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Müller S, Kartheus M, Hendinger E, Hübner DC, Schnell E, Rackow S, Bertsche A, Köhling R, Kirschstein T. Persistent Kv7.2/7.3 downregulation in the rat pilocarpine model of mesial temporal lobe epilepsy. Epilepsy Res 2024; 200:107296. [PMID: 38219422 DOI: 10.1016/j.eplepsyres.2024.107296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/04/2023] [Accepted: 01/05/2024] [Indexed: 01/16/2024]
Abstract
Mutations within the Kv7.2 and Kv7.3 genes are well described causes for genetic childhood epilepsies. Knowledge on these channels in acquired focal epilepsy, especially in mesial temporal lobe epilepsy (mTLE), however, is scarce. Here, we used the rat pilocarpine model of drug-resistant mTLE to elucidate both expression and function by quantitative polymerase-chain reaction, immunohistochemistry, and electrophysiology, respectively. We found transcriptional downregulation of Kv7.2 and Kv7.3 as well as reduced Kv7.2 expression in epileptic CA1. Consequences were altered synaptic transmission, hyperexcitability which consisted of epileptiform afterpotentials, and increased susceptibility to acute GABAergic disinhibition. Importantly, blocking Kv7 channels with XE991 increased hyperexcitability in control tissue, but not in chronically epileptic tissue suggesting that the Kv7 deficit had precluded XE991 effects in this tissue. Conversely, XE991 resulted in comparable reduction of the paired-pulse ratio in both experimental groups implying preserved presynaptic Kv7.2 function of Schaffer collateral terminals. Consistent with Kv7.2/7.3 downregulation, the Kv7.3 channel opener β-hydroxybutyrate failed to mitigate hyperexcitability. Our findings demonstrate that compromised Kv7 function is not only relevant in genetic epilepsy, but also in acquired focal epilepsy. Moreover, they help explain reduced anti-seizure efficacy of Kv7 channel openers in drug-resistant epilepsy.
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Affiliation(s)
- Steffen Müller
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Mareike Kartheus
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Elisabeth Hendinger
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | | | - Emma Schnell
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Simone Rackow
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Astrid Bertsche
- Department Neuropaediatrics, Hospital for Children and Adolescents, University Medicine Greifswald, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany; Center of Transdisciplinary Neurosciences Rostock (CTNR), University Medicine Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany; Center of Transdisciplinary Neurosciences Rostock (CTNR), University Medicine Rostock, Germany.
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Postnikova TY, Diespirov GP, Amakhin DV, Vylekzhanina EN, Soboleva EB, Zaitsev AV. Impairments of Long-Term Synaptic Plasticity in the Hippocampus of Young Rats during the Latent Phase of the Lithium-Pilocarpine Model of Temporal Lobe Epilepsy. Int J Mol Sci 2021; 22:ijms222413355. [PMID: 34948152 PMCID: PMC8705146 DOI: 10.3390/ijms222413355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/06/2021] [Accepted: 12/10/2021] [Indexed: 12/14/2022] Open
Abstract
Status epilepticus (SE) causes persistent abnormalities in the functioning of neuronal networks, often resulting in worsening epileptic seizures. Many details of cellular and molecular mechanisms of seizure-induced changes are still unknown. The lithium–pilocarpine model of epilepsy in rats reproduces many features of human temporal lobe epilepsy. In this work, using the lithium–pilocarpine model in three-week-old rats, we examined the morphological and electrophysiological changes in the hippocampus within a week following pilocarpine-induced seizures. We found that almost a third of the neurons in the hippocampus and dentate gyrus died on the first day, but this was not accompanied by impaired synaptic plasticity at that time. A diminished long-term potentiation (LTP) was observed following three days, and the negative effect of SE on plasticity increased one week later, being accompanied by astrogliosis. The attenuation of LTP was caused by the weakening of N-methyl-D-aspartate receptor (NMDAR)-dependent signaling. NMDAR-current was more than two-fold weaker during high-frequency stimulation in the post-SE rats than in the control group. Application of glial transmitter D-serine, a coagonist of NMDARs, allows the enhancement of the NMDAR-dependent current and the restoration of LTP. These results suggest that the disorder of neuron–astrocyte interactions plays a critical role in the impairment of synaptic plasticity.
