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Developmental Inhibitory Changes in the Primary Somatosensory Cortex of the Stargazer Mouse Model of Absence Epilepsy. Biomolecules 2023; 13:biom13010186. [PMID: 36671571 PMCID: PMC9856073 DOI: 10.3390/biom13010186] [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: 12/18/2022] [Revised: 01/08/2023] [Accepted: 01/11/2023] [Indexed: 01/19/2023] Open
Abstract
Childhood absence epilepsy seizures arise in the cortico-thalamocortical network due to multiple cellular and molecular mechanisms, which are still under investigation. Understanding the precise mechanisms is imperative given that treatment fails in ~30% of patients while adverse neurological sequelae remain common. Impaired GABAergic neurotransmission is commonly reported in research models investigating these mechanisms. Recently, we reported a region-specific reduction in the whole-tissue and synaptic GABAA receptor (GABAAR) α1 subunit and an increase in whole-tissue GAD65 in the primary somatosensory cortex (SoCx) of the adult epileptic stargazer mouse compared with its non-epileptic (NE) littermate. The current study investigated whether these changes occurred prior to the onset of seizures on postnatal days (PN) 17-18, suggesting a causative role. Synaptic and cytosolic fractions were biochemically isolated from primary SoCx lysates followed by semiquantitative Western blot analyses for GABAAR α1 and GAD65. We found no significant changes in synaptic GABAAR α1 and cytosolic GAD65 in the primary SoCx of the stargazer mice at the critical developmental stages of PN 7-9, 13-15, and 17-18. This indicates that altered levels of GABAAR α1 and GAD65 in adult mice do not directly contribute to the initial onset of absence seizures but are a later consequence of seizure activity.
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De Deurwaerdère P, Casarrubea M, Cassar D, Radic M, Puginier E, Chagraoui A, Crescimanno G, Crunelli V, Di Giovanni G. Cannabinoid 1/2 Receptor Activation Induces Strain-Dependent Behavioral and Neurochemical Changes in Genetic Absence Epilepsy Rats From Strasbourg and Non-epileptic Control Rats. Front Cell Neurosci 2022; 16:886033. [PMID: 35677756 PMCID: PMC9169225 DOI: 10.3389/fncel.2022.886033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/14/2022] [Indexed: 11/13/2022] Open
Abstract
Childhood absence epilepsy (CAE) is characterized by absence seizures, which are episodes of lack of consciousness accompanied by electrographic spike-wave discharges. About 60% of children and adolescents with absence seizures are affected by major neuropsychological comorbidities, including anxiety. Endocannabinoids and monoamines are likely involved in the pathophysiology of these CAE psychiatric comorbidities. Here, we show that the synthetic cannabinoid receptor type 1/2 (CB1/2R) agonist WIN 55,212-2 (2 mg/kg) has a strain-dependent effect on anxiety-like and motor behavior when assess in the hole board test and cerebral monoaminergic levels in Genetic Absence Epilepsy Rats from Strasbourg (GAERS) and their non-epileptic control (NEC) rat strain. Using quantitative and Temporal pattern (T-pattern) analyses, we found that WIN 55,212-2 did not affect the emotional status of GAERS, but it was anxiolytic in NEC. Conversely, WIN 55,212-2 had a sedative effect in GAERS but was ineffective in NEC. Moreover, vehicle-treated GAERS more motivated to explore by implementing more complex and articulated strategies. These behavioral changes correlate with the reduction of 5-HT in the hippocampus and substantia nigra (SN) and noradrenaline (NA) in the entopeduncular nucleus (EPN) in vehicle-treated GAERS compared to NEC rats, which could contribute to their low anxiety status and hypermotility, respectively. On the other hand, the increased level of NA in the EPN and 5-HT in the SN is consistent with an activation of the basal ganglia output-mediated motor suppression observed in WIN 55,212-2-treated GAERS rats. These data support the view of a strain-dependent alteration of the endocannabinoid system in absence epilepsy by adding evidence of a lower emotional responsiveness and a basal ganglia hypersensitivity to cannabinoids in GAERS compared to NEC rats.
