1
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Dong L, Zhao T, Duan JK, Tian L, Zheng Y. Effect of high-frequency stimulation on the complexity of low-Mg 2+-induced epileptiform discharge rhythm waves in the CA3 region of rat hippocampal slices. Biochem Biophys Res Commun 2023; 673:59-66. [PMID: 37356146 DOI: 10.1016/j.bbrc.2023.06.048] [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: 06/07/2023] [Accepted: 06/14/2023] [Indexed: 06/27/2023]
Abstract
High-frequency stimulation (HFS) is a crucial therapeutic approach for neurodegenerative conditions, such as epilepsy. However, its underlying mechanism of inhibition remains unclear. In this study, a rat model of epileptiform discharges (EDs) was constructed by perfusing brain slices with magnesium-free artificial cerebrospinal fluid (aCSF), where after HFS was used to stimulate the CA3 area of the hippocampus. The EDs signals of each sub-region of hippocampal slices before and after HFS were recorded based on a multi-electrode Array (MEA). Secondly, the changes of approximate entropy (ApEn) complexity of rhythms in different regions of hippocampal slices before and after HFS were deeply analyzed The results showed that different rhythm characteristics of EDs signals exhibited significant differences before and after HFS. Here HFS significantly inhibited the delta rhythm of field potential and enhanced the beta rhythm. Finally, the changing rhythm of the EDs signal in the propagation path before and after HFS was analyzed, and it was found that the inhibitory target of HFS on EDs signal was in the CA3b sub-region. The rhythm would gradually decline with the propagation of EDs signal in the hippocampal neural pathway. This study shows that HFS can modulate the local field potential, thus inhibiting the pathological rhythm caused by epilepsy, which provides a novel research incentive for HFS to inhibit EDs.
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Affiliation(s)
- Lei Dong
- School of Life Sciences, Tiangong University, Tianjin, 300387, China; State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin, 300072, China
| | - Tong Zhao
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
| | - Jia-Kang Duan
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
| | - Lei Tian
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
| | - Yu Zheng
- School of Life Sciences, Tiangong University, Tianjin, 300387, China.
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2
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Liu M, Liu H, Feng F, Krook-Magnuson E, Dudley SC. TRPM7 kinase mediates hypomagnesemia-induced seizure-related death. Sci Rep 2023; 13:7855. [PMID: 37188671 DOI: 10.1038/s41598-023-34789-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 05/08/2023] [Indexed: 05/17/2023] Open
Abstract
Hypomagnesemia (HypoMg) can cause seizures and death, but the mechanism is unknown. Transient receptor potential cation channel subfamily M 7 (TRPM7) is a Mg transporter with both channel and kinase function. In this study, we focused on the kinase role of TRPM7 in HypoMg-induced seizures and death. Wild type C57BL/6J mice and transgenic mice with a global homozygous mutation in the TRPM7 kinase domain (TRPM7K1646R, with no kinase function) were fed with control diet or a HypoMg diet. After 6 weeks of HypoMg diet, mice had significantly decreased serum Mg, elevated brain TRPM7, and a significant rate of death, with females being most susceptible. Deaths were immediately preceded by seizure events. TRPM7K1646R mice showed resistance to seizure-induced death. HypoMg-induced brain inflammation and oxidative stress were suppressed by TRPM7K1646R. Compared to their male counterparts, HypoMg female mice had higher levels of inflammation and oxidative stress in the hippocampus. We concluded that TRPM7 kinase function contributes seizure-induced deaths in HypoMg mice and that inhibiting the kinase reduced inflammation and oxidative stress.
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Affiliation(s)
- Man Liu
- Cardiovascular Division, Department of Medicine, The Lillehei Heart Institute, University of Minnesota at Twin Cities, 2231 6th Street SE, CCRB 4-141, Minneapolis, MN, 55455, USA
| | - Hong Liu
- Cardiovascular Division, Department of Medicine, The Lillehei Heart Institute, University of Minnesota at Twin Cities, 2231 6th Street SE, CCRB 4-141, Minneapolis, MN, 55455, USA
| | - Feng Feng
- Cardiovascular Division, Department of Medicine, The Lillehei Heart Institute, University of Minnesota at Twin Cities, 2231 6th Street SE, CCRB 4-141, Minneapolis, MN, 55455, USA
| | - Esther Krook-Magnuson
- Department of Neuroscience, University of Minnesota at Twin Cities, Minneapolis, MN, USA
| | - Samuel C Dudley
- Cardiovascular Division, Department of Medicine, The Lillehei Heart Institute, University of Minnesota at Twin Cities, 2231 6th Street SE, CCRB 4-141, Minneapolis, MN, 55455, USA.