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Zaitsev АV, Amakhin DV, Dyomina AV, Zakharova MV, Ergina JL, Postnikova TY, Diespirov GP, Magazanik LG. Synaptic Dysfunction in Epilepsy. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s002209302103008x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Synaptic GluN2A-Containing NMDA Receptors: From Physiology to Pathological Synaptic Plasticity. Int J Mol Sci 2020; 21:ijms21041538. [PMID: 32102377 PMCID: PMC7073220 DOI: 10.3390/ijms21041538] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 12/16/2022] Open
Abstract
N-Methyl-d-Aspartate Receptors (NMDARs) are ionotropic glutamate-gated receptors. NMDARs are tetramers composed by several homologous subunits of GluN1-, GluN2-, or GluN3-type, leading to the existence in the central nervous system of a high variety of receptor subtypes with different pharmacological and signaling properties. NMDAR subunit composition is strictly regulated during development and by activity-dependent synaptic plasticity. Given the differences between GluN2 regulatory subunits of NMDAR in several functions, here we will focus on the synaptic pool of NMDARs containing the GluN2A subunit, addressing its role in both physiology and pathological synaptic plasticity as well as the contribution in these events of different types of GluN2A-interacting proteins.
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Mayer J, Kirschstein T, Resch T, Porath K, Krause BJ, Köhling R, Lange F. Perampanel attenuates epileptiform phenotype in C6 glioma. Neurosci Lett 2019; 715:134629. [PMID: 31734290 DOI: 10.1016/j.neulet.2019.134629] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/30/2019] [Accepted: 11/12/2019] [Indexed: 02/07/2023]
Abstract
Epileptic seizures are frequent in patients with glioma, and anticonvulsive treatment is often indicated. Glioma cells release glutamate via the Xc- antiporter system, which appears to be a major pathomechanism of glioma-associated seizures and excitotoxicity. In addition, the proliferation and survival of the tumor cells are promoted. Therefore, anticonvulsants that attenuate glutamate-mediated receptor activation could be especially effective. In this study, we investigated the effects of AMPA receptor antagonist perampanel in rat C6 glioma model. In first pilot experiments, perampanel reduced glucose uptake but had no impact of extracellular glutamate level in vitro. To analyze the effects of perampanel in vivo, we injected C6 cells orthotopically into the neocortex of Wistar rats in order to establish a model of glioma-associated epilepsy. Spontaneous recurrent discharges in brain slices were abolished upon perfusion with the AMPA receptor blocker perampanel, supporting the major role of glutamatergic excitation. With respect to the tumor progression, no effect of perampanel on survival of the animals or on glioma size was determined. Our data demonstrate that perampanel inhibit epileptiform discharges in organotypic brain slices of glioma, but failed to attenuate tumor growth or promote animal survival.
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Affiliation(s)
- Johannes Mayer
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Rostock, Germany; Psychology Department, University of California, Riverside, 900 University Avenue Riverside, CA, 92521, United States.
| | - Timo Kirschstein
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Rostock, Germany; Center for Transdisciplinary Neurosciences Rostock, Rostock University Medical Center, Rostock, Germany.
| | - Tobias Resch
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Rostock, Germany.
| | - Katrin Porath
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Rostock, Germany.
| | - Bernd Joachim Krause
- Department of Nuclear Medicine, Rostock University Medical Center, Rostock, Germany; Center for Transdisciplinary Neurosciences Rostock, Rostock University Medical Center, Rostock, Germany.
| | - Rüdiger Köhling
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Rostock, Germany; Center for Transdisciplinary Neurosciences Rostock, Rostock University Medical Center, Rostock, Germany.
| | - Falko Lange
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Rostock, Germany; Center for Transdisciplinary Neurosciences Rostock, Rostock University Medical Center, Rostock, Germany.