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Affiliation(s)
| | - Maurizio Casarrubea
- Laboratory of Behavioral Physiology, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Human Physiology Section “Giuseppe Pagano”, University of Palermo, Palermo, Italy
- *Correspondence: Maurizio Casarrubea,
| | - Daniel Cassar
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Manuela Radic
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Emilie Puginier
- Centre National de la Recherche Scientifique, UMR 5287, Bordeaux Cedex, France
| | - Abdeslam Chagraoui
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, University of Cagliari, Cagliari, Italy
- Normandie Université, UNIROUEN, INSERM, U1239, CHU Rouen, Neuronal and Neuroendocrine Differentiation and Communication Laboratory, Institute for Research and Innovation in Biomedicine of Normandy (IRIB), Rouen, France
- Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Giuseppe Crescimanno
- Laboratory of Behavioral Physiology, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Human Physiology Section “Giuseppe Pagano”, University of Palermo, Palermo, Italy
| | - Vincenzo Crunelli
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
- Giuseppe Di Giovanni,
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Adotevi N, Su A, Peiris D, Hassan M, Leitch B. Altered Neurotransmitter Expression in the Corticothalamocortical Network of an Absence Epilepsy Model with impaired Feedforward Inhibition. Neuroscience 2021; 467:73-80. [PMID: 34048799 DOI: 10.1016/j.neuroscience.2021.05.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 05/03/2021] [Accepted: 05/17/2021] [Indexed: 11/16/2022]
Abstract
The episodes of brief unconsciousness in patients with childhood absence epilepsy are a result of corticothalamocortical circuitry dysfunction. This dysfunction may arise from multifactorial mechanisms in patients from different genetic backgrounds. In previous studies using the epileptic stargazer mutant mouse, which experience frequent absence seizures, we reported a deficit in AMPAR-mediated feed-forward inhibition of parvalbumin-containing (PV+) interneurons. Currently, in order to determine the downstream effects of this impairment on neurotransmitter expression, we performed HPLC of tissue lysates and post-embedding electron microscopy from the cortical and thalamic regions. We report region-specific alterations in GABA expression, but not of glutamate, and most prominently at PV+ synaptic terminals. These results suggest that impaired feed forward inhibition may occur via reduced activation of these interneurons and concomitant decreased GABAergic signaling. Further investigations into GABAergic control of corticothalamocortical network activity could be key in our understanding of absence seizure pathogenesis.
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Affiliation(s)
- Nadia Adotevi
- Department of Anatomy, Brain Health Research Centre, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Aini Su
- Department of Anatomy, Brain Health Research Centre, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Danushi Peiris
- Department of Anatomy, Brain Health Research Centre, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Muhammad Hassan
- Department of Anatomy, Brain Health Research Centre, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Beulah Leitch
- Department of Anatomy, Brain Health Research Centre, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
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Crunelli V, Lőrincz ML, McCafferty C, Lambert RC, Leresche N, Di Giovanni G, David F. Clinical and experimental insight into pathophysiology, comorbidity and therapy of absence seizures. Brain 2020; 143:2341-2368. [PMID: 32437558 PMCID: PMC7447525 DOI: 10.1093/brain/awaa072] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/19/2019] [Accepted: 01/31/2020] [Indexed: 12/24/2022] Open
Abstract
Absence seizures in children and teenagers are generally considered relatively benign because of their non-convulsive nature and the large incidence of remittance in early adulthood. Recent studies, however, show that 30% of children with absence seizures are pharmaco-resistant and 60% are affected by severe neuropsychiatric comorbid conditions, including impairments in attention, cognition, memory and mood. In particular, attention deficits can be detected before the epilepsy diagnosis, may persist even when seizures are pharmacologically controlled and are aggravated by valproic acid monotherapy. New functional MRI-magnetoencephalography and functional MRI-EEG studies provide conclusive evidence that changes in blood oxygenation level-dependent signal amplitude and frequency in children with absence seizures can be detected in specific cortical networks at least 1 min before the start of a seizure, spike-wave discharges are not generalized at seizure onset and abnormal cortical network states remain during interictal periods. From a neurobiological perspective, recent electrical recordings and imaging of large neuronal ensembles with single-cell resolution in non-anaesthetized models show that, in contrast to the predominant opinion, cortical mechanisms, rather than an exclusively thalamic rhythmogenesis, are key in driving seizure ictogenesis and determining spike-wave frequency. Though synchronous ictal firing characterizes cortical and thalamic activity at the population level, individual cortico-thalamic and thalamocortical neurons are sparsely recruited to successive seizures and consecutive paroxysmal cycles within a seizure. New evidence strengthens previous findings on the essential role for basal ganglia networks in absence seizures, in particular the ictal increase in firing of substantia nigra GABAergic neurons. Thus, a key feature of thalamic ictogenesis is the powerful increase in the inhibition of thalamocortical neurons that originates at least from two sources, substantia nigra and thalamic reticular nucleus. This undoubtedly provides a major contribution to the ictal decrease in total firing and the ictal increase of T-type calcium channel-mediated burst firing of thalamocortical neurons, though the latter is not essential for seizure expression. Moreover, in some children and animal models with absence seizures, the ictal increase in thalamic inhibition is enhanced by the loss-of-function of the astrocytic GABA transporter GAT-1 that does not necessarily derive from a mutation in its gene. Together, these novel clinical and experimental findings bring about paradigm-shifting views of our understanding of absence seizures and demand careful choice of initial monotherapy and continuous neuropsychiatric evaluation of affected children. These issues are discussed here to focus future clinical and experimental research and help to identify novel therapeutic targets for treating both absence seizures and their comorbidities.
