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Witkin JM, Radin DP, Rana S, Fuller DD, Fusco AF, Demers JC, Pradeep Thakre P, Smith JL, Lippa A, Cerne R. AMPA receptors play an important role in the biological consequences of spinal cord injury: Implications for AMPA receptor modulators for therapeutic benefit. Biochem Pharmacol 2024:116302. [PMID: 38763261 DOI: 10.1016/j.bcp.2024.116302] [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: 03/04/2024] [Revised: 05/07/2024] [Accepted: 05/16/2024] [Indexed: 05/21/2024]
Abstract
Spinal cord injury (SCI) afflicts millions of individuals globally. There are few therapies available to patients. Ascending and descending excitatory glutamatergic neural circuits in the central nervous system are disrupted by SCI, making α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) a potential therapeutic drug target. Emerging research in preclinical models highlights the involvement of AMPARs in vital processes following SCI including breathing, pain, inflammation, bladder control, and motor function. However, there are no clinical trial data reported in this patient population to date. No work on the role of AMPA receptors in sexual dysfunction after SCI has been disclosed. Compounds with selective antagonist and potentiating effects on AMPA receptors have benefit in animal models of SCI, with antagonists generally showing protective effects early after injury and potentiators (ampakines) producing improved breathing and bladder function. The role of AMPARs in pathophysiology and recovery after SCI depends upon the time post injury, and the timing of AMPAR augmentation or antagonism. The roles of inflammation, synaptic plasticity, sensitization, neurotrophic factors, and neuroprotection are considered in this context. The data summarized and discussed in this paper document proof of principle and strongly encourage additional studies on AMPARs as novel gateways to therapeutic benefit for patients suffering from SCI. The availability of both AMPAR antagonists such as perampanel and AMPAR allosteric modulators (i.e., ampakines) such as CX1739, that have been safely administered to humans, provides an expedited means of clinical inquiry for possible therapeutic advances.
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Affiliation(s)
- Jeffrey M Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; Departments of Neuroscience and Trauma Research, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA.
| | | | - Sabhya Rana
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Anna F Fusco
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Julie C Demers
- Indiana University/Purdue University, Indianapolis, IN, USA
| | - Prajwal Pradeep Thakre
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Jodi L Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA
| | - Arnold Lippa
- RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA
| | - Rok Cerne
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA; Faculty of Medicine, University of Ljubljana, Zaloška Cesta 4, Ljubljana, Slovenia
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2
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Yu J, Wang G, Chen Z, Wan L, Zhou J, Cai J, Liu X, Wang Y. Deficit of PKHD1L1 in the dentate gyrus increases seizure susceptibility in mice. Hum Mol Genet 2023; 32:506-519. [PMID: 36067019 DOI: 10.1093/hmg/ddac220] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/28/2022] [Accepted: 08/30/2022] [Indexed: 01/24/2023] Open
Abstract
Epilepsy is a chronic neurological disorder featuring recurrent, unprovoked seizures, which affect more than 65 million people worldwide. Here, we discover that the PKHD1L1, which is encoded by polycystic kidney and hepatic disease1-like 1 (Pkhd1l1), wildly distributes in neurons in the central nervous system (CNS) of mice. Disruption of PKHD1L1 in the dentate gyrus region of the hippocampus leads to increased susceptibility to pentylenetetrazol-induced seizures in mice. The disturbance of PKHD1L1 leads to the overactivation of the mitogen-activated protein kinase (MAPK)/extracellular regulated kinase (ERK)-Calpain pathway, which is accompanied by remarkable degradation of cytoplasmic potassium chloride co-transporter 2 (KCC2) level together with the impaired expression and function of membrane KCC2. However, the reduction of membrane KCC2 is associated with the damaged inhibitory ability of the vital GABA receptors, which ultimately leads to the significantly increased susceptibility to epileptic seizures. Our data, thus, indicate for the first time that Pkhd1l1, a newly discovered polycystic kidney disease (PKD) association gene, is required in neurons to maintain neuronal excitability by regulation of KCC2 expression in CNS. A new mechanism of the clinical association between genetic PKD and seizures has been built, which could be a potential therapeutic target for treating PKD-related seizures.
