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Michetti C, Ferrante D, Parisi B, Ciano L, Prestigio C, Casagrande S, Martinoia S, Terranova F, Millo E, Valente P, Giovedi' S, Benfenati F, Baldelli P. Low glycemic index diet restrains epileptogenesis in a gender-specific fashion. Cell Mol Life Sci 2023; 80:356. [PMID: 37947886 PMCID: PMC10638170 DOI: 10.1007/s00018-023-04988-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/25/2023] [Accepted: 09/27/2023] [Indexed: 11/12/2023]
Abstract
Dietary restriction, such as low glycemic index diet (LGID), have been successfully used to treat drug-resistant epilepsy. However, if such diet could also counteract antiepileptogenesis is still unclear. Here, we investigated whether the administration of LGID during the latent pre-epileptic period, prevents or delays the appearance of the overt epileptic phenotype. To this aim, we used the Synapsin II knockout (SynIIKO) mouse, a model of temporal lobe epilepsy in which seizures manifest 2-3 months after birth, offering a temporal window in which LGID may affect epileptogenesis. Pregnant SynIIKO mice were fed with either LGID or standard diet during gestation and lactation. Both diets were maintained in weaned mice up to 5 months of age. LGID delayed the seizure onset and induced a reduction of seizures severity only in female SynIIKO mice. In parallel with the epileptic phenotype, high-density multielectrode array recordings revealed a reduction of frequency, amplitude, duration, velocity of propagation and spread of interictal events by LGID in the hippocampus of SynIIKO females, but not mutant males, confirming the gender-specific effect. ELISA-based analysis revealed that LGID increased cortico-hippocampal allopregnanolone (ALLO) levels only in females, while it was unable to affect ALLO plasma concentrations in either sex. The results indicate that the gender-specific interference of LGID with the epileptogenic process can be ascribed to a gender-specific increase in cortical ALLO, a neurosteroid known to strengthen GABAergic transmission. The study highlights the possibility of developing a personalized gender-based therapy for temporal lobe epilepsy.
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Affiliation(s)
- Caterina Michetti
- Department of Experimental Medicine, University of Genova, Genoa, Italy.
- Center for Synaptic Neuroscience and Technology, Italian Institute of Technology, Genoa, Italy.
| | - Daniele Ferrante
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Barbara Parisi
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Lorenzo Ciano
- Department of Experimental Medicine, University of Genova, Genoa, Italy
- Center for Synaptic Neuroscience and Technology, Italian Institute of Technology, Genoa, Italy
| | - Cosimo Prestigio
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Silvia Casagrande
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Sergio Martinoia
- Department of Informatics, Bioengineering, Robotics and System Engineering, University of Genova, Genoa, Italy
| | - Fabio Terranova
- Department of Informatics, Bioengineering, Robotics and System Engineering, University of Genova, Genoa, Italy
| | - Enrico Millo
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Pierluigi Valente
- Department of Experimental Medicine, University of Genova, Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
| | - Silvia Giovedi'
- Department of Experimental Medicine, University of Genova, Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Italian Institute of Technology, Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genova, Genoa, Italy.
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy.
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Morris G, Avoli M, Bernard C, Connor K, de Curtis M, Dulla CG, Jefferys JGR, Psarropoulou C, Staley KJ, Cunningham MO. Can in vitro studies aid in the development and use of antiseizure therapies? A report of the ILAE/AES Joint Translational Task Force. Epilepsia 2023; 64:2571-2585. [PMID: 37642296 DOI: 10.1111/epi.17744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/11/2023] [Accepted: 08/11/2023] [Indexed: 08/31/2023]
Abstract
In vitro preparations (defined here as cultured cells, brain slices, and isolated whole brains) offer a variety of approaches to modeling various aspects of seizures and epilepsy. Such models are particularly amenable to the application of anti-seizure compounds, and consequently are a valuable tool to screen the mechanisms of epileptiform activity, mode of action of known anti-seizure medications (ASMs), and the potential efficacy of putative new anti-seizure compounds. Despite these applications, all disease models are a simplification of reality and are therefore subject to limitations. In this review, we summarize the main types of in vitro models that can be used in epilepsy research, describing key methodologies as well as notable advantages and disadvantages of each. We argue that a well-designed battery of in vitro models can form an effective and potentially high-throughput screening platform to predict the clinical usefulness of ASMs, and that in vitro models are particularly useful for interrogating mechanisms of ASMs. To conclude, we offer several key recommendations that maximize the potential value of in vitro models in ASM screening. This includes the use of multiple in vitro tests that can complement each other, carefully combined with in vivo studies, the use of tissues from chronically epileptic (rather than naïve wild-type) animals, and the integration of human cell/tissue-derived preparations.
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Affiliation(s)
- Gareth Morris
- Division of Neuroscience, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, Montréal, Quebec, Canada
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Christophe Bernard
- Inserm, INS, Institut de Neurosciences des Systèmes, Aix Marseille Univ, Marseille, France
| | - Kate Connor
- Discipline of Physiology, School of Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Chris G Dulla
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - John G R Jefferys
- Department of Physiology, 2nd Medical School, Motol, Charles University, Prague, Czech Republic
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Caterina Psarropoulou
- Laboratory of Animal and Human Physiology, Department of Biological Applications and Technology, Faculty of Health Sciences, University of Ioannina, Ioannina, Greece
| | - Kevin J Staley
- Neurology Department, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mark O Cunningham
- Discipline of Physiology, School of Medicine, Trinity College Dublin, Dublin 2, Ireland
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Kreir M, Floren W, Policarpo R, De Bondt A, Van den Wyngaert I, Teisman A, Gallacher DJ, Lu HR. Is the forming of neuronal network activity in human-induced pluripotent stem cells important for the detection of drug-induced seizure risks? Eur J Pharmacol 2022; 931:175189. [PMID: 35987255 DOI: 10.1016/j.ejphar.2022.175189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 08/03/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND Functional network activity is a characteristic for neuronal cells, and the complexity of the network activity represents the necessary substrate to support complex brain functions. Drugs that drastically increase the neuronal network activity may have a potential higher risk for seizures in human. Although there has been some recent considerable progress made using cultures from different types of human-induced pluripotent stem cell (hiPSC) derived neurons, one of the primary limitations is the lack of - or very low - network activity. METHOD In the present study, we investigated whether the limited neuronal network activity in commercial hiPSC-neurons (CNS.4U®) is capable of detecting drug-induced potential seizure risks. Therefore, we compared the hiPSC-results to those in rat primary neurons with known high neuronal network activity in vitro. RESULTS Gene expression and electrical activity from in vitro developing neuronal networks were assessed at multiple time-points. Transcriptomes of 7, 28, and 50 days in vitro were analyzed and compared to those from human brain tissues. Data from measurements of electrical activity using multielectrode arrays (MEAs) indicate that neuronal networks matured gradually over time, albeit in hiPSC this developed slower than rat primary cultures. The response of neuronal networks to neuronal active reference drugs modulating glutamatergic, acetylcholinergic and GABAergic pathways could be detected in both hiPSC-neurons and rat primary neurons. However, in comparison, GABAergic responses were limited in hiPSC-neurons. CONCLUSION Overall, despite a slower network development and lower network activity, CNS.4U® hiPSC-neurons can be used to detect drug induced changes in neuronal network activity, as shown by well-known seizurogenic drugs (affecting e.g., the Glycine receptor and Na+ channel). However, lower sensitivity to GABA antagonists has been observed.
