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Daquin G, Bonini F. The landscape of drug resistant absence seizures in adolescents and adults: Pathophysiology, electroclinical spectrum and treatment options. Rev Neurol (Paris) 2024; 180:256-270. [PMID: 38413268 DOI: 10.1016/j.neurol.2023.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/17/2023] [Accepted: 11/21/2023] [Indexed: 02/29/2024]
Abstract
The persistence of typical absence seizures (AS) in adolescence and adulthood may reduce the quality of life of patients with genetic generalized epilepsies (GGEs). The prevalence of drug resistant AS is probably underestimated in this patient population, and treatment options are relatively scarce. Similarly, atypical absence seizures in developmental and epileptic encephalopathies (DEEs) may be unrecognized, and often persist into adulthood despite improvement of more severe seizures. These two seemingly distant conditions, represented by typical AS in GGE and atypical AS in DEE, share at least partially overlapping pathophysiological and genetic mechanisms, which may be the target of drug and neurostimulation therapies. In addition, some patients with drug-resistant typical AS may present electroclinical features that lie in between the two extremes represented by these generalized forms of epilepsy.
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Affiliation(s)
- G Daquin
- Epileptology and Cerebral Rythmology, AP-HM, Timone hospital, Marseille, France
| | - F Bonini
- Epileptology and Cerebral Rythmology, AP-HM, Timone hospital, Marseille, France; Aix Marseille Univ, Inserm, INS, Inst Neurosci Syst, Marseille, France.
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2
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Abstract
GABAB receptors are implicated in numerous central nervous system-based behaviours and mechanisms, including cognitive processing in preclinical animal models. Homeostatic changes in the expression and function of these receptors across brain structures have been found to affect cognitive processing. Numerous preclinical studies have focused on the role of GABAB receptors in learning, memory and cognition per se with some interesting, although sometimes contradictory, findings. The majority of the existing clinical literature focuses on alterations in GABAB receptor function in conditions and disorders whose main symptomatology includes deficits in cognitive processing. The aim of this chapter is to delineate the role of GABAB receptors in cognitive processes in health and disease of animal models and human clinical populations. More specifically, this review aims to present literature on the role of GABAB receptors in animal models with cognitive deficits, especially those of learning and memory. Further, it aims to capture the progress and advances of research studies on the effects of GABAB receptor compounds in neurodevelopmental and neurodegenerative conditions with cognitive dysfunctions. The neurodevelopmental conditions covered include autism spectrum disorders, fragile X syndrome and Down's syndrome and the neurodegenerative conditions discussed are Alzheimer's disease, epilepsy and autoimmune anti-GABAB encephalitis. Although some findings are contradictory, results indicate a possible therapeutic role of GABAB receptor compounds for the treatment of cognitive dysfunction and learning/memory impairments for some of these conditions, especially in neurodegeneration. Moreover, future research efforts should aim to develop selective GABAB receptor compounds with minimal, if any, side effects.
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3
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Metabolomic Analysis of Plasma from GABAB(1) Knock-Out Mice Reveals Decreased Levels of Elaidic Trans-Fatty Acid. Metabolites 2020; 10:metabo10120484. [PMID: 33255896 PMCID: PMC7760308 DOI: 10.3390/metabo10120484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/20/2020] [Accepted: 11/22/2020] [Indexed: 11/17/2022] Open
Abstract
Mice lacking the GABAB(1) subunit of gamma-aminobutyric acid (GABA) type B receptors exhibit spontaneous seizures, hyperalgesia, hyperlocomotor activity, and memory impairment. Although mice lacking the GABAB(1) subunit are viable, they are sterile, and to generate knockout (KO) mice, it is necessary to cross heterozygous (HZ) mice. The aim of our study was to detect the metabolic differences between the three genotypes of GABAB(1) KO mice in order to further characterize this experimental animal model. Plasma samples were collected from wild-type (WT), HZ, and KO mice. Samples were analyzed by means of a gas chromatography-mass spectrometry (GC-MS) platform. Univariate t-test, and partial least square discriminant analysis (PLS-DA) were performed to compare the metabolic pattern of different genotypes. The metabolomic analysis highlighted differences between the three genotypes and identified some metabolites less abundant in KO mice, namely elaidic acid and other fatty acids, and chiro-inositol.