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Affiliation(s)
- Jiangning Yu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Guoxiang Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Zhiyun Chen
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Li Wan
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China.,Rehabilitation Center, Shenzhen Second People's Hospital/the First Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518035, China
| | - Jing Zhou
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China.,Rehabilitation Center, Shenzhen Second People's Hospital/the First Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518035, China
| | - Jingyi Cai
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Xu Liu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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3
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Chen L, Yu J, Wan L, Wu Z, Wang G, Hu Z, Ren L, Zhou J, Qian B, Zhao X, Zhang J, Liu X, Wang Y. Furosemide prevents membrane KCC2 downregulation during convulsant stimulation in the hippocampus. IBRO Neurosci Rep 2022; 12:355-365. [PMID: 35746976 PMCID: PMC9210493 DOI: 10.1016/j.ibneur.2022.04.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/15/2022] [Accepted: 04/25/2022] [Indexed: 02/08/2023] Open
Abstract
In adults, γ-aminobutyric acid (GABA) type A receptor (GABAAR)-mediated inhibition depends on the maintenance of low intracellular chloride anion concentration through neuron-specific potassium-chloride cotransporter-2 (KCC2). KCC2 has been widely reported to have a plasticity change during the course of epilepsy development, with an early downregulation and late recovery in neuronal cell membranes after epileptic stimulation, which facilitates epileptiform burst activity. Furosemide is a clinical loop diuretic that inhibits KCC2. Here, we first confirmed that furosemide pretreatment could effectively prevented convulsant stimulation-induced neuronal membrane KCC2 downregulation in the hippocampus in both in vivo and in vitro cyclothiazide-induced seizure model. Second, we verified that furosemide pretreatment rescued KCC2 function deficits, as indicated by E GABA depolarizing shift and GABAAR inhibitory function impairment induced via cyclothiazide treatment. Further, we demonstrated that furosemide also suppressed cyclothiazide-induced epileptiform burst activity in cultured hippocampal neurons and lowered the mortality rate during acute seizure induction. Overall, furosemide prevents membrane KCC2 downregulation during acute seizure induction, restores KCC2-mediated GABA inhibition, and interrupts the progression from acute seizure to epileptogenesis.
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Affiliation(s)
- Lulan Chen
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Jiangning Yu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Li Wan
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
- Rehabilitation Center, Shenzhen Second People's Hospital/ the First Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518035, China Institute of
| | - Zheng Wu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Guoxiang Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Zihan Hu
- Department of Anesthesiology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Liang Ren
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Jing Zhou
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
- Rehabilitation Center, Shenzhen Second People's Hospital/ the First Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen 518035, China Institute of
| | - Binbin Qian
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Xuan Zhao
- Department of Anesthesiology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
- Correspondence to: Department of Anesthesiology, Shanghai Tenth People’s Hospital, China.
| | - Jinwei Zhang
- Biomedical and Clinical Sciences, Medical School, College of Medicine and Health, University of Exeter, Hatherly Laboratories, Exeter EX4 4PS, UK
| | - Xu Liu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
- Correspondence to: Department of Neurology, Zhongshan Hospital, Fudan University, China.
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
- Correspondence to: Institutes of Brain Science, Fudan University, Shanghai 200032, China.
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Sun JH, Chen J, Ayala Valenzuela FE, Brown C, Masser-Frye D, Jones M, Romero LP, Rinaldi B, Li WL, Li QQ, Wu D, Gerard B, Thorpe E, Bayat A, Shi YS. X-linked neonatal-onset epileptic encephalopathy associated with a gain-of-function variant p.R660T in GRIA3. PLoS Genet 2021; 17:e1009608. [PMID: 34161333 PMCID: PMC8259962 DOI: 10.1371/journal.pgen.1009608] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 07/06/2021] [Accepted: 05/18/2021] [Indexed: 12/02/2022] Open
Abstract
The X-linked GRIA3 gene encodes the GLUA3 subunit of AMPA-type glutamate receptors. Pathogenic variants in this gene were previously reported in neurodevelopmental diseases, mostly in male patients but rarely in females. Here we report a de novo pathogenic missense variant in GRIA3 (c.1979G>C; p. R660T) identified in a 1-year-old female patient with severe epilepsy and global developmental delay. When exogenously expressed in human embryonic kidney (HEK) cells, GLUA3_R660T showed slower desensitization and deactivation kinetics compared to wildtype (wt) GLUA3 receptors. Substantial non-desensitized currents were observed with the mutant but not for wt GLUA3 with prolonged exposure to glutamate. When co-expressed with GLUA2, the decay kinetics were similarly slowed in GLUA2/A3_R660T with non-desensitized steady state currents. In cultured cerebellar granule neurons, miniature excitatory postsynaptic currents (mEPSCs) were significantly slower in R660T transfected cells than those expressing wt GLUA3. When overexpressed in hippocampal CA1 neurons by in utero electroporation, the evoked EPSCs and mEPSCs were slower in neurons expressing R660T mutant compared to those expressing wt GLUA3. Therefore our study provides functional evidence that a gain of function (GoF) variant in GRIA3 may cause epileptic encephalopathy and global developmental delay in a female subject by enhancing synaptic transmission. Glutamate is the excitatory neurotransmitter in brain, abnormality of which causes excitotoxicity and diseases. Here we identified a pathogenic missense variant in GRIA3 gene in a female patient with severe epilepsy and global developmental delay. The X-linked GRIA3 gene encodes GLUA3, a subunit of glutamate receptors. Through electrophysiological analysis of the mutant GLUA3 in a cell line and mouse neurons, we found this mutant makes strengthened glutamate receptors. This study thus indicates that the variant causes epileptic encephalopathy and global developmental delay by enhancing glutamate signaling in brain.
