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Toplu A, Mutlu N, Erdeve ET, Sariyildiz Ö, Çelik M, Öz-Arslan D, Akman Ö, Molnár Z, Çarçak N, Onat F. Involvement of orexin type-2 receptors in genetic absence epilepsy rats. Front Neurol 2023; 14:1282494. [PMID: 38107640 PMCID: PMC10721972 DOI: 10.3389/fneur.2023.1282494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 11/10/2023] [Indexed: 12/19/2023] Open
Abstract
Introduction Orexin is a neuropeptide neurotransmitter that regulates the sleep/wake cycle produced by the lateral hypothalamus neurons. Recent studies have shown the involvement of orexin system in epilepsy. Limited data is available about the possible role of orexins in the pathophysiology of absence seizures. This study aims to understand the role of orexinergic signaling through the orexin-type 2 receptor (OX2R) in the pathophysiology of absence epilepsy. The pharmacological effect of a selective OX2R agonist, YNT-185 on spike-and-wave-discharges (SWDs) and the OX2R receptor protein levels in the cortex and thalamus in adult GAERS were investigated. Methods The effect of intracerebroventricular (ICV) (100, 300, and 600 nmol/10 μL), intrathalamic (30 and 40 nmol/500 nL), and intracortical (40 nmol/500 nL) microinjections of YNT-185 on the duration and number of spontaneous SWDs were evaluated in adult GAERS. The percentage of slow-wave sleep (SWS) and spectral characteristics of background EEG were analyzed after the ICV application of 600 nmol YNT-185. The level of OX2R expression in the somatosensory cortex and projecting thalamic nuclei of adult GAERS were examined by Western blot and compared with the non-epileptic Wistar rats. Results We showed that ICV administration of YNT-185 suppressed the cumulative duration of SWDs in GAERS compared to the saline-administered control group (p < 0.05). However, intrathalamic and intracortical microinjections of YNT-185 did not show a significant effect on SWDs. ICV microinjections of YNT-185 affect sleep states by increasing the percentage of SWS and showed a significant treatment effect on the 1-4 Hz delta frequency band power during the 1-2 h post-injection period where YNT-185 significantly decreased the SWDs. OXR2 protein levels were significantly reduced in the cortex and thalamus of GAERS when compared to Wistar rats. Conclusion This study investigated the efficacy of YNT-185 for the first time on absence epilepsy in GAERS and revealed a suppressive effect of OX2R agonist on SWDs as evidenced by the significantly reduced expression of OX2R in the cortex and thalamus. YNT-185 effect on SWDs could be attributed to its regulation of wake/sleep states. The results constitute a step toward understanding the effectiveness of orexin neuropeptides on absence seizures in GAERS and might be targeted by therapeutic intervention for absence epilepsy.
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Affiliation(s)
- Aylin Toplu
- Department of Medical Pharmacology, School of Medicine, Marmara University, Istanbul, Türkiye
- Department of Neuroscience, Health Sciences Institute, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
| | - Nursima Mutlu
- Department of Molecular Biotechnology and Genetics, Institute of Science, Istanbul University, Istanbul, Türkiye
| | - Elif Tuğçe Erdeve
- Department of Pharmacology, Health Sciences Institute, Istanbul University, Istanbul, Türkiye
| | - Özge Sariyildiz
- Department of Neuroscience, Health Sciences Institute, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
| | - Musa Çelik
- Department of Biophysics, Health Sciences Institute, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
| | - Devrim Öz-Arslan
- Department of Neuroscience, Health Sciences Institute, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
- Department of Biophysics, Health Sciences Institute, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
- Department of Biophysics, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
| | - Özlem Akman
- Department of Physiology, Faculty of Medicine, Demiroglu Bilim University, Istanbul, Türkiye
| | - Zoltan Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Nihan Çarçak
- Department of Neuroscience, Health Sciences Institute, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Türkiye
| | - Filiz Onat
- Department of Neuroscience, Health Sciences Institute, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
- Department of Medical Pharmacology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
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King H, Reiber M, Philippi V, Stirling H, Aulehner K, Bankstahl M, Bleich A, Buchecker V, Glasenapp A, Jirkof P, Miljanovic N, Schönhoff K, von Schumann L, Leenaars C, Potschka H. Anesthesia and analgesia for experimental craniotomy in mice and rats: a systematic scoping review comparing the years 2009 and 2019. Front Neurosci 2023; 17:1143109. [PMID: 37207181 PMCID: PMC10188949 DOI: 10.3389/fnins.2023.1143109] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/27/2023] [Indexed: 05/21/2023] Open