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Dolleman-van der Weel MJ, Witter MP. The thalamic midline nucleus reuniens: potential relevance for schizophrenia and epilepsy. Neurosci Biobehav Rev 2020; 119:422-439. [PMID: 33031816 DOI: 10.1016/j.neubiorev.2020.09.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 09/03/2020] [Accepted: 09/28/2020] [Indexed: 01/08/2023]
Abstract
Anatomical, electrophysiological and behavioral studies in rodents have shown that the thalamic midline nucleus reuniens (RE) is a crucial link in the communication between hippocampal formation (HIP, i.e., CA1, subiculum) and medial prefrontal cortex (mPFC), important structures for cognitive and executive functions. A common feature in neurodevelopmental and neurodegenerative brain diseases is a dysfunctional connectivity/communication between HIP and mPFC, and disturbances in the cognitive domain. Therefore, it is assumed that aberrant functioning of RE may contribute to behavioral/cognitive impairments in brain diseases characterized by cortico-thalamo-hippocampal circuit dysfunctions. In the human brain the connections of RE are largely unknown. Yet, recent studies have found important similarities in the functional connectivity of HIP-mPFC-RE in humans and rodents, making cautious extrapolating experimental findings from animal models to humans justifiable. The focus of this review is on a potential involvement of RE in schizophrenia and epilepsy.
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Affiliation(s)
- M J Dolleman-van der Weel
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, NTNU Norwegian University of Science and Technology, Trondheim NO-7491, Norway.
| | - M P Witter
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, NTNU Norwegian University of Science and Technology, Trondheim NO-7491, Norway.
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Zhu L, Chen L, Xu P, Lu D, Dai S, Zhong L, Han Y, Zhang M, Xiao B, Chang L, Wu Q. Genetic and molecular basis of epilepsy-related cognitive dysfunction. Epilepsy Behav 2020; 104:106848. [PMID: 32028124 DOI: 10.1016/j.yebeh.2019.106848] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 02/02/2023]
Abstract
Epilepsy is a common neurological disease characterized by recurrent seizures. About 70 million people were affected by epilepsy or epileptic seizures. Epilepsy is a complicated complex or symptomatic syndromes induced by structural, functional, and genetic causes. Meanwhile, several comorbidities are accompanied by epileptic seizures. Cognitive dysfunction is a long-standing complication associated with epileptic seizures, which severely impairs quality of life. Although the definitive pathogenic mechanisms underlying epilepsy-related cognitive dysfunction remain unclear, accumulating evidence indicates that multiple risk factors are probably involved in the development and progression of cognitive dysfunction in patients with epilepsy. These factors include the underlying etiology, recurrent seizures or status epilepticus, structural damage that induced secondary epilepsy, genetic variants, and molecular alterations. In this review, we summarize several theories that may explain the genetic and molecular basis of epilepsy-related cognitive dysfunction.
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Affiliation(s)
- Lin Zhu
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Lu Chen
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Puying Xu
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Di Lu
- Biomedicine Engineering Research Center, Kunming Medical University, 1168 Chun Rong West Road, Kunming, Yunnan 650500, PR China
| | - Shujuan Dai
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Lianmei Zhong
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Yanbing Han
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Mengqi Zhang
- Department of Neurology, Xiangya Hospital, Central South University, 87 Xiang Ya Road, Changsha, Hunan 410008, PR China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, 87 Xiang Ya Road, Changsha, Hunan 410008, PR China
| | - Lvhua Chang
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China.
| | - Qian Wu
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China.
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Benke D, Möhler H. Impact on GABA systems in monogenetic developmental CNS disorders: Clues to symptomatic treatment. Neuropharmacology 2017; 136:46-55. [PMID: 28764992 DOI: 10.1016/j.neuropharm.2017.07.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 07/26/2017] [Accepted: 07/28/2017] [Indexed: 12/26/2022]
Abstract
Animal studies of several single-gene disorders demonstrate that reversing the molecular signaling deficits can result in substantial symptomatic improvements in function. Focusing on the ratio of excitation to inhibition as a potential pathophysiological hallmark, seven single-gene developmental CNS disorders are reviewed which are characterized by a striking dysregulation of neuronal inhibition. Deficits in inhibition and excessive inhibition are found. The examples of developmental disorders encompass Neurofibromatosis type 1, Fragile X syndrome, Rett syndrome, Dravet syndrome including autism-like behavior, NONO-mutation-induced intellectual disability, Succinic semialdehyde dehydrogenase deficiency and Congenital nystagmus due to FRMD7 mutations. The phenotype/genotype correlations observed in animal models point to potential treatment options and will continue to inspire clinical research. Three drugs are presently in clinical trials: acamprosate and ganoxolon for Fragile X syndrome and SGS-742 for SSADH deficiency. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Affiliation(s)
- Dietmar Benke
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Drug Discovery Network Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Hanns Möhler
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Vladimir-Prelog-Weg 10, 8023 Zurich, Switzerland.