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Affiliation(s)
- Jia-Hui Sun
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Department of Neurology, Affiliated Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Jiang Chen
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Department of Neurology, Affiliated Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
| | | | - Carolyn Brown
- Illumina Inc., San Diego, California, United States of America
| | - Diane Masser-Frye
- Division of Genetics, Department of Pediatrics, UC San Diego School of Medicine, Rady Children’s Hospital, San Diego, California, United States of America
| | - Marilyn Jones
- Division of Genetics, Department of Pediatrics, UC San Diego School of Medicine, Rady Children’s Hospital, San Diego, California, United States of America
| | - Leslie Patron Romero
- Facultad de Medicina y Psicología, Universidad Autónoma de Baja California, Tijuana, Mexico
| | - Berardo Rinaldi
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Wenhui Laura Li
- Breakthrough Genomics Inc., Irvine, California, United States of America
| | - Qing-Qing Li
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Department of Neurology, Affiliated Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Dan Wu
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Department of Neurology, Affiliated Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Benedicte Gerard
- Laboratoires de diagnostic génétique, Institut Medical d’Alsace, Hôpitaux Universitaire de Strasbourg, Strasbourg, France
| | - Erin Thorpe
- Illumina Inc., San Diego, California, United States of America
- * E-mail: (ET); (AB); (YSS)
| | - Allan Bayat
- Department for Genetics and Personalized Medicine, Danish Epilepsy Centre, Dianalund, Denmark
- Institute for Regional Health Services Research, University of Southern Denmark, Odense, Denmark
- * E-mail: (ET); (AB); (YSS)
| | - Yun Stone Shi
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Department of Neurology, Affiliated Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Nanjing University, Nanjing, China
- Institute for Brain Sciences, Nanjing University, Nanjing, China
- Chemistry and Biomedicine Innovation Center, Nanjing University, Nanjing, China
- * E-mail: (ET); (AB); (YSS)
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5
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Wan L, Chen L, Yu J, Wang G, Wu Z, Qian B, Liu X, Wang Y. Coordinated downregulation of KCC2 and GABA A receptor contributes to inhibitory dysfunction during seizure induction. Biochem Biophys Res Commun 2020; 532:489-495. [PMID: 32892950 DOI: 10.1016/j.bbrc.2020.08.082] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 08/22/2020] [Indexed: 01/25/2023]
Abstract
The GABAA receptor (GABAAR) is the main inhibitory receptor in the adult mammalian brain. GABAAR function is dependent on its expression, distribution, and the chloride (Cl-) transmembrane gradient, which is determined by the potassium-chloride cotransporter 2 (KCC2) in the adult brain. KCC2 and GABAAR are downregulated in an activity-dependent manner during seizure induction. Functionally, KCC2 and GABAAR are closely related membrane proteins which modulate GABAergic inhibition. However, it remains unclear how their downregulation during seizure induction is coordinated. This study aimed to assess this interaction. Our results revealed that KCC2 and GABAAR were simultaneously downregulated in both in vivo and in vitro seizure models induced by the convulsant cyclothazide (CTZ), which was at least partly due to structural coupling in hippocampal neuronal membranes. Immunohistochemistry revealed colocalization of gephyrin with KCC2 and co-immunoprecipitation exhibited a direct coupling between GABAAR α1-subunit and KCC2 protein in hippocampal cell membranes. KCC2 specific short hairpin RNA (KCC2-shRNA) was employed to specifically reduce the expression of KCC2 in cultured hippocampal neurons. This resulted in a significant reduction in KCC2-independent GABAergic miniature inhibitory post-synaptic current (mIPSC) amplitude in shKCC2-transfected neurons. Further, pre-treatment with furosemide, a KCC2 inhibitor, during CTZ stimulation followed by washout significantly prevented convulsant stimulation-induced membrane KCC2 downregulation and significantly attenuated GABAAR downregulation concomitant with recovery of suppressed KCC2-independent GABAergic mIPSC amplitude. Our results suggest that the coordinated downregulation of KCC2 and GABAAR during seizure induction exerts a strong functional impact on GABAAR, highlighting an important regulatory mechanism in epilepsy.
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Affiliation(s)
- Li Wan
- Rehabilitation Center, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, 518035, China.
| | - Lulan Chen
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Jiangning Yu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Guoxiang Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Zheng Wu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Binbin Qian
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Xu Liu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
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Neurochemical investigation of multiple locally induced seizures using microdialysis sampling: Epilepsy effects on glutamate release. Brain Res 2019; 1722:146360. [PMID: 31377104 DOI: 10.1016/j.brainres.2019.146360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/30/2019] [Accepted: 07/31/2019] [Indexed: 12/30/2022]
Abstract
The objective of this study was to develop an in vivo model for locally induced epilepsy. Epilepsy is a prominent neurological disorder that affects millions of people worldwide. Patients may experience either global seizures, affecting the entire brain, or focal seizures, affecting only one brain region. The majority of epileptic patients experience focal seizures but they go undiagnosed because such seizures can be difficult to detect. To better understand the effects of focal epilepsy on the neurochemistry of a brain region with high seizure diathesis, an animal model for locally induced seizures in the hippocampus was developed. In this model, two seizure events were chemically induced by administering the epileptogenic agent, 3-mercaptopropionic acid (3-MPA), to the hippocampus to disturb the balance between excitatory and inhibitory neurotransmitters in the brain. Microdialysis was used for local delivery of 3-MPA as well as for collection of dialysate for neurochemical analyses. Two periods of seizures separated by varying inter-seizure recovery times were employed, and changes in the release of the excitatory transmitter, glutamate, were measured. Significant differences in glutamate release were observed between the first and second seizure episodes. Diminished glutamate biosynthesis, enhanced glutamate re-uptake, and/or neuronal death were considered possible causes of the attenuated glutamate release during the second seizure episode. Biochemical measurements were indicative that a combination of these factors led to the attenuation in glutamate release.