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3
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Dong L, Song LL, Zhao WJ, Zhao L, Tian L, Zheng Y. Modulatory effects of real-time electromagnetic stimulation on epileptiform activity in juvenile rat hippocampus based on multi-electrode array recordings. Brain Res Bull 2023; 198:27-35. [PMID: 37084982 DOI: 10.1016/j.brainresbull.2023.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 04/10/2023] [Accepted: 04/18/2023] [Indexed: 04/23/2023]
Abstract
Electromagnetic stimulation (EMS) has proven to be useful for the focal suppression of epileptiform activity (EFA) in the hippocampus. There is a critical period during EFA for achieving the transition from brief interictal discharges (IIDs) to prolonged ictal discharges (IDs), and it is unknown whether EMS can modulate this transition. Therefore, this study aimed to evaluate the intensity- and time-dependent effect of EMS on the transition of EFA. A juvenile rat EFA model was constructed by perfusing magnesium-free artificial cerebrospinal fluid (aCSF) on brain slices, and the induced EFA was recorded using a micro-electrode array (MEA) platform. After a stable EFA event was recorded for some time, real-time pulsed magnetic stimulation with low and high peak-to-peak input magnetic field intensities was carried out. A 5-min intervention with real-time magnetic fields with low intensity was found to reduce the amplitude of IDs (ID events still existed), whereas a 5-min intervention with real-time magnetic fields with high input voltages completely suppressed IDs. Short-time magnetic fields (9s and 1min) with high or low input intensity had no effect on EFA. Real-time magnetic fields can block the normal EFA process from IIDs to IDs (i.e., a complete EFA cycle) and this suppression effect is dependent on input intensities and intervention duration. The experimental findings further indicate that magnetic stimulation may be chosen as an alternative antiepileptic therapy.
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Affiliation(s)
- Lei Dong
- School of Life Sciences, Tiangong University, Tianjin 300387, China; State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Lin-Lin Song
- School of Life Sciences, Tiangong University, Tianjin 300387, China; School of Electronic and Information Engineering, Tiangong University, Tianjin 300387, China
| | - Wen-Jun Zhao
- School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Ling Zhao
- School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Lei Tian
- School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Yu Zheng
- School of Life Sciences, Tiangong University, Tianjin 300387, China.
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4
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Bamhraz AA, Franken GAC, de Baaij JHF, Rodrigues A, Grady R, Deveau S, Chanchlani R. Diagnostic Dilemma in an Adolescent Girl with an Eating Disorder, Intellectual Disability, and Hypomagnesemia. Nephron Clin Pract 2021; 145:717-720. [PMID: 34515155 DOI: 10.1159/000518173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 06/15/2021] [Indexed: 11/19/2022] Open
Abstract
Neurological disorders, including seizures, migraine, depression, and intellectual disability, are frequently associated with hypomagnesemia. Specifically, magnesium (Mg2+) channel transient receptor potential melastatin (TRPM) 6 and TRPM7 are essential for brain function and development. Both channels are also localized in renal and intestinal epithelia and are crucial for Mg2+(re)absorption. Cyclin M2 (CNNM2) is located on the basolateral side of the distal convoluted tubule. In addition, it plays a role in the maintenance of plasma Mg2+ levels along with TRPM6, which is present at the apical level. The CNNM2 gene is crucial for renal magnesium handling, brain development, and neurological functioning. Here, we identified a novel mutation in the CNNM2 gene causing a cognitive delay in a girl with hypomagnesemia. We suggest testing for CNNM2 mutation in patients with neurological impairment and hypomagnesemia.
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Affiliation(s)
- Abdulaziz A Bamhraz
- Division of Pediatric Nephrology, Department of Pediatrics, McMaster Children's Hospital, McMaster University, Hamilton, Ontario, Canada,
| | - Gijs A C Franken
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Allison Rodrigues
- Division of Adolescent Medicine, Department of Pediatrics, McMaster Children's Hospital, McMaster University, Hamilton, Ontario, Canada
| | - Rosheen Grady
- Division of Adolescent Medicine, Department of Pediatrics, McMaster Children's Hospital, McMaster University, Hamilton, Ontario, Canada
| | - Stephanie Deveau
- Division of Adolescent Medicine, Department of Pediatrics, McMaster Children's Hospital, McMaster University, Hamilton, Ontario, Canada
| | - Rahul Chanchlani
- Division of Pediatric Nephrology, Department of Pediatrics, McMaster Children's Hospital, McMaster University, Hamilton, Ontario, Canada
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5