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Cardiac Arrest Induces Ischemic Long-Term Potentiation of Hippocampal CA1 Neurons That Occludes Physiological Long-Term Potentiation. Neural Plast 2018; 2018:9275239. [PMID: 29853851 PMCID: PMC5944194 DOI: 10.1155/2018/9275239] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/15/2018] [Accepted: 04/05/2018] [Indexed: 01/31/2023] Open
Abstract
Ischemic long-term potentiation (iLTP) is a form of synaptic plasticity that occurs in acute brain slices following oxygen-glucose deprivation. In vitro, iLTP can occlude physiological LTP (pLTP) through saturation of plasticity mechanisms. We used our murine cardiac arrest and cardiopulmonary resuscitation (CA/CPR) model to produce global brain ischemia and assess whether iLTP is induced in vivo, contributing to the functionally relevant impairment of pLTP. Adult male mice were subjected to CA/CPR, and slice electrophysiology was performed in the hippocampal CA1 region 7 or 30 days later. We observed increased miniature excitatory postsynaptic current amplitudes, suggesting a potentiation of postsynaptic AMPA receptor function after CA/CPR. We also observed increased phosphorylated GluR1 in the postsynaptic density of hippocampi after CA/CPR. These data support the in vivo induction of ischemia-induced plasticity. Application of a low-frequency stimulus (LFS) to CA1 inputs reduced excitatory postsynaptic potentials in slices from mice subjected to CA/CPR, while having no effects in sham controls. These results are consistent with a reversal, or depotentiation, of iLTP. Further, depotentiation with LFS partially restored induction of pLTP with theta burst stimulation. These data provide evidence for iLTP following in vivo ischemia, which occludes pLTP and likely contributes to network disruptions that underlie memory impairments.
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Status epilepticus alters hippocampal long-term synaptic potentiation in a rat lithium-pilocarpine model. Neuroreport 2018; 27:1191-5. [PMID: 27495218 DOI: 10.1097/wnr.0000000000000656] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Seizure-induced memory deficits are frequent in patients with temporal lobe epilepsy. However, the neural mechanisms responsible for this memory impairment are not entirely clear. Persistent changes in synaptic efficacy, long-term potentiation (LTP), and depression are considered a cellular substrate underlying the learning and memory processes. Using a lithium-pilocarpine model to induce status epilepticus (SE) in rats, the present study investigated whether the induction of LTP was altered in hippocampal slices obtained 3 h, 1, 3, and 7 days after SE. One week after SE, LTP induction was decreased in hippocampal slices. The reduced plasticity in post-SE tissue was attributable to N-methyl-D-aspartate receptor-dependent LTP. In contrast to control tissue, ifenprodil, a GluN2B-selective antagonist, did not reduce the LTP level in post-SE tissue, suggesting that SE disturbs the functional properties of GluN2B-containing N-methyl-D-aspartate receptors. These changes in synaptic transmission may contribute toward the genesis of epilepsy and seizure-associated memory deficits.
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Dammann F, Kirschstein T, Guli X, Müller S, Porath K, Rohde M, Tokay T, Köhling R. Bidirectional shift of group III metabotropic glutamate receptor-mediated synaptic depression in the epileptic hippocampus. Epilepsy Res 2017; 139:157-163. [PMID: 29224956 DOI: 10.1016/j.eplepsyres.2017.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 11/08/2017] [Accepted: 12/02/2017] [Indexed: 01/20/2023]
Abstract
A common function of group III metabotropic glutamate receptors (mGluRs) located at the presynaptic site of a glutamatergic synapse is synaptic depression. Here, we studied synaptic depression mediated by group III mGluR activation at Schaffer collateral-CA1 (SC-CA1) synapses and associational-commissural-CA3 (AC-CA3) synapses by recording field excitatory postsynaptic potentials in the in vitro brain slice preparation. In order to gauge the impact of synaptic depression in chronically epileptic tissue, we compared rats after pilocarpine-induced status epilepticus (post-SE) with control animals. We observed that synaptic transmission at control AC-CA3 synapses was sensitive to the group III mGluR agonist L-AP4 (10μM), while there was no effect of this compound at SC-CA1 synapses in the same tissue. In contrast, synaptic depression at AC-CA3 synapses by L-AP4 was lost in chronically epileptic tissue, and we found a significant synaptic depression at SC-CA1 synapses in post-SE tissue by L-AP4 and by the mGluR8-selective agonist DCPG. The depression by L-AP4 and DCPG in CA1 was also demonstrated in immature control tissue suggesting developmental down-regulation of mGluR8 at this synapse as well as re-appearance of this isoform under pathological conditions. Quantitative real-time RT-PCR was used to identify mGluR isoforms and to assess their transcriptional changes in post-SE tissue. These analyses revealed down-regulation of mGluR4 and mGluR6 at AC-CA3 and up-regulation of mGluR8 at SC-CA1 synapses. We conclude that group III mGluR-mediated synaptic depression is differentially altered in chronically epileptic tissue by a bidirectional shift of the transcriptional level.