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Ghadiri T, Vakilzadeh G, Hajali V, Khodagholi F. Progesterone modulates post-traumatic epileptogenesis through regulation of BDNF-TrkB signaling and cell survival-related pathways in the rat hippocampus. Neurosci Lett 2019; 709:134384. [PMID: 31325580 DOI: 10.1016/j.neulet.2019.134384] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/02/2019] [Accepted: 07/17/2019] [Indexed: 01/20/2023]
Abstract
Female sex hormone, progesterone, in addition to seizure modifying activity is also known as a potential protective agent against various brain injury conditions. Considering the predisposal role of traumatic brain injury (TBI) on developing post-traumatic epilepsy (PTE), the effect of progesterone on post-traumatic epileptogenesis is not investigated yet. Male Wistar rats were given a moderate focal weight drop injury (500 gr) or sham surgery and then progesterone (16 and 32mg/kg) was given daily for two consecutive weeks. On day 15 of injury, seizures were induced by administration of a GABAA receptor antagonist, pentylenetetrazole (PTZ, 30 mg/kg). Seizures were then assessed over a 1-h period using the Racine clinical rating scale. Traumatized animals that received 32 mg/kg progesterone had reduced score, duration of seizures and almost did not show tonic-clonic seizures during 60 min versus the untreated trauma group. In line with behavioral alterations, 32 mg/kg progesterone enhanced the amount of Nrf2 and HO-1 proteins and decreased the level of NF-kB, BDNF, Caspase 3 and ratio of Bax/Bcl-2 in the ipsilateral hippocampus. Additionally, the number of TUNEL-positive apoptotic cells, as well as injured dark neurons in the parietal cortex and hippocampal CA1 of 32 mg/kg-treated animals showed a significant reduction. Administration of 16 mg/kg progesterone elevated production of BDNF, Bax and Caspase 3 and decreased anti-apoptotic Bcl-2 protein. Taken together, an early administration of 32 mg/kg of progesterone after TBI for two weeks post-injury modified seizure activity. Our findings suggest that post-traumatic anti-epileptogenesis property of a high dose of progesterone partly occurs through the manipulation of BDNF-TrkB axis along with control of cell survival pathways.
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Affiliation(s)
- Tahereh Ghadiri
- Department of Neurosciences, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
| | | | - Vahid Hajali
- Quchan Higher Health Education Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Fariba Khodagholi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Wan L, Ren L, Chen L, Wang G, Liu X, Wang BH, Wang Y. M-Calpain Activation Facilitates Seizure Induced KCC2 Down Regulation. Front Mol Neurosci 2018; 11:287. [PMID: 30186110 PMCID: PMC6110871 DOI: 10.3389/fnmol.2018.00287] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 07/30/2018] [Indexed: 12/12/2022] Open
Abstract
Potassium chloride co-transporter 2 (KCC2), a major chloride transporter that maintains GABAA receptor inhibition in mature mammalian neurons, is down-regulated in the hippocampus during epileptogenesis. Impaired KCC2 function accelerates or facilitates seizure onset. Calpain, with two main subtypes of m- and μ-calpain, is a Ca2+-dependent cysteine protease that mediates the nonlysosomal degradation of KCC2. Although recent studies have demonstrated that calpain inhibitors exert antiepileptic and neuroprotective effects in animal models of acute and chronic epilepsy, whether calpain activation affects seizure induction through KCC2 degradation remains unknown. Our results showed that: (1) Blockade of calpain by non-selective calpain inhibitor MDL-28170 prevented convulsant stimulation induced KCC2 downregulation, and reduced the incidence and the severity of pentylenetetrazole (PTZ) induced seizures. (2) m-calpain, but not μ-calpain, inhibitor mimicked MDL-28170 effect on preventing KCC2 downregulation. (3) Phosphorylation of m-calpain has been significantly enhanced during seizure onset, which was partly mediated by the calcium independent MAPK/ERK signaling pathway activation. (4) MAPK/ERK signaling blockade also had similar effect as total calpain blockade on both KCC2 downregulation and animal seizure induction. The results indicate that upregulated m-calpain activation by MAPK/ERK during convulsant stimulation down regulates both cytoplasm- and membrane KCC2, and in turn facilitates seizure induction. This finding may provide a foundation for the development of highly effective antiepileptic drugs targeting of m-calpain.