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Dong L, Li G, Gao Y, Lin L, Cao XB, Zheng Y. Exploring the Inhibitory Effect of Low-frequency Magnetic Fields on Epileptiform Discharges in Juvenile Rat Hippocampus. Neuroscience 2021; 467:1-15. [PMID: 34033871 DOI: 10.1016/j.neuroscience.2021.05.016] [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: 08/12/2020] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 10/01/2022]
Abstract
Stimulation with a low frequency electromagnetic field (LF-EMF) has proven to represent a powerful method for the suppression of seizures, as demonstrated in select clinical and laboratory studies. However, the mechanism by which LF-EMF suppresses seizures remains unclear. The purpose of the present study was to explore the modulatory effect of LF-EMF on epileptiform discharges (EDs) using rat hippocampal slices and investigate the underlying mechanisms that mediate these effects. EDs in hippocampal slices was induced by magnesium-free (zero-Mg2+) artificial cerebrospinal fluid (ACSF) and recorded using an in vitro micro-electrode array (MEA). A small sub-decimeter coil was designed and incorporated in a flexible magnetic stimulation device that allowed electromagnetic fields with different parameters to be delivered to slices. After a stable ED event was recorded, magnetic fields of 0.5 Hz (30 min) with a magnetic intensity of 0.13 mT (5 Vpp voltage input) and 0.25 mT (20 Vpp voltage input) were applied. The results indicated that a high-amplitude 0.5 Hz magnetic field could lead to persistent suppression of ictal discharges (IDs), while low-amplitude magnetic fields did not influence IDs. The persistent suppression of complex ED was prevented if the magnetic fields were applied in the presence of 10 μmol/L bicuculline (BIC), a γ-aminobutyric acid type A (GABAA) receptor antagonist, while the application of BIC subsequent to a magnetic field application led to the reappearance of ID. The addition of BIC resulted in EDs that had previously been inhibited by magnetic fields, reappearing. Low-frequency magnetic stimulation was able to inhibit the conversion from interictal discharges (IIDs) or preictal discharges (PIDs) to IDs. This suppression was attributed to the modulation of GABAA receptor activity.
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Affiliation(s)
- Lei Dong
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Biomedical Detecting Techniques & Instruments, Tianjin University, Tianjin 300072, China
| | - Gang Li
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Biomedical Detecting Techniques & Instruments, Tianjin University, Tianjin 300072, China
| | - Yang Gao
- School of Information Technology and Electrical Engineering, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Ling Lin
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Biomedical Detecting Techniques & Instruments, Tianjin University, Tianjin 300072, China
| | - Xue-Bin Cao
- Department of Cardiology, 252 Hospital of PLA, Baoding, Hebei 071000, China.
| | - Yu Zheng
- School of Life Sciences, Tiangong University, Tianjin 300387, China.
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6
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Dong L, Li G, Gao Y, Lin L, Zhang KH, Tian CX, Cao XB, Zheng Y. Effect of priming low-frequency magnetic fields on zero-Mg2+ -induced epileptiform discharges in rat hippocampal slices. Epilepsy Res 2020; 167:106464. [DOI: 10.1016/j.eplepsyres.2020.106464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/02/2020] [Accepted: 09/05/2020] [Indexed: 12/16/2022]
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7
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Zheng Y, Zhang K, Dong L, Tian C. Study on the mechanism of high-frequency stimulation inhibiting low-Mg 2+-induced epileptiform discharges in juvenile rat hippocampal slices. Brain Res Bull 2020; 165:1-13. [PMID: 32961285 DOI: 10.1016/j.brainresbull.2020.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/02/2020] [Accepted: 09/09/2020] [Indexed: 11/29/2022]
Abstract
Study on the mechanism of high-frequency stimulation inhibiting low-Mg2+-induced epileptiform discharges in juvenile rat hippocampal slices High-frequency stimulation (HFS) has been demonstrated to be an effective treatment for inhibiting epilepsy in some clinical and laboratory studies. However, the mechanisms underlying the therapeutic effects of HFS are not yet fully understood. In our present study, epileptiform discharges (EDs) in acutely isolated hippocampal slices of male Sprague-Dawley (SD) juvenile rats induced by low-Mg2+ artificial cerebrospinal fluid (ACSF), and electrical stimulation (square wave, 900 pulses, 50 % duty-cycle, 130 Hz) was performed on the CA3 using concentric bipolar electrodes. EDs of neurons in hippocampal were recorded by multi-electrode arrays (MEA). After stable EDs events had been recorded for at least 20 min, HFS was added, followed by 10 μmol/L gamma-aminobutyric acid type A (GABAA) receptors blocker bicuculline (BIC). The results show that the HFS can increase the discharges frequency of inter-ictal discharges (IIDs) and decrease the duration of ictal discharges (IDs). However, the HFS had no effect on the slices with 10 μmol/L BIC. These results indicated that the GABAA receptors are activated when HFS inhibited EDs, thereby achieving the inhibition of low-Mg2+-induced EDs in slices.