Abstract
Experimental craniotomies are a common surgical procedure in neuroscience. Because inadequate analgesia appears to be a problem in animal-based research, we conducted this review and collected information on management of craniotomy-associated pain in laboratory mice and rats. A comprehensive search and screening resulted in the identification of 2235 studies, published in 2009 and 2019, describing craniotomy in mice and/or rats. While key features were extracted from all studies, detailed information was extracted from a random subset of 100 studies/year. Reporting of perioperative analgesia increased from 2009 to 2019. However, the majority of studies from both years did not report pharmacologic pain management. Moreover, reporting of multimodal treatments remained at a low level, and monotherapeutic approaches were more common. Among drug groups, reporting of pre- and postoperative administration of non-steroidal anti-inflammatory drugs, opioids, and local anesthetics in 2019 exceeded that of 2009. In summary, these results suggest that inadequate analgesia and oligoanalgesia are persistent issues associated with experimental intracranial surgery. This underscores the need for intensified training of those working with laboratory rodents subjected to craniotomies. Systematic review registration https://osf.io/7d4qe.
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Affiliation(s)
- Hannah King
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Maria Reiber
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Vanessa Philippi
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Helen Stirling
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Katharina Aulehner
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Marion Bankstahl
- Hannover Medical School, Institute for Laboratory Animal Science, Hanover, Germany
| | - André Bleich
- Hannover Medical School, Institute for Laboratory Animal Science, Hanover, Germany
| | - Verena Buchecker
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Aylina Glasenapp
- Hannover Medical School, Institute for Laboratory Animal Science, Hanover, Germany
| | - Paulin Jirkof
- Office for Animal Welfare and 3Rs, University of Zurich, Zurich, Switzerland
| | - Nina Miljanovic
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Katharina Schönhoff
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Lara von Schumann
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
| | - Cathalijn Leenaars
- Hannover Medical School, Institute for Laboratory Animal Science, Hanover, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilian University of Munich, Munich, Germany
- *Correspondence: Heidrun Potschka,
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Çarçak N, Karanfil C, Akat Ş, Akman Ö, Onat F. The effect of chronic treatment with sodium channel blocker lacosamide on early development of absence seizures in genetic absence epilepsy rats. Epilepsy Res 2022; 182:106896. [DOI: 10.1016/j.eplepsyres.2022.106896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 02/07/2022] [Accepted: 03/04/2022] [Indexed: 11/03/2022]
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Onat FY, Eşkazan E. Are Absence and Limbic Seizures Mutually Exclusive?: An Experimental Approach to Enigmatic Clinical Concept. JOURNAL OF PEDIATRIC EPILEPSY 2021. [DOI: 10.1055/s-0041-1722870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AbstractThe impressive advances in the several disciplines including neurophysiology, molecular biology, neuroimmunology, neurogenetics, neuroimaging, and neuropharmacology of epilepsies have been stimulating a mutual interaction among basic scientists, clinicians, and professionals from other disciplines, leading to the identification of clinical questions and then the design of basic science paradigms to test enigmatic clinical issues. Based on a clinical observation that the coexistence of genetic (idiopathic) generalized typical absence and mesial temporal lobe epilepsy in the same patient is extremely rare and debatable, we addressed the rare coexistence in the same individual, designed an experimental approach to test the validity of this clinical concept and to study the underlying mechanisms involved. Here we presented evidence of a mutual cross-interaction in the circuits involved in typical absence and temporal lobe epilepsy. This article delineates a phenomenological picture and comprehends a theoretical understanding of a mutual cross-interaction in typical absence as a representative of genetic generalized epilepsies and limbic epilepsy in which seizures often start from the mesial temporal lobe.