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Affiliation(s)
- Mohamed Kreir
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium.
| | - Wim Floren
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Rafaela Policarpo
- Neuroscience Therapeutic Area, Janssen Research & Development, A Division of Janssen Pharmaceutica NV, Belgium
| | - An De Bondt
- High Dimensional & Computational Biology, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Ilse Van den Wyngaert
- High Dimensional & Computational Biology, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Ard Teisman
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - David J Gallacher
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Hua Rong Lu
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
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Won D, Kim J, Choi J, Kim H, Han S, Ha I, Bang J, Kim KK, Lee Y, Kim TS, Park JH, Kim CY, Ko SH. Digital selective transformation and patterning of highly conductive hydrogel bioelectronics by laser-induced phase separation. SCIENCE ADVANCES 2022; 8:eabo3209. [PMID: 35675404 PMCID: PMC9177068 DOI: 10.1126/sciadv.abo3209] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/21/2022] [Indexed: 05/19/2023]
Abstract
The patterning of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hydrogels with excellent electrical property and spatial resolution is a challenge for bioelectronic applications. However, most PEDOT:PSS hydrogels are fabricated by conventional manufacturing processes such as photolithography, inkjet printing, and screen printing with complex fabrication steps or low spatial resolution. Moreover, the additives used for fabricating PEDOT:PSS hydrogels are mostly cytotoxic, thus requiring days of detoxification. Here, we developed a previously unexplored ultrafast and biocompatible digital patterning process for PEDOT:PSS hydrogel via phase separation induced by a laser. We enhanced the electrical properties and aqueous stability of PEDOT:PSS by selective laser scanning, which allowed the transformation of PEDOT:PSS into water-stable hydrogels. PEDOT:PSS hydrogels showed high electrical conductivity of 670 S/cm with 6-μm resolution in water. Furthermore, electrochemical properties were maintained even after 6 months in a physiological environment. We further demonstrated stable neural signal recording and stimulation with hydrogel electrodes fabricated by laser.
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Affiliation(s)
- Daeyeon Won
- Soft Robotics Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Jin Kim
- Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- College of Veterinary Medicine, Konkuk University, 120, Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Joonhwa Choi
- Soft Robotics Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - HyeongJun Kim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Seonggeun Han
- Soft Robotics Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Inho Ha
- Soft Robotics Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Junhyuk Bang
- Soft Robotics Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Kyun Kyu Kim
- Soft Robotics Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Youngseok Lee
- Soft Robotics Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Taek-Soo Kim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Jae-Hak Park
- Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - C-Yoon Kim
- College of Veterinary Medicine, Konkuk University, 120, Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
- Corresponding author. (S.H.K.); (C.-Y.K.)
| | - Seung Hwan Ko
- Soft Robotics Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Institute of Advanced Machines and Design/Institute of Engineering Research, Seoul National University, Seoul 08826, Republic of Korea
- Corresponding author. (S.H.K.); (C.-Y.K.)
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5
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Longatti A, Ponzoni L, Moretto E, Giansante G, Lattuada N, Colombo MN, Francolini M, Sala M, Murru L, Passafaro M. Arhgap22 Disruption Leads to RAC1 Hyperactivity Affecting Hippocampal Glutamatergic Synapses and Cognition in Mice. Mol Neurobiol 2021; 58:6092-6110. [PMID: 34455539 PMCID: PMC8639580 DOI: 10.1007/s12035-021-02502-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 07/15/2021] [Indexed: 11/03/2022]
Abstract
Rho GTPases are a class of G-proteins involved in several aspects of cellular biology, including the regulation of actin cytoskeleton. The most studied members of this family are RHOA and RAC1 that act in concert to regulate actin dynamics. Recently, Rho GTPases gained much attention as synaptic regulators in the mammalian central nervous system (CNS). In this context, ARHGAP22 protein has been previously shown to specifically inhibit RAC1 activity thus standing as critical cytoskeleton regulator in cancer cell models; however, whether this function is maintained in neurons in the CNS is unknown. Here, we generated a knockout animal model for arhgap22 and provided evidence of its role in the hippocampus. Specifically, we found that ARHGAP22 absence leads to RAC1 hyperactivity and to an increase in dendritic spine density with defects in synaptic structure, molecular composition, and plasticity. Furthermore, arhgap22 silencing causes impairment in cognition and a reduction in anxiety-like behavior in mice. We also found that inhibiting RAC1 restored synaptic plasticity in ARHGAP22 KO mice. All together, these results shed light on the specific role of ARHGAP22 in hippocampal excitatory synapse formation and function as well as in learning and memory behaviors.
