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Connolly MJ, Jiang S, Samuel LC, Gutekunst CA, Gross RE, Devergnas A. Seizure onset and offset pattern determine the entrainment of the cortex and substantia nigra in the nonhuman primate model of focal temporal lobe seizures. PLoS One 2024; 19:e0307906. [PMID: 39197026 PMCID: PMC11356443 DOI: 10.1371/journal.pone.0307906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 07/13/2024] [Indexed: 08/30/2024] Open
Abstract
Temporal lobe epilepsy (TLE) is the most common form of drug-resistant epilepsy. A major focus of human and animal studies on TLE network has been the limbic circuit. However, there is also evidence suggesting an active role of the basal ganglia in the propagation and control of temporal lobe seizures. Here, we characterize the involvement of the substantia nigra (SN) and somatosensory cortex (SI) during temporal lobe (TL) seizures induced by penicillin injection in the hippocampus (HPC) of two nonhuman primates. The seizure onset and offset patterns were manually classified and spectral power and coherence were calculated. We then compared the 3-second segments recorded in pre-ictal, onset, offset and post-ictal periods based on the seizure onset and offset patterns. Our results demonstrated an involvement of the SN and SI dependent on the seizure onset and offset pattern. We found that low amplitude fast activity (LAF) and high amplitude slow activity (HAS) onset patterns were associated with an increase in activity of the SN while the change in activity was limited to LAF seizures in the SI. However, the increase in HPC/SN coherence was specific to the farther-spreading LAF onset pattern. As for the role of the SN in seizure cessation, we observed that the coherence between the HPC/SN was reduced during burst suppression (BS) compared to other termination phases. Additionally, we found that this coherence returned to normal levels after the seizure ended, with no significant difference in post-ictal periods among the three types of seizure offsets. This study constitutes the first demonstration of TL seizures entraining the SN in the primate brain. Moreover, these findings provide evidence that this entrainment is dependent on the onset and offset pattern and support the hypothesis that the SN might play a role in the maintenance and termination of some specific temporal lobe seizure.
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Affiliation(s)
- Mark J. Connolly
- Emory National Primate Research Center, Emory University, Atlanta, GA, United States of America
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States of America
| | - Sujin Jiang
- Emory College of Arts & Sciences, Emory University, Atlanta, GA, United States of America
| | - Lim C. Samuel
- Emory College of Arts & Sciences, Emory University, Atlanta, GA, United States of America
| | - Claire-Anne Gutekunst
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, United States of America
| | - Robert E. Gross
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States of America
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, United States of America
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, United States of America
| | - Annaelle Devergnas
- Emory National Primate Research Center, Emory University, Atlanta, GA, United States of America
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States of America
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Connolly MJ, Jiang S, Samuel L, Gutekunst CA, Gross RE, Devergnas A. Seizure onset and offset pattern determine the entrainment of the cortex and substantia nigra in the nonhuman primate model of focal temporal lobe seizures. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.04.543608. [PMID: 37333298 PMCID: PMC10274660 DOI: 10.1101/2023.06.04.543608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Temporal lobe (TL) epilepsy is the most common form of drug-resistant epilepsy. A major focus of human and animal studies on TLE network has been the limbic circuit and the structures composing the temporal lobe. However, there is also evidence suggesting an active role of the basal ganglia in the propagation and control of temporal lobe seizures. Evidence suggests that the network involved in temporal lobe seizure may depend on their onset and offset pattern but studies on the relationship between the patterns and extralimbic activity are limited. Here, we characterize the involvement of the substantia nigra (SN) and somatosensory cortex (SI) during temporal lobe seizures induced in two nonhuman primates (NHP). The seizure onset and offset patterns were manually classified and spectral power and coherence were calculated. We then analyzed the three first and last seconds of the seizure as well as 3-second segments of recorded in pre-ictal and post-ictal periods and compared the changes based on the seizure onset and offset patterns. Our results demonstrated an involvement of the SN and SI dependent on the seizure onset and offset pattern. We found that seizures with both low amplitude fast activity (LAF) and high amplitude slow activity (HAS) onset patterns were associated with an increase in activity of the SN while the change in activity was limited to LAF seizures in the SI. However, the increase of HPC/SI coherence was similar for both type of onset, while the increase in HPC/SN coherence was specific to the farther-spreading LAF onset pattern. As for the role of the SN in seizure cessation, we observed that the coherence between the HPC/SN was reduced during burst suppression (BS) compared to other termination phases. Additionally, we found that this coherence returned to normal levels after the seizure ended, with no significant difference in post-ictal periods among the three types of seizure offsets. This result suggests that the SN might be involved differently in the termination of the BS seizure pattern. This study constitutes the first demonstration of temporal lobe seizures entraining the SN in the primate brain. Moreover, these findings provide evidence that this entrainment is dependent on the seizure onset pattern and support the hypothesis that the SN might play a role in the maintenance and termination of some specific temporal lobe seizure.
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Affiliation(s)
- Mark J. Connolly
- Emory National Primate Research Center, Emory University, Atlanta, GA 30329, USA
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Sujin Jiang
- Emory College of Arts & Sciences, Emory University, Atlanta, GA, 30322, USA
| | - Lim Samuel
- Emory College of Arts & Sciences, Emory University, Atlanta, GA, 30322, USA
| | - Claire-Anne Gutekunst
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Robert E. Gross
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Annaelle Devergnas
- Emory National Primate Research Center, Emory University, Atlanta, GA 30329, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
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Mensah-Brown KG, Naylor RM, Graepel S, Brinjikji W. Neuromodulation: What the neurointerventionalist needs to know. Interv Neuroradiol 2024:15910199231224554. [PMID: 38454831 DOI: 10.1177/15910199231224554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024] Open
Abstract
Neuromodulation is the alteration of neural activity in the central, peripheral, or autonomic nervous systems. Consequently, this term lends itself to a variety of organ systems including but not limited to the cardiac, nervous, and even gastrointestinal systems. In this review, we provide a primer on neuromodulation, examining the various technological systems employed and neurological disorders targeted with this technology. Ultimately, we undergo a historical analysis of the field's development, pivotal discoveries and inventions gearing this review to neuro-adjacent subspecialties with a specific focus on neurointerventionalists.
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Affiliation(s)
| | - Ryan M Naylor
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, USA
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MacKeigan D, Feja M, Gernert M. Chronic intermittent convection-enhanced delivery of vigabatrin to the bilateral subthalamic nucleus in an acute rat seizure model. Epilepsy Res 2024; 199:107276. [PMID: 38091904 DOI: 10.1016/j.eplepsyres.2023.107276] [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: 09/25/2023] [Revised: 11/16/2023] [Accepted: 12/05/2023] [Indexed: 01/13/2024]
Abstract
Targeted intracerebral drug delivery is an attractive experimental approach for the treatment of drug-resistant epilepsies. In this regard, the subthalamic nucleus (STN) represents a focus-independent target involved in the remote modulation and propagation of seizure activity. Indeed, acute and chronic pharmacological inhibition of the STN with vigabatrin (VGB), an irreversible inhibitor of GABA transaminase, has been shown to produce antiseizure effects. This effect, however, is lost over time as tolerance develops with chronic, continuous intracerebral pharmacotherapy. Here we investigated the antiseizure effects of chronic intermittent intra-STN convection-enhanced delivery of VGB in an acute rat seizure model focusing on circumventing tolerance development and preventing adverse effects. Timed intravenous pentylenetetrazol (PTZ) seizure threshold testing was conducted before and after implantation of subcutaneous drug pumps and bilateral intra-STN cannulas. Drug pumps infused vehicle or VGB twice daily (0.4 µg) or once weekly (2.5 µg, 5 µg) over three weeks. Putative adverse effects were evaluated and found to be prevented by intermittent compared to previous continuous VGB delivery. Clonic seizure thresholds were more clearly raised by intra-STN VGB compared to myoclonic twitch. Both twice daily and once weekly intra-STN VGB significantly elevated clonic seizure thresholds depending on dose and time point, with responder rates of up to 100% observed at tolerable doses. However, tolerance could not be completely avoided, as tolerance rates of 40-75% were observed with chronic VGB treatment. Results indicate that the extent of tolerance development after intermittent intra-STN VGB delivery varies depending on infusion dose and regimen.
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Affiliation(s)
- Devlin MacKeigan
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany; Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Bünteweg 2, D-30559 Hannover, Germany
| | - Malte Feja
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany; Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Bünteweg 2, D-30559 Hannover, Germany.
| | - Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany; Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Bünteweg 2, D-30559 Hannover, Germany.
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Metto AC, Telgkamp P, McLane-Svoboda AK, Gilad AA, Pelled G. Closed-loop neurostimulation via expression of magnetogenetics-sensitive protein in inhibitory neurons leads to reduction of seizure activity in a rat model of epilepsy. Brain Res 2023; 1820:148591. [PMID: 37748572 DOI: 10.1016/j.brainres.2023.148591] [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: 08/04/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/27/2023]
Abstract
On-demand neurostimulation has shown success in epilepsy patients with pharmacoresistant seizures. Seizures produce magnetic fields that can be recorded using magnetoencephalography. We developed a new closed-loop approach to control seizure activity based on magnetogenetics using the electromagnetic perceptive gene (EPG) that encodes a protein that responds to magnetic fields. The EPG transgene was expressed in inhibitory interneurons under the hDlx promoter and kainic acid was used to induce acute seizures. In vivo electrophysiological signals were recorded. We found that hDlx EPG rats exhibited a significant delay in the onset of first seizure (1142.72 ± 186.35 s) compared to controls (644.03 ± 15.06 s) and significantly less seizures (4.11 ± 1.03) compared to controls (8.33 ± 1.58). These preliminary findings suggest that on-demand activation of EPG expressed in inhibitory interneurons suppresses seizure activity, and magnetogenetics via EPG may be an effective strategy to alleviate seizure severity in a closed-loop, and cell-specific fashion.
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Affiliation(s)
- Abigael C Metto
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI, United States
| | - Petra Telgkamp
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, United States
| | - Autumn K McLane-Svoboda
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI, United States
| | - Assaf A Gilad
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI, United States; Department of Radiology, Michigan State University, East Lansing, MI, United States; Neuroscience Program, Michigan State University, East Lansing, MI, United States
| | - Galit Pelled
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, United States; Department of Radiology, Michigan State University, East Lansing, MI, United States; Neuroscience Program, Michigan State University, East Lansing, MI, United States.