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Affiliation(s)
- Filiz Yılmaz Onat
- Department of Medical Pharmacology, School of Medicine, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Turkey
- Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Esat Eşkazan
- Department of Pharmacology, Cerrahpaşa School of Medicine, Istanbul, Turkey
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Cheng H, Wang Y, Chen J, Chen Z. The piriform cortex in epilepsy: What we learn from the kindling model. Exp Neurol 2020; 324:113137. [DOI: 10.1016/j.expneurol.2019.113137] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 11/25/2019] [Accepted: 11/29/2019] [Indexed: 12/14/2022]
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Bay HH, Özkan M, Onat F, Çavdar S. Do the Dento-Thalamic Connections of Genetic Absence Epilepsy Rats from Strasbourg Differ from Those of Control Wistar Rats? Brain Connect 2019; 9:703-710. [PMID: 31591912 DOI: 10.1089/brain.2019.0694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The thalamo-cortical circuit is important in the genesis of absence epilepsy. This circuit can be influenced by connecting pathways from various parts of central nervous system. The aim of the present study is to define the dento-thalamic connections in Wistar animals and compare the results with genetic absence epilepsy rats from Strasbourg (GAERS) using the biotinylated dextran amine (BDA) tracer. We injected BDA into the dentate nucleus of 13 (n = 6 Wistar and n = 7 GAERS) animals. The dento-thalamic connections in the Wistar animals were denser and were connected to a wider range of thalamic nuclei compared with GAERS. The dentate nucleus was bilaterally connected to the central (central medial [CM], paracentral [PC]), ventral (ventral medial [VM], ventral lateral [VL], and ventral posterior lateral [VPL]), and posterior (Po) thalamic nuclei in Wistar animals. The majority of these connections were dense contralaterally and scarce ipsilaterally. Contralateral connections were present with the parafascicular (PF), ventral posterior medial, ventral anterior (VA), and central lateral (CL) thalamic nuclei in Wistar animals. Whereas in GAERS, bilateral connections were observed with the VL and CM. Contralateral connections were present with the PC, VM, VA, and PF thalamic nuclei in GAERS. The CL, VPL, and Po thalamic nucleus connections were not observed in GAERS. The present study showed weak/deficit dento-thalamic connections in GAERS compared with control Wistar animals. The scarce information flow from the dentate nucleus to thalamus in GAERS may have a deficient modulatory role on the thalamus and thus may affect modulation of the thalamo-cortical circuit.
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Affiliation(s)
| | - Mazhar Özkan
- Department of Anatomy, Marmara University School of Medicine, Istanbul, Turkey
| | - Filiz Onat
- Department of Pharmacology and Clinic Pharmacology, Marmara University School of Medicine, Istanbul, Turkey
| | - Safiye Çavdar
- Department of Anatomy, Koç University School of Medicine, Istanbul, Turkey
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7
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Anatomical imaging of the piriform cortex in epilepsy. Exp Neurol 2019; 320:113013. [DOI: 10.1016/j.expneurol.2019.113013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 06/08/2019] [Accepted: 07/15/2019] [Indexed: 11/23/2022]
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Young JC, Paolini AG, Pedersen M, Jackson GD. Genetic absence epilepsy: Effective connectivity from piriform cortex to mediodorsal thalamus. Epilepsy Behav 2019; 97:219-228. [PMID: 31254842 DOI: 10.1016/j.yebeh.2019.05.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The objective of the study was to quantify effective connectivity from the piriform cortex to mediodorsal thalamus, in Genetic Absence Epilepsy Rats from Strasbourg (GAERS). METHODS Local field potentials (LFPs) were recorded using microelectrode arrays implanted in the mediodorsal thalamus and piriform cortex, in three urethane anesthetized GAERS and three control rats. Screw electrodes were placed in the primary motor cortex to identify epileptiform discharges. We used transfer entropy to measure effective connectivity from piriform cortex to mediodorsal thalamus prior to and during generalized epileptiform discharges. RESULTS We observed increased theta band effective connectivity from piriform cortex to mediodorsal thalamus, prior to and during epileptiform discharges in GAERS compared with controls. Increased effective connectivity was also observed in beta and gamma bands from the piriform cortex to mediodorsal thalamus, but only during epileptiform discharges. CONCLUSIONS This preliminary study suggests that increased effective theta connectivity from the piriform cortex to the mediodorsal thalamus may be a feature of the 'epileptic network' associated with genetic absence epilepsy. Our findings indicate an underlying predisposition of this direct pathway to propagate epileptiform discharges in genetic absence epilepsy.