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Affiliation(s)
- Anna Longatti
- Institute of Neuroscience, CNR, Milan, 20129, Italy
- Department of Pharmacological and Biomolecular Sciences, Università Degli Studi Di Milano, 20133, Milan, Italy
| | | | - Edoardo Moretto
- Institute of Neuroscience, CNR, Milan, 20129, Italy
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy
| | - Giorgia Giansante
- Institute of Neuroscience, CNR, Milan, 20129, Italy
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy
| | - Norma Lattuada
- Department of Medical Biotechnology and Translational Medicine, Università Degli Studi Di Milano, 20129, Milan, Italy
| | - Maria Nicol Colombo
- Department of Medical Biotechnology and Translational Medicine, Università Degli Studi Di Milano, 20129, Milan, Italy
| | - Maura Francolini
- Department of Medical Biotechnology and Translational Medicine, Università Degli Studi Di Milano, 20129, Milan, Italy
| | - Mariaelvina Sala
- Institute of Neuroscience, CNR, Milan, 20129, Italy
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy
| | - Luca Murru
- Institute of Neuroscience, CNR, Milan, 20129, Italy.
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy.
| | - Maria Passafaro
- Institute of Neuroscience, CNR, Milan, 20129, Italy.
- NeuroMI Milan Center for Neuroscience, Università Milano-Bicocca, 20126, Milan, Italy.
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Akyuz E, Koklu B, Uner A, Angelopoulou E, Paudel YN. Envisioning the role of inwardly rectifying potassium (Kir) channel in epilepsy. J Neurosci Res 2021; 100:413-443. [PMID: 34713909 DOI: 10.1002/jnr.24985] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 09/23/2021] [Accepted: 10/01/2021] [Indexed: 01/29/2023]
Abstract
Epilepsy is a devastating neurological disorder characterized by recurrent seizures attributed to the disruption of the dynamic excitatory and inhibitory balance in the brain. Epilepsy has emerged as a global health concern affecting about 70 million people worldwide. Despite recent advances in pre-clinical and clinical research, its etiopathogenesis remains obscure, and there are still no treatment strategies modifying disease progression. Although the precise molecular mechanisms underlying epileptogenesis have not been clarified yet, the role of ion channels as regulators of cellular excitability has increasingly gained attention. In this regard, emerging evidence highlights the potential implication of inwardly rectifying potassium (Kir) channels in epileptogenesis. Kir channels consist of seven different subfamilies (Kir1-Kir7), and they are highly expressed in both neuronal and glial cells in the central nervous system. These channels control the cell volume and excitability. In this review, we discuss preclinical and clinical evidence on the role of the several subfamilies of Kir channels in epileptogenesis, aiming to shed more light on the pathogenesis of this disorder and pave the way for future novel therapeutic approaches.
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Affiliation(s)
- Enes Akyuz
- Faculty of International Medicine, Department of Biophysics, University of Health Sciences, Istanbul, Turkey
| | - Betul Koklu
- Faculty of Medicine, Namık Kemal University, Tekirdağ, Turkey
| | - Arda Uner
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Yam Nath Paudel
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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7
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Kalkan ÖF, Şahin Z, Öztürk H, Keser H, Aydın-Abidin S, Abidin İ. Phoenixin-14 reduces the frequency of interictal-like events in mice brain slices. Exp Brain Res 2021; 239:2841-2849. [PMID: 34283252 DOI: 10.1007/s00221-021-06179-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/13/2021] [Indexed: 01/17/2023]
Abstract
Phoenixin-14 (PNX-14) has a wide bioactivity in the central nervous system. Its role in the hypothalamus has been investigated, and it has been reported that it is involved in the regulation of excitability in hypothalamic neurons. However, its role in the regulation of excitability in entorhinal cortex and the hippocampus is unknown. In this study, we investigated whether i. PNX-14 induces any synchronous discharges or epileptiform activity and ii. PNX-14 has any effect on already initiated epileptiform discharges. We used 350 µm thick acute horizontal hippocampal-entorhinal cortex slices obtained from 30- to 35-day-old mice. Extracellular field potential recordings were evaluated in the entorhinal cortex and hippocampus CA1 region. Bath application of PNX-14 did not initiate any epileptiform activity or abnormal discharges. 4-Aminopyridine was applied to induce epileptiform activity in the slices. We found that 200 nM PNX-14 reduced the frequency of interictal-like events in both the entorhinal cortex and hippocampus CA1 region which was induced by 4-aminopyridine. Furthermore, PNX-14 led to a similar suppression in the total power of local field potentials of 1-120 Hz. The frequency or the duration of the ictal events was not affected. These results exhibited for the first time that PNX-14 has a modulatory effect on synchronized neuronal discharges which should be considered in future therapeutic approaches.
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Affiliation(s)
- Ömer Faruk Kalkan
- Department of Physiology, Faculty of Medicine, Karadeniz Technical University, 61080, Trabzon, Turkey.