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Joshi K, Shen L, Michaeli A, Salter M, Thibault-Messier G, Hashmi S, Eubanks JH, Cortez MA, Snead OC. Infantile spasms in down syndrome: Rescue by knockdown of the GIRK2 channel. Ann Neurol 2016; 80:511-21. [PMID: 27462820 DOI: 10.1002/ana.24749] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 07/25/2016] [Accepted: 07/25/2016] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The Ts65Dn (Ts) mouse model of Down syndrome (DS) is exquisitely sensitive to an infantile spasms phenotype induced by γ-aminobutyric acidB receptor (GABAB R) agonists. The Ts mouse contains the core genomic triplication of the DS critical region, which includes 3 copies of the Kcnj6 gene that encodes the GABAB R-coupled G protein-coupled inward rectifying potassium channel subunit 2 (GIRK2) channel. We test the hypothesis that GIRK2 is necessary for the GABAB R agonist-induced infantile spasms phenotype in Ts. METHODS We assessed the result of either genetic or pharmacological knockdown of the GIRK2 channel in Ts brain upon the GABAB R agonist-induced infantile spasms phenotype in the Ts mouse model of DS. As well, we examined GABAB R currents in hippocampal neurons prepared from GIRK2-trisomic Ts control mice and GIRK2-disomic Ts mice in which Kcnj6 had been genetically knocked down from 3 to 2 copies. RESULTS The reduction of the copy number of Kcnj6 in Ts mice rescued the GABAB R agonist-induced infantile spasms phenotype. There was an increase in GABAB R-mediated GIRK2 currents in GIRK2-trisomic Ts mouse hippocampal neurons, which were normalized in the GIRK2-disomic Ts mice. Similarly, pharmacological knockdown of the GIRK2 channel in Ts brain using the GIRK antagonist tertiapin-Q also rescued the GABAB R agonist-induced infantile spasms phenotype in Ts mutants. INTERPRETATION The GABAB R-coupled GIRK2 channel is necessary for the GABAB R agonist-induced infantile spasms phenotype in the Ts mouse and may represent a novel therapeutic target for the treatment of infantile spasms in DS. Ann Neurol 2016;80:511-521.
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Affiliation(s)
- Krutika Joshi
- Neuroscience and Mental Health Program, Hospital for Sick Children, Toronto, Ontario, Canada. .,Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
| | - Lily Shen
- Neuroscience and Mental Health Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Avner Michaeli
- Neuroscience and Mental Health Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Michael Salter
- Neuroscience and Mental Health Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | | | - Sumaiya Hashmi
- Neuroscience and Mental Health Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - James H Eubanks
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,University Health Network, Toronto Western Research Institute, Toronto, Ontario, Canada
| | - Miguel A Cortez
- Neuroscience and Mental Health Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Pediatrics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - O Carter Snead
- Neuroscience and Mental Health Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Pediatrics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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8
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Role of GABA(B) receptors in learning and memory and neurological disorders. Neurosci Biobehav Rev 2016; 63:1-28. [PMID: 26814961 DOI: 10.1016/j.neubiorev.2016.01.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/31/2015] [Accepted: 01/21/2016] [Indexed: 01/13/2023]
Abstract
Although it is evident from the literature that altered GABAB receptor function does affect behavior, these results often do not correspond well. These differences could be due to the task protocol, animal strain, ligand concentration, or timing of administration utilized. Because several clinical populations exhibit learning and memory deficits in addition to altered markers of GABA and the GABAB receptor, it is important to determine whether altered GABAB receptor function is capable of contributing to the deficits. The aim of this review is to examine the effect of altered GABAB receptor function on synaptic plasticity as demonstrated by in vitro data, as well as the effects on performance in learning and memory tasks. Finally, data regarding altered GABA and GABAB receptor markers within clinical populations will be reviewed. Together, the data agree that proper functioning of GABAB receptors is crucial for numerous learning and memory tasks and that targeting this system via pharmaceuticals may benefit several clinical populations.