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Affiliation(s)
- Li Wan
- Department of Neurology, Institutes of Brain Science & State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Liang Ren
- Department of Neurology, Institutes of Brain Science & State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Lulan Chen
- Department of Neurology, Institutes of Brain Science & State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Guoxiang Wang
- Department of Neurology, Institutes of Brain Science & State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xu Liu
- Department of Neurology, Institutes of Brain Science & State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Benjamin H Wang
- Department of Neurology, Institutes of Brain Science & State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science & State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, China
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Huang Y, Zhang Y, Kong S, Zang K, Jiang S, Wan L, Chen L, Wang G, Jiang M, Wang X, Hu J, Wang Y. GIRK1-mediated inwardly rectifying potassium current suppresses the epileptiform burst activities and the potential antiepileptic effect of ML297. Biomed Pharmacother 2018; 101:362-370. [PMID: 29499411 DOI: 10.1016/j.biopha.2018.02.114] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 02/23/2018] [Accepted: 02/23/2018] [Indexed: 12/24/2022] Open
Abstract
G protein-gated inwardly rectifying potassium (GIRK) channels are important inhibitory regulators of neuronal excitability in central nervous system, and the impairment of GIRK channel function has been reported to be associated with the susceptibility of epilepsy. However, the dynamics of GIRK channels in the pathogenesis of epilepsy are still unclear. In this study, our results showed that cyclothiazide, a potent convulsant, dose dependently increased the epileptiform bursting activities and suppressed the baclofen induced GIRK currents. In addition, TPQ, a selective GIRK antagonist, significantly decreased the total inwardly rectifying potassium (Kir) current, and increased the neuronal epileptiform activities. In contrast, ML297, a potent and selective GIRK channel agonist, reversed the cyclothiazide induced decrease of GIRK currents and the increase of neuronal excitability in cultured hippocampal neurons. Further investigation revealed that GIRK1, but not GIRK2, played a key role in suppressing epileptic activities. Finally, in pilocarpine mice seizure model, we demonstrated that ML297 significantly suppressed the seizure behavior. In summary, our current results indicate that GIRK channels, especially GIRK1-containing channels, are involved in epileptic activities and ML297 has a potential antiepileptic effect.
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Affiliation(s)
- Yian Huang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China; State Key Laboratory of New Drug and Pharmaceutical Process, Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai 200437, China
| | - Yuwen Zhang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Shuzhen Kong
- College of Environment and Resource, Chongqing Technology and Business University, Chongqing 400067, China
| | - Kai Zang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Shize Jiang
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200032, China
| | - Li Wan
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Lulan Chen
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Guoxiang Wang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Min Jiang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Xin Wang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Jie Hu
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai 200032, China.
| | - Yun Wang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
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Huang Y, Liu X, Wang G, Wang Y. SK channels participate in the formation of after burst hyperpolarization and partly inhibit the burst strength of epileptic ictal discharges. Mol Med Rep 2017; 17:1762-1774. [PMID: 29257204 PMCID: PMC5780121 DOI: 10.3892/mmr.2017.8068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 10/16/2017] [Indexed: 01/03/2023] Open
Abstract
Epilepsy is a common disease of the central nervous system. Tetanic spasms and convulsions are the key symptoms exhibited during epileptic seizures. However, the majority of patients have a significant post-seizure silence following a serious seizure; the underlying molecular neural mechanisms in this burst interval are unclear. The aim of the present study was to reveal the effect and role of calcium-activated potassium channels during this seizure interval silence period. Cyclothiazide (CTZ) was used to establish the seizure model in rat hippocampal cultured neurons, then the after-burst hyperpolarization (ABH) activities were recorded using the patch clamp technique. By comparing the amplitude and duration of hyperpolarizations, the present study analyzed the association between epileptiform bursts and ABHs when treated with different concentrations of CTZ. In addition, apamin and iberiotoxin were used for pharmacological tests. An intracranial electroencephalogram (EEG) recording was also performed when the CTZ experiments were repeated on animals. The experimental results revealed that treatment with high levels of CTZ induced larger ABHs and was associated with stronger burst activities, which suggested a positive correlation between ABH and epileptiform burst. Apamin, an antagonist of small conductance calcium-activated potassium (SK) channels, decreased the amplitude of ABH; however, reduced ABH was associated with enhanced burst activity, in burst probability and burst strength. These results revealed an important role of SK channels in the formation of ABH and in the inhibition of burst activity. Iberiotoxin, an antagonist of big conductance calcium-activated potassium (BK) channels, had no significant effect on ABH and burst activity. In addition, a positive correlation was identified between burst duration and ABH parameters. An intracellular calcium chelator impaired the amplitude of ABH; however, it did not affect the burst parameters. The rat cortical EEG recordings also exhibited a similar positive correlation between the duration of epileptic burst and after burst depression. Collectively, the results indicate that ABH may serve in the physiological feedback system to reduce the strength of epileptic hyperexcitation, a process in which SK channels are important.