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6
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MacKeigan D, Feja M, Meller S, Deking L, Javadova A, Veenhuis A, Felmy F, Gernert M. Long-lasting antiseizure effects of chronic intrasubthalamic convection-enhanced delivery of valproate. Neurobiol Dis 2023; 187:106321. [PMID: 37832796 DOI: 10.1016/j.nbd.2023.106321] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/25/2023] [Accepted: 10/10/2023] [Indexed: 10/15/2023] Open
Abstract
Intracerebral drug delivery is an experimental approach for the treatment of drug-resistant epilepsies that allows for pharmacological intervention in targeted brain regions. Previous studies have shown that targeted pharmacological inhibition of the subthalamic nucleus (STN) via modulators of the GABAergic system produces antiseizure effects. However, with chronic treatment, antiseizure effects are lost as tolerance develops. Here, we report that chronic intrasubthalamic microinfusion of valproate (VPA), an antiseizure medication known for its wide range of mechanisms of action, can produce long-lasting antiseizure effects over three weeks in rats. In the intravenous pentylenetetrazole seizure-threshold test, seizure thresholds were determined before and during chronic VPA application (480 μg/d, 720 μg/d, 960 μg/d) to the bilateral STN. Results indicate a dose-dependent variation in VPA-induced antiseizure effects with mean increases in seizure threshold of up to 33%, and individual increases of up to 150%. The lowest VPA dose showed a complete lack of tolerance development with long-lasting antiseizure effects. Behavioral testing with all doses revealed few, acceptable adverse effects. VPA concentrations were high in STN and low in plasma and liver. In vitro electrophysiology with bath applied VPA revealed a reduction in spontaneous firing rate, increased background membrane potential, decreased input resistance and a significant reduction in peak NMDA, but not AMPA, receptor currents in STN neurons. Our results suggest an advantage of VPA over purely GABAergic modulators in preventing tolerance development with chronic intrasubthalamic drug delivery and provide first mechanistic insights in intracerebral pharmacotherapy targeting the STN.
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Affiliation(s)
- Devlin MacKeigan
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Malte Feja
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
| | - Sebastian Meller
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Lillian Deking
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Amina Javadova
- Center for Systems Neuroscience, 30559 Hannover, Germany; Institute for Zoology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Alva Veenhuis
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Felix Felmy
- Center for Systems Neuroscience, 30559 Hannover, Germany; Institute for Zoology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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Gernert M, MacKeigan D, Deking L, Kaczmarek E, Feja M. Acute and chronic convection-enhanced muscimol delivery into the rat subthalamic nucleus induces antiseizure effects associated with high responder rates. Epilepsy Res 2023; 190:107097. [PMID: 36736200 DOI: 10.1016/j.eplepsyres.2023.107097] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/13/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023]
Abstract
Intracerebral drug delivery is an emerging treatment strategy aiming to manage seizures in patients with systemic drug-resistant epilepsies. In rat seizure and epilepsy models, the GABAA receptor agonist muscimol has shown powerful antiseizure potential when injected acutely into the subthalamic nucleus (STN), known for its capacity to provide remote control of different seizure types. However, chronic intrasubthalamic muscimol delivery required for long-term seizure suppression has not yet been investigated. We tested the hypothesis that chronic convection-enhanced delivery (CED) of muscimol into the STN produces long-lasting antiseizure effects in the intravenous pentylenetetrazole seizure threshold test in female rats. Acute microinjection was included to verify efficacy of intrasubthalamic muscimol delivery in this seizure model and caused significant antiseizure effects at 30 and 60 ng per hemisphere with a dose-dependent increase of responders and efficacy and only mild adverse effects compared to controls. For the chronic study, muscimol was bilaterally infused into the STN over three weeks at daily doses of 60, 300, or 600 ng per hemisphere using an implantable pump and cannula system. Chronic intrasubthalamic CED of muscimol caused significant long-lasting antiseizure effects for up to three weeks at 300 and 600 ng daily. Drug responder rate increased dose-dependently, as did drug tolerance rates. Transient ataxia and body weight loss were the main adverse effects. Drug distribution was comparable (about 2-3 mm) between acute and chronic delivery. This is the first study providing proof-of-concept that not only acute, but also chronic, continuous CED of muscimol into the STN raises seizure thresholds.
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Affiliation(s)
- Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany; Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Bünteweg 2, D-30559 Hannover, Germany.
| | - Devlin MacKeigan
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany; Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Bünteweg 2, D-30559 Hannover, Germany
| | - Lillian Deking
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany
| | - Edith Kaczmarek
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany
| | - Malte Feja
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany; Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Bünteweg 2, D-30559 Hannover, Germany.
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Yan H, Ren L, Yu T. Deep brain stimulation of the subthalamic nucleus for epilepsy. Acta Neurol Scand 2022; 146:798-804. [PMID: 36134756 DOI: 10.1111/ane.13707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/04/2022] [Indexed: 12/16/2022]
Abstract
Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a promising palliative option for patients with refractory epilepsy. However, crucial questions remain unanswered: Which patients are the optimal candidates? How, where, and when to stimulate the STN? And what is the mechanism of STN-DBS action on epilepsy? Thus, we reviewed the clinical evidence on the antiepileptic effects of STN-DBS and its possible mechanisms on drug-resistant epilepsy, its safety, and the factors influencing stimulation outcomes. This information may guide clinical decision-making. In addition, based on the current knowledge on the effect of STN-DBS on epilepsy, we suggest research that needs to be carried out in the future.
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Affiliation(s)
- Hao Yan
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Liankun Ren
- Department of Neurology, Comprehensive Epilepsy Center of Beijing, Beijing Key Laboratory of Neuromodulation, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Tao Yu
- Department of Functional Neurosurgery, Beijing Institute of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
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Bröer S. Not Part of the Temporal Lobe, but Still of Importance? Substantia Nigra and Subthalamic Nucleus in Epilepsy. Front Syst Neurosci 2020; 14:581826. [PMID: 33381016 PMCID: PMC7768985 DOI: 10.3389/fnsys.2020.581826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/09/2020] [Indexed: 01/15/2023] Open
Abstract
The most researched brain region in epilepsy research is the temporal lobe, and more specifically, the hippocampus. However, numerous other brain regions play a pivotal role in seizure circuitry and secondary generalization of epileptic activity: The substantia nigra pars reticulata (SNr) and its direct input structure, the subthalamic nucleus (STN), are considered seizure gating nuclei. There is ample evidence that direct inhibition of the SNr is capable of suppressing various seizure types in experimental models. Similarly, inhibition via its monosynaptic glutamatergic input, the STN, can decrease seizure susceptibility as well. This review will focus on therapeutic interventions such as electrical stimulation and targeted drug delivery to SNr and STN in human patients and experimental animal models of epilepsy, highlighting the opportunities for overcoming pharmacoresistance in epilepsy by investigating these promising target structures.
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Affiliation(s)
- Sonja Bröer
- Faculty of Veterinary Medicine, Institute of Pharmacology and Toxicology, Freie Universität Berlin, Berlin, Germany
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Gernert M, Feja M. Bypassing the Blood-Brain Barrier: Direct Intracranial Drug Delivery in Epilepsies. Pharmaceutics 2020; 12:pharmaceutics12121134. [PMID: 33255396 PMCID: PMC7760299 DOI: 10.3390/pharmaceutics12121134] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/18/2020] [Accepted: 11/21/2020] [Indexed: 02/06/2023] Open
Abstract
Epilepsies are common chronic neurological diseases characterized by recurrent unprovoked seizures of central origin. The mainstay of treatment involves symptomatic suppression of seizures with systemically applied antiseizure drugs (ASDs). Systemic pharmacotherapies for epilepsies are facing two main challenges. First, adverse effects from (often life-long) systemic drug treatment are common, and second, about one-third of patients with epilepsy have seizures refractory to systemic pharmacotherapy. Especially the drug resistance in epilepsies remains an unmet clinical need despite the recent introduction of new ASDs. Apart from other hypotheses, epilepsy-induced alterations of the blood-brain barrier (BBB) are thought to prevent ASDs from entering the brain parenchyma in necessary amounts, thereby being involved in causing drug-resistant epilepsy. Although an invasive procedure, bypassing the BBB by targeted intracranial drug delivery is an attractive approach to circumvent BBB-associated drug resistance mechanisms and to lower the risk of systemic and neurologic adverse effects. Additionally, it offers the possibility of reaching higher local drug concentrations in appropriate target regions while minimizing them in other brain or peripheral areas, as well as using otherwise toxic drugs not suitable for systemic administration. In our review, we give an overview of experimental and clinical studies conducted on direct intracranial drug delivery in epilepsies. We also discuss challenges associated with intracranial pharmacotherapy for epilepsies.
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Affiliation(s)
- Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany;
- Center for Systems Neuroscience, D-30559 Hannover, Germany
- Correspondence: ; Tel.: +49-(0)511-953-8527
| | - Malte Feja
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany;
- Center for Systems Neuroscience, D-30559 Hannover, Germany
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11
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Sirvanci S, Akakin D, Gulcebi İdrizoglu M, Kaya OT, Karamahmutoglu T, Turgan Aşık ZN, Onat F. Ultrastructural GABA immunogold labeling in the substantia nigra pars reticulata of kindled genetic absence epilepsy rats. Ultrastruct Pathol 2020; 44:379-386. [PMID: 33118420 DOI: 10.1080/01913123.2020.1839153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Genetic Absence Epilepsy Rats from Strasbourg (GAERS) is a well-known animal model of absence epilepsy and they are resistant to electrical kindling stimulations. The present study aimed to examine possible differences in gamma-aminobutyric acid (GABA) levels and synapse counts in the substantia nigra pars reticulata anterior (SNRa) and posterior (SNRp) regions between GAERS and Wistar rats receiving kindling stimulations. Animals in the kindling group either received six stimulations in the amygdala and had grade 2 seizures or they were kindled, having grade five seizures. Rats were decapitated one hour after the last stimulation. SNR regions were obtained after vibratome sectioning of the brain tissue. GABA immunoreactivity was detected by immunogold method and synapses were counted. Sections were observed by transmission electron microscope and analyzed by Image J program. GABA density in the SNRa region of fully kindled GAERS and Wistar groups increased significantly compared to that of their corresponding grade 2 groups. The number of synapses increased significantly in kindled and grade 2 GAERS groups, compared to kindled and grade 2 Wistar groups, respectively, in the SNRa region. GABA density in the SNRp region of kindled GAERS group increased significantly compared to that of GAERS grade 2 group. In the SNRp region, both kindled and grade 2 GAERS groups were found to have increased number of synapses compared to that of GAERS control group. We concluded that both SNRa and SNRp regions may be important in modulating resistance of GAERS to kindling stimulations.