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Cortez MA, Kostopoulos GK, Snead OC. Acute and chronic pharmacological models of generalized absence seizures. J Neurosci Methods 2015; 260:175-84. [PMID: 26343323 DOI: 10.1016/j.jneumeth.2015.08.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/28/2015] [Accepted: 08/30/2015] [Indexed: 12/28/2022]
Abstract
This article reviews the contribution of pharmacologically induced acute and chronic animal models to our understanding of epilepsies featuring non-convulsive generalized seizures, the typical and atypical absence seizures. Typical absences comprise about 5% of all epilepsies regardless of age and the atypical ones are even more common. Although absence epilepsy was thought to be relatively benign, children with childhood epilepsy (CAE) turn out to have a high rate of pretreatment attention deficits that persist despite seizure freedom. The phenomenon of the absence seizure has long attracted research interest because of the clear temporal relationship of the conspicuous EEG rhythm of 3 Hz generalized spike and wave discharges (GSWD) and the parallel transient "loss of consciousness" characterizing these seizures which is time-locked with the GSWD. Indeed, clinical epileptologists, basic scientists and neurophysiologists have long recognized in GSWD a unique electrographic and behavioral marker of the genetic predisposition to most types of epilepsy. Interestingly, the subject is still controversial since it has recently been proposed that both classification terms of CAE currently in use: idiopathic and primary generalized, be abandoned - a point of debate. Both issues - underlying mechanisms and focal origin of absence seizures - may be further enlightened by observations in valid animal models.
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Affiliation(s)
- Miguel A Cortez
- Division of Neurology, Neuroscience and Mental Health Program, SickKids Research Institute, Hospital for Sick Children, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | | | - O Carter Snead
- Division of Neurology, Neuroscience and Mental Health Program, SickKids Research Institute, Hospital for Sick Children, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada.
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Venzi M, Di Giovanni G, Crunelli V. A critical evaluation of the gamma-hydroxybutyrate (GHB) model of absence seizures. CNS Neurosci Ther 2015; 21:123-40. [PMID: 25403866 PMCID: PMC4335601 DOI: 10.1111/cns.12337] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/13/2014] [Accepted: 09/17/2014] [Indexed: 12/13/2022] Open
Abstract
Typical absence seizures (ASs) are nonconvulsive epileptic events which are commonly observed in pediatric and juvenile epilepsies and may be present in adults suffering from other idiopathic generalized epilepsies. Our understanding of the pathophysiological mechanisms of ASs has been greatly advanced by the availability of genetic and pharmacological models, in particular the γ-hydroxybutyrate (GHB) model which, in recent years, has been extensively used in studies in transgenic mice. GHB is an endogenous brain molecule that upon administration to various species, including humans, induces not only ASs but also a state of sedation/hypnosis. Analysis of the available data clearly indicates that only in the rat does there exist a set of GHB-elicited behavioral and EEG events that can be confidently classified as ASs. Other GHB activities, particularly in mice, appear to be mostly of a sedative/hypnotic nature: thus, their relevance to ASs requires further investigation. At the molecular level, GHB acts as a weak GABA-B agonist, while the existence of a GHB receptor remains elusive. The pre- and postsynaptic actions underlying GHB-elicited ASs have been thoroughly elucidated in thalamus, but little is known about the cellular/network effects of GHB in neocortex, the other brain region involved in the generation of ASs.
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Affiliation(s)
- Marcello Venzi
- Neuroscience DivisionSchool of BioscienceCardiff UniversityCardiffUK
| | - Giuseppe Di Giovanni
- Neuroscience DivisionSchool of BioscienceCardiff UniversityCardiffUK
- Department of Physiology and BiochemistryMalta UniversityMsida, Malta
| | - Vincenzo Crunelli
- Neuroscience DivisionSchool of BioscienceCardiff UniversityCardiffUK
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van Luijtelaar G, Onat FY, Gallagher MJ. Animal models of absence epilepsies: what do they model and do sex and sex hormones matter? Neurobiol Dis 2014; 72 Pt B:167-79. [PMID: 25132554 DOI: 10.1016/j.nbd.2014.08.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 08/05/2014] [Accepted: 08/07/2014] [Indexed: 11/28/2022] Open
Abstract