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Affiliation(s)
- James C Young
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia.
| | - Antonio G Paolini
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia; ISN Psychology - Institute for Social Neuroscience, Melbourne, Australia; School of Psychology and Public Health, La Trobe University, Melbourne, Australia
| | - Mangor Pedersen
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
| | - Graeme D Jackson
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia; Department of Neurology, Austin Health, Melbourne, Australia
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Young JC, Nasser HM, Casillas-Espinosa PM, O'Brien TJ, Jackson GD, Paolini AG. Multiunit cluster firing patterns of piriform cortex and mediodorsal thalamus in absence epilepsy. Epilepsy Behav 2019; 97:229-243. [PMID: 31254843 DOI: 10.1016/j.yebeh.2019.05.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/09/2019] [Accepted: 05/20/2019] [Indexed: 01/24/2023]
Abstract
OBJECTIVE The objective of the study were to investigate patterns of multiunit cluster firing in the piriform cortex (PC) and mediodorsal thalamus (MDT) in a rat model of genetic generalized epilepsy (GGE) with absence seizures and to assess whether these regions contribute to the initiation or spread of generalized epileptiform discharges. METHODS Multiunit clusters and their corresponding local field potentials (LFPs) were recorded from microelectrode arrays implanted in the PC and MDT in urethane anesthetized Genetic Absence Epilepsy Rats from Strasbourg (GAERS) and nonepileptic control (NEC) rats. Peristimulus time histograms (PSTHs) and cross-correlograms were used to observe transient changes in both the rate of firing and synchrony over time. The phase locking of multiunit clusters to LFP signals (spike-LFP phase locking) was calculated for frequency bands associated with olfactory communication between the two brain regions. RESULTS There were significant increases in both rate of firing and synchronous activity at the onset of generalized epileptiform discharges in both PC and MDT. Prior to and following these increases in synchronous activity, there were periods of suppression. Significant increases in spike-LFP phase locking were observed within the PC prior to the onset of epileptiform discharges across all spectral bands. There were also significant increases in spike-LFP phase locking within the theta band of the MDT prior to onset. Between the two brain regions, there was a significant decrease in spike-LFP phase locking -0.5 s prior to onset in the theta band which coincided with a significant elevation in spike-LFP phase locking in the gamma band. CONCLUSIONS Both the PC and MDT are engaged in the absence epilepsy network. Early spike-LFP phase locking between these two brain regions suggests potential involvement in the initiation of seizure activity.
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Affiliation(s)
- James C Young
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia.
| | - Helen M Nasser
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia; ISN Psychology - Institute for Social Neuroscience, Melbourne, Australia
| | - Pablo M Casillas-Espinosa
- Department of Neuroscience, Monash University, Melbourne, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Australia; Department of Neurology, The Royal Melbourne Hospital, The University of Melbourne, Australia
| | - Terence J O'Brien
- Department of Neuroscience, Monash University, Melbourne, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Australia; Department of Neurology, The Royal Melbourne Hospital, The University of Melbourne, Australia
| | - Graeme D Jackson
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia; Department of Neurology, Austin Health, Melbourne, Australia
| | - Antonio G Paolini
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia; ISN Psychology - Institute for Social Neuroscience, Melbourne, Australia; School of Psychology and Public Health, La Trobe University, Melbourne, Australia