| | - Zafer Şahin
- Department of Physiology, Faculty of Medicine, Karadeniz Technical University, 61080, Trabzon, Turkey
| | - Hilal Öztürk
- Department of Physiology, Faculty of Medicine, Karadeniz Technical University, 61080, Trabzon, Turkey
| | - Hatice Keser
- Department of Physiology, Faculty of Medicine, Karadeniz Technical University, 61080, Trabzon, Turkey
| | - Selcen Aydın-Abidin
- Department of Physiology, Faculty of Medicine, Karadeniz Technical University, 61080, Trabzon, Turkey
| | - İsmail Abidin
- Department of Physiology, Faculty of Medicine, Karadeniz Technical University, 61080, Trabzon, Turkey
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Serrano-Reyes M, García-Vilchis B, Reyes-Chapero R, Cáceres-Chávez VA, Tapia D, Galarraga E, Bargas J. Spontaneous Activity of Neuronal Ensembles in Mouse Motor Cortex: Changes after GABAergic Blockade. Neuroscience 2020; 446:304-322. [PMID: 32860933 DOI: 10.1016/j.neuroscience.2020.08.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/02/2020] [Accepted: 08/18/2020] [Indexed: 01/12/2023]
Abstract
The mouse motor cortex exhibits spontaneous activity in the form of temporal sequences of neuronal ensembles in vitro without the need of tissue stimulation. These neuronal ensembles are defined as groups of neurons with a strong correlation between its firing patterns, generating what appears to be a predetermined neural conduction mode that needs study. Each ensemble is commonly accompanied by one or more parvalbumin expressing neurons (PV+) or fast spiking interneurons. Many of these interneurons have functional connections between them, helping to form a circuit configuration similar to a small-world network. However, rich club metrics show that most connected neurons are neurons not expressing parvalbumin, mainly pyramidal neurons (PV-) suggesting feed-forward propagation through pyramidal cells. Ensembles with PV+ neurons are connected to these hubs. When ligand-gated fast GABAergic transmission is blocked, temporal sequences of ensembles collapse into a unique synchronous and recurrent ensemble, showing the need of inhibition for coding cortical spontaneous activity. This new ensemble has a duration and electrophysiological characteristics of brief recurrent interictal epileptiform discharges (IEDs) composed by the coactivity of both PV- and PV+ neurons, demonstrating that GABA transmission impedes its occurrence. Synchronous ensembles are clearly divided into two clusters one of them lasting longer and mainly composed by PV+ neurons. Because an ictal-like event was not recorded after several minutes of IEDs recording, it is inferred that an external stimulus and/or fast GABA transmission are necessary for its appearance, making this preparation ideal to study both the neuronal machinery to encode cortical spontaneous activity and its transformation into brief non-ictal epileptiform discharges.
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Affiliation(s)
- Miguel Serrano-Reyes
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City 04510, Mexico
| | - Brisa García-Vilchis
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City 04510, Mexico
| | - Rosa Reyes-Chapero
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City 04510, Mexico
| | | | - Dagoberto Tapia
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City 04510, Mexico
| | - Elvira Galarraga
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City 04510, Mexico
| | - José Bargas
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City 04510, Mexico.
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9
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Djemil S, Chen X, Zhang Z, Lee J, Rauf M, Pak DTS, Dzakpasu R. Activation of nicotinic acetylcholine receptors induces potentiation and synchronization within in vitro hippocampal networks. J Neurochem 2019; 153:468-484. [PMID: 31821553 DOI: 10.1111/jnc.14938] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 12/04/2019] [Accepted: 12/05/2019] [Indexed: 01/08/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are known to play a role in cognitive functions of the hippocampus, such as memory consolidation. Given that they conduct Ca2+ and are capable of regulating the release of glutamate and γ-aminobutyric acid (GABA) within the hippocampus, thereby shifting the excitatory-inhibitory ratio, we hypothesized that the activation of nAChRs will result in the potentiation of hippocampal networks and alter synchronization. We used nicotine as a tool to investigate the impact of activation of nAChRs on neuronal network dynamics in primary embryonic rat hippocampal cultures prepared from timed-pregnant Sprague-Dawley rats. We perturbed cultured hippocampal networks with increasing concentrations of bath-applied nicotine and performed network extracellular recordings of action potentials using a microelectrode array. We found that nicotine modulated network dynamics in a concentration-dependent manner; it enhanced firing of action potentials as well as facilitated bursting activity. In addition, we used pharmacological agents to determine the contributions of discrete nAChR subtypes to the observed network dynamics. We found that β4-containing nAChRs are necessary for the observed increases in spiking, bursting, and synchrony, while the activation of α7 nAChRs augments nicotine-mediated network potentiation but is not necessary for its manifestation. We also observed that antagonists of N-methyl-D-aspartate receptors (NMDARs) and group I metabotropic glutamate receptors (mGluRs) partially blocked the effects of nicotine. Furthermore, nicotine exposure promoted autophosphorylation of Ca2+ /calmodulin-dependent kinase II (CaMKII) and serine 831 phosphorylation of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunit GluA1. These results suggest that nicotinic receptors induce potentiation and synchronization of hippocampal networks and glutamatergic synaptic transmission. Findings from this work highlight the impact of cholinergic signaling in generating network-wide potentiation in the form of enhanced spiking and bursting dynamics that coincide with molecular correlates of memory such as increased phosphorylation of CaMKII and GluA1. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Sarra Djemil
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA
| | - Xin Chen
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Ziyue Zhang
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Jisoo Lee
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA
| | - Mikael Rauf
- Department of Human Science, Georgetown University Medical Center, Washington, DC, USA
| | - Daniel T S Pak
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA.,Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Rhonda Dzakpasu
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA.,Department of Physics, Georgetown University, Washington, DC, USA.,Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, USA
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10
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McColgan T, Kuokkanen PT, Carr CE, Kempter R. Dynamics of synaptic extracellular field potentials in the nucleus laminaris of the barn owl. J Neurophysiol 2019; 121:1034-1047. [PMID: 30575430 DOI: 10.1152/jn.00648.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Synaptic currents are frequently assumed to make a major contribution to the extracellular field potential (EFP). However, in any neuronal population, the explicit separation of synaptic sources from other contributions such as postsynaptic spikes remains a challenge. Here we take advantage of the simple organization of the barn owl nucleus laminaris (NL) in the auditory brain stem to isolate synaptic currents through the iontophoretic application of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-receptor antagonist 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[ f]quinoxaline-7-sulfonamide (NBQX). Responses to auditory stimulation show that the temporal dynamics of the evoked synaptic contributions to the EFP are consistent with synaptic short-term depression (STD). The estimated time constants of an STD model fitted to the data are similar to the fast time constants reported from in vitro experiments in the chick. Overall, the putative synaptic EFPs in the barn owl NL are significant but small (<1% change of the variance by NBQX). This result supports the hypothesis that the EFP in NL is generated mainly by axonal spikes, in contrast to most other neuronal systems. NEW & NOTEWORTHY Synaptic currents are assumed to make a major contribution to the extracellular field potential in the brain, but it is hard to directly isolate these synaptic components. Here we take advantage of the simple organization of the barn owl nucleus laminaris in the auditory brain stem to isolate synaptic currents through the iontophoretic application of a synaptic blocker. We show that the responses are consistent with a simple model of short-term synaptic depression.