While epidemiological data suggest a female prevalence in human childhood- and adolescence-onset typical absence epilepsy syndromes, the sex difference is less clear in adult-onset syndromes. In addition, although there are more females than males diagnosed with typical absence epilepsy syndromes, there is a paucity of studies on sex differences in seizure frequency and semiology in patients diagnosed with any absence epilepsy syndrome. Moreover, it is unknown if there are sex differences in the prevalence or expression of atypical absence epilepsy syndromes. Surprisingly, most studies of animal models of absence epilepsy either did not investigate sex differences, or failed to find sex-dependent effects. However, various rodent models for atypical syndromes such as the AY9944 model (prepubertal females show a higher incidence than prepubertal males), BN model (also with a higher prevalence in males) and the Gabra1 deletion mouse in the C57BL/6J strain offer unique possibilities for the investigation of the mechanisms involved in sex differences. Although the mechanistic bases for the sex differences in humans or these three models are not yet known, studies of the effects of sex hormones on seizures have offered some possibilities. The sex hormones progesterone, estradiol and testosterone exert diametrically opposite effects in genetic absence epilepsy and pharmacologically-evoked convulsive types of epilepsy models. In addition, acute pharmacological effects of progesterone on absence seizures during proestrus are opposite to those seen during pregnancy. 17β-Estradiol has anti-absence seizure effects, but it is only active in atypical absence models. It is speculated that the pro-absence action of progesterone, and perhaps also the delayed pro-absence action of testosterone, are mediated through the neurosteroid allopregnanolone and its structural and functional homolog, androstanediol. These two steroids increase extrasynaptic thalamic tonic GABAergic inhibition by selectively targeting neurosteroid-selective subunits of GABAA receptors (GABAARs). Neurosteroids also modulate the expression of GABAAR containing the γ2, α4, and δ subunits. It is hypothesized that differences in subunit expression during pregnancy and ovarian cycle contribute to the opposite effects of progesterone in these two hormonal states.
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Affiliation(s)
- Gilles van Luijtelaar
- Donders Centre of Cognition, Radboud University Nijmegen, Nijmegen, The Netherlands.
| | - Filiz Yilmaz Onat
- Department of Pharmacology, School of Medicine, Marmara University, Istanbul, Turkey
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Are alterations in transmitter receptor and ion channel expression responsible for epilepsies? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 813:211-29. [PMID: 25012379 DOI: 10.1007/978-94-017-8914-1_17] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neuronal voltage-gated ion channels and ligand-gated synaptic receptors play a critical role in maintaining the delicate balance between neuronal excitation and inhibition within neuronal networks in the brain. Changes in expression of voltage-gated ion channels, in particular sodium, hyperpolarization-activated cyclic nucleotide-gated (HCN) and calcium channels, and ligand-gated synaptic receptors, in particular GABA and glutamate receptors, have been reported in many types of both genetic and acquired epilepsies, in animal models and in humans. In this chapter we review these and discuss the potential pathogenic role they may play in the epilepsies.
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Bony G, Szczurkowska J, Tamagno I, Shelly M, Contestabile A, Cancedda L. Non-hyperpolarizing GABAB receptor activation regulates neuronal migration and neurite growth and specification by cAMP/LKB1. Nat Commun 2013; 4:1800. [PMID: 23653212 DOI: 10.1038/ncomms2820] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 03/28/2013] [Indexed: 12/28/2022] Open
Abstract
γ-Aminobutyric acid is the principal inhibitory neurotransmitter in adults, acting through ionotropic chloride-permeable GABAA receptors (GABAARs), and metabotropic GABABRs coupled to calcium or potassium channels, and cyclic AMP signalling. During early development, γ-aminobutyric acid is the main neurotransmitter and is not hyperpolarizing, as GABAAR activation is depolarizing while GABABRs lack coupling to potassium channels. Despite extensive knowledge on GABAARs as key factors in neuronal development, the role of GABABRs remains unclear. Here we address GABABR function during rat cortical development by in utero knockdown (short interfering RNA) of GABABR in pyramidal-neuron progenitors. GABABR short interfering RNA impairs neuronal migration and axon/dendrite morphological maturation by disrupting cyclic AMP signalling. Furthermore, GABABR activation reduces cyclic AMP-dependent phosphorylation of LKB1, a kinase involved in neuronal polarization, and rescues LKB1 overexpression-induced defects in cortical development. Thus, non-hyperpolarizing activation of GABABRs during development promotes neuronal migration and morphological maturation by cyclic AMP/LKB1 signalling.