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Affiliation(s)
- Yian Huang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, P.R. China
| | - Xu Liu
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, P.R. China
| | - Guoxiang Wang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, P.R. China
| | - Yun Wang
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Department of Neurology at Zhongshan Hospital, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, P.R. China
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11
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Chen L, Wan L, Wu Z, Ren W, Huang Y, Qian B, Wang Y. KCC2 downregulation facilitates epileptic seizures. Sci Rep 2017; 7:156. [PMID: 28279020 PMCID: PMC5427808 DOI: 10.1038/s41598-017-00196-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/13/2017] [Indexed: 11/18/2022] Open
Abstract
GABAA receptor-mediated inhibition depends on the maintenance of low level intracellular [Cl-] concentration, which in adult depends on neuron specific K+-Cl- cotransporter-2 (KCC2). Previous studies have shown that KCC2 was downregulated in both epileptic patients and various epileptic animal models. However, the temporal relationship between KCC2 downregulation and seizure induction is unclear yet. In this study, we explored the temporal relationship and the influence of KCC2 downregulation on seizure induction. Significant downregulation of plasma membrane KCC2 was directly associated with severe (Racine Score III and above) behavioral seizures in vivo, and occurred before epileptiform bursting activities in vitro induced by convulsant. Overexpression of KCC2 using KCC2 plasmid effectively enhanced resistance to convulsant-induced epileptiform bursting activities in vitro. Furthermore, suppression of membrane KCC2 expression, using shRNAKCC2 plasmid in vitro and shRNAKCC2 containing lentivirus in vivo, induced spontaneous epileptiform bursting activities in vitro and Racine III seizure behaviors accompanied by epileptic EEG in vivo. Our findings novelly demonstrated that altered expression of KCC2 is not the consequence of seizure occurrence but likely is the contributing factor.
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Affiliation(s)
- Lulan Chen
- Institutes of Brain Science, State Key Laboratory for Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Li Wan
- Institutes of Brain Science, State Key Laboratory for Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Zheng Wu
- Institutes of Brain Science, State Key Laboratory for Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Wanting Ren
- Institutes of Brain Science, State Key Laboratory for Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Yian Huang
- Institutes of Brain Science, State Key Laboratory for Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Binbin Qian
- Institutes of Brain Science, State Key Laboratory for Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Yun Wang
- Institutes of Brain Science, State Key Laboratory for Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
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12
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Stockdale TP, Williams CM. Pharmaceuticals that contain polycyclic hydrocarbon scaffolds. Chem Soc Rev 2015; 44:7737-63. [DOI: 10.1039/c4cs00477a] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review comprehensively explores approved pharmaceutical compounds that contain polycyclic scaffolds and the properties that these skeletons convey.
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Affiliation(s)
- Tegan P. Stockdale
- School of Chemistry and Molecular Biosciences
- University of Queensland
- St Lucia
- Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences
- University of Queensland
- St Lucia
- Australia
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13
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Kellinghaus C, Gorji A. Proconvulsive effect of hydrochlorothiazide in an in vitro rat seizure model. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2014; 17:860-6. [PMID: 25691927 PMCID: PMC4328094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 07/14/2014] [Indexed: 11/05/2022]
Abstract
OBJECTIVES Protective effects of diuretics, particularly of hydrochlorothiazide (HCT), for the development of epilepsy have been described in vivo. However, its mechanism of action is unknown. MATERIALS AND METHODS Extracellular field potentials were recorded from the CA1- and CA3-subfields of the hippocampus of rats. Epileptiform discharges were induced by omission of Mg2+ from the artificial cerebrospinal fluid (ACSF). HCT was added to the ACSF at a concentration of 2 mmol/l, 0.2 mmol/l or 0.02 mmol/l. Frequency, amplitude and duration of the epileptiform discharges were evaluated. Long-term potentiation (LTP) was induced with and without the presence of HCT (n=6; 2 mmol/l). In addition, rats were injected with HCT (n=4) or saline (n=2), and the brain tissue was analyzed using HPLC. RESULTS Application of 0.02, 0.2, and 2 mmol/l HCT accelerated the frequency of discharges by 50%, 91%, and 100%, respectively. The amplitude of burst discharges also increased by 9%, 54%, and 300%, and the duration of epileptiform discharges increased by 10%, 30% and 120%. All parameters returned close to the basal levels after 60min washout of the substance. HCT increased the electrical evoked potentials but did not affect the LTP in hippocampal tissues. There was no evidence of HCT in the rat brain after intraperitoneal injection. CONCLUSION Exposure of hippocampal slices to HCT enhanced epileptiform activity in a dose-dependent manner. In addition, HCT does not seem to cross the blood brain barrier in rats. Thus, the anticonvulsive effect of HCT most likely is not through direct neuronal effect.
