, USA
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46
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Schmitt FC, Buchheim K, Meierkord H, Holtkamp M. Anticonvulsant properties of hypothermia in experimental status epilepticus. Neurobiol Dis 2006; 23:689-96. [PMID: 16843675 DOI: 10.1016/j.nbd.2006.05.008] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 03/28/2006] [Accepted: 05/29/2006] [Indexed: 10/24/2022] Open
Abstract
Status epilepticus in patients often does not respond to first-line anticonvulsants, and subsequent treatment escalation with continuous intravenous anesthetics may be associated with significant side-effects. Therefore, alternative treatment regimens are urgently needed. Hypothermia has been shown to reduce excitatory transmission and may thus serve as an interesting adjunct in the management of status epilepticus. In the current experiments, three treatment groups were compared. Animals with self-sustaining status epilepticus were treated with external cooling for 3 h, with low-dose diazepam, or with a combination of both. The effect of these regimens on epileptic activity was compared with untreated controls. Animals that underwent cooling were rewarmed, and all animals were monitored for 5 h to assess occurrence and severity of motor seizures and frequency and amplitude of spontaneous epileptic discharges. Cooling alone significantly reduced number and severity of motor seizures but did not alter epileptic discharges. Cooling in addition to low-dose diazepam significantly diminished amplitudes and frequencies of epileptic discharges, while diazepam alone had only a minor reducing effect on discharge amplitudes. However, at later stages of status epilepticus, diazepam significantly reduced motor seizures. Following rewarming, the discharge frequency tended to increase again, suggesting partial reversibility. The current experiments show that in status epilepticus hypothermia exhibits anticonvulsant effects which are most pronounced if co-administered with low-dose diazepam. The results still require confirmation in other animal models and also clinical studies are urgently needed. However, our data indicate that cooling could well become a future adjunct in the treatment of status epilepticus in patients.
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Affiliation(s)
- F C Schmitt
- Department of Neurology, Charité-Universitätsmedizin Berlin, Schumannstr. 20/21, 10117 Berlin, Germany
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Pena F, Amuzescu B, Neaga E, Flonta ML. Thermodynamic properties of hyperpolarization-activated current (Ih) in a subgroup of primary sensory neurons. Exp Brain Res 2006; 173:282-90. [PMID: 16676167 DOI: 10.1007/s00221-006-0473-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Accepted: 03/24/2006] [Indexed: 11/25/2022]
Abstract
Ih is a poorly selective cation current that activates upon hyperpolarization, present in various types of neurons. Our aim was to perform a detailed thermodynamic analysis of Ih gating kinetics, in order to assess putative structural changes associated with its activation and deactivation. To select dorsal root ganglia neurons that exhibit large Ih, we applied a current signature method by Petruska et al. (J Neurophysiol 84:2365-2379, 2000) and found appropriate neurons in cluster 4. Currents elicited by 3,000-ms hyperpolarizing pulses at 25 and 33 degrees C were fitted with double exponential functions, yielding time constants similar to those of HCN1. The fast activation and deactivation rates showed temperature coefficients (Q10) of 2.9 and 3.1, respectively, while Q10 of the absolute conductance was 1.3. Using the Arrhenius-Eyring formalism we computed heights of voltage-independent Gibbs free energy and entropy barriers for each rate. The free energy barriers of the fast rates were just approximately 2RT units lower than those of the corresponding slow rates (31.3 vs. 33.2RT for activation, and 24.7 vs. 25.8RT for deactivation, at 25 degrees C). Interestingly, the entropy barriers of the slow rates were negative: -15.2R units for activation and -11.9R units for deactivation, compared to 4.6 and 1.3R units, respectively, for the fast component. The equivalent gating charge (zg) (3.75 +/- 0.32, mean +/- SEM, at 25 degrees C) and half-activation potential (V1/2) (-70.0 +/- 1.3 mV at 25 degrees C) did not vary significantly with temperature.