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Affiliation(s)
- Vincenzo Crunelli
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff, UK
| | - Magor L Lőrincz
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff, UK.,Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Cian McCafferty
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Régis C Lambert
- Sorbonne Université, CNRS, INSERM, Neuroscience Paris Seine and Institut de Biologie Paris Seine (NPS - IBPS), Paris, France
| | - Nathalie Leresche
- Sorbonne Université, CNRS, INSERM, Neuroscience Paris Seine and Institut de Biologie Paris Seine (NPS - IBPS), Paris, France
| | - Giuseppe Di Giovanni
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff, UK
| | - François David
- Cerebral dynamics, learning and plasticity, Integrative Neuroscience and Cognition Center - UMR 8002, Paris, France
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Yavuz M, Albayrak N, Özgür M, Gülçebi İdriz Oğlu M, Çavdar S, Onat F. The effect of prenatal and postnatal caffeine exposure on pentylentetrazole induced seizures in the non-epileptic and epileptic offsprings. Neurosci Lett 2019; 713:134504. [PMID: 31539618 DOI: 10.1016/j.neulet.2019.134504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/27/2019] [Accepted: 09/16/2019] [Indexed: 11/29/2022]
Abstract
Caffeine, a central nervous system stimulant, has been reported to modulate seizure activity in various studies. In this study the effects of caffeine exposure on the pentylenetetrazole (PTZ) induced seizure thresholds and seizure stages in the Wistar and genetic absence epilepsy model offsprings were examined. Adult female and male Wistar rats and genetic absence epilepsy rats from Strasbourg (GAERS) consumed caffeine dissolved in water (0.3 g/L) before conception, during the gestational periods and lactation period whereas control groups of each strain received tap water. All offsprings at postnatal day 30 (PN30) subjected to 70 mg/kg of PTZ were evaluated in terms of overall seizure stages, the latency to the first generalized seizure and the c-Fos protein activity in the brain regions of somatosensorial cortex (SSCx), reticular thalamic nucleus (Rt), ventrobasal thalamus (VB), centromedial nucleus (CM) and lateral geniculate nucleus (LGN). The Wistar caffeine group had significantly shorter latency to the first generalized seizure (1.53 ± 0.49 min) comparing to the Wistar control offsprings (3.40 ± 0.68 min). GAERS caffeine group (6.52 ± 2.48 min) showed significantly longer latency comparing to Wistar caffeine group (1.53 ± 0.49 min). Although statistically not significant, GAERS caffeine group showed a longer latency comparing to the GAERS control group (4.71 ± 1.82 min). In all regions of SSCx, Rt, VB, CM and LGN, GAERS caffeine group had lower c-Fos protein expression comparing to the GAERS control group (p < 0.05). Wistar caffeine rats had lower expression of c-Fos protein comparing to the Wistar control group only in SSCx. In CM, GAERS rats expressed lower c-Fos protein comparing to the Wistar control (p < 0.05). In conclusion differential effects of caffeine in the seizure modulation may involve c-Fos protein activity-dependent protection mechanisms.
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Affiliation(s)
- Melis Yavuz
- Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Nazlı Albayrak
- School of Medicine, Acibadem M. A. Aydınlar University, Istanbul, Turkey
| | - Merve Özgür
- Department of Anatomy, School of Medicine, Koç University, Istanbul, Turkey
| | - Medine Gülçebi İdriz Oğlu
- Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey; Epilepsy Research Centre (EPAM), Marmara University, Istanbul, Turkey
| | - Safiye Çavdar
- Department of Anatomy, School of Medicine, Koç University, Istanbul, Turkey
| | - Filiz Onat
- Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey; Epilepsy Research Centre (EPAM), Marmara University, Istanbul, Turkey.