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Affiliation(s)
- Serap Sirvanci
- Department of Histology and Embryology, School of Medicine, Marmara University , Maltepe, Turkey
| | - Dilek Akakin
- Department of Histology and Embryology, School of Medicine, Marmara University , Maltepe, Turkey
| | | | - Ozlem Tugce Kaya
- Department of Histology and Embryology, School of Medicine, Marmara University , Maltepe, Turkey
| | - Tugba Karamahmutoglu
- Department of Medical Pharmacology, School of Medicine, Marmara University , Maltepe, Turkey
| | - Zehra Nur Turgan Aşık
- Department of Medical Pharmacology, School of Medicine, Marmara University , Maltepe, Turkey
| | - Filiz Onat
- Department of Medical Pharmacology, School of Medicine, Marmara University , Maltepe, Turkey
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Aupy J, Ribot B, Dovero S, Biendon N, Nguyen TH, Porras G, Deffains M, Guehl D, Burbaud P. Acute Striato-Cortical Synchronization Induces Focal Motor Seizures in Primates. Cereb Cortex 2020; 30:6469-6480. [PMID: 32776091 DOI: 10.1093/cercor/bhaa212] [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: 03/03/2020] [Revised: 07/15/2020] [Accepted: 07/15/2020] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVE Whether the basal ganglia are involved in the cortical synchronization during focal seizures is still an open question. In the present study, we proposed to synchronize cortico-striatal activities acutely inducing striatal disinhibition, performing GABA-antagonist injections within the putamen in primates. METHOD Experiments were performed on three fascicularis monkeys. During each experimental session, low volumes of bicuculline (0.5-4 μL) were injected at a slow rate of 1 μL/min. Spontaneous behavioral changes were classified according to Racine's scale modified for primates. These induced motor behaviors were correlated with electromyographic, electroencephalographic, and putaminal and pallidal local field potentials changes in activity. RESULTS acute striatal desinhibition induced focal motor seizures. Seizures were closely linked to cortical epileptic activity synchronized with a striatal paroxysmal activity. These changes in striatal activity preceded the cortical epileptic activity and the induced myoclonia, and both cortical and subcortical activities were coherently synchronized during generalized seizures. INTERPRETATION Our results strongly suggest the role of the sensorimotor striatum in the regulation and synchronization of cortical excitability. These dramatic changes in the activity of this "gating" pathway might influence seizure susceptibility by modulating the threshold for the initiation of focal motor seizures.
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Affiliation(s)
- Jerome Aupy
- University of Bordeaux, Bordeaux Neurocampus, IMN, UMR CNRS 5293, 33076 Bordeaux, France.,Department of Clinical Neurosciences, Bordeaux University Hospital, 33076 Bordeaux, France
| | - Bastien Ribot
- University of Bordeaux, Bordeaux Neurocampus, IMN, UMR CNRS 5293, 33076 Bordeaux, France
| | - Sandra Dovero
- University of Bordeaux, Bordeaux Neurocampus, IMN, UMR CNRS 5293, 33076 Bordeaux, France
| | - Nathalie Biendon
- University of Bordeaux, Bordeaux Neurocampus, IMN, UMR CNRS 5293, 33076 Bordeaux, France
| | - Tho-Hai Nguyen
- University of Bordeaux, Bordeaux Neurocampus, IMN, UMR CNRS 5293, 33076 Bordeaux, France
| | - Gregory Porras
- University of Bordeaux, Bordeaux Neurocampus, IMN, UMR CNRS 5293, 33076 Bordeaux, France
| | - Marc Deffains
- University of Bordeaux, Bordeaux Neurocampus, IMN, UMR CNRS 5293, 33076 Bordeaux, France
| | - Dominique Guehl
- University of Bordeaux, Bordeaux Neurocampus, IMN, UMR CNRS 5293, 33076 Bordeaux, France.,Department of Clinical Neurosciences, Bordeaux University Hospital, 33076 Bordeaux, France
| | - Pierre Burbaud
- University of Bordeaux, Bordeaux Neurocampus, IMN, UMR CNRS 5293, 33076 Bordeaux, France.,Department of Clinical Neurosciences, Bordeaux University Hospital, 33076 Bordeaux, France
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Du T, Chen Y, Shi L, Liu D, Liu Y, Yuan T, Zhang X, Zhu G, Zhang J. Deep brain stimulation of the anterior nuclei of the thalamus relieves basal ganglia dysfunction in monkeys with temporal lobe epilepsy. CNS Neurosci Ther 2020; 27:341-351. [PMID: 33085171 PMCID: PMC7871793 DOI: 10.1111/cns.13462] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/19/2020] [Accepted: 09/21/2020] [Indexed: 12/20/2022] Open
Abstract
Aims Deep brain stimulation of the anterior nuclei of the thalamus (ANT‐DBS) is effective in temporal lobe epilepsy (TLE). Previous studies have shown that the basal ganglia are involved in seizure propagation in TLE, but the effects of ANT‐DBS on the basal ganglia have not been clarified. Methods ANT‐DBS was applied to monkeys with kainic acid–induced TLE using a robot‐assisted system. Behavior was monitored continuously. Immunofluorescence analysis and Western blotting were used to estimate protein expression levels in the basal ganglia and the effects of ANT stimulation. Results The seizure frequency decreased after ANT‐DBS. D1 and D2 receptor levels in the putamen and caudate were significantly higher in the ANT‐DBS group than in the epilepsy (EP) model. Neuronal loss and apoptosis were less severe in the ANT‐DBS group. Glutamate receptor 1 (GluR1) in the nucleus accumbens (NAc) shell and globus pallidus internus (GPi) increased in the EP group but decreased after ANT‐DBS. γ‐Aminobutyric acid receptor A (GABAA‐R) decreased and glutamate decarboxylase 67 (GAD67) increased in the GPi of the EP group, whereas the reverse tendencies were observed after ANT‐DBS. Conclusion ANT‐DBS exerts neuroprotective effects on the caudate and putamen, enhances D1 and D2 receptor expression, and downregulates GPi overactivation, which enhanced the antiepileptic function of the basal ganglia.
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Affiliation(s)
- Tingting Du
- Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Yingchuan Chen
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Lin Shi
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Defeng Liu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yuye Liu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Tianshuo Yuan
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xin Zhang
- Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Guanyu Zhu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jianguo Zhang
- Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Neurostimulation, Beijing, China
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Wang Y, Li Z. RNA-seq analysis of blood of valproic acid-responsive and non-responsive pediatric patients with epilepsy. Exp Ther Med 2019; 18:373-383. [PMID: 31258675 PMCID: PMC6566089 DOI: 10.3892/etm.2019.7538] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 04/09/2019] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is the most common chronic neurological disorder, affecting ~70 million individuals worldwide. However, approximately one-third of the patients are refractory to epilepsy medication. Of note, 100% of patients with genetic epilepsy who are resistant to the traditional drug, valproic acid (VPA), are also refractory to the other anti-epileptic drugs. The aim of the present study was to compare the transcriptomes in VPA responders and non-responders, to explore the mechanism of action of VPA and identify possible biomarkers to predict VPA resistance. Thus, RNA-seq was employed for transcriptomic analysis, differentially expressed genes (DEGs) were analyzed using Cuffdiff software and the DAVID database was used to infer the functions of the DEGs. A protein-protein interaction network was obtained using STRING and visualized with Cytoscape. A total of 389 DEGs between VPA-responsive and non-responsive pediatric patients were identified. Of these genes, 227 were upregulated and 162 were downregulated. The upregulated DEGs were largely associated with cytokines, chemokines and chemokine receptor-binding factors, whereas the downregulated DEGs were associated with cation channels, iron ion binding proteins, and immunoglobulin E receptors. In the pathway analysis, the toll-like receptor signaling pathway, pathways in cancer, and cytokine-cytokine receptor interaction were mostly enriched by the DEGs. Furthermore, three modules were identified by protein-protein interaction analysis, and the potential hub genes, chemokine (C-C motif) ligand 3 and 4, chemokine (C-X-C motif) ligand 9, tumor necrosis factor-α and interleukin-1β, which are known to be closely associated with epilepsy, were identified. These specific chemokines may participate in processes associated with VPA resistance and may be potential biomarkers for monitoring the efficacy of VPA.