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Affiliation(s)
- Yu Zheng
- School of Life Sciences, Tiangong University, Tianjin, 300387, China.
| | - Kanghui Zhang
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
| | - Lei Dong
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin, 300072, China
| | - Chunxiao Tian
- School of Life Sciences, Tiangong University, Tianjin, 300387, China
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8
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Punnakkal P, Dominic D. NMDA Receptor GluN2 Subtypes Control Epileptiform Events in the Hippocampus. Neuromolecular Med 2018; 20:90-96. [PMID: 29335819 DOI: 10.1007/s12017-018-8477-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/03/2018] [Indexed: 12/19/2022]
Abstract
NMDA receptors (NMDARs) play a key role in synaptic plasticity and excitotoxicity. Subtype-specific role of NMDAR in neural disorders is an emerging area. Recent studies have revealed that mutations in NMDARs are a cause for epilepsy. Hippocampus is a known focal point for epilepsy. In hippocampus, expression of the NMDAR subtypes GluN1/GluN2A and GluN1/GluN2B is temporally regulated. However, the pharmacological significance of these subtypes is not well understood in epileptic context/models. To investigate this, epilepsy was induced in hippocampal slices by the application of artificial cerebrospinal fluid that contained high potassium but no magnesium. Epileptiform events (EFEs) were recorded from the CA1 and DG areas of hippocampus with or without subtype-specific antagonists. Irrespective of the age group, CA1 and DG showed epileptiform activity. The NMDAR antagonist AP5 was found to reduce the number of EFEs significantly. However, the application of subtype-specific antagonists (TCN 201 for GluN1/GluN2A and Ro 25-69811 for GluN1/GluN2B) revealed that EFEs had area-specific and temporal components. In slices from neonates, EFEs in CA1 were effectively reduced by Ro 25-69811, but were largely insensitive to TCN 201. In contrast, EFEs in DG were equally sensitive to both of the subtype-specific antagonists. However, the differential sensitivity for the antagonists observed in neonates was absent in later developmental stages. The study provides a functional insight into the NMDAR subtype-dependent contribution of EFEs in hippocampus of young rats, which may have implications in treating childhood epilepsy and avoiding unnecessary side effects of broad spectrum antagonists.
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Affiliation(s)
- Pradeep Punnakkal
- Molecular Medicine, Applied Biology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, 695012, India.
| | - Deity Dominic
- Molecular Medicine, Applied Biology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, 695012, India
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9
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Wong SB, Cheng SJ, Hung WC, Lee WT, Min MY. Rosiglitazone Suppresses In Vitro Seizures in Hippocampal Slice by Inhibiting Presynaptic Glutamate Release in a Model of Temporal Lobe Epilepsy. PLoS One 2015; 10:e0144806. [PMID: 26659605 PMCID: PMC4685987 DOI: 10.1371/journal.pone.0144806] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 11/24/2015] [Indexed: 12/13/2022] Open
Abstract
Peroxisomal proliferator-activated receptor gamma (PPARγ) is a nuclear hormone receptor whose agonist, rosiglitazone has a neuroprotective effect to hippocampal neurons in pilocarpine-induced seizures. Hippocampal slice preparations treated in Mg2+ free medium can induce ictal and interictal-like epileptiform discharges, which is regarded as an in vitro model of N-methyl-D-aspartate (NMDA) receptor-mediated temporal lobe epilepsy (TLE). We applied rosiglitazone in hippocampal slices treated in Mg2+ free medium. The effects of rosiglitazone on hippocampal CA1-Schaffer collateral synaptic transmission were tested. We also examined the neuroprotective effect of rosiglitazone toward NMDA excitotoxicity on cultured hippocampal slices. Application of 10μM rosiglitazone significantly suppressed amplitude and frequency of epileptiform discharges in CA1 neurons. Pretreatment with the PPARγ antagonist GW9662 did not block the effect of rosiglitazone on suppressing discharge frequency, but reverse the effect on suppressing discharge amplitude. Application of rosiglitazone suppressed synaptic transmission in the CA1-Schaffer collateral pathway. By miniature excitatory-potential synaptic current (mEPSC) analysis, rosiglitazone significantly suppressed presynaptic neurotransmitter release. This phenomenon can be reversed by pretreating PPARγ antagonist GW9662. Also, rosiglitazone protected cultured hippocampal slices from NMDA-induced excitotoxicity. The protective effect of 10μM rosiglitazone was partially antagonized by concomitant high dose GW9662 treatment, indicating that this effect is partially mediated by PPARγ receptors. In conclusion, rosiglitazone suppressed NMDA receptor-mediated epileptiform discharges by inhibition of presynaptic neurotransmitter release. Rosiglitazone protected hippocampal slice from NMDA excitotoxicity partially by PPARγ activation. We suggest that rosiglitazone could be a potential agent to treat patients with TLE.