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Affiliation(s)
- Guillaume Bony
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Via Morego, 30 Genoa 16163, Italy
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Gaiarsa JL, Porcher C. Emerging neurotrophic role of GABAB receptors in neuronal circuit development. Front Cell Neurosci 2013; 7:206. [PMID: 24282395 PMCID: PMC3824957 DOI: 10.3389/fncel.2013.00206] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 10/18/2013] [Indexed: 12/22/2022] Open
Abstract
The proper development of highly organized structures in the central nervous system is a complex process during which key events – neurogenesis, migration, growth, differentiation, and synaptogenesis – have to take place in an appropriate manner to create functional neuronal networks. It is now well established that GABA, the main inhibitory neurotransmitter in the adult mammalian brain, plays more than a classical inhibitory role and can function as an important developmental signal early in life. GABA binds to chloride-permeable ionotropic GABAA receptors and to G-protein-coupled GABAB receptors (GABAB-Rs). Although most of the trophic actions of GABA have been attributed to the activation of GABAA receptors, recent advances show that GABAB-Rs also regulate fundamental steps of network development. This review summarizes some of the recent progress about the neurotrophic role of GABAB-Rs to neuronal development.
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Affiliation(s)
- Jean-Luc Gaiarsa
- Institut National de la Santé et de la Recherche Médicale U-901 Marseille, France ; Aix-Marseille Université, UMR S901 Marseille, France ; Institut de Neurobiologie de la Méditerranée Marseille, France
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15
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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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Jung S, Seo JS, Kim BS, Lee D, Jung KH, Chu K, Lee SK, Jeon D. Social deficits in the AY-9944 mouse model of atypical absence epilepsy. Behav Brain Res 2013; 236:23-29. [DOI: 10.1016/j.bbr.2012.08.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 08/17/2012] [Accepted: 08/18/2012] [Indexed: 02/06/2023]
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17
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Lalonde R, Strazielle C. Brain regions and genes affecting myoclonus in animals. Neurosci Res 2012; 74:69-79. [PMID: 22824643 DOI: 10.1016/j.neures.2012.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 06/02/2012] [Accepted: 07/12/2012] [Indexed: 01/26/2023]
Abstract
Myoclonus is defined as large-amplitude rhythmic movements. Brain regions underlying myoclonic jerks include brainstem, cerebellum, and cortex. Gamma-aminobutyric acid (GABA) appears to be the main neurotransmitter involved in myoclonus, possibly interacting with biogenic amines, opiates, acetylcholine, and glycine. Myoclonic jumping is a specific subtype seen in rodents, comprising rearing and hopping continuously against a wall. Myoclonic jumping can be seen in normal mouse strains, possibly as a result of simply being put inside a cage. Like other types, it is also triggered by changes in GABA, 5HT, and dopamine neurotransmission. Implicated brain regions include hippocampus and dorsal striatum, possibly with respect to D(1) dopamine, NMDA, and δ opioid receptors. There is reason to suspect that myoclonic jumping is underreported due to insufficient observations into mouse cages.
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Affiliation(s)
- R Lalonde
- Université de Rouen, UFR des Sciences Humaines et Sociales, Laboratoire de Psychologie et Neurosciences: Intégration COgnitive du NEurone à la Société (ICONES), 76821 Mont Saint-Aignan Cedex, France.
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Badawy RAB, Johnson KA, Cook MJ, Harvey AS. A mechanistic appraisal of cognitive dysfunction in epilepsy. Neurosci Biobehav Rev 2012; 36:1885-96. [PMID: 22617705 DOI: 10.1016/j.neubiorev.2012.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/24/2012] [Accepted: 05/13/2012] [Indexed: 12/14/2022]
Abstract
A strong relationship between the clinical characteristics of epilepsy and the nature of cognitive impairments associated with the condition has been found, but the nature of this relationship appears to be quite complex and not well understood. This review presents a summary of the research on the interaction between cognition and epilepsy, surveyed from a mechanistic perspective with the aim of clarifying factors that contribute to the co-existence of both disorders. The physiological basis underpinning cognitive processing is first reviewed. The physiology of epilepsy is reviewed, with emphasis placed on interictal discharges and seizures. The nature of the impact of epilepsy on cognition is described, with transient and prolonged effects distinguished. Finally, the complexity of the co-morbidity between cognitive dysfunction and epilepsy is discussed in relation to childhood and adult-onset epilepsy syndromes and severe epileptic encephalopathies. Structural and functional abnormalities exist in patients with epilepsy that may underpin both the cognitive dysfunction and epilepsy, highlighting the complexity of the association. Research, possibly of a longitudinal nature, is needed to elucidate this multifactorial relationship between cognitive dysfunction and epilepsy.