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Affiliation(s)
- Yan Wang
- Department of Pharmacy, Children's Hospital of Fudan University, Shanghai 201102, P.R. China.,Hainan Provincial Key Lab of R&D of Tropical Herbs, College of Pharmacy, Hainan Medical University, Haikou, Hainan 571199, P.R. China
| | - Zhiping Li
- Department of Pharmacy, Children's Hospital of Fudan University, Shanghai 201102, P.R. China
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Yang H, Shan W, Zhu F, Yu T, Fan J, Guo A, Li F, Yang X, Wang Q. C-Fos mapping and EEG characteristics of multiple mice brain regions in pentylenetetrazol-induced seizure mice model. Neurol Res 2019; 41:749-761. [PMID: 31038018 DOI: 10.1080/01616412.2019.1610839] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Purpose: To confirm different local brain activities characterized in pentylenetetrazol (PTZ)-induced seizure model. Methods: we induced seizure response by a single dose of PTZ injection (45 mg/kg, i.p.). Local activity was recorded in different brain regions by EEG in time and c-Fos staining at different time points (0.5 h, 1 h, 2 h, 4 h) after PTZ treatment. Results: EEG recordings showed distinctive features of activation in different brain areas. With the aggravation of behavioral manifestations of seizures, the frequency and amplitude of the discharges on EEG were increasing gradually. The epileptic response on EEG immediately ended after reaching the maximum stage of seizures, followed by a short period of suppression. The labeling of c-Fos was enhanced in the medial prefrontal cortex, the piriform cortex, the amygdala, hippocampal CA1, CA3 and dentate gyrus, but inapparent in the striatum. The most potent changes in c-Fos were observed in cortex, amygdala nuclei, and dentate gyrus. EEG and c-Fos immunolabeling in neuronal activation showed discrepancies in the striatum. For each brain region, the maximum c-Fos labeling was observed at 2 h after injection and diminished at 4 h. The level of c-Fos immunoreactivity was even lower than the control group, which was accompanied by increased labeling of parvalbumin neurons (PVNs). Conclusions: These findings validated PTZ-induced seizure as a seizure model with a specific spatial-temporal profile. Neuronal activity was enhanced and then subsequently inhibited during seizure evolution. Abbreviations: AEDs: anti-epileptic drugs; AF: Alexa Fluor; CA1: Cornu Ammonis area 1; CA3: Cornu Ammonis area 3; DAB, 3: 3P-diaminobenzidine; DAPI: 4',6-diamidino-2-phenylindole; DG: dentate gyrus; EEG: electroencephalogram; GABA: gamma-aminobutyric acid; IEG: immediate early gene; mPFC: medial prefrontal cortex; NAc: nucleus accumbens; PB: phosphate buffer; PBS: phosphate buffered saline; PBST: phosphate buffered saline with Tween; PFA, paraformaldehyde; PTZ: pentylenetetrazol; PVN: parvalbumin neuron; ROI: regions of interest; SE: status epilepticus.
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Affiliation(s)
- Huajun Yang
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Wei Shan
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Fei Zhu
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Tingting Yu
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Jingjing Fan
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Anchen Guo
- b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
| | - Fei Li
- d Beijing institute of pharmacology and toxicology , Beijing , P.R.China
| | - Xiaofeng Yang
- b Beijing Institute for Brain Disorders , Beijing , P.R.China
| | - Qun Wang
- a Department of Neurology, Beijing Tiantan Hospital, Capital Medical University , Beijing , P.R.China.,b Beijing Institute for Brain Disorders , Beijing , P.R.China.,c National Center for Clinical Medicine of Neurological Diseases , Beijing , P.R.China
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Backofen-Wehrhahn B, Gey L, Bröer S, Petersen B, Schiff M, Handreck A, Stanslowsky N, Scharrenbroich J, Weißing M, Staege S, Wegner F, Niemann H, Löscher W, Gernert M. Anticonvulsant effects after grafting of rat, porcine, and human mesencephalic neural progenitor cells into the rat subthalamic nucleus. Exp Neurol 2018; 310:70-83. [PMID: 30205107 DOI: 10.1016/j.expneurol.2018.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/20/2018] [Accepted: 09/07/2018] [Indexed: 12/11/2022]
Abstract
Cell transplantation based therapy is a promising strategy for treating intractable epilepsies. Inhibition of the subthalamic nucleus (STN) or substantia nigra pars reticulata (SNr) is a powerful experimental approach for remote control of different partial seizure types, when targeting the seizure focus is not amenable. Here, we tested the hypothesis that grafting of embryonic/fetal neural precursor cells (NPCs) from various species (rat, human, pig) into STN or SNr of adult rats induces anticonvulsant effects. To rationally refine this approach, we included NPCs derived from the medial ganglionic eminence (MGE) and ventral mesencephalon (VM), both of which are able to develop a GABAergic phenotype. All VM- and MGE-derived cells showed intense migration behavior after grafting into adult rats, developed characteristics of inhibitory interneurons, and survived at least up to 4 months after transplantation. By using the intravenous pentylenetetrazole (PTZ) seizure threshold test in adult rats, transient anticonvulsant effects were observed after bilateral grafting of NPCs derived from human and porcine VM into STN, but not after SNr injection (site-specificity). In contrast, MGE-derived NPCs did not cause anticonvulsant effects after grafting into STN or SNr (cell-specificity). Neither induction of status epilepticus by lithium-pilocarpine to induce neuronal damage prior to the PTZ test nor pretreatment of MGE cells with retinoic acid and potassium chloride to increase differentiation into GABAergic neurons could enhance anticonvulsant effectiveness of MGE cells. This is the first proof-of-principle study showing anticonvulsant effects by bilateral xenotransplantation of NPCs into the STN. Our study highlights the value of VM-derived NPCs for interneuron-based cell grafting targeting the STN.
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Affiliation(s)
- Bianca Backofen-Wehrhahn
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Laura Gey
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Sonja Bröer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Björn Petersen
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Mariensee, Germany
| | - Miriam Schiff
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Annelie Handreck
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | | | - Jessica Scharrenbroich
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Michael Weißing
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Selma Staege
- Center for Systems Neuroscience, Hannover, Germany; Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Florian Wegner
- Center for Systems Neuroscience, Hannover, Germany; Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Heiner Niemann
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Mariensee, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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Vuong J, Devergnas A. The role of the basal ganglia in the control of seizure. J Neural Transm (Vienna) 2017; 125:531-545. [PMID: 28766041 DOI: 10.1007/s00702-017-1768-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/23/2017] [Indexed: 12/19/2022]
Abstract
Epilepsy is a network disorder and each type of seizure involves distinct cortical and subcortical network, differently implicated in the control and propagation of the ictal activity. The role of the basal ganglia has been revealed in several cases of focal and generalized seizures. Here, we review the data that show the implication of the basal ganglia in absence, temporal lobe, and neocortical seizures in animal models (rodent, cat, and non-human primate) and in human. Based on these results and the advancement of deep brain stimulation for Parkinson's disease, basal ganglia neuromodulation has been tested with some success that can be equally seen as promising or disappointing. The effect of deep brain stimulation can be considered promising with a 76% in seizure reduction in temporal lobe epilepsy patients, but also disappointing, since only few patients have become seizure free and the antiepileptic effects have been highly variable among patients. This variability could probably be explained by the heterogeneity among the patients included in these clinical studies. To illustrate the importance of specific network identification, electrophysiological activity of the putamen and caudate nucleus has been recorded during penicillin-induced pre-frontal and motor seizures in one monkey. While an increase of the firing rate was found in putamen and caudate nucleus during pre-frontal seizures, only the activity of the putamen cells was increased during motor seizures. These preliminary results demonstrate the implication of the basal ganglia in two types of neocortical seizures and the necessity of studying the network to identify the important nodes implicated in the propagation and control of each type of seizure.
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Affiliation(s)
- J Vuong
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Road NE, Atlanta, GA, 30329, USA
| | - Annaelle Devergnas
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Road NE, Atlanta, GA, 30329, USA. .,Department of Neurology, Emory University, Atlanta, GA, 30322, USA.
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Continuous bilateral infusion of vigabatrin into the subthalamic nucleus: Effects on seizure threshold and GABA metabolism in two rat models. Neurobiol Dis 2016; 91:194-208. [DOI: 10.1016/j.nbd.2016.03.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/07/2016] [Accepted: 03/10/2016] [Indexed: 01/26/2023] Open
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Low-frequency stimulation of the external globus palladium produces anti-epileptogenic and anti-ictogenic actions in rats. Acta Pharmacol Sin 2015; 36:957-65. [PMID: 26095038 DOI: 10.1038/aps.2015.45] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/07/2015] [Indexed: 01/03/2023] Open
Abstract
AIM To investigate the anti-epileptic effects of deep brain stimulation targeting the external globus palladium (GPe) in rats. METHODS For inducing amygdala kindling and deep brain stimulation, bipolar stainless-steel electrodes were implanted in SD rats into right basolateral amygdala and right GPe, respectively. The effects of deep brain stimulation were evaluated in the amygdala kindling model, maximal electroshock model (MES) and pentylenetetrazole (PTZ) model. Moreover, the background EEGs in the amygdala and GPe were recorded. RESULTS Low-frequency stimulation (0.1 ms, 1 Hz, 15 min) at the GPe slowed the progression of seizure stages and shortened the after-discharge duration (ADD) during kindling acquisition. Furthermore, low-frequency stimulation significantly decreased the incidence of generalized seizures, suppressed the average stage, and shortened the cumulative ADD and generalized seizure duration in fully kindled rats. In addition, low-frequency stimulation significantly suppressed the average stage of MES-induced seizures and increased the latency to generalized seizures in the PTZ model. High-frequency stimulation (0.1 ms, 130 Hz, 5 min) at the GPe had no anti-epileptic effect and even aggravated epileptogenesis induced by amygdala kindling. EEG analysis showed that low-frequency stimulation at the GPe reversed the increase in delta power, whereas high-frequency stimulation at the GPe had no such effect. CONCLUSION Low-frequency stimulation, but not high-frequency stimulation, at the GPe exerts therapeutic effect on temporal lobe epilepsy and tonic-colonic generalized seizures, which may be due to interference with delta rhythms. The results suggest that modulation of GPe activity using low-frequency stimulation or drugs may be a promising epilepsy treatment.
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Handreck A, Backofen-Wehrhahn B, Bröer S, Löscher W, Gernert M. Anticonvulsant Effects by Bilateral and Unilateral Transplantation of GABA-Producing Cells into the Subthalamic Nucleus in an Acute Seizure Model. Cell Transplant 2014. [DOI: 10.3727/096368912x658944] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Neural transplantation of GABA-producing cells into key structures within seizure-suppressing circuits holds promise for medication-resistant epilepsy patients not eligible for resection of the epileptic focus. The substantia nigra pars reticulata (SNr), a basal ganglia output structure, is well known to modulate different seizure types. A recent microinjection study by our group indicated that the subthalamic nucleus (STN), which critically regulates nigral activity, might be a more promising target for focal therapy in epilepsies than the SNr. As a proof of principle, we therefore assessed the anticonvulsant efficacy of bilateral and unilateral allografting of GABA-producing cell lines into the STN using the timed intravenous pentylenetetrazole seizure threshold test, which allows repeated seizure threshold determinations in individual rats. We observed (a) that grafted cells survived up to the end of the experiments, (b) that anticonvulsant effects can be induced by bilateral transplantation into the STN using immortalized GABAergic cells derived from the rat embryonic striatum and cells additionally transfected to obtain higher GABA synthesis than the parent cell line, and (c) that anticonvulsant effects were observed even after unilateral transplantation into the STN. Neither grafting of control cells nor transplantation outside the STN induced anticonvulsant effects, emphasizing the site and cell specificity of the observed anticonvulsant effects. To our knowledge, the present study is the first showing anticonvulsant effects by grafting of GABA-producing cells into the STN. The STN can be considered a highly promising target region for modulation of seizure circuits and, moreover, has the advantage of being clinically established for functional neurosurgery.