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MESH Headings
- Action Potentials/drug effects
- Anilides/pharmacology
- Animals
- CA1 Region, Hippocampal/drug effects
- CA1 Region, Hippocampal/metabolism
- CA1 Region, Hippocampal/pathology
- Culture Media/chemistry
- Culture Media/pharmacology
- Epilepsy, Temporal Lobe/drug therapy
- Epilepsy, Temporal Lobe/genetics
- Epilepsy, Temporal Lobe/metabolism
- Epilepsy, Temporal Lobe/pathology
- Excitatory Postsynaptic Potentials/drug effects
- Gene Expression Regulation
- Glutamic Acid/metabolism
- Magnesium/pharmacology
- Microtomy
- Models, Biological
- Neurons/drug effects
- Neurons/metabolism
- Neurons/pathology
- Neuroprotective Agents/antagonists & inhibitors
- Neuroprotective Agents/pharmacology
- PPAR gamma/antagonists & inhibitors
- PPAR gamma/genetics
- PPAR gamma/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, N-Methyl-D-Aspartate/agonists
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, N-Methyl-D-Aspartate/metabolism
- Rosiglitazone
- Seizures/drug therapy
- Seizures/genetics
- Seizures/metabolism
- Seizures/pathology
- Synaptic Transmission/drug effects
- Thiazolidinediones/antagonists & inhibitors
- Thiazolidinediones/pharmacology
- Tissue Culture Techniques
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Affiliation(s)
- Shi-Bing Wong
- Department of Pediatrics, Taipei Tzu Chi General Hospital, Buddhist Tzu Chi Medical Foundation, Taipei, Taiwan
- Institute of Zoology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Sin-Jhong Cheng
- Neuroscience Program in Academia Sinica, Taipei, Taiwan
- Institute of Biomedical Sciences; Academia Sinica, Taipei, Taiwan
| | - Wei-Chen Hung
- Department of Pediatrics, Taipei Tzu Chi General Hospital, Buddhist Tzu Chi Medical Foundation, Taipei, Taiwan
| | - Wang-Tso Lee
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
- * E-mail: (WTL); (MYM)
| | - Ming-Yuan Min
- Institute of Zoology, College of Life Science, National Taiwan University, Taipei, Taiwan
- * E-mail: (WTL); (MYM)
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10
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Ruangkittisakul A, Sharopov S, Kantor C, Kuribayashi J, Mildenberger E, Luhmann H, Kilb W, Ballanyi K. Methylxanthine-evoked perturbation of spontaneous and evoked activities in isolated newborn rat hippocampal networks. Neuroscience 2015; 301:106-20. [DOI: 10.1016/j.neuroscience.2015.05.069] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/11/2015] [Accepted: 05/27/2015] [Indexed: 11/29/2022]
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11
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Arjona FJ, de Baaij JHF, Schlingmann KP, Lameris ALL, van Wijk E, Flik G, Regele S, Korenke GC, Neophytou B, Rust S, Reintjes N, Konrad M, Bindels RJM, Hoenderop JGJ. CNNM2 mutations cause impaired brain development and seizures in patients with hypomagnesemia. PLoS Genet 2014; 10:e1004267. [PMID: 24699222 PMCID: PMC3974678 DOI: 10.1371/journal.pgen.1004267] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 02/05/2014] [Indexed: 01/08/2023] Open
Abstract
Intellectual disability and seizures are frequently associated with hypomagnesemia and have an important genetic component. However, to find the genetic origin of intellectual disability and seizures often remains challenging because of considerable genetic heterogeneity and clinical variability. In this study, we have identified new mutations in CNNM2 in five families suffering from mental retardation, seizures, and hypomagnesemia. For the first time, a recessive mode of inheritance of CNNM2 mutations was observed. Importantly, patients with recessive CNNM2 mutations suffer from brain malformations and severe intellectual disability. Additionally, three patients with moderate mental disability were shown to carry de novo heterozygous missense mutations in the CNNM2 gene. To elucidate the physiological role of CNNM2 and explain the pathomechanisms of disease, we studied CNNM2 function combining in vitro activity assays and the zebrafish knockdown model system. Using stable Mg2+ isotopes, we demonstrated that CNNM2 increases cellular Mg2+ uptake in HEK293 cells and that this process occurs through regulation of the Mg2+-permeable cation channel TRPM7. In contrast, cells expressing mutated CNNM2 proteins did not show increased Mg2+ uptake. Knockdown of cnnm2 isoforms in zebrafish resulted in disturbed brain development including neurodevelopmental impairments such as increased embryonic spontaneous contractions and weak touch-evoked escape behaviour, and reduced body Mg content, indicative of impaired renal Mg2+ absorption. These phenotypes were rescued by injection of mammalian wild-type Cnnm2 cRNA, whereas mammalian mutant Cnnm2 cRNA did not improve the zebrafish knockdown phenotypes. We therefore concluded that CNNM2 is fundamental for brain development, neurological functioning and Mg2+ homeostasis. By establishing the loss-of-function zebrafish model for CNNM2 genetic disease, we provide a unique system for testing therapeutic drugs targeting CNNM2 and for monitoring their effects on the brain and kidney phenotype. Mental retardation affects 1–3% of the population and has a strong genetic etiology. Consequently, early identification of the genetic causes of mental retardation is of significant importance in the diagnosis of the disease, as predictor of the progress of the disease and for the determination of treatment. In this study, we identify mutations in the gene encoding for cyclin M2 (CNNM2) to be causative for mental retardation and seizures in patients with hypomagnesemia. Particularly, in patients with a recessive mode of inheritance, the intellectual disability caused by dysfunctional CNNM2 is dramatically severe and is accompanied by severely limited motor skills and brain malformations suggestive of impaired early brain development. Although hypomagnesemia has been associated to several neurological diseases, Mg2+ status is not regularly assessed in patients with seizures and mental disability. Our findings establish CNNM2 as an important protein for renal magnesium handling, brain development and neurological functioning, thus explaining the physiology of human disease caused by (dysfunctional) mutations in CNNM2. CNNM2 mutations should be taken into account in patients with seizures and mental disability, specifically in combination with hypomagnesemia.