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Evaluation of GAD67 immunoreactivity in the region of substantia nigra pars reticulata in resistance to development of convulsive seizure in genetic absence epilepsy rats. North Clin Istanb 2017; 3:161-167. [PMID: 28275746 PMCID: PMC5336619 DOI: 10.14744/nci.2016.16056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 11/06/2016] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE: Nonconvulsive absence epilepsy and convulsive epilepsy seizures are rarely seen in the same patient. It has been demonstrated that there is a resistance to development of convulsive seizures in genetic absence epilepsy models. The present study investigated glutamic acid decarboxylase (GAD) immunoreactivity in the brain region related to the interaction of these two seizure types, namely substantia nigra pars reticulata (SNR) subregions, SNRanterior and SNRposterior. METHODS: Nonepileptic adult male Wistar rats and Genetic Absence Epilepsy Rats from Strasbourg (GAERS) were used. Experimental groups of Wistar and GAERS were electrically stimulated for kindling model to induce convulsive epileptic seizures. An electrical stimulation cannula was stereotaxically implanted to the basolateral amygdala and recording electrodes were placed on the cortex. Sagittal sections of SNR were used to evaluate immunohistochemical reaction. Sections were incubated with anti-GAD67 antibody. Densitometric analysis of GAD67 immunoreactive neurons was performed using photographs of stained sections. One-way analysis of variance and post hoc Bonferroni test were used for statistical analysis of the data. RESULTS: There was no difference in GAD67 immunoreactivity of SNR subregions of control Wistar and control GAERS. An increase in GAD67 immunoreactivity was detected in SNRposterior subregion of stimulated Wistar rats, whereas there was a decrease in GAD67 immunoreactivity in SNRposterior of stimulated GAERS. The difference in GAD67 immunoreactivity between these two groups was statistically significant. CONCLUSION: Level of synthetized gamma-aminobutyric acid in SNRposterior subregion plays an important role in the interaction of nonconvulsive absence epilepsy seizures and convulsive epilepsy seizures.
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Increased inhibitory synaptic activity in the hippocampus (CA1) of genetic absence epilepsy rats: Relevance of kindling resistance. Epilepsy Res 2016; 126:70-7. [PMID: 27434859 DOI: 10.1016/j.eplepsyres.2016.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/31/2016] [Accepted: 06/25/2016] [Indexed: 11/21/2022]
Abstract
PURPOSE Genetic absence epilepsy rats from Strasbourg (GAERS), a well-validated genetic rat model for typical absence epilepsy, are known to manifest a resistance to secondary generalization of abnormal focal electrical activity evoked by kindling. The mechanism of this resistance is still unclear. In order to understand the possible mechanism of kindling resistance, we investigated for the first time, the differences of short-term synaptic plasticity by using a paired-pulse paradigm as an indicator of GABAergic activity in CA1 region of hippocampus in GAERS and non-epileptic Wistar rats in-vivo. METHODS Rats were subjected to kindling process, basolateral amygdala was stimulated twice a day, with a supra-threshold current, until they displayed limbic or convulsive seizures. One hour after the last kindling stimulation, evoked field potentials from CA1 pyramidal layer of hippocampus were recorded in-vivo under urethane anesthesia. RESULTS In response to supra-threshold kindling stimulations GAERS showed a significantly delayed kindling progression and displayed a significant increase in hippocampal excitability at early stages of kindling that is the critical for the development of convulsive seizures. In control rats that were not received kindling stimulation, paired-pulse depression (PPD) was significantly pronounced in GAERS with respect to the Wistar group. During the kindling course, PPD was gradually reduced in the Wistar rats as kindling progression was advanced. However in GAERS, PPD ratios were not significantly changed at early stages of kindling. When GAERS reached convulsive stage, their PPD ratios became similar to that of Wistar rats. DISCUSSION The increased inhibition in paired-pulse responses at early stages of kindling in GAERS suggests the role of augmented GABAergic activity as one of the underlying mechanisms of kindling resistance observed in genetic rat models of absence epilepsy.