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Affiliation(s)
- Thomas McColgan
- Bernstein Center for Computational Neuroscience , Berlin , Germany.,Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, Berlin , Germany
| | - Paula T Kuokkanen
- Bernstein Center for Computational Neuroscience , Berlin , Germany.,Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, Berlin , Germany.,Department of Biology, University of Maryland , College Park, Maryland
| | - Catherine E Carr
- Department of Biology, University of Maryland , College Park, Maryland
| | - Richard Kempter
- Bernstein Center for Computational Neuroscience , Berlin , Germany.,Institute for Theoretical Biology, Department of Biology, Humboldt-Universität zu Berlin, Berlin , Germany.,Einstein Center for Neurosciences , Berlin , Germany
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11
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Chang YY, Gong XW, Gong HQ, Liang PJ, Zhang PM, Lu QC. GABA A Receptor Activity Suppresses the Transition from Inter-ictal to Ictal Epileptiform Discharges in Juvenile Mouse Hippocampus. Neurosci Bull 2018; 34:1007-1016. [PMID: 30128691 DOI: 10.1007/s12264-018-0273-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 05/31/2018] [Indexed: 12/12/2022] Open
Abstract
Exploring the transition from inter-ictal to ictal epileptiform discharges (IDs) and how GABAA receptor-mediated action affects the onset of IDs will enrich our understanding of epileptogenesis and epilepsy treatment. We used Mg2+-free artificial cerebrospinal fluid (ACSF) to induce epileptiform discharges in juvenile mouse hippocampal slices and used a micro-electrode array to record the discharges. After the slices were exposed to Mg2+-free ACSF for 10 min-20 min, synchronous recurrent seizure-like events were recorded across the slices, and each event evolved from inter-ictal epileptiform discharges (IIDs) to pre-ictal epileptiform discharges (PIDs), and then to IDs. During the transition from IIDs to PIDs, the duration of discharges increased and the inter-discharge interval decreased. After adding 3 μmol/L of the GABAA receptor agonist muscimol, PIDs and IDs disappeared, and IIDs remained. Further, the application of 10 μmol/L muscimol abolished all the epileptiform discharges. When the GABAA receptor antagonist bicuculline was applied at 10 μmol/L, IIDs and PIDs disappeared, and IDs remained at decreased intervals. These results indicated that there are dynamic changes in the hippocampal network preceding the onset of IDs, and GABAA receptor activity suppresses the transition from IIDs to IDs in juvenile mouse hippocampus.
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Affiliation(s)
- Yan-Yan Chang
- Department of Neurology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Xin-Wei Gong
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hai-Qing Gong
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Pei-Ji Liang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Pu-Ming Zhang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Qin-Chi Lu
- Department of Neurology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China.
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12
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A Microfluidic Platform for the Characterisation of CNS Active Compounds. Sci Rep 2017; 7:15692. [PMID: 29146949 PMCID: PMC5691080 DOI: 10.1038/s41598-017-15950-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 11/03/2017] [Indexed: 01/19/2023] Open
Abstract
New in vitro technologies that assess neuronal excitability and the derived synaptic activity within a controlled microenvironment would be beneficial for the characterisation of compounds proposed to affect central nervous system (CNS) function. Here, a microfluidic system with computer controlled compound perfusion is presented that offers a novel methodology for the pharmacological profiling of CNS acting compounds based on calcium imaging readouts. Using this system, multiple applications of the excitatory amino acid glutamate (10 nM–1 mM) elicited reproducible and reversible transient increases in intracellular calcium, allowing the generation of a concentration response curve. In addition, the system allows pharmacological investigations to be performed as evidenced by application of glutamatergic receptor antagonists, reversibly inhibiting glutamate-induced increases in intracellular calcium. Importantly, repeated glutamate applications elicited significant increases in the synaptically driven activation of the adjacent, environmentally isolated neuronal network. Therefore, the proposed new methodology will enable neuropharmacological analysis of CNS active compounds whilst simultaneously determining their effect on synaptic connectivity.
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13
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Treatment with pentylenetetrazole (PTZ) and 4-aminopyridine (4-AP) differently affects survival, locomotor activity, and biochemical markers in Drosophila melanogaster. Mol Cell Biochem 2017; 442:129-142. [DOI: 10.1007/s11010-017-3198-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 10/06/2017] [Indexed: 01/02/2023]
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14
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Assaf F, Schiller Y. The antiepileptic and ictogenic effects of optogenetic neurostimulation of PV-expressing interneurons. J Neurophysiol 2016; 116:1694-1704. [PMID: 27486107 DOI: 10.1152/jn.00744.2015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 07/13/2016] [Indexed: 11/22/2022] Open
Abstract
Parvalbumin (PV)-expressing interneurons exert powerful inhibitory effects on the normal cortical network; thus optogenetic activation of PV interneurons may also possess antiepileptic properties. To investigate this possibility we expressed channelrhodopsin 2 in PV interneurons by locally injecting the Cre-dependent viral vector AAV2/1-EF1a-DIO-ChETA-EYFP into the S1 barrel cortex of PV-Cre mice. Approximately 3-4 wk later recurrent electrographic seizures were evoked by local application of the chemoconvulsant 4-aminopyridine (4-AP); the ECoG and unit activity were monitored with extracellular silicone electrodes; and PV interneurons were activated optogenetically during the ictal and interictal phases. Five- to ten-second optogenetic activation of PV interneurons applied during electrographic seizures (ictal phase) terminated 33.7% of electrographic seizures compared with only 6% during sham stimulation, and the average electrographic seizure duration shortened by 38.7 ± 34.2% compared with sham stimulation. In contrast, interictal optogenetic activation of PV interneurons showed powerful and robust ictogenic effects. Approximately 60% of interictal optogenetic stimuli resulted in electrographic seizure initiation. Single-unit recordings revealed that presumptive PV-expressing interneurons markedly increased their firing during optogenetic stimulation, while many presumptive excitatory pyramidal neurons showed a biphasic response, with initial suppression of firing during the optogenetic pulse followed by a synchronized rebound increase in firing at the end of the laser pulse. Our findings indicated that ictal activation of PV-expressing interneurons possesses antiepileptic properties probably due to suppression of firing in pyramidal neurons during the laser pulse. However, in addition interictal activation of PV-expressing interneurons possesses powerful ictogenic properties, probably due to synchronized postinhibition rebound firing of pyramidal neurons.