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Affiliation(s)
- Francisco J Arjona
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Karl P Schlingmann
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - Anke L L Lameris
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Radboud university medical center, Nijmegen, The Netherlands
| | - Gert Flik
- Department of Organismal Animal Physiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Sabrina Regele
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | | | - Birgit Neophytou
- Department of Neuropediatrics, St. Anna Children's Hospital, Medical University Vienna, Vienna, Austria
| | - Stephan Rust
- Leibniz Institute of Arteriosclerosis Research, University of Münster, Münster, Germany
| | - Nadine Reintjes
- Institute of Human Genetics, University of Cologne, Cologne, Germany
| | - Martin Konrad
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
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12
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Chen R, Okabe A, Sun H, Sharopov S, Hanganu-Opatz IL, Kolbaev SN, Fukuda A, Luhmann HJ, Kilb W. Activation of glycine receptors modulates spontaneous epileptiform activity in the immature rat hippocampus. J Physiol 2014; 592:2153-68. [PMID: 24665103 DOI: 10.1113/jphysiol.2014.271700] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
While the expression of glycine receptors in the immature hippocampus has been shown, no information about the role of glycine receptors in controlling the excitability in the immature CNS is available. Therefore, we examined the effect of glycinergic agonists and antagonists in the CA3 region of an intact corticohippocampal preparation of the immature (postnatal days 4-7) rat using field potential recordings. Bath application of 100 μM taurine or 10 μM glycine enhanced the occurrence of recurrent epileptiform activity induced by 20 μM 4-aminopyridine in low Mg(2+) solution. This proconvulsive effect was prevented by 3 μM strychnine or after incubation with the loop diuretic bumetanide (10 μM), suggesting that it required glycine receptors and an active NKCC1-dependent Cl(-) accumulation. Application of higher doses of taurine (≥ 1 mM) or glycine (100 μM) attenuated recurrent epileptiform discharges. The anticonvulsive effect of taurine was also observed in the presence of the GABAA receptor antagonist gabazine and was attenuated by strychnine, suggesting that it was partially mediated by glycine receptors. Bath application of the glycinergic antagonist strychnine (0.3 μM) induced epileptiform discharges. We conclude from these results that in the immature hippocampus, activation of glycine receptors can mediate both pro- and anticonvulsive effects, but that a persistent activation of glycine receptors is required to suppress epileptiform activity. In summary, our study elucidated the important role of glycine receptors in the control of neuronal excitability in the immature hippocampus.
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Affiliation(s)
- Rongqing Chen
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Akihito Okabe
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan
| | - Haiyan Sun
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Salim Sharopov
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Ileana L Hanganu-Opatz
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany University Medical Center Hamburg Eppendorf, Developmental Neurophysiology, Falkenried 94, D-20251, Hamburg, Germany
| | - Sergei N Kolbaev
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
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Sharopov S, Moser J, Chen R, Kolbaev SN, Bernedo VE, Werhahn KJ, Luhmann HJ, Kilb W. Dopaminergic modulation of low-Mg2+-induced epileptiform activity in the intact hippocampus of the newborn mouse in vitro. J Neurosci Res 2012; 90:2020-33. [DOI: 10.1002/jnr.23084] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 04/11/2012] [Accepted: 04/13/2012] [Indexed: 11/12/2022]
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Chen CR, Tan R, Qu WM, Wu Z, Wang Y, Urade Y, Huang ZL. Magnolol, a major bioactive constituent of the bark of Magnolia officinalis, exerts antiepileptic effects via the GABA/benzodiazepine receptor complex in mice. Br J Pharmacol 2012; 164:1534-46. [PMID: 21518336 DOI: 10.1111/j.1476-5381.2011.01456.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The aim of this study was to evaluate the anti-convulsant effects of magnolol (6, 6', 7, 12-tetramethoxy-2, 2'-dimethyl-1-β-berbaman, C18H18O2) and the mechanisms involved. EXPERIMENTAL APPROACH Mice were treated with magnolol (20, 40 and 80 mg·kg(-1)) 30 min before injection with pentylenetetrazol (PTZ, 60 mg·kg(-1), i.p.). The anti-seizure effects of magnolol were analysed using seizure models of behaviour, EEG and in vitro electrophysiology and c-Fos expression in the hippocampus and cortex. KEY RESULTS Magnolol at doses of 40 and 80 mg·kg(-1) significantly delayed the onset of myoclonic jerks and generalized clonic seizures, and decreased the seizure stage and mortality compared with those of the vehicle-treated animals. EEG recordings showed that magnolol (40 and 80 mg·kg(-1)) prolonged