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Affiliation(s)
- Radwa A B Badawy
- Department of Clinical Neurosciences, St. Vincent's Hospital, Melbourne, Victoria, Australia; Department of Medicine, Melbourne, Victoria, Australia; Electrical and Electronic Engineering, Melbourne, Victoria, Australia. ,
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del Campo CM, Velázquez JLP, Freire MAC. EEG recording in rodents, with a focus on epilepsy. ACTA ACUST UNITED AC 2010; Chapter 6:Unit 6.24. [PMID: 19802816 DOI: 10.1002/0471142301.ns0624s49] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This unit describes the materials, methods, and analytical techniques available for the study of electrical activity of neural tissue in rodents in both homeostatic and disease states, with emphasis on epileptogenesis. A table containing a list of suppliers of relevant materials and equipment is also provided.
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Wang X, Stewart L, Cortez MA, Wu Y, Velazquez JLP, Liu CC, Shen L, Snead OC. The circuitry of atypical absence seizures in GABA(B)R1a transgenic mice. Pharmacol Biochem Behav 2009; 94:124-30. [PMID: 19666047 DOI: 10.1016/j.pbb.2009.07.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 07/20/2009] [Accepted: 07/28/2009] [Indexed: 01/30/2023]
Abstract
The objective of the current study was to determine the origin of the slow spike and wave discharges (SSWD) in the transgenic mouse with postnatal over-expression of the GABA(B) receptor subunit R1a (GABA(B)R1a(tg)), a mutant animal with a characteristic phenotype consisting of atypical absence seizures and cognitive dysfunction. Using simultaneous electrocorticographic (ECoG) recordings from cortical and depth electrodes in freely moving GABA(B)R1a(tg) mice, we showed that the SSWD in this model of atypical absence seizures arise exclusively from midline thalamus (MT), reticular nucleus of the thalamus (nRT), and the CA1 region of the hippocampus. Lesioning of the MT and nRT with ibotenic acid abolished SSWD. Microinjection of the GABA(B) receptor agonist, (-) baclofen, into MT and nRT exacerbated, and the GABA(B)R antagonist, CGP 35348 abolished, SSWD in the GABA(B)R1a(tg) mice. These data suggest that the nRT and MT are necessary for the generation of SSWD in the GABA(B)R1a(tg) model of atypical absence seizures, and indicate that GABA(B)R-mediated mechanisms within thalamus are necessary for the genesis of SSWD in atypical absence seizures. A putative cortico-thalamo-hippocampal circuit is proposed to explain the unique electrographic findings, ictal behavior, pharmacology, and impairment of cognition that characterize atypical absence seizures.
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Affiliation(s)
- Xiaomei Wang
- Neuroscience and Mental Health Program, Faculty of Medicine, University of Toronto, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G1X8, Canada.
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Galanopoulou AS, Moshé SL. The epileptic hypothesis: developmentally related arguments based on animal models. Epilepsia 2009; 50 Suppl 7:37-42. [PMID: 19682049 DOI: 10.1111/j.1528-1167.2009.02217.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The significant morbidity linked to epileptic encephalopathies of childhood has prompted the need to identify and dissect the factors and mechanisms that contribute to the resultant functional regression. Although experiments specifically assessing language in rodents are difficult to design, a number of studies have shed light on the conditions that contribute to the functional deterioration. In particular, interictal spikes and seizures, especially if prolonged or frequent, may cause acute or long-lasting effects on brain functioning and development, which may impair performance in a variety of behavioral tests. These effects are further modified by a number of genetic, biological, and epigenetic factors, including age, sex, and underlying pathology, which further diversify outcome. Of special importance is the developmental age when the epileptic disorder manifests, because it may dictate outcome but also may be a deciding factor in selecting appropriate therapies.
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Affiliation(s)
- Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY 10461, U.S.A.
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Cortez MA, Shen L, Wu Y, Aleem IS, Trepanier CH, Sadeghnia HR, Ashraf A, Kanawaty A, Liu CC, Stewart L, Snead OC. Infantile spasms and Down syndrome: a new animal model. Pediatr Res 2009; 65:499-503. [PMID: 19190545 DOI: 10.1203/pdr.0b013e31819d9076] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Infantile spasms is a catastrophic childhood seizure disorder for which few animal models exist. Children with Down syndrome are highly susceptible to infantile spasms. The Ts65Dn mouse is a valid model for Down syndrome; therefore, we tested the hypothesis that the Ts65Dn mouse represents a substrate for an animal model of infantile spasms. The baseline of naïve Ts65Dn mice showed spontaneous spike-and-wave discharges, a pattern that worsened with baclofen and gamma-butyrolactone, which induced acute epileptic extensor spasms (AEES) associated with epileptiform polyspike bursts and an electrodecremental response on the EEG. GABABR-agonist-induced AEES were significantly reduced with vigabatrin, rodent ACTH fragment, valproic acid, ethosuximide, and CGP 35348. Porcine ACTH had no effect. GABABR protein expression was significantly increased in the thalamus and medulla oblongata of Ts65D mice in comparison with wild-type controls. The GABABR agonist-treated Ts65Dn mouse shows the unique clinical, electrographic, and pharmacologic signature of infantile spasms and represents a valid, acute model of this disorder. GABABR-mediated mechanisms may contribute to the increased susceptibility of children with Down syndrome to infantile spasms.