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Affiliation(s)
- Fadi Assaf
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel; and
| | - Yitzhak Schiller
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel; and Department of Neurology, Rambam Medical Center, Haifa, Israel
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15
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Suresh J, Radojicic M, Pesce LL, Bhansali A, Wang J, Tryba AK, Marks JD, van Drongelen W. Network burst activity in hippocampal neuronal cultures: the role of synaptic and intrinsic currents. J Neurophysiol 2016; 115:3073-89. [PMID: 26984425 DOI: 10.1152/jn.00995.2015] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 03/04/2016] [Indexed: 12/20/2022] Open
Abstract
The goal of this work was to define the contributions of intrinsic and synaptic mechanisms toward spontaneous network-wide bursting activity, observed in dissociated rat hippocampal cell cultures. This network behavior is typically characterized by short-duration bursts, separated by order of magnitude longer interburst intervals. We hypothesize that while short-timescale synaptic processes modulate spectro-temporal intraburst properties and network-wide burst propagation, much longer timescales of intrinsic membrane properties such as persistent sodium (Nap) currents govern burst onset during interburst intervals. To test this, we used synaptic receptor antagonists picrotoxin, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), and 3-(2-carboxypiperazine-4-yl)propyl-1-phosphonate (CPP) to selectively block GABAA, AMPA, and NMDA receptors and riluzole to selectively block Nap channels. We systematically compared intracellular activity (recorded with patch clamp) and network activity (recorded with multielectrode arrays) in eight different synaptic connectivity conditions: GABAA + NMDA + AMPA, NMDA + AMPA, GABAA + AMPA, GABAA + NMDA, AMPA, NMDA, GABAA, and all receptors blocked. Furthermore, we used mixed-effects modeling to quantify the aforementioned independent and interactive synaptic receptor contributions toward spectro-temporal burst properties including intraburst spike rate, burst activity index, burst duration, power in the local field potential, network connectivity, and transmission delays. We found that blocking intrinsic Nap currents completely abolished bursting activity, demonstrating their critical role in burst onset within the network. On the other hand, blocking different combinations of synaptic receptors revealed that spectro-temporal burst properties are uniquely associated with synaptic functionality and that excitatory connectivity is necessary for the presence of network-wide bursting. In addition to confirming the critical contribution of direct excitatory effects, mixed-effects modeling also revealed distinct combined (nonlinear) contributions of excitatory and inhibitory synaptic activity to network bursting properties.
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Affiliation(s)
- Jyothsna Suresh
- Department of Pediatrics, The University of Chicago, Chicago, Illinois; Committee on Computational Neuroscience, The University of Chicago, Chicago, Illinois;
| | - Mihailo Radojicic
- Department of Pediatrics, The University of Chicago, Chicago, Illinois
| | - Lorenzo L Pesce
- Department of Pediatrics, The University of Chicago, Chicago, Illinois; The Computation Institute, The University of Chicago, Chicago, Illinois; and
| | - Anita Bhansali
- Department of Pediatrics, The University of Chicago, Chicago, Illinois
| | - Janice Wang
- Department of Pediatrics, The University of Chicago, Chicago, Illinois
| | - Andrew K Tryba
- Department of Pediatrics, The University of Chicago, Chicago, Illinois
| | - Jeremy D Marks
- Department of Pediatrics, The University of Chicago, Chicago, Illinois; Committee on Neurobiology, The University of Chicago, Chicago, Illinois
| | - Wim van Drongelen
- Department of Pediatrics, The University of Chicago, Chicago, Illinois; Committee on Computational Neuroscience, The University of Chicago, Chicago, Illinois; The Computation Institute, The University of Chicago, Chicago, Illinois; and Committee on Neurobiology, The University of Chicago, Chicago, Illinois
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16
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Serafini R, Dettloff S, Loeb JA. Neocortical slices from adult chronic epileptic rats exhibit discharges of higher voltages and broader spread. Neuroscience 2016; 322:509-24. [PMID: 26892299 DOI: 10.1016/j.neuroscience.2016.02.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 02/10/2016] [Accepted: 02/11/2016] [Indexed: 11/30/2022]
Abstract
Much of the current understanding of epilepsy mechanisms has been built on data recorded with one or a few electrodes from temporal lobe slices of normal young animals stimulated with convulsants. Mechanisms of adult, extratemporal, neocortical chronic epilepsy have not been characterized as much. A more advanced understanding of epilepsy mechanisms can be obtained by recording epileptiform discharges simultaneously from multiple points of an epileptic focus so as to define their sites of initiation and pathways of spreading. Brain slice recordings can characterize epileptic mechanisms in a simpler, more controlled preparation than in vivo. Yet, the intrinsic hyper-excitability of a chronic epileptic focus may not be entirely preserved in slices following the severing of connections in slice preparation. This study utilizes recordings of multiple electrode arrays to characterize which features of epileptic hyper-excitability present in in vivo chronic adult neocortical epileptic foci are preserved in brain slices. After tetanus toxin somatosensory cortex injections, adult rats manifest chronic spontaneous epileptic discharges both in the injection site (primary focus) and in the contralateral side (secondary focus). We prepared neocortical slices from these epileptic animals. When perfused with 4-Aminopyridine in a magnesium free medium, epileptic rat slices exhibit higher voltage discharges and broader spreading than control rat slices. Rates of discharges are similar in slices of epileptic and normal rats, however. Ictal and interictal discharges are distributed over most cortical layers, though with significant differences between primary and secondary foci. A chronic neocortical epileptic focus in slices does not show increased spontaneous pacemakers initiating epileptic discharges but shows discharges with higher voltages and broader spread, consistent with an enhanced synchrony of cellular and synaptic generators over wider surfaces.