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Affiliation(s)
- Fabian Dammann
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany.
| | - Xiati Guli
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Steffen Müller
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Katrin Porath
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Marco Rohde
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Tursonjan Tokay
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
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Functional Metaplasticity of Hippocampal Schaffer Collateral-CA1 Synapses Is Reversed in Chronically Epileptic Rats. Neural Plast 2017; 2017:8087401. [PMID: 29098091 PMCID: PMC5642871 DOI: 10.1155/2017/8087401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 07/27/2017] [Accepted: 08/27/2017] [Indexed: 11/17/2022] Open
Abstract
Spatial learning and associating spatial information with individual experience are crucial for rodents and higher mammals. Hence, studying the cellular and molecular cascades involved in the key mechanism of information storage in the brain, synaptic plasticity, has led to enormous knowledge in this field. A major open question applies to the interdependence between synaptic plasticity and its behavioral correlates. In this context, it has become clear that behavioral aspects may impact subsequent synaptic plasticity, a phenomenon termed behavioral metaplasticity. Here, we trained control and pilocarpine-treated chronically epileptic rats of two different age groups (adolescent and adult) in a spatial memory task and subsequently tested long-term potentiation (LTP) in vitro at Schaffer collateral-CA1 synapses. As expected, memory acquisition in the behavioral task was significantly impaired both in pilocarpine-treated animals and in adult controls. Accordingly, these groups, without being tested in the behavioral training task, showed reduced CA1-LTP levels compared to untrained young controls. Spatial memory training significantly reduced subsequent CA1-LTP in vitro in the adolescent control group yet enhanced CA1-LTP in the adult pilocarpine-treated group. Such training in the adolescent pilocarpine-treated and adult control groups resulted in intermediate changes. Our study demonstrates age-dependent functional metaplasticity following a spatial memory training task and its reversal under pathological conditions.
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Ivanov AD, Zaitsev AV. NMDAR-independent hippocampal long-term depression impairment after status epilepticus in a lithium-pilocarpine model of temporal lobe epilepsy. Synapse 2017; 71. [PMID: 28432779 DOI: 10.1002/syn.21982] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 03/29/2017] [Accepted: 04/13/2017] [Indexed: 11/07/2022]
Abstract
Temporal lobe epilepsy is usually associated with cognitive decline and memory deficits. Despite numerous existing studies on various animal models, the mechanisms of these deficits remain largely unclear. A specific form of long-term synaptic efficacy changes-long-term depression (LTD)-is thought to play an important role in memory formation and learning. However, extremely little is known about the possible alteration of LTD induction and dynamics after a status epilepticus (SE). In this work, we investigated the acute and delayed effects of lithium-pilocarpine-induced SE on NMDAR-dependent and NMDAR-independent hippocampal LTD in vitro. We found that SE affected the NMDAR-dependent and NMDAR-independent forms of LTD in different manners. The NMDAR-dependent form of LTD was almost intact 3 days after SE, but it switched from a predominantly presynaptic to a more postsynaptic locus of expression. In contrast, the NMDAR-independent LTD in the hippocampal Schaffer collaterals-CA1 synapses was fully abolished 3 days after SE. Our results emphasize the role of non-NMDA-dependent synaptic plasticity changes in the processes of epileptogenesis and the potential for therapy development.
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Affiliation(s)
- Andrey D Ivanov
- Neurophysiology of Learning Laboratory, Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences (IHNA), Moscow, Russia
| | - Aleksey V Zaitsev
- Molecular Mechanisms of Neuronal Interactions Laboratory, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences (IEPhB), Saint Petersburg, Russia.,Institute of Experimental Medicine, Federal Almazov North-West Medical Research Centre, Saint Petersburg, Russia
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