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Akman O, Gulcebi MI, Carcak N, Ketenci Ozatman S, Eryigit T, Moshé SL, Galanopoulou AS, Onat FY. The role of the substantia nigra pars reticulata in kindling resistance in rats with genetic absence epilepsy. Epilepsia 2015; 56:1793-802. [PMID: 26471261 DOI: 10.1111/epi.13204] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2015] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Genetic Absence Epilepsy Rats from Strasbourg (GAERS) show a resistance to secondary generalization of focal limbic seizures evoked by kindling. The substantia nigra pars reticulata (SNR) is involved in the propagation and modulation of seizures in kindling. We first examined the role of the SNRanterior and SNRposterior subregions in the resistance to the development of kindling in GAERS. Subsequently, to determine whether kindling resistance relates to differential sensitivity of γ-aminobutyric acid γ-aminobutyric acid (GABA)ergic or dopaminergic SNR neurons to kindling, we studied the effects of kindling-inducing stimulations on parvalbumin (PRV; GABAergic neuron marker) or tyrosine hydroxylase (TH; dopaminergic neuron marker) immunoreactivity (ir), respectively, in GAERS and in nonepileptic control (NEC) Wistar rats that lack kindling resistance. METHODS Adult male GAERS were implanted with a stimulation electrode in the amygdala, and bilateral injection cannulas for lidocaine or saline injection (30 min before each kindling stimulation until the animals reached three stage 5 seizures or the 22 stimulations) into the SNRanterior or SNRposterior . In another experiment, PRV-ir in SNRanterior and SNRposterior and TH-ir in SNRposterior only were densitometrically compared in GAERS-SHAM, NEC-SHAM GAERS-STIM, and NEC-STIM animals (6 kindling stimulations). RESULTS Bilateral SNRposterior infusions of lidocaine eliminated the kindling resistance and resulted in stage 5 generalized motor seizures in all kindled rats. Bilateral lidocaine infusions in the SNRanterior failed to alter the kindling resistance in GAERS. PRV-ir in the SNRposterior was unaltered in GAERS-STIM but increased in NEC-STIM group. Cellular TH-ir in the SNRposterior significantly increased by kindling stimulations in both NEC-STIM and GAERS-STIM groups. SIGNIFICANCE The kindling resistance in GAERS is mediated by the SNRposterior in a lidocaine-sensitive manner. The insensitivity to kindling stimulation of PRV-ir in SNRposterior of GAERS but not NEC rats, implicate GABAergic SNRposterior neurons in kindling resistance. In contrast, the observed stimulation-specific increase in TH-ir in the SNRposterior is unrelated to kindling resistance.
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Affiliation(s)
- Ozlem Akman
- Department of Physiology, Faculty of Medicine, Istanbul Bilim University, Istanbul, Turkey
| | - Medine I Gulcebi
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Nihan Carcak
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
| | - Sema Ketenci Ozatman
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey.,Vocational School of Health Service, Istanbul Bilim University, Istanbul, Turkey
| | - Tugba Eryigit
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Solomon L Moshé
- Laboratory of Developmental Epilepsy, Saul R. Korey Department of Neurology, Montefiore Epilepsy Management Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, U.S.A.,Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, U.S.A.,Department of Pediatrics, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, U.S.A
| | - Aristea S Galanopoulou
- Laboratory of Developmental Epilepsy, Saul R. Korey Department of Neurology, Montefiore Epilepsy Management Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, U.S.A.,Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, U.S.A
| | - Filiz Yilmaz Onat
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey.,Epilepsy Research Center, Marmara University, Istanbul, Turkey
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Kim SH, Lim SC, Kim W, Kwon OH, Jeon S, Lee JM, Shon YM. Extrafrontal structural changes in juvenile myoclonic epilepsy: A topographic analysis of combined structural and microstructural brain imaging. Seizure 2015. [DOI: 10.1016/j.seizure.2015.06.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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The involvement of limbic structures in typical and atypical absence epilepsy. Epilepsy Res 2013; 103:111-23. [DOI: 10.1016/j.eplepsyres.2012.08.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 08/15/2012] [Accepted: 08/22/2012] [Indexed: 11/21/2022]
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Vinogradova LV, Shatskova AB. Lateral asymmetry of early seizure manifestations in experimental generalized epilepsy. Neuroscience 2012; 213:133-43. [PMID: 22525136 DOI: 10.1016/j.neuroscience.2012.03.060] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 03/13/2012] [Accepted: 03/14/2012] [Indexed: 10/28/2022]
Abstract