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Affiliation(s)
- Christoph Kellinghaus
- Department of Neurology, Klinikum Osnabruck, Am Finkenhugel 1, 49076 Osnabruck, Germany
| | - Ali Gorji
- Institute of Neurophysiology, University of Munster, Robert-Koch-Str. 115, 48149 Munster, Germany
- Department of Neurology and Department of Neurosurgery, University of Munster, Albert-Schweitzer-Campus A1, 48029 Munster, Germany
- Shefa Neuroscience Center, Khatam Hospital, Rashid Yasemi St., Valiasr Ave, Tehran, Iran
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14
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Activation of extrasynaptic GABA(A) receptors inhibits cyclothiazide-induced epileptiform activity in hippocampal CA1 neurons. Neurosci Bull 2014; 30:866-76. [PMID: 25260800 DOI: 10.1007/s12264-014-1466-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/17/2014] [Indexed: 12/20/2022] Open
Abstract
Extrasynaptic GABA(A) receptors (GABA(A)Rs)-mediated tonic inhibition is reported to involve in the pathogenesis of epilepsy. In this study, we used cyclothiazide (CTZ)-induced in vitro brain slice seizure model to explore the effect of selective activation of extrasynaptic GABA(A)Rs by 4,5,6,7-tetrahydroisoxazolo[5,4-c] pyridine-3-ol (THIP) on the CTZ-induced epileptiform activity in hippocampal neurons. Perfusion with CTZ dose-dependently induced multiple epileptiform peaks of evoked population spikes (PSs) in CA1 pyramidal neurons, and treatment with THIP (5 μmol/L) significantly reduced the multiple PS peaks induced by CTZ stimulation. Western blot showed that the δ-subunit of the GABA(A)R, an extrasynaptic specific GABA(A)R subunit, was also significantly down-regulated in the cell membrane 2 h after CTZ treatment. Our results suggest that the CTZ-induced epileptiform activity in hippocampal CA1 neurons is suppressed by the activation of extrasynaptic GABA(A)Rs, and further support the hypothesis that tonic inhibition mediated by extrasynaptic GABA(A)Rs plays a prominent role in seizure generation.
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15
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Naresh G, Kant R, Narender T. Molecular Iodine Promoted Divergent Synthesis of Benzimidazoles, Benzothiazoles, and 2-Benzyl-3-phenyl-3,4-dihydro-2H-benzo[e][1,2,4]thiadiazines. J Org Chem 2014; 79:3821-9. [DOI: 10.1021/jo5000797] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Gunaganti Naresh
- Medicinal
and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, India 226001
| | - Ruchir Kant
- Molecular
and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India 226001
| | - Tadigoppula Narender
- Medicinal
and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, India 226001
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16
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Downregulated GABA and BDNF-TrkB pathway in chronic cyclothiazide seizure model. Neural Plast 2014; 2014:310146. [PMID: 24757570 PMCID: PMC3976828 DOI: 10.1155/2014/310146] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 01/28/2014] [Indexed: 12/12/2022] Open
Abstract
Cyclothiazide (CTZ) has been reported to simultaneously enhance glutamate receptor excitation and inhibit GABAA receptor inhibition, and in turn it evokes epileptiform activities in hippocampal neurons. It has also been shown to acutely induce epileptic seizure behavior in freely moving rats. However, whether CTZ induced seizure rats could develop to have recurrent seizure still remains unknown. In the current study, we demonstrated that 46% of the CTZ induced seizure rats developed to have recurrent seizure behavior as well as epileptic EEG with a starting latency between 2 weeks and several months. In those chronic seizure rats 6 months after the seizure induction by the CTZ, our immunohistochemistry results showed that both GAD and GAT-1 were significantly decreased across CA1, CA3, and dentate gyrus area of the hippocampus studied. In addition, both BDNF and its receptor TrkB were also decreased in hippocampus of the chronic CTZ seizure rats. Our results indicate that CTZ induced seizure is capable of developing to have recurrent seizure, and the decreased GABA synthesis and transport as well as the impaired BDNF-TrkB signaling pathway may contribute to the development of the recurrent seizure. Thus, CTZ seizure rats may provide a novel animal model for epilepsy study and anticonvulsant drug testing in the future.
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17
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Sun Y, Wu Z, Kong S, Jiang D, Pitre A, Wang Y, Chen G. Regulation of epileptiform activity by two distinct subtypes of extrasynaptic GABAA receptors. Mol Brain 2013; 6:21. [PMID: 23634821 PMCID: PMC3652748 DOI: 10.1186/1756-6606-6-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 04/20/2013] [Indexed: 11/13/2022] Open
Abstract
Background GABAergic deficit is one of the major mechanisms underlying epileptic seizures. Previous studies have mainly focused on alterations of synaptic GABAergic inhibition during epileptogenesis. Recent work suggested that tonic inhibition may also play a role in regulating epileptogenesis, but the underlying mechanism is not well understood. Results We employed molecular and pharmacological tools to investigate the role of tonic inhibition during epileptogenesis both in vitro and in vivo. We overexpressed two distinct subtypes of extrasynaptic GABAA receptors, α5β3γ2 and α6β3δ receptors, in cultured hippocampal neurons. We demonstrated that overexpression of both α5β3γ2 and α6β3δ receptors enhanced tonic inhibition and reduced epileptiform activity in vitro. We then showed that injection of THIP (5 μM), a selective agonist for extrasynaptic GABAA receptors at low concentration, into rat brain also suppressed epileptiform burst activity and behavioral seizures in vivo. Mechanistically, we discovered that low concentration of THIP had no effect on GABAergic synaptic transmission and did not affect the basal level of action potentials, but significantly inhibited high frequency neuronal activity induced by epileptogenic agents. Conclusions Our studies suggest that extrasynaptic GABAA receptors play an important role in controlling hyperexcitatory activity, such as that during epileptogenesis, but a less prominent role in modulating a low level of basal activity. We propose that tonic inhibition may play a greater role under pathological conditions than in physiological conditions in terms of modulating neural network activity.