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Arkan S, Kasap M, Akman Ö, Akpınar G, Ateş N, Karson A. The lower expression of parvalbumin in the primary somatosensory cortex of WAG/Rij rats may facilitate the occurrence of absence seizures. Neurosci Lett 2019; 709:134299. [DOI: 10.1016/j.neulet.2019.134299] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 05/12/2019] [Accepted: 05/27/2019] [Indexed: 12/29/2022]
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Studer F, Laghouati E, Jarre G, David O, Pouyatos B, Depaulis A. Sensory coding is impaired in rat absence epilepsy. J Physiol 2019; 597:951-966. [PMID: 30548850 DOI: 10.1113/jp277297] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 12/12/2018] [Indexed: 01/16/2023] Open
Abstract
KEY POINTS Absence epilepsy is characterized by the occurrence of spike-and-wave discharges concomitant with an alteration of consciousness and is associated with cognitive comorbidities. In a genetic model of absence epilepsy in the rat, the genetic absence epilepsy rat from Strasbourg (GAERS), spike-and-wave discharges are shown to be initiated in the barrel field primary somatosensory cortex that codes whisker-related information, therefore playing an essential role in the interactions of rodents with their environment. Sensory-information processing is impaired in the epileptic barrel field primary somatosensory cortex of GAERS, with a delayed sensory-evoked potential and a duplicated neuronal response to whisker stimulation in in vivo extracellular recordings. Yet, GAERS present no defaults of performance in a texture discrimination task, suggesting the existence of a compensatory mechanism within the epileptic neuronal network. The results of the present study indicate that physiological primary functions are processed differently in an epileptic cortical network. ABSTRACT Several neurodevelopmental pathologies are associated with disorganized cortical circuits that may alter primary functions such as sensory processes. In the present study, we investigated whether the function of a cortical area is altered in the seizure onset zone of absence epilepsy, a prototypical form of childhood genetic epilepsy associated with cognitive impairments. We first combined in vivo multichannel electrophysiological recordings and histology to precisely localize the seizure onset zone in the genetic absence epilepsy rat from Strasbourg (GAERS). We then investigated the functionality of this epileptic zone using extracellular silicon probe recordings of sensory-evoked local field potentials and multi-unit activity, as well as a behavioural test of texture discrimination. We show that seizures in this model are initiated in the barrel field part of the primary somatosensory cortex and are associated with high-frequency oscillations. In this cortex, we found an increased density of parvalbumin-expressing interneurons in layer 5 in GAERS compared to non-epileptic Wistar rats. Its functional investigation revealed that sensory abilities of GAERS are not affected in a texture-discrimination task, whereas the intracortical processing of sensory-evoked information is delayed and duplicated. Altogether, these results suggest that absence seizures are associated with an increase of parvalbumin-inhibitory neurons, which may promote the functional relationship between epileptic oscillations and high-frequency activities. Our findings suggest that cortical circuits operate differently in the epileptic onset zone and may adapt to maintain their ability to process highly specialized information.
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Affiliation(s)
- Florian Studer
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble, France.,Inserm, U1216, Grenoble, France
| | - Emel Laghouati
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble, France.,Inserm, U1216, Grenoble, France
| | - Guillaume Jarre
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble, France.,Inserm, U1216, Grenoble, France
| | - Olivier David
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble, France.,Inserm, U1216, Grenoble, France
| | - Benoît Pouyatos
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble, France.,Inserm, U1216, Grenoble, France.,Present address: INRS, F-54519, Vandoeuvre Les Nancy, France
| | - Antoine Depaulis
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, Grenoble, France.,Inserm, U1216, Grenoble, France
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Fangjing decoction relieves febrile seizures-induced hippocampal neuron apoptosis in rats via regulating the Akt/mTOR pathway. Biosci Rep 2018; 38:BSR20181206. [PMID: 30287501 PMCID: PMC6209604 DOI: 10.1042/bsr20181206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 08/30/2018] [Accepted: 09/13/2018] [Indexed: 12/28/2022] Open
Abstract
Background: Fangjing decoction is a Traditional Chinese Medicine that exhibits anticonvulsive effects in treating febrile seizures (FS). Its action mechanism and the regulation on Akt/mammalian target of rapamycin (mTOR) pathway were revealed in the present study. Methods: FS model was established in Sprague–Dawley rats with or without Fangjing decoction treatment. On day 5, following initiation of drug treatment, seizures were monitored. Hippocampal neuron apoptosis was assessed using terminal dUTP nick end-labeling method. The levels of Bax, protein kinase B (Akt), phospho-Akt (p-Akt), mTOR, and p-mTOR proteins were analyzed using Western blotting. The content of hippocampal γ-aminobutyric acid (GABA) was measured by using ELISA assay. Results: Compared with the control group (n=8), Fangjing decoction effectively shortened escape latency and duration of FS and decreased the frequency of FS in rats (n=8). Concomitantly, the apoptosis of hippocampal neurons, as well as Bax protein levels were also decreased in FS rats which were treated with Fangjing decoction. In addition, the Akt/mTOR signaling was found to be activated in rat hippocampus following FS, as evidenced by increased p-Akt and p-mTOR, while Fangjing decoction could inhibit the activation of Akt/mTOR signaling. Furthermore, the low GABA content in rat hippocampus following FS was significantly elevated by Fangjing decoction treatment. More importantly, SC79, a specific activator for Akt, apparently attenuated the protective effects of Fangjing decoction on FS rats. Conclusion: These results suggest that Fangjing decoction protects the hippocampal neurons from apoptosis by inactivating Akt/mTOR pathway, which may contribute to mitigating FS-induced brain injury.
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