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Affiliation(s)
- R Serafini
- Department of Neurology, University of Utah, Clinical Neuroscience Center, George E. Wahlen VA Medical Center, Salt Lake City, UT, United States.
| | - S Dettloff
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, United States
| | - J A Loeb
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, United States; Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, IL, United States
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17
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Deng PY, Klyachko VA. Genetic upregulation of BK channel activity normalizes multiple synaptic and circuit defects in a mouse model of fragile X syndrome. J Physiol 2015; 594:83-97. [PMID: 26427907 DOI: 10.1113/jp271031] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/29/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Single-channel recordings in CA3 pyramidal neurons revealed that large-conductance calcium-activated K(+) (BK) channel open probability was reduced by loss of fragile X mental retardation protein (FMRP) and that FMRP acts on BK channels by modulating the channel's gating kinetics. Fmr1/BKβ4 double knockout mice were generated to genetically upregulate BK channel activity in the absence of FMRP. Deletion of the BKβ4 subunit alleviated reduced BK channel open probability via increasing BK channel open frequency, but not through prolonging its open duration. Genetic upregulation of BK channel activity via deletion of BKβ4 normalized action potential duration, excessive glutamate release and short-term synaptic plasticity during naturalistic stimulus trains in excitatory hippocampal neurons in the absence of FMRP. Genetic upregulation of BK channel activity via deletion of BKβ4 was sufficient to normalize excessive epileptiform activity in an in vitro model of seizure activity in the hippocampal circuit in the absence of FMRP. Loss of fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS), yet the mechanisms underlying the pathophysiology of FXS are incompletely understood. Recent studies identified important new functions of FMRP in regulating neural excitability and synaptic transmission via both translation-dependent mechanisms and direct interactions of FMRP with a number of ion channels in the axons and presynaptic terminals. Among these presynaptic FMRP functions, FMRP interaction with large-conductance calcium-activated K(+) (BK) channels, specifically their auxiliary β4 subunit, regulates action potential waveform and glutamate release in hippocampal and cortical pyramidal neurons. Given the multitude of ion channels and mechanisms that mediate presynaptic FMRP actions, it remains unclear, however, to what extent FMRP-BK channel interactions contribute to synaptic and circuit defects in FXS. To examine this question, we generated Fmr1/β4 double knockout (dKO) mice to genetically upregulate BK channel activity in the absence of FMRP and determine its ability to normalize multilevel defects caused by FMRP loss. Single-channel analyses revealed that FMRP loss reduced BK channel open probability, and this defect was compensated in dKO mice. Furthermore, dKO mice exhibited normalized action potential duration, glutamate release and short-term dynamics during naturalistic stimulus trains in hippocampal pyramidal neurons. BK channel upregulation was also sufficient to correct excessive seizure susceptibility in an in vitro model of seizure activity in hippocampal slices. Our studies thus suggest that upregulation of BK channel activity normalizes multi-level deficits caused by FMRP loss.
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Affiliation(s)
- Pan-Yue Deng
- Departments of Cell Biology and Physiology, Biomedical Engineering, CIMED, Washington University, St Louis, MO, USA
| | - Vitaly A Klyachko
- Departments of Cell Biology and Physiology, Biomedical Engineering, CIMED, Washington University, St Louis, MO, USA
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18
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Zhang M, Kibler AB, Gonzales-Reyes LE, Durand DM. Neural activity propagation in an unfolded hippocampal preparation with a penetrating micro-electrode array. J Vis Exp 2015. [PMID: 25868081 DOI: 10.3791/52601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
This protocol describes a method for preparing a new in vitro flat hippocampus preparation combined with a micro-machined array to map neural activity in the hippocampus. The transverse hippocampal slice preparation is the most common tissue preparation to study hippocampus electrophysiology. A longitudinal hippocampal slice was also developed in order to investigate longitudinal connections in the hippocampus. The intact mouse hippocampus can also be maintained in vitro because its thickness allows adequate oxygen diffusion. However, these three preparations do not provide direct access to neural propagation since some of the tissue is either missing or folded. The unfolded intact hippocampus provides both transverse and longitudinal connections in a flat configuration for direct access to the tissue to analyze the full extent of signal propagation in the hippocampus in vitro. In order to effectively monitor the neural activity from the cell layer, a custom made penetrating micro-electrode array (PMEA) was fabricated and applied to the unfolded hippocampus. The PMEA with 64 electrodes of 200 µm in height could record neural activity deep inside the mouse hippocampus. The unique combination of an unfolded hippocampal preparation and the PMEA provides a new in-vitro tool to study the speed and direction of propagation of neural activity in the two-dimensional CA1-CA3 regions of the hippocampus with a high signal to noise ratio.
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Affiliation(s)
- Mingming Zhang
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University
| | - Andrew B Kibler
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University
| | - Luis E Gonzales-Reyes
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University
| | - Dominique M Durand
- Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University;
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19
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Serafini R, Andrade R, Loeb JA. Coalescence of deep and superficial epileptic foci into larger discharge units in adult rat neocortex. Neuroscience 2015; 292:148-58. [PMID: 25701714 DOI: 10.1016/j.neuroscience.2015.02.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 02/06/2015] [Accepted: 02/10/2015] [Indexed: 11/19/2022]
Abstract
Epilepsy is a disease of neuronal hyper-synchrony that can involve both neocortical and hippocampal brain regions. While much is known about the network properties of the hippocampus little is known of how epileptic neocortical hyper-synchrony develops. We aimed at characterizing the properties of epileptic discharges of a neocortical epileptic focus. We established a multi-electrode-array method to record the spatial patterns of epileptiform potentials in acute adult rat brain slices evoked by 4-Aminopyridine in the absence of magnesium. Locations of discharges mapped to two anatomical regions over the somatosensory cortex and over the lateral convexity separated by a gap at a location matching the dysgranular zone. Focal epileptiform discharges were recorded in superficial and deep neocortical layers but over superficial layers, they exhibited larger surface areas. They were often independent even when closely spaced to one another but they became progressively coupled resulting in larger zones of coherent discharge. The gradual coupling of multiple, independent, closely spaced, spatially restricted, focal discharges between deep and superficial neocortical layers represents a possible mechanism of the development of an epileptogenic zone.