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Affiliation(s)
- Florentina Pena
- Department of Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest, 76201, Romania
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48
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Yang XF, Ouyang Y, Kennedy BR, Rothman SM. Cooling blocks rat hippocampal neurotransmission by a presynaptic mechanism: observations using 2-photon microscopy. J Physiol 2005; 567:215-24. [PMID: 15961429 PMCID: PMC1474157 DOI: 10.1113/jphysiol.2005.088948] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Over the past decade there has been great interest in the therapeutic potential of brain cooling for epilepsy, stroke, asphyxia and other neurological diseases. However, there is still no consensus regarding the neurophysiological effect(s) of brain cooling. We employed standard physiological techniques and 2-photon microscopy to directly examine the effect of temperature on evoked neurotransmitter release in rat hippocampal slices. We observed a monotonic decline in extracellular synaptic potentials and their initial slope over the temperature range 33-20 degrees C, when the slices were cooled to a new set point in less than 5 s. Imaging the fluorescent synaptic marker FM1-43 with 2-photon microscopy showed that the same cooling protocol dramatically reduced transmitter release between 33 and 20 degrees C. Cooling also reduced the terminal FM1-43 destaining that was induced by direct depolarization with elevated K+, indicating that axonal conduction block cannot account for our observations. The temperature dependence of FM1-43 destaining correlated well with the effect of temperature on field potential slope, compatible with a presynaptic explanation for our electrophysiological observations. Optical measurement of FM1-43 dissociation from cell membranes was not affected by temperature, and rapid cooling of slices loaded with FM1-43 did not increase their fluorescence. Our experiments provide visible evidence that a major neurophysiological effect of cooling in the mammalian brain is a reduction in the efficacy of neurotransmitter release. This presynaptic effect may account for some of the therapeutic benefits of cooling in epilepsy and possibly stroke.
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Affiliation(s)
- Xiao-Feng Yang
- Department of Neurology, Box 8111, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO 63110, USA.
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Baulac S, Gourfinkel-An I, Nabbout R, Huberfeld G, Serratosa J, Leguern E, Baulac M. Fever, genes, and epilepsy. Lancet Neurol 2004; 3:421-30. [PMID: 15207799 DOI: 10.1016/s1474-4422(04)00808-7] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
About 13% of patients with epilepsy have a history of febrile seizures (FS). Studies of familial forms suggest a genetic component to the epidemiological link. Indeed, in certain monogenic forms of FS, for which several loci have been reported, some patients develop epilepsy with a higher risk than in the general population. Patients with generalised epilepsy with febrile seizures plus (GEFS+) can have typical and isolated FS, FS lasting more beyond age 6 years, and subsequent afebrile (typically generalised) seizures. Mutations associated with GEFS+ were identified in genes for subunits of the voltage-gated sodium channel and the gamma2 subunit of the ligand-gated GABAA receptor. Screening for these genes in patients with severe myoclonic epilepsy in infancy showed de novo mutations of the alpha1 subunit of the voltage-gated sodium channel. Antecedent FS are commonly observed in temporal-lobe epilepsy (TLE). In sporadic mesial TLE-characterised by the sequence of complex FS in childhood, hippocampal sclerosis, and refractory temporal-lobe seizures-association studies suggested the role of several susceptibility genes. Work on some large pedigrees also suggests that FS and temporal-lobe seizures may have a common genetic basis, whether hippocampus sclerosis is present or not. The molecular defects identified in the genetic associations of FS and epileptic seizures are very attractive models to aid our understanding of epileptogenesis and susceptibility to seizure-provoking factors, especially fever.
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Karlsson KAE, Blumberg MS. Temperature-Induced Reciprocal Activation of Hippocampal Field Activity. J Neurophysiol 2004; 91:583-8. [PMID: 14573549 DOI: 10.1152/jn.00953.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hippocampal network activity oscillates between sustained rhythms (e.g., theta) and aperiodic population spikes (e.g., sharp waves, dentate spikes). Although temperature is known to modulate various aspects of rhythmic hippocampal activity, little is known regarding the influence of temperature on the incidence of population spikes. We recorded spontaneous hippocampal activity along the CA1-dentate gyrus axis using multisite silicon electrodes in urethanized infant rats (P2-P16) at brain temperatures of 37 and 27°C. Theta and gamma activity, as well as sharp waves, were detected at 37°C but not at 27°C. In contrast, dentate spikes were rare at 37°C but their incidence increased several-fold at 27°C (epileptiform activity also emerged at 27°C in the oldest pups). This surprising increase in the incidence of dentate spike activity in a cold brain represents the first such demonstration for a neuronal field pattern. In addition, these findings indicate that changes in brain temperature produce systems-level shifts in the balance among reciprocally interacting hippocampal components.
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Affiliation(s)
- Karl A E Karlsson
- Program in Behavioral and Cognitive Neuroscience, Department of Psychology, University of Iowa, Iowa City, Iowa 52242, USA
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