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Affiliation(s)
- Miguel A Cortez
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
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Stewart LS, Wu Y, Eubanks JH, Han H, Leschenko Y, Perez Velazquez JL, Cortez MA, Snead OC. Severity of atypical absence phenotype in GABAB transgenic mice is subunit specific. Epilepsy Behav 2009; 14:577-81. [PMID: 19435582 DOI: 10.1016/j.yebeh.2009.01.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 01/19/2009] [Accepted: 01/24/2009] [Indexed: 10/21/2022]
Abstract
Overexpression of GABA(B)R1a receptors in mice (R1a(+)) results in an atypical absence seizure phenotype characterized by 3- to 6-Hz slow spike-and-wave discharges (SSWDs), reduced synaptic plasticity, and cognitive impairment. Here we tested the hypothesis that increased R1 expression causes atypical absence epilepsy and is not subunit specific. GABA(B)R1b receptors were overexpressed in mouse forebrain (R1b(+)) and confirmed by immunoblot and (3)H-CGP54626A autoradiography. The R1b(+) mice showed a reduction in hippocampal long-term potentiation and GABA(A) receptor-mediated inhibitory postsynaptic currents. R1b(+) mice manifested an electrographic, pharmacological, and behavioral phenotype consistent with atypical absence seizures, though less robust than R1a(+) in terms of SSWD duration and severity of cognitive impairment. These results suggest that abnormal GABA(B)R1b function plays a lesser role in the development of atypical absence epilepsy.
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Affiliation(s)
- Lee S Stewart
- Neurosciences and Mental Health Research Program, The Hospital for Sick Children, Toronto, ON, Canada
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Bercovici E, Cortez MA, Wang X, Snead III OC. Monoamine variability in the chronic model of atypical absence seizures. Epilepsia 2009; 50:768-75. [DOI: 10.1111/j.1528-1167.2008.01880.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Huo JZ, Cortez MA, Snead III OC. GABA receptor proteins within lipid rafts in the AY-9944 model of atypical absence seizures. Epilepsia 2009; 50:776-88. [DOI: 10.1111/j.1528-1167.2008.01903.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ulrich D, Besseyrias V, Bettler B. Functional mapping of GABA(B)-receptor subtypes in the thalamus. J Neurophysiol 2007; 98:3791-5. [PMID: 17881477 DOI: 10.1152/jn.00756.2007] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The thalamus plays an important role in attention mechanisms and the generation of brain rhythms. gamma-Aminobutyric acid type B (GABA(B)) receptors are known to regulate the main output neurons of the thalamus, the thalamocortical relay (TCR) cells. However, the contributions of the two predominant GABA(B)-receptor subtypes, GABA(B(1a,2)) and GABA(B(1b,2)), to the control of TCR cell activity are unknown. Here, we used genetic and electrophysiological methods to investigate subtype-specific GABA(B) effects at the inputs to TCR cells. We found that mainly GABA(B(1a,2)) receptors inhibit the release of glutamate from corticothalamic fibers impinging onto TCR cells. In contrast, both GABA(B(1a,2)) and GABA(B(1b,2)) receptors efficiently inhibit the release of GABA from thalamic reticular nucleus (TRN) neurons onto TCR neurons. Likewise, both GABA(B(1a,2)) and GABA(B(1b,2)) receptors efficiently activate somatodendritic K(+) currents in TCR cells. In summary, our data show that GABA(B(1b,2)) receptors cannot compensate for the absence of GABA(B(1a,2)) receptors at glutamatergic inputs to TCR cells. This shows that the predominant association of GABA(B(1a,2)) receptors with glutamatergic terminals is a feature that is preserved at several brain synapses. Furthermore, our data indicate that the cognitive deficits observed with mice lacking GABA(B(1a,2)) receptors could to some extent relate to attention deficits caused by disinhibited release of glutamate onto TCR neurons.
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Affiliation(s)
- Daniel Ulrich
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland.
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