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Affiliation(s)
- Ruggero Serafini
- Department of Neurology, University of Utah, Clinical Neuroscience Center, Salt Lake City, UT, United States; George E. Wahlen VA Medical Center, Salt Lake City, UT, United States.
| | - Rodrigo Andrade
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
| | - Jeffrey A Loeb
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, United States; Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, IL, United States
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20
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Reinhard K, Tikidji-Hamburyan A, Seitter H, Idrees S, Mutter M, Benkner B, Münch TA. Step-by-step instructions for retina recordings with perforated multi electrode arrays. PLoS One 2014; 9:e106148. [PMID: 25165854 PMCID: PMC4148441 DOI: 10.1371/journal.pone.0106148] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 06/13/2014] [Indexed: 11/18/2022] Open
Abstract
Multi-electrode arrays are a state-of-the-art tool in electrophysiology, also in retina research. The output cells of the retina, the retinal ganglion cells, form a monolayer in many species and are well accessible due to their proximity to the inner retinal surface. This structure has allowed the use of multi-electrode arrays for high-throughput, parallel recordings of retinal responses to presented visual stimuli, and has led to significant new insights into retinal organization and function. However, using conventional arrays where electrodes are embedded into a glass or ceramic plate can be associated with three main problems: (1) low signal-to-noise ratio due to poor contact between electrodes and tissue, especially in the case of strongly curved retinas from small animals, e.g. rodents; (2) insufficient oxygen and nutrient supply to cells located on the bottom of the recording chamber; and (3) displacement of the tissue during recordings. Perforated multi-electrode arrays (pMEAs) have been found to alleviate all three issues in brain slice recordings. Over the last years, we have been using such perforated arrays to study light evoked activity in the retinas of various species including mouse, pig, and human. In this article, we provide detailed step-by-step instructions for the use of perforated MEAs to record visual responses from the retina, including spike recordings from retinal ganglion cells and in vitro electroretinograms (ERG). In addition, we provide in-depth technical and methodological troubleshooting information, and show example recordings of good quality as well as examples for the various problems which might be encountered. While our description is based on the specific equipment we use in our own lab, it may also prove useful when establishing retinal MEA recordings with other equipment.
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Affiliation(s)
- Katja Reinhard
- Werner Reichardt Centre for Integrative Neuroscience and Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Alexandra Tikidji-Hamburyan
- Werner Reichardt Centre for Integrative Neuroscience and Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Hartwig Seitter
- Werner Reichardt Centre for Integrative Neuroscience and Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Saad Idrees
- Werner Reichardt Centre for Integrative Neuroscience and Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Marion Mutter
- Werner Reichardt Centre for Integrative Neuroscience and Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Boris Benkner
- Werner Reichardt Centre for Integrative Neuroscience and Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Thomas A. Münch
- Werner Reichardt Centre for Integrative Neuroscience and Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
- * E-mail:
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21
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Hilar somatostatin interneurons contribute to synchronized GABA activity in an in vitro epilepsy model. PLoS One 2014; 9:e86250. [PMID: 24465989 PMCID: PMC3897672 DOI: 10.1371/journal.pone.0086250] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 12/12/2013] [Indexed: 01/01/2023] Open
Abstract
Epilepsy is a disorder characterized by excessive synchronized neural activity. The hippocampus and surrounding temporal lobe structures appear particularly sensitive to epileptiform activity. Somatostatin (SST)-positive interneurons within the hilar region have been suggested to gate hippocampal activity, and therefore may play a crucial role in the dysregulation of hippocampal activity. In this study, we examined SST interneuron activity in the in vitro 4-aminopyridine (4-AP) model of epilepsy. We employed a multi-disciplinary approach, combining extracellular multi-electrode array (MEA) recordings with patch-clamp recordings and optical imaging using a genetically encoded calcium sensor. We observed that hilar SST interneurons are strongly synchronized during 4-AP-induced local field potentials (LFPs), as assayed by Ca2+ imaging as well as juxtacellular or intracellular recording. SST interneurons were particularly responsive to GABA-mediated LFPs that occurred in the absence of ionotropic glutamatergic transmission. Our results present evidence that the extensive synchronized activity of SST-expressing interneurons contribute to the generation of GABAergic LFPs in an in vitro model of temporal lobe seizures.
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Visockis V, King AE. M-channels modulate network excitatory activity induced by 4-aminopyridine in immature rat substantia gelatinosa in vitro. Brain Res 2013; 1513:9-16. [PMID: 23566815 DOI: 10.1016/j.brainres.2013.03.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 03/22/2013] [Accepted: 03/24/2013] [Indexed: 11/25/2022]
Abstract
There is strong evidence that M-currents modulate peripheral sensory afferent excitability and that altered M-current efficacy may underpin aspects of pain-induced nociceptor sensitization. Less clear is the role of the M-current in regulating central excitability within spinal dorsal horn nociceptive circuitry. In this study, an in vitro model of central hyperexcitability that uses the potassium channel blocker 4-aminopyridine (4-AP) to induce large amplitude population spikes and 4-12Hz oscillatory activity within rat spinal substantia gelatinosa (SG) has been used to determine the impact of pharmacological modulation of the M-current on central excitability. The M-current enhancers Retigabine (10 and 30μM) and Flupirtine (30μM) had a depressant effect on 4-AP-induced excitation in SG such that the frequency of large amplitude population spikes and the power of 4-12Hz oscillatory activity were both significantly reduced. In contrast, the M-current blockers XE911 (5μM) or Linopirdine (20μM) significantly potentiated 4-12Hz oscillatory activity as evidenced by significant increases in the parameters of power amplitude and power area but had no effect on large amplitude population spikes. These data indicate that pharmacological modulation of the M-current can influence excitability of nociceptive circuitry especially under conditions of central hyperexcitability, as may occur in chronic pain conditions. It is not clear whether these effects reflect a direct effect on interneurones localized to SG or indirectly via sensory afferent terminals. Nonetheless, these central actions should be taken into account alongside peripheral actions in terms of evaluating the potential therapeutic analgesic potency of novel M-current enhancers.
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Affiliation(s)
- V Visockis
- School of Biomedical Sciences, University of Leeds, Leeds, UK
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