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Affiliation(s)
- Yajie Sun
- Institutes of Brain Science and State Key Laboratory for Medical Neurobiology, Fudan University, Shanghai, 200032, China
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18
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Liu X, Liu J, Liu J, Liu XL, Jin LY, Fan W, Ding J, Peng LC, Wang Y, Wang X. BDNF-TrkB signaling pathway is involved in pentylenetetrazole-evoked progression of epileptiform activity in hippocampal neurons in anesthetized rats. Neurosci Bull 2013; 29:565-75. [PMID: 23550026 DOI: 10.1007/s12264-013-1326-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 11/28/2012] [Indexed: 12/30/2022] Open
Abstract
Pentylenetetrazole (PTZ) is a widely-used convulsant used in studies of epilepsy; its subcutaneous injection generates an animal model with stable seizures. Here, we compared the ability of PTZ via the intravenous and subcutaneous routes to evoke progressive epileptiform activity in the hippocampal CA1 neurons of anesthetized rats. The involvement of the BDNF-TrkB pathway was then investigated. When PTZ was given intravenously, it induced epileptiform bursting activity at a short latency in a dose-dependent manner. However, when PTZ was given subcutaneously, it induced a slowly-developing pattern of epileptogenesis; first, generating multiple population-spike peaks, then spontaneous interictal discharge-like spike, leading to the final ictal discharge-like, highly synchronized bursting fi ring in the CA1 pyramidal layer of the hippocampus. K252a, a TrkB receptor antagonist, when given by intracerebroventricular injection, significantly reduced the probability of multiple population spike peaks induced by subcutaneous injection of PTZ, delayed the latency of spontaneous spikes, and reduced the burst frequency. Our results indicate that PTZ induces a progressive change of neuronal epileptiform activity in the hippocampus, and the BDNF-TrkB signaling pathway is mainly involved in the early phases of epileptogenesis, but not the synchronized neuronal burst activity associated with epileptic seizure in the PTZ animal model. These results provide basic insights into the changing pattern of hippocampal neuronal activity during the development of the PTZ seizure model, and establish an in vivo seizure model useful for future electrophysiological studies of epilepsy.
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Affiliation(s)
- Xu Liu
- Neurology Department, Zhongshan Hospital, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China
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Chen CR, Tan R, Qu WM, Wu Z, Wang Y, Urade Y, Huang ZL. Magnolol, a major bioactive constituent of the bark of Magnolia officinalis, exerts antiepileptic effects via the GABA/benzodiazepine receptor complex in mice. Br J Pharmacol 2012; 164:1534-46. [PMID: 21518336 DOI: 10.1111/j.1476-5381.2011.01456.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The aim of this study was to evaluate the anti-convulsant effects of magnolol (6, 6', 7, 12-tetramethoxy-2, 2'-dimethyl-1-β-berbaman, C18H18O2) and the mechanisms involved. EXPERIMENTAL APPROACH Mice were treated with magnolol (20, 40 and 80 mg·kg(-1)) 30 min before injection with pentylenetetrazol (PTZ, 60 mg·kg(-1), i.p.). The anti-seizure effects of magnolol were analysed using seizure models of behaviour, EEG and in vitro electrophysiology and c-Fos expression in the hippocampus and cortex. KEY RESULTS Magnolol at doses of 40 and 80 mg·kg(-1) significantly delayed the onset of myoclonic jerks and generalized clonic seizures, and decreased the seizure stage and mortality compared with those of the vehicle-treated animals. EEG recordings showed that magnolol (40 and 80 mg·kg(-1)) prolonged the latency of seizure onset and decreased the number of seizure spikes. The anti-epileptic effect of magnolol was reversed by the GABA(A)/benzodiazepine receptor antagonist flumazenil. Pretreatment with flumazenil decreased the effects of magnolol on prolongation of seizure latency and decline of seizure stage. In a Mg(2+)-free model of epileptiform activity, using multi-electrode array recordings in mouse hippocampal slices, magnolol decreased spontaneous epileptiform discharges. Magnolol also significantly decreased seizure-induced Fos immunoreactivity in the piriform cortex, dentate gyrus and hippocampal area CA1. These effects were attenuated by pretreatment with flumazenil. CONCLUSIONS AND IMPLICATIONS These findings indicate that the inhibitory effects of magnolol on epileptiform activity were mediated by the GABA(A) /benzodiazepine receptor complex.
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Affiliation(s)
- C R Chen
- Department of Pharmacology, Shanghai Medical College, Fudan University, Shanghai, China
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Qian B, Sun Y, Wu Z, Wan L, Chen L, Kong S, Zhang B, Zhang F, Wang ZY, Wang Y. Epileptiform response of CA1 neurones to convulsant stimulation by cyclothiazide, kainic acid and pentylenetetrazol in anaesthetized rats. Seizure 2011; 20:312-9. [DOI: 10.1016/j.seizure.2010.12.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 12/18/2010] [Accepted: 12/27/2010] [Indexed: 12/27/2022] Open
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