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Affiliation(s)
- Annelie Handreck
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Bianca Backofen-Wehrhahn
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
| | - Sonja Bröer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
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22
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Neurostimulation in the treatment of epilepsy. Exp Neurol 2013; 244:87-95. [DOI: 10.1016/j.expneurol.2013.04.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 04/04/2013] [Accepted: 04/08/2013] [Indexed: 11/24/2022]
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Intracranial Neurostimulation for Epilepsy. Can J Neurol Sci 2012. [DOI: 10.1017/s0317167100018126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Wu C, Sharan AD. Neurostimulation for the Treatment of Epilepsy: A Review of Current Surgical Interventions. Neuromodulation 2012; 16:10-24; discussion 24. [DOI: 10.1111/j.1525-1403.2012.00501.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bröer S, Backofen-Wehrhahn B, Bankstahl M, Gey L, Gernert M, Löscher W. Vigabatrin for focal drug delivery in epilepsy: Bilateral microinfusion into the subthalamic nucleus is more effective than intranigral or systemic administration in a rat seizure model. Neurobiol Dis 2012; 46:362-76. [DOI: 10.1016/j.nbd.2012.01.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 11/23/2011] [Accepted: 01/31/2012] [Indexed: 01/04/2023] Open
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Vignoli T, Nehlig A, Massironi SG, Coimbra RDCS, Mazzacoratti MDGN, Silva IR, Neto EFDC, Persike DS, Fernandes MJDS. Consequences of pilocarpine-induced status epilepticus in immunodeficient mice. Brain Res 2012; 1450:125-37. [PMID: 22405727 DOI: 10.1016/j.brainres.2012.02.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 02/01/2012] [Accepted: 02/12/2012] [Indexed: 12/16/2022]
Abstract
Systemic injection of pilocarpine in rodents induces status epilepticus (SE) and reproduces the main characteristics of temporal lobe epilepsy (TLE). Different mechanisms are activated by SE contributing to cell death and immune system activation. We used BALB/c nude mice, a mutant that is severely immunocompromised, to characterize seizure pattern, neurochemical changes, cell death and c-Fos activation secondarily to pilocarpine-induced SE. The behavioral seizures were less severe in BALB/c nude than in BALB/c wild type mice. However, nude mice presented more tonic-clonic episodes and higher mortality rate during SE. The c-Fos expression was most prominent in the caudate-putamen, CA3 (p<0.05), dentate gyrus, entorhinal cortex (p<0.001), basolateral nucleus of amygdala (p<0.01) and piriform cortex (p<0.05) of BALB/c nude mice than of BALB/c. Besides, nude mice subjected to SE presented high number of Fluorojade-B (FJB) stained cells in the piriform cortex, amygdala (p<0.05) and hilus (p<0.001) in comparison with BALB/c mice. A significant increase in the level of glutamate and GABA was found in the hippocampus and cortex of BALB/c mice presenting SE in comparison to controls. However, the level of glutamate was higher in the brains of BALB nude mice than in the brains of BALB/c wild type mice, while the levels of GABA were unchanged. These results indicate that the brains of immunodeficient nude mice are more vulnerable to the deleterious effects of pilocarpine-induced SE as they present intense activation, increased glutamate levels and more cell death.
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Affiliation(s)
- Thiago Vignoli
- Departamento de Neurologia e Neurocirurgia, Disciplina de Neurologia Experimental, Universidade Federal de São Paulo, SP, Brazil
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HAMANI CLEMENT, ANDRADE DANIELLE, HODAIE MOJGAN, WENNBERG RICHARD, LOZANO ANDRES. DEEP BRAIN STIMULATION FOR THE TREATMENT OF EPILEPSY. Int J Neural Syst 2011; 19:213-26. [DOI: 10.1142/s0129065709001975] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
During the last decade, deep brain stimulation (DBS) has been used to treat several neurologic disorders, including epilepsy. Promising results have been reported with stimulation in different brain regions. At present however, several issues remain unanswered. As an example, it is still unclear whether particular seizure types and syndromes should be treated with DBS in different targets or with different stimulation parameters. In addition, clinical, electrophysiological and anatomical features capable of predicting a good postoperative outcome are still unknown. We review the published literature on DBS, cortical and cerebellar stimulation for the treatment of epilepsy focusing predominantly on the rationale and clinical outcome in each target.
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Affiliation(s)
- CLEMENT HAMANI
- Division of Neurosurgery Toronto Western Hospital — University of Toronto, Division of Neurosurgery, Toronto Western Hospital, 399 Bathurst Street 4th floor WW, Toronto, ON, Canada
| | - DANIELLE ANDRADE
- Division of Neurology Toronto Western Hospital — University of, Toronto
| | - MOJGAN HODAIE
- Division of Neurosurgery Toronto Western Hospital — University of Toronto, Division of Neurosurgery, Toronto Western Hospital, 399 Bathurst Street 4th floor WW, Toronto, ON, Canada
| | - RICHARD WENNBERG
- Division of Neurology Toronto Western Hospital — University of, Toronto
| | - ANDRES LOZANO
- Division of Neurosurgery Toronto Western Hospital — University of Toronto, Division of Neurosurgery, Toronto Western Hospital, 399 Bathurst Street 4th floor WW, Toronto, ON, Canada
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Chronic bilateral subthalamic stimulation after anterior callosotomy in drug-resistant epilepsy: long-term clinical and functional outcome of two cases. Epilepsy Res 2011; 98:135-9. [PMID: 21962765 DOI: 10.1016/j.eplepsyres.2011.08.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 08/20/2011] [Accepted: 08/27/2011] [Indexed: 11/23/2022]
Abstract
We explored the efficacy and safety of bilateral SubThalamic Nucleus (STN) stimulation in two subjects suffering from drug-resistant epilepsy even after anterior callosotomy. Case 1 had about 65% decrease of partial motor seizures and the complete disappearance of tonic-clonic generalized attacks. Case 2, with sudden drop (atonic) attacks, partial complex seizures, atypical absences and rare tonic-clonic seizures, showed no meaningful reduction of fits and a stimulation associated atypical absence rate increase.
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Shehab S, Al-Nahdi A, Al-Zaabi F, Al-Mugaddam F, Al-Sultan M, Ljubisavljevic M. Effective inhibition of substantia nigra by deep brain stimulation fails to suppress tonic epileptic seizures. Neurobiol Dis 2011; 43:725-35. [DOI: 10.1016/j.nbd.2011.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/22/2011] [Accepted: 06/06/2011] [Indexed: 11/28/2022] Open
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Abstract
Abstract
Neuromodulation strategies have been proposed to treat a variety of neurological disorders, including medication-resistant epilepsy. Electrical stimulation of both central and peripheral nervous systems has emerged as a possible alternative for patients who are not deemed to be good candidates for resective procedures. In addition to well-established treatments such as vagus nerve stimulation, epilepsy centers around the world are investigating the safety and efficacy of neurostimulation at different brain targets, including the hippocampus, thalamus, and subthalamic nucleus. Also promising are the preliminary results of responsive neuromodulation studies, which involve the delivery of stimulation to the brain in response to detected epileptiform or preepileptiform activity. In addition to electrical stimulation, novel therapeutic methods that may open new horizons in the management of epilepsy include transcranial magnetic stimulation, focal drug delivery, cellular transplantation, and gene therapy. We review the current strategies and future applications of neuromodulation in epilepsy.
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Affiliation(s)
- Faisal A Al-Otaibi
- King Faisal Specialist Hospital & Research Centre, Neurosciences Department, Riyadh, Saudi Arabia
| | - Clement Hamani
- Division of Neurosurgery, Toronto Western Hospital, Toronto Western Research Institute, Ontario, Canada
| | - Andres M Lozano
- Division of Neurosurgery, Toronto Western Hospital, Toronto Western Research Institute, Ontario, Canada
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Abstract
Mesial temporal lobe epilepsy (MTLE) is characterized by focal seizures, associated with hippocampal sclerosis, and often resistance to antiepileptic drugs. The parafascicular nucleus (PF) of the thalamus is involved in the generation of physiological oscillatory rhythms. It receives excitatory inputs from the cortex and inhibitory inputs from the basal ganglia, a system implicated in the control of epileptic seizures. The aim of this study was to examine the involvement of the PF in the occurrence of hippocampal paroxysmal discharges (HPDs) in a chronic animal model of MTLE in male mice. We recorded the local field potential (LFP) and the extracellular and intracellular activity of hippocampal and PF neurons during spontaneous HPDs in vivo. The end of the HPDs was concomitant with a slow repolarization in hippocampal neurons leading to an electrical silence. In contrast, it was associated in the PF with a transient increase in the power of the 10-20 Hz band in LFPs and a depolarization of PF neurons resulting in a sustained firing. We tested the role of the PF in the control of HPDs by single 130 Hz electrical stimulation of this nucleus and bilateral intra-PF injection of NMDA and GABA(A) antagonist and agonist. High-frequency PF stimulation interrupted ongoing HPDs at an intensity devoid of behavioral effects. NMDA antagonist and GABA(A) agonist suppressed hippocampal discharges in a dose-dependent way, whereas NMDA agonist and GABA(A) antagonist increased HPDs. Altogether, these data suggest that the PF nucleus plays a role in the modulation of MTLE seizures.