the latency of seizure onset and decreased the number of seizure spikes. The anti-epileptic effect of magnolol was reversed by the GABA(A)/benzodiazepine receptor antagonist flumazenil. Pretreatment with flumazenil decreased the effects of magnolol on prolongation of seizure latency and decline of seizure stage. In a Mg(2+)-free model of epileptiform activity, using multi-electrode array recordings in mouse hippocampal slices, magnolol decreased spontaneous epileptiform discharges. Magnolol also significantly decreased seizure-induced Fos immunoreactivity in the piriform cortex, dentate gyrus and hippocampal area CA1. These effects were attenuated by pretreatment with flumazenil. CONCLUSIONS AND IMPLICATIONS These findings indicate that the inhibitory effects of magnolol on epileptiform activity were mediated by the GABA(A) /benzodiazepine receptor complex.
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Affiliation(s)
- C R Chen
- Department of Pharmacology, Shanghai Medical College, Fudan University, Shanghai, China
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Intact In Vitro Preparations of the Neonatal Rodent Cortex: Analysis of Cellular Properties and Network Activity. ISOLATED CENTRAL NERVOUS SYSTEM CIRCUITS 2012. [DOI: 10.1007/978-1-62703-020-5_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Investigation of The Initiation Site and Propagation of Epileptiform Discharges in Hippocampal Slices Using Microelectrode Array. PROG BIOCHEM BIOPHYS 2011. [DOI: 10.3724/sp.j.1206.2010.00065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Three-week combination treatment with ACTH + magnesium sulfate versus ACTH monotherapy for infantile spasms: a 24-week, randomized, open-label, follow-up study in China. Clin Ther 2010; 32:692-700. [PMID: 20435238 DOI: 10.1016/j.clinthera.2010.04.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2010] [Indexed: 11/20/2022]
Abstract
BACKGROUND Infantile spasms (IS) is an age-specific and severe epileptic encephalopathy that occurs in infancy and early childhood and is usually refractory to conventional antiepileptic drugs. Adrenocorticotropic hormone (ACTH) has been the treatment of choice for IS, but ACTH use has been associated with infection and hypertension. Magnesium ion is an N-methyl-D-aspartic acid (NMDA)-noncompetitive antagonist that might inhibit NMDA activity and has antiepileptic and neuroprotective effects. OBJECTIVE This study compared the efficacy and tolerability of ACTH + magnesium sulfate (MgSO(4)) versus ACTH monotherapy for the treatment of IS. METHODS This 24-week, randomized, open-label follow-up study enrolled male and female infants with IS. Patients were randomly assigned to receive ACTH 25 U/d + MgSO(4) 0.25 g/kg/d, or ACTH 25 U/d only (control), intravenously for 3 weeks. Efficacy was assessed over a period of 24 weeks based on seizure frequency, EEG, and Gesell testing of psychomotor skills (subscales: language, motor, adaptive, and personal-social skills; measured using a developmental quotient [DQ] ). Tolerability was assessed by monitoring for adverse events using laboratory analysis and clinical evaluation. RESULTS Thirty-eight infants were enrolled (23 male, 15 female; median age, 9.2 months; 19 patients per group). At 12 weeks, 14 patients (73.7%) who received ACTH + MgSO(4) and 9 patients (47.4%) in the control group were seizure free. At 24 weeks, seizure-free rates were 12 (63.2%) in the ACTH + MgSO(4) group and 10 (52.6%) in the control group. On EEG, 9 patients (47.4%) in the ACTH + MgSO(4) group achieved complete recovery (normalized EEG), 5 (26.3 %) attained partial improvement (multifocal spike wave), and 5 (26.3%) had no improvement (hypsarrhythmia or modified hypsarrhythmia). At 4 weeks, in the control group, 5 patients (26.3 %) achieved complete recovery, 6 (31.6%) achieved partial improvement, and 8 (42.1%) had no improvement. Of the 12 patients who were seizure free at 24 weeks in the ACTH + MgSO(4) group, 11 (91.7%) had complete recovery (normalized EEG); this rate was 7 of 10 (70.0%) in the control group. In the ACTH + MgSO(4) group, the change from baseline to 24 weeks in mean (SD) personal-social DQ was significant (from 48.6 [6.4] to 65.2 [7.1], respectively; P < 0.05). In the control group, the difference before and after treatment was nonsignificant (47.7 [6.0] vs 49.9 [4.4]). None of the other Gesell test findings were significant versus baseline. The most common AEs included upper respiratory tract infection and pyrexia (both, 3 [15.8%] per group); diarrhea (2 [10.5%] per group); and hypertension, insomnia, and irritability (all, 0 in the ACTH + MgSO(4) group and 2 [10.5%] in the control group). None of the between-group differences in the prevalences of AEs were significant between the 2 groups. CONCLUSIONS In this study in infants with IS, the proportions of patients who were seizure free from 4 to 24 weeks were significantly greater in the ACTH + MgSO(4) group compared with the ACTH monotherapy group. Personal-social neurodevelopment was significantly improved from baseline in the group that received combination treatment. Both treatments were generally well tolerated. International Standard Randomized Controlled Trial no. ISRCTN 78654111.