Reorganization of seizure networks during epileptogenesis involves cortico-subcortical and interhemispheric interactions. In the audiogenic kindling (AK) model of generalized tonic-clonic seizures, upstream seizure propagation along ascending brainstem-to-forebrain pathways determines progressive intensification of repeated sound-induced convulsions. Full-blown audiogenic seizures are bilaterally symmetric and their repetition results in bisynchronous recruiting the cortex in secondary epileptogenesis. The present study describes lateral asymmetry of initial behavioral and EEG manifestations of audiogenic seizures and AK in Wistar and WAG/Rij rats with acoustic hypersensitivity. These rats exhibit consistent individual lateralization of running seizures (run directionality) induced by repeated binaural stimulation. Since this initial preconvulsive running reflects seizure onset in the auditory brainstem, the running asymmetry suggests non-symmetric early epileptic activation of brainstem substrates by sound in these rats. Repetition of the asymmetric brainstem seizures led to asynchronous recruiting the cortex into seizure network and lateralization of running seizures was predictive for asymmetry of early cortical seizure manifestations in Wistar and WAG/Rij rats. Both electrographic markers of AK, spreading depression (SD) and post-running afterdischarge, first appeared in the cortex ipsilateral to run direction, suggesting lateralized brainstem-to-forebrain seizure generalization during AK. At the population level, no bias in lateralization of running and SD was found in Wistar and WAG/Rij rats but incidence of secondary cortical seizures varied, depending on strain and run laterality. Among Wistar rats, cortical seizures developed more rarely in right-runners than in left-runners, suggesting enhanced resistance of the right hemisphere to epileptogenesis in rats of this strain. WAG/Rij rats with mixed (absence and audiogenic) epilepsy showed weak lateralization of early cortical seizures and no left-right difference in their incidence during AK. Present findings suggest (1) lateralized brainstem-to-forebrain seizure propagation and hemispheric difference in its facility in Wistar rats, (2) alterations of intra- and interhemispheric seizure propagation in WAG/Rij rats with genetic absence epilepsy.
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Affiliation(s)
- L V Vinogradova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences - RAS, Butlerova Street 5A, 117485 Moscow, Russia.
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Greenhill SD, Morgan NH, Massey PV, Woodhall GL, Jones RSG. Ethosuximide modifies network excitability in the rat entorhinal cortex via an increase in GABA release. Neuropharmacology 2011; 62:807-14. [PMID: 21945797 DOI: 10.1016/j.neuropharm.2011.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 09/01/2011] [Accepted: 09/06/2011] [Indexed: 10/17/2022]
Abstract
Ethosuximide is the drug of choice for treating generalized absence seizures, but its mechanism of action is still a matter of debate. It has long been thought to act by disrupting a thalamic focus via blockade of T-type channels and, thus, generation of spike-wave activity in thalamocortical pathways. However, there is now good evidence that generalized absence seizures may be initiated at a cortical focus and that ethosuximide may target this focus. In the present study we have looked at the effect ethosuximide on glutamate and GABA release at synapses in the rat entorhinal cortex in vitro, using two experimental approaches. Whole-cell patch-clamp studies revealed an increase in spontaneous GABA release by ethosuximide concurrent with no change in glutamate release. This was reflected in studies that estimated global background inhibition and excitation from intracellularly recorded membrane potential fluctuations, where there was a substantial rise in the ratio of network inhibition to excitation, and a concurrent decrease in excitability of neurones embedded in this network. These studies suggest that, in addition to well-characterised effects on ion channels, ethosuximide may directly elevate synaptic inhibition in the cortex and that this could contribute to its anti-absence effects. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.
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Affiliation(s)
- Stuart D Greenhill
- Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
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François J, Germe K, Ferrandon A, Koning E, Nehlig A. Carisbamate has powerful disease-modifying effects in the lithium-pilocarpine model of temporal lobe epilepsy. Neuropharmacology 2011; 61:313-28. [PMID: 21539848 DOI: 10.1016/j.neuropharm.2011.04.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 04/13/2011] [Accepted: 04/15/2011] [Indexed: 11/30/2022]
Abstract
Lithium-pilocarpine, a relevant model of temporal lobe epilepsy was used to test the neuroprotective and antiepileptogenic effects of carisbamate. Status epilepticus (SE) was induced in adult rats by lithium and pilocarpine. Carisbamate (30, 60, 90, and 120 mg/kg) was injected at 1 and 9 h after SE onset and continued twice daily for 6 additional days. The reference groups received diazepam instead of carisbamate. Neuroprotection was assessed during the first 24 h of SE with Fluoro-Jade B and after 14 days with thionine staining. SE severity and epileptic outcome were assessed by video, and surface and depth electroencephalographic recordings. At the two highest doses, carisbamate treatment reduced SE severity; produced strong neuroprotection of hippocampus, ventral cortices, thalamus, and amygdala; prevented mossy fiber sprouting in the dentate gyrus of the hippocampus; and delayed or suppressed the occurrence of spontaneous motor seizures. Rats with no spontaneous motor seizures displayed spike-and-wave discharges that share all the characteristics of absence seizures. In conclusion, carisbamate is able to induce strong neuroprotection and affect the nature of epileptogenic events occurring during and after lithium-pilocarpine status epilepticus, reflecting marked insult- and disease-modifying effects.