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Castillo CG, Mendoza S, Saavedra J, Giordano M. Lack of effect of intranigral transplants of a GABAergic cell line on absence seizures. Epilepsy Behav 2010; 18:358-65. [PMID: 20634143 DOI: 10.1016/j.yebeh.2010.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 06/03/2010] [Accepted: 06/05/2010] [Indexed: 01/12/2023]
Abstract
The substantia nigra pars reticulata (SNpr) is involved in controlling a variety of seizure phenomena. Intranigral transplants of GABAergic cells have been shown to decrease the severity of already established epileptic seizures, but the effects observed have been short-lived. This study evaluated the ability of intranigral transplants of GABA-producing cells to reduce spontaneous absence seizures in a genetic animal model for periods up to 3 months after transplantation. Intranigral transplants did not induce any behavioral deficits in the animals, and they did not form tumors; however, the transplants failed to decrease absence seizures in the genetic model. The assumed increase in intranigral levels of GABA after the transplants may be insufficient to counteract all the factors involved in generating the absence seizures; in this animal model, it may be necessary to further decrease nigral activity by implanting GABAergic cells in another area. These results bear down on the fact that cell transplants need to be tailored for each type of convulsive disorder in terms of the type of cells delivered and the location of the transplants.
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Affiliation(s)
- Claudia G Castillo
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, México
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URINO T, HASHIZUME K, MAEHARA M, KATO K, OKADA Y, HORI T, TANAKA T. Epileptic Focus Stimulation and Seizure Control in the Rat Model of Kainic Acid-Induced Limbic Seizures. Neurol Med Chir (Tokyo) 2010; 50:355-60. [DOI: 10.2176/nmc.50.355] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Tomoyuki URINO
- Department of Neurosurgery, Tokyo Women's Medical University
| | | | - Michiyo MAEHARA
- Department of Clinical Laboratory, Tokyo Women's Medical University
| | - Kouichi KATO
- Department of Neurosurgery, Tokyo Women's Medical University
| | - Yoshikazu OKADA
- Department of Neurosurgery, Tokyo Women's Medical University
| | - Tomokatsu HORI
- Department of Neurosurgery, Tokyo Women's Medical University
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Szyndler J, Maciejak P, Turzyńska D, Sobolewska A, Taracha E, Skórzewska A, Lehner M, Bidziński A, Hamed A, Wisłowska-Stanek A, Krzaścik P, Płaźnik A. Mapping of c-Fos expression in the rat brain during the evolution of pentylenetetrazol-kindled seizures. Epilepsy Behav 2009; 16:216-24. [PMID: 19713157 DOI: 10.1016/j.yebeh.2009.07.030] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 07/17/2009] [Accepted: 07/18/2009] [Indexed: 11/24/2022]
Abstract
c-Fos protein immunocytochemistry was used to map the brain structures recruited during the evolution of seizures that follows repeated administration of a subconvulsive dose (35mg/kg, ip) of pentylenetetrazol in rats. c-Fos appeared earliest in nucleus accumbens shell, piriform cortex, prefrontal cortex, and striatum (stages 1 and 2 of kindling in comparison to control, saline-treated animals). At the third stage of kindling, central amygdala nuclei, entorhinal cortex, and lateral septal nuclei had enhanced concentrations of c-Fos. At the fourth stage of kindling, c-Fos expression was increased in basolateral amygdala and CA1 area of the hippocampus. Finally, c-Fos labeling was enhanced in the dentate gyrus of the hippocampus only when tonic-clonic convulsions were fully developed. The most potent changes in c-Fos were observed in dentate gyrus, piriform cortex, CA1, lateral septal nuclei, basolateral amygdala, central amygdala nuclei, and prefrontal cortex. Piriform cortex, entorhinal cortex, prefrontal cortex, lateral septal nuclei, and CA3 area of the hippocampus appeared to be the brain structures selectively involved in the process of chemically induced kindling of seizures.
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Affiliation(s)
- Janusz Szyndler
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Warsaw, Poland.
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Carçak N, Ferrandon A, Koning E, Aker RG, Ozdemir O, Onat FY, Nehlig A. Effect of stage 2 kindling on local cerebral blood flow rates in rats with genetic absence epilepsy. Epilepsia 2008; 50:33-43. [PMID: 18657179 DOI: 10.1111/j.1528-1167.2008.01712.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
PURPOSE Genetic absence epilepsy rats from Strasbourg (GAERS) are resistant to the progression of kindling seizures. We studied local cerebral blood flow (LCBF) changes in brain regions involved in seizures in both GAERS and nonepileptic rats (NEC) to map the differences that may be related to the resistance to kindling. METHODS Electrodes were implanted in the amygdala of adult NEC and GAERS male rats, which were stimulated to reach stage 2. Quantitative autoradiographic measurements of LCBF were performed by the [(14)C]-iodoantipyrine ([(14)C]IAP) autoradiographic technique allowing the precise mapping of regional perfusion changes. LCBF rates were measured bilaterally in 43 brain regions. The tracer infusion lasted for 60 s and started at 15 s before seizure induction. RESULTS Rates of LCBF increased in stimulated GAERS and NEC groups compared to nonstimulated controls. The LCBF increase in stimulated GAERS was larger and more widespread than that observed in stimulated NEC. The LCBF increase in the somatosensory cortex, ventrobasal and anterior thalamic nuclei, hypothalamus, subthalamic nucleus, piriform, entorhinal and perirhinal cortex, amygdala, CA2 region of hippocampus, and substantia nigra was statistically significantly larger in stimulated GAERS compared to stimulated NEC rats. CONCLUSION The results show that more brain regions are activated by kindling stimulation in GAERS. This widespread activation in GAERS involves the somatosensory cortex and thalamus, which are both known to be involved in the expression of absence seizures as well as numerous limbic regions thought not to play a role in the expression of absence seizures, suggesting an interaction between corticothalamocortical and limbic circuitries.
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Affiliation(s)
- Nihan Carçak
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
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Shi LH, Luo F, Woodward DJ, McIntyre DC, Chang JY. Temporal sequence of ictal discharges propagation in the corticolimbic basal ganglia system during amygdala kindled seizures in freely moving rats. Epilepsy Res 2006; 73:85-97. [PMID: 17049434 PMCID: PMC1941664 DOI: 10.1016/j.eplepsyres.2006.08.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 08/16/2006] [Accepted: 08/29/2006] [Indexed: 10/24/2022]
Abstract
We used a multiple channel, single unit recording technique to investigate the neural activity in different corticolimbic and basal ganglia regions in freely moving rats before and during generalized amygdala kindled seizures. Neural activity was recorded simultaneously in the sensorimotor cortex (Ctx), hippocampus, amygdala, substantia nigra pars reticulata (SNr) and the subthalamic nucleus (STN). We observed massive synchronized activity among neurons of different brain regions during seizure episodes. Neurons in the kindled amygdala led other regions in synchronized firing, revealed by time lags of neurons in other regions in crosscorrelogram analysis. While there was no obvious time lag between Ctx and SNr, the STN and hippocampus did lag behind the Ctx and SNr in correlated firing. Activity in the amygdala and SNr contralateral to the kindling stimulation site lagged behind their ipsilateral counterparts. However, no time lag was found between the kindling and contralateral sides of Ctx, hippocampus and STN. Our data confirm that the amygdala is an epileptic focus that emits ictal discharges to other brain regions. The observed temporal pattern indicates that ictal discharges from the amygdala arrive first at Ctx and SNr, and then spread to the hippocampus and STN. The simultaneous activation of both sides of the Ctx suggests that the neocortex participates in kindled seizures as a unisonant entity to provoke the clonic motor seizures. Early activation of the SNr (before the STN and hippocampus) points to an important role of the SNr in amygdala kindled seizures and supports the view that different SNr manipulations may be effective ways to control seizures.
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Affiliation(s)
- Li-Hong Shi
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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Handforth A, DeSalles AAF, Krahl SE. Deep brain stimulation of the subthalamic nucleus as adjunct treatment for refractory epilepsy. Epilepsia 2006; 47:1239-41. [PMID: 16886990 DOI: 10.1111/j.1528-1167.2006.00563.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE We studied the efficacy and safety of bilateral subthalamic deep brain stimulation (DBS) for refractory partial-onset epilepsy in two cases. METHODS This was an open treatment pilot study for subjects who had failed numerous medications and had seizure injuries. Seizure counts and adverse events were collected during a 3-4 month baseline, and for 26-32 months after DBS surgery, with AEDs held constant. RESULTS Case 1, age 45, with bitemporal seizures, had about half the seizure frequency but still fell with injuries. Case 2, age 46, with left frontal encephalomalacia, had a frequency reduction of about one-third, but a more meaningful reduction of seizure severity and injuries. CONCLUSIONS Subthalamic DBS partly reduced partial-onset seizures, but the quality of life was more affected by seizure-related injuries.
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Affiliation(s)
- Adrian Handforth
- Department of Neurology, VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA.
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Shehab SAS, Ljubisavljevic M, Al-Halhali F, Al-Awadhi A, Madathil M, Abdul-Kareem A, Redgrave P. Experimental manipulations of the subthalamic nucleus fail to suppress tonic seizures in the electroshock model of epilepsy. Exp Brain Res 2006; 173:274-81. [PMID: 16676172 DOI: 10.1007/s00221-006-0439-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2006] [Accepted: 03/07/2006] [Indexed: 12/18/2022]
Abstract
Recently, it has been shown that the subthalamic nucleus (STN) has anticonvulsant effects on epileptic seizures originating from the forebrain. The aim of the present study was to determine whether the anticonvulsant properties of the STN extend to the suppression of tonic seizures originating from the brainstem elicited by electroshock in rats. Three different procedures were used to manipulate activity in the STN and in each case the duration of tonic hindlimb extension elicited by electroshock was used as a measure of seizure-severity. Under general anesthesia, two groups of rats received chronic implants of either bilateral stainless steel guide cannulae or bilateral bipolar stimulating electrodes stereotaxically implanted and aimed at the STN. After 3 days of recovery, each rat in the first group was tested with electroshock on three consecutive days after having received 220 nl bilateral microinjections into the STN of either 200 or 400 pmol of muscimol (a GABA agonist) dissolved in saline or the same volume of normal saline. In the second group the electroshock test was conducted, again on three consecutive days, immediately following high frequency electrical stimulation (HFS) of the STN at 130 or 260 Hz or a no current control condition. In the third group, rats were tested with electroshock before and after bilateral excitotoxic lesions of the STN with either kainic or ibotenic acids. None of these manipulations produced significant suppression of the tonic hind limb extension elicited by electroshock compared with the relevant control conditions. This suggests that, within the limitations of the current procedures, the anticonvulsant properties of the STN appear to be ineffective against tonic seizures originating in the brainstem.