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Standard antiepileptic drugs fail to block epileptiform activity in rat organotypic hippocampal slice cultures. Br J Pharmacol 2008; 154:709-24. [PMID: 18414393 DOI: 10.1038/bjp.2008.112] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND AND PURPOSE Earlier studies had demonstrated that tonic-clonic seizure-like events (SLEs) resembling electrographic correlates of limbic seizures in animals and humans can be induced in organotypic hippocampal slice cultures (OHSCs). We have explored OHSCs for their suitability to serve as in vitro models of limbic seizures for studying seizure mechanisms and screening new antiepileptic compounds. EXPERIMENTAL APPROACH OHSCs were cultivated according to the interface method. Neuronal activity and extracellular potassium concentration were recorded under submerged conditions. SLEs were induced by lowering magnesium concentration or by applying the potassium channel blocker 4-aminopyridine. The effects of standard antiepileptic drugs (AEDs), carbamazepine, phenytoin, valproic acid, clonazepam, diazepam and phenobarbital sodium on SLEs were analysed. KEY RESULTS In more than 93% of OHSCs, AEDs did not prevent the induction of SLEs or stop ongoing seizure activity even when toxic concentrations were applied. This pharmacoresistance was independent of the method of seizure provocation, postnatal age at explantation (P2-P10) and cultivation time in vitro (2 months). SLEs were reversibly blocked by glutamate antagonists or the GABA(A)-agonist muscimol. CONCLUSIONS AND IMPLICATIONS We present a simple to establish in vitro model of tonic-clonic SLEs that is a priori pharmacoresistant and thus has an advantage over animal models of pharmacoresistant seizures in which responders and non-responders can be sorted out only after an experiment. OHSCs could be suitable for exploring mechanisms of pharmacoresistant seizures and be used for the identification of new anticonvulsive compounds eventually effective in drug refractory epilepsy.
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Dzhala VI, Brumback AC, Staley KJ. Bumetanide enhances phenobarbital efficacy in a neonatal seizure model. Ann Neurol 2008; 63:222-35. [DOI: 10.1002/ana.21229] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kilb W, Sinning A, Luhmann HJ. Model-specific effects of bumetanide on epileptiform activity in the in-vitro intact hippocampus of the newborn mouse. Neuropharmacology 2007; 53:524-33. [PMID: 17681355 DOI: 10.1016/j.neuropharm.2007.06.015] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Revised: 05/21/2007] [Accepted: 06/19/2007] [Indexed: 11/16/2022]
Abstract
The immature brain has a higher susceptibility to develop seizures, which often respond poorly to classical pharmacological treatment. It has been recently suggested that bumetanide, which blocks Na(+)-dependent K(+)-Cl(-)-cotransporter isoform 1 (NKCC1) and thus attenuates depolarizing GABAergic responses, could soothe epileptiform activity in immature nervous systems. To evaluate whether bumetanide consistently attenuates epileptiform activity, we investigated the effect of 10 microM bumetanide in five different in-vitro epilepsy models using field potential recordings in the CA3 region of intact mouse hippocampal preparations at postnatal day 4-7. Bumetanide reduced amplitude and frequency of ictal-like events (ILE) induced by 8.5 mM K(+), but it increased the frequency of ILE induced by 1 microM kainate. Inhibition of ligand-gated Cl(-) channels by 10 microM gabazine and 30 microM strychnine induced interictal activity (IA) that was only marginally affected by bumetanide. Removal of extracellular Mg(2+) induced both ILE and IA. Bumetanide had no effect on these ILE but enhanced the IA. Low-Mg(2+) solution containing 20 microM 4-AP induced late-recurrent discharges, which were slightly attenuated by bumetanide. In summary, our results demonstrate that bumetanide exerts diverse effects in different in-vitro epilepsy models.
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Affiliation(s)
- W Kilb
- Institute of Physiology and Pathophysiology, Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany.
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