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Affiliation(s)
- Jennifer François
- InsermU666, University Louis Pasteur; Faculty of Medicine, 11 rue Humann, 67085 Strasbourg Cedex, France.
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18
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Nicolazzo JA, Steuten JA, Charman SA, Taylor N, Davies PJ, Petrou S. Brain uptake of diazepam and phenytoin in a genetic animal model of absence epilepsy. Clin Exp Pharmacol Physiol 2010; 37:647-9. [PMID: 20082623 DOI: 10.1111/j.1440-1681.2010.05362.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. Although many studies have assessed changes to brain uptake of anti-epileptic drugs (AEDs) in chemically and electrically induced seizure models, there are limited data available on changes to brain uptake of AEDs in spontaneous seizure animal models, such as genetic absence epilepsy. 2. In the present study, the brain uptake of diazepam and phenytoin was assessed in a genetic mouse model of absence seizures harbouring a human GABA(A) receptor gamma2-subunit gene GABRG2 mutation (R43Q) and results were compared with those obtained during acute seizures induced by subcutaneous administration of pentylenetetrazole (PTZ; 90 mg/kg). Diazepam and phenytoin were administered intraperitoneally at doses of 2 and 30 mg/kg, respectively, and brain and plasma concentrations were determined 60 min after administration using liquid chromatography-mass spectrometry. 3. Although the brain uptake of phenytoin was significantly reduced following PTZ administration, no changes were observed in phenytoin disposition in the genetic absence epilepsy model. Similarly, the brain uptake of diazepam was significantly enhanced following PTZ administration, but it was not affected in absence epilepsy. 4. The cerebrovascular plasma volume (assessed by administration of the non-absorbable marker [(14)C]-inulin) was not significantly different in saline-treated compared with PTZ-treated mice and in wild-type compared with mutant R43Q mice. 5. These results demonstrate that although the brain uptake of AEDs may be altered in acute seizure models, similar changes to brain uptake may not be observed in the non-convulsive genetic absence epileptic model.
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Affiliation(s)
- Joseph A Nicolazzo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
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Schreibman Cohen A, Daley M, Siddarth P, Levitt J, Loesch IK, Altshuler L, Ly R, Shields WD, Gurbani S, Caplan R. Amygdala volumes in childhood absence epilepsy. Epilepsy Behav 2009; 16:436-41. [PMID: 19766541 DOI: 10.1016/j.yebeh.2009.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 07/11/2009] [Accepted: 08/10/2009] [Indexed: 02/03/2023]
Abstract
Abnormal amygdala volumes in pediatric mood-anxiety disorders and attention deficit hyperactivity disorder (ADHD), as well as high rates of these diagnoses in childhood absence epilepsy (CAE), prompted this study of amygdala volume in CAE. Twenty-six children with CAE and 23 normal children, aged 6.6-15.8 years, underwent MRI at 1.5 T. The tissue imaged with MRI was segmented, and amygdala volumes were obtained by manual tracings. There were no significant amygdala volume differences between the CAE and normal groups. Within the CAE group, however, the children with ADHD had significantly smaller amygdala volumes than the subjects with CAE with no psychopathology and those with mood/anxiety diagnoses. There was also a significant relationship between higher seizure frequency and greater amygdala asymmetry in the epilepsy group. Given ongoing development of the amygdala during late childhood and adolescence, despite the lack of significant group differences in amygdala volumes, the association of amygdala volume abnormalities with ADHD and seizure frequency implies a possible impact of the disorder on amygdala development and CAE-associated comorbidities, such as ADHD.
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Affiliation(s)
- Ayelet Schreibman Cohen
- Department of Psychiatry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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