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Affiliation(s)
- S A S Shehab
- Department of Anatomy, Faculty of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al-Ain, UAE.
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Shi LH, Luo F, Woodward D, Chang JY. Deep brain stimulation of the substantia nigra pars reticulata exerts long lasting suppression of amygdala-kindled seizures. Brain Res 2006; 1090:202-7. [PMID: 16647692 DOI: 10.1016/j.brainres.2006.03.050] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 03/14/2006] [Accepted: 03/16/2006] [Indexed: 10/24/2022]
Abstract
Deep brain stimulation (DBS) has been used to treat a variety of neurological disorders including epilepsy. However, we have limited knowledge about effective target areas, optimal stimulation parameters, and long-term effect of DBS on epileptic seizures. Here we examined the effects of DBS of the substantia nigra pars reticulata (SNr) on amygdala-kindled seizures. Microwire electrodes were implanted into the SNr and amygdala of adult male rats. When stage 5-kindled seizures were achieved by daily amygdala kindling, high frequency stimulation was delivered to the SNr bilaterally 1 s after cessation of kindling. Our DBS protocol completely blocked kindled seizures in 10 out of 23 (43.5%) rats studied. Furthermore, when the same amygdala kindling procedure was performed 24 h later without DBS, the kindling failed to elicit any seizure signs in 6 of these 10 rats. Some of the post-DBS period of seizure suppression lasted for up to 4 days. In other 3 rats, only mild stage 1 to 2 seizures appeared following amygdala kindling. Only 1 of the 10 rats for which DBS had blocked kindled seizures exhibited full-scale 5 stage-kindled seizures 24 h after DBS. These results suggest that highly plastic neural networks are involved in amygdala-kindled seizures and that DBS, if well timed with the onset of amygdala kindling, may exert long lasting effects on the networks that may prevent the recurrence of kindled seizures.
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Affiliation(s)
- Li-Hong Shi
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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Chassagnon S, André V, Koning E, Ferrandon A, Nehlig A. Optimal window for ictal blood flow mapping. Insight from the study of discrete temporo-limbic seizures in rats. Epilepsy Res 2006; 69:100-18. [PMID: 16503120 DOI: 10.1016/j.eplepsyres.2006.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2005] [Revised: 01/16/2006] [Accepted: 01/16/2006] [Indexed: 10/25/2022]
Abstract
RATIONALE Measurement of local cerebral blood flow (LCBF) is routinely used to locate the areas involved in the generation and spread of seizures in epileptic patients. Since the spatial distribution and extent of ictal LCBF depends on the epileptogenic network, but also on the timing of injection of tracer, we used a rat model of amygdala kindled seizures to follow time-dependent changes in the distribution of seizure-induced LCBF changes. METHODS Rats were implanted with a left amygdala electrode and were stimulated until reaching stage 1. LCBF was measured by the quantitative [14C]iodoantipyrine autoradiographic technique. The tracer was injected either at 15 s before seizure induction (early ictal) or simultaneously with the amygdala stimulation (ictal) in rats undergoing a stage 0 or 1 seizure. RESULTS During stage 0 seizures, LCBF rates increased significantly ipsilaterally in medial and central amygdala and substantia nigra. During stage 1 seizures, LCBF increased unilaterally in amygdala, piriform cortex, substantia nigra, ventral tegmental area and cerebellum and bilaterally in several limbic and subcortical structures, excepted in hippocampus and pallidum. When pooling stages 0 and 1 but considering only tracer injection time, discrete LCBF changes occurred ipsilaterally in amygdala and substantia nigra at early ictal time. At true ictal time, significant changes occurred in several subcortical structures bilaterally while limbic structures displayed more localized and lateralized changes. CONCLUSION LCBF mapping appears unable to identify in rats the ictal onset zone of clinically significant amygdala-triggered seizures (stage 1), while the study of sub-clinical seizures (stage 0) allowed to correctly locate the amygdala onset of the seizures within the limbic network. Compared to human SPECT studies, this work confirms that some ictal hyperperfused areas belong to the spreading network rather than to the epileptogenic zone. The spatial recruitment of remote subcortical structures could be further investigated to strengthen the rationale of therapeutic stimulation of basal ganglia in drug-resistant epilepsies.
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Gernert M, Fedrowitz M, Wlaz P, Löscher W. Subregional changes in discharge rate, pattern, and drug sensitivity of putative GABAergic nigral neurons in the kindling model of epilepsy. Eur J Neurosci 2004; 20:2377-86. [PMID: 15525279 DOI: 10.1111/j.1460-9568.2004.03699.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The substantia nigra pars reticulata (SNr) is thought to act as a seizure-gating mechanism in kindling and other epilepsy models. We investigated whether the kindling process induces site-specific (anterior-posterior) and seizure-outlasting alterations in the activity of putative GABAergic SNr neurons and in their response to pharmacological manipulation. Female Wistar rats were kindled via the basolateral amygdala by daily stimulation. In vivo extracellular single unit recordings of SNr neurons were performed in kindled rats 1 day after a generalized seizure in order to examine activity changes that outlast the kindled seizures. Sham-kindled and naive rats served as controls. We found a significant and seizure-outlasting increase of discharge rates within the posterior but not within the anterior SNr of kindled rats when compared to controls. Furthermore, kindling resulted in seizure-outlasting burst-like firing pattern of SNr neurons. The antiepileptic drug valproic acid (VPA; 100 mg/kg i.v.) significantly reduced SNr discharge rates in all animal groups. Interestingly, neurons located in the anterior SNr of kindled rats were significantly less depressed by VPA compared to the reduction obtained in naive controls. The present data disclose kindling induced functional plasticity within basal ganglia regions. The findings are relevant for a better understanding of the mechanisms underlying the seizure-gating function of the SNr and might provide new targets for rational therapeutic manipulations, which aim to establish a remote control of epileptic seizures.
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Affiliation(s)
- Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Bünteweg 17, D-30559 Hannover, Germany.
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Morimoto K, Fahnestock M, Racine RJ. Kindling and status epilepticus models of epilepsy: rewiring the brain. Prog Neurobiol 2004; 73:1-60. [PMID: 15193778 DOI: 10.1016/j.pneurobio.2004.03.009] [Citation(s) in RCA: 613] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Accepted: 03/24/2004] [Indexed: 01/09/2023]
Abstract
This review focuses on the remodeling of brain circuitry associated with epilepsy, particularly in excitatory glutamate and inhibitory GABA systems, including alterations in synaptic efficacy, growth of new connections, and loss of existing connections. From recent studies on the kindling and status epilepticus models, which have been used most extensively to investigate temporal lobe epilepsy, it is now clear that the brain reorganizes itself in response to excess neural activation, such as seizure activity. The contributing factors to this reorganization include activation of glutamate receptors, second messengers, immediate early genes, transcription factors, neurotrophic factors, axon guidance molecules, protein synthesis, neurogenesis, and synaptogenesis. Some of the resulting changes may, in turn, contribute to the permanent alterations in seizure susceptibility. There is increasing evidence that neurogenesis and synaptogenesis can appear not only in the mossy fiber pathway in the hippocampus but also in other limbic structures. Neuronal loss, induced by prolonged seizure activity, may also contribute to circuit restructuring, particularly in the status epilepticus model. However, it is unlikely that any one structure, plastic system, neurotrophin, or downstream effector pathway is uniquely critical for epileptogenesis. The sensitivity of neural systems to the modulation of inhibition makes a disinhibition hypothesis compelling for both the triggering stage of the epileptic response and the long-term changes that promote the epileptic state. Loss of selective types of interneurons, alteration of GABA receptor configuration, and/or decrease in dendritic inhibition could contribute to the development of spontaneous seizures.
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Affiliation(s)
- Kiyoshi Morimoto
- Department of Neuropsychiatry, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan
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Chapter 77 Brain stimulation: current clinical indications and future prospects. ADVANCES IN CLINICAL NEUROPHYSIOLOGY, PROCEEDINGS OF THE 27TH INTERNATIONAL CONGRESS OF CLINICAL NEUROPHYSIOLOGY, AAEM 50TH ANNIVERSARY AND 57TH ANNUAL MEETING OF THE ACNS JOINT MEETING 2004. [DOI: 10.1016/s1567-424x(09)70413-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Lado FA, Velísek L, Moshé SL. The effect of electrical stimulation of the subthalamic nucleus on seizures is frequency dependent. Epilepsia 2003; 44:157-64. [PMID: 12558568 DOI: 10.1046/j.1528-1157.2003.33802.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Animal studies and anecdotal human case reports have indicated that the subthalamic nucleus (STN) may be a site of anticonvulsant action. METHODS We tested the hypothesis that continuous electrical stimulation of the STN inhibits seizures acutely. We determined the effects of three stimulation frequencies, 130 Hz, 260 Hz, and 800 Hz, on generalized clonic and tonic-clonic flurothyl seizures. Adult male rats were implanted with concentric bipolar stimulating electrodes in the STN bilaterally. After recovery, rats underwent flurothyl seizures to compare the effects of each stimulation frequency on seizure threshold. Rats were tested 4 times, twice in the stimulated condition, and twice in the unstimulated condition. The order of trials was random, except that stimulation trials alternated with control trials. Flurothyl seizure thresholds under each stimulation condition were compared with control values from the same animal. RESULTS Bilateral stimulation of the STN at 130 Hz produced a significant increase in the seizure threshold for clonic flurothyl seizures, whereas stimulation at 260 Hz did not appear to have any effect on seizures. STN stimulation at 800 Hz significantly lowered seizure threshold for tonic-clonic seizures. CONCLUSIONS We conclude that electrical stimulation of the STN can be anticonvulsant, but the effects appear to depend on the stimulation frequency and the type of seizure.
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Affiliation(s)
- Fred A Lado
- Department of Neurology, Comprehensive Epilepsy Management Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, U.S.A.
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Bressand K, Dematteis M, Ming Gao D, Vercueil L, Louis Benabid A, Benazzouz A. Superior colliculus firing changes after lesion or electrical stimulation of the subthalamic nucleus in the rat. Brain Res 2002; 943:93-100. [PMID: 12088842 DOI: 10.1016/s0006-8993(02)02541-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent data have suggested a critical role for the basal ganglia in the remote control of epileptic seizures. In particular, it has been shown that inhibition of either substantia nigra pars reticulata or subthalamic nucleus as well as activation of the superior colliculus suppresses generalized seizures in several animal models. It was previously shown that high frequency stimulation of the subthalamic nucleus, thought to act as functional inhibition, stopped ongoing non-convulsive generalized seizures in rats. In order to determine whether high frequency stimulation of the subthalamic nucleus involved an activation of superior colliculus neurons, we examined the effects of subthalamic nucleus manipulation, by either high frequency stimulation or chemical lesion, on the spontaneous electrical activity of superior colliculus neurons. Acute high frequency stimulation of the subthalamic nucleus (frequency 130 Hz) induced an immediate increase of unitary activity in 70% of responding cells, mainly located within the deep layers, whereas a reduction was observed in the remaining 30%. The latter responses are dependent on the intensity and frequency of the stimulation. Unilateral excitotoxic lesion of the subthalamic nucleus induced a delayed and transient decrease of superior colliculus activity. Our data suggest that high frequency stimulation of the subthalamic nucleus suppresses generalised epileptic seizures through superior colliculus activation.
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Affiliation(s)
- Karine Bressand
- Laboratoire de Neurobiologie Préclinique, INSERM U318, Centre Hospitalier Universitaire, Grenoble, France.
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46
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Rektor I, Kuba R, Brázdil M. Interictal and ictal EEG activity in the basal ganglia: an SEEG study in patients with temporal lobe epilepsy. Epilepsia 2002; 43:253-62. [PMID: 11906510 DOI: 10.1046/j.1528-1157.2002.28001.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE The interictal and ictal EEG activity in the basal ganglia in patients with temporal lobe epilepsy were studied during invasive EEG monitoring. METHODS Eight epilepsy surgery candidates, each with a proven mesiotemporal seizure-onset zone, participated in the study. We used two invasive EEG methods to determine the seizure-onset zone. In both methods, diagonal electrodes were targeted into the amygdalohippocampal complex via a frontal approach and were passed through the basal ganglia with several leads. We analyzed 16 partial epileptic seizures, four of which became secondarily generalized. RESULTS No epileptic interictal or ictal discharges were noticed in the basal ganglia. The interictal activity in the basal ganglia was a mixture of low-voltage beta activity and medium-voltage alpha-theta activity. When the ictal paroxysmal activity remained localized to the seizure-onset zone, the activity of the basal ganglia did not change. The spread of epileptic activity to other cortical structures was associated with the basal ganglia EEG slowing to a theta-delta range of 3-7 Hz. This slowing was dependent on the spread of ictal discharge within the ipsilateral temporal lobe (related to the investigated basal ganglia structures); alternatively, the slowing occurred in association with the regional spread of ictal activity from the mesiotemporal region to the temporal neocortex contralaterally to the investigated basal ganglia. Secondary generalization was associated with a further slowing of basal ganglia activity. CONCLUSIONS The basal ganglia do not generate specific epileptic EEG activity. Despite the absence of spikes, the basal ganglia participate in changing or reflect changes in the distribution of the ictal epileptic activity.
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Affiliation(s)
- Ivan Rektor
- Epilepsy Centre, 1st Department of Neurology, Masaryk University, St. Anne's Hospital, Brno, Czech Republic.
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47
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Hamani C, Sakabe S, Bortolotto ZA, Cavalheiro EA, Mello LEAM. Inhibitory role of the zona incerta in the pilocarpine model of epilepsy. Epilepsy Res 2002; 49:73-80. [PMID: 11948009 DOI: 10.1016/s0920-1211(02)00017-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recent experiments have suggested that the zona incerta might be regarded as a highly sensitive structure for seizure induction. This sensitivity has been linked to this structure's abundant expression of cholinergic receptors. Here we have decided to investigate the participation of the GABAergic system of the zona incerta, one of its major neurotransmitters with widespread projections to the neocortex, in the pilocarpine (Pilo) model of epilepsy. Stereotaxic administration of a GABA(A) agonist (muscimol), antagonist (bicuculline) or saline (controls) bilaterally into the zona incerta of adult male Wistar rats was performed 30 min prior to the systemic injection of pilocarpine. Animals were electroencephalographically and behaviorally monitored for seizure activity. Administration of muscimol had a pro-convulsant effect characterised by a higher percentage of animals developing SE with a shorter latency. Conversely, administration of bicuculline had a dose dependent anticonvulsant effect, with no animals displaying SE. Our results contribute to the further characterisation of the regulatory role of the zona incerta in seizure-related phenomena, suggesting that its modulation might be a relevant target for anticonvulsant strategies.
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Affiliation(s)
- Clement Hamani
- Depto de Fisiologia, EPM-UNIFESP, -SP 04023-900, Sao Paulo, Brazil.
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48
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Loddenkemper T, Pan A, Neme S, Baker KB, Rezai AR, Dinner DS, Montgomery EB, Lüders HO. Deep brain stimulation in epilepsy. J Clin Neurophysiol 2001; 18:514-32. [PMID: 11779965 DOI: 10.1097/00004691-200111000-00002] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Since the pioneering studies of Cooper et al. to influence epilepsy by cerebellar stimulation, numerous attempts have been made to reduce seizure frequency by stimulation of deep brain structures. Evidence from experimental animal studies suggests the existence of a nigral control of the epilepsy system. It is hypothesized that the dorsal midbrain anticonvulsant zone in the superior colliculi is under inhibitory control of efferents from the substantia nigra pars reticulata. Inhibition of the subthalamic nucleus (STN) could release the inhibitory effect of the substantia nigra pars reticulata on the dorsal midbrain anticonvulsant zone and thus activate the latter, raising the seizure threshold. Modulation of the seizure threshold by stimulation of deep brain structures-in particular, of the STN-is a promising future treatment option for patients with pharmacologically intractable epilepsy. Experimental studies supporting the existence of the nigral control of epilepsy system and preliminary results of STN stimulation in animals and humans are reviewed, and alternative mechanisms of seizure suppression by STN stimulation are discussed.
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Affiliation(s)
- T Loddenkemper
- Department of Neurology, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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49
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Deransart C, Lê-Pham BT, Hirsch E, Marescaux C, Depaulis A. Inhibition of the substantia nigra suppresses absences and clonic seizures in audiogenic rats, but not tonic seizures: evidence for seizure specificity of the nigral control. Neuroscience 2001; 105:203-11. [PMID: 11483312 DOI: 10.1016/s0306-4522(01)00165-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
GABAergic inhibition of the substantia nigra pars reticulata has been shown to suppress seizures in most models of epilepsy involving forebrain networks, such as absences or clonic seizures. No such antiepileptic effects were observed, however, in genetically audiogenic rats exhibiting tonic seizures generated in the brainstem. This suggests a constitutive dysfunction of the nigral GABAergic neurotransmission in this strain of rat or a selective action of the nigral control on specific networks. In the present study, we first confirmed that bilateral injection of muscimol (700 pmol/side) in the substantia nigra had no effect in Wistar rats with audiogenic seizures (Wistar AS). [3H]Muscimol autoradiography suggested a 40% reduced density of GABA(A) receptors in the substantia nigra of Wistar AS, whereas no change was observed in the cortex and the superior colliculus (superficial and intermediate layers), as compared to control animals. In Wistar AS where 40 repetitions of audiogenic stimulations progressively induced generalised convulsive seizures with both tonic and clonic components, bilateral injection of muscimol (350 pmol/side) in the substantia nigra suppressed the clonic component but had no effect on tonic seizures. In hybrid rats issued from cross-breeding between Wistar AS and rats with spontaneous absence seizures, bilateral injection of muscimol (18 pmol/side) in the substantia nigra abolished cortical spike-and-wave discharges, but had no effect on tonic audiogenic seizures at doses up to 700 pmol/side. These results show that despite a decreased number of GABA(A) receptors in the substantia nigra, inhibition of this structure in Wistar AS still leads to inhibition of seizures involving forebrain structures. These results confirm that GABAergic inhibition of the substantia nigra has antiepileptic effects through the control of forebrain circuits. They suggest that this control mechanism has no inhibitory effect on circuits underlying audiogenic tonic seizures.
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Affiliation(s)
- C Deransart
- Klinikum der Albert-ludwigs-Universität, Neurozentrum, Freiburg-im-Breisgau, Germany
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50
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Kodama M, Yamada N, Sato K, Sato T, Morimoto K, Kuroda S. The insular but not the perirhinal cortex is involved in the expression of fully-kindled amygdaloid seizures in rats. Epilepsy Res 2001; 46:169-78. [PMID: 11463518 DOI: 10.1016/s0920-1211(01)00279-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously reported an important excitatory role of the perirhinal cortex (PRC) in rat kindling development using an immunohistochemistry technique. In this study, we investigated the roles of the PRC and the insular cortex (INS) located rostral to the PRC, in fully-kindled amygdaloid seizures, using a microinjection technique in the rat kindling model of epilepsy. Following the establishment of daily kindling, we investigated the effects of microinjections of procaine hydrochloride, 2-amino-5-phosphonovalerate (APV; an N-methyl-D-aspartate (NMDA) receptor antagonist) and 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)-quinoxaline (NBQX; an alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) receptor antagonist). Microinjections of these drugs into the ipsilateral PRC did not suppress kindled seizures. The possibility is that the process of kindling development forms novel seizure-generalization pathways that do not require further activation of the PRC. On the other hand, procaine and APV injected into the ipsilateral INS significantly suppressed kindled seizures. The manner of suppression appeared to be 'all or none'. It is therefore possible that at least the activation of NMDA receptors in the INS is necessary to express generalized kindled amygdaloid seizures.
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Affiliation(s)
- M Kodama
- Department of Neuropsychiatry, Okayama University Medical School, 2-5-1 Shikata-cho, Okayama-city, 700-8558, Okayama, Japan
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