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Cho J, Hong E, Kim Y, Song J, Ju YH, Kim H, Lee H, Kim H, Nam M. Baicalin and baicalein from Scutellaria baicalensis Georgi alleviate aberrant neuronal suppression mediated by GABA from reactive astrocytes. CNS Neurosci Ther 2024; 30:e14740. [PMID: 38715318 PMCID: PMC11076983 DOI: 10.1111/cns.14740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 03/17/2024] [Accepted: 04/01/2024] [Indexed: 05/12/2024] Open
Abstract
AIMS γ-aminobutyric acid (GABA) from reactive astrocytes is critical for the dysregulation of neuronal activity in various neuroinflammatory conditions. While Scutellaria baicalensis Georgi (S. baicalensis) is known for its efficacy in addressing neurological symptoms, its potential to reduce GABA synthesis in reactive astrocytes and the associated neuronal suppression remains unclear. This study focuses on the inhibitory action of monoamine oxidase B (MAO-B), the key enzyme for astrocytic GABA synthesis. METHODS Using a lipopolysaccharide (LPS)-induced neuroinflammation mouse model, we conducted immunohistochemistry to assess the effect of S. baicalensis on astrocyte reactivity and its GABA synthesis. High-performance liquid chromatography was performed to reveal the major compounds of S. baicalensis, the effects of which on MAO-B inhibition, astrocyte reactivity, and tonic inhibition in hippocampal neurons were validated by MAO-B activity assay, qRT-PCR, and whole-cell patch-clamp. RESULTS The ethanolic extract of S. baicalensis ameliorated astrocyte reactivity and reduced excessive astrocytic GABA content in the CA1 hippocampus. Baicalin and baicalein exhibited significant MAO-B inhibition potential. These two compounds downregulate the mRNA levels of genes associated with reactive astrogliosis or astrocytic GABA synthesis. Additionally, LPS-induced aberrant tonic inhibition was reversed by both S. baicalensis extract and its key compounds. CONCLUSIONS In summary, baicalin and baicalein isolated from S. baicalensis reduce astrocyte reactivity and alleviate aberrant tonic inhibition of hippocampal neurons during neuroinflammation.
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Affiliation(s)
- Juyeong Cho
- Center for Brain Function, Brain Science InstituteKorea Institute of Science and Technology (KIST)SeoulRepublic of Korea
| | - Eun‐Bin Hong
- Center for Brain Function, Brain Science InstituteKorea Institute of Science and Technology (KIST)SeoulRepublic of Korea
| | - Young‐Sik Kim
- Department of Herbology, College of Korean MedicineWoosuk UniversityJeonju‐siRepublic of Korea
| | - Jungbin Song
- Department of Herbal Pharmacology, College of Korean MedicineKyung Hee UniversitySeoulRepublic of Korea
| | - Yeon Ha Ju
- Center for Brain Function, Brain Science InstituteKorea Institute of Science and Technology (KIST)SeoulRepublic of Korea
| | - Hyunjin Kim
- Center for Brain Function, Brain Science InstituteKorea Institute of Science and Technology (KIST)SeoulRepublic of Korea
- Department of KHU‐KIST Convergence Science and TechnologyKyung Hee UniversitySeoulRepublic of Korea
| | - Hyowon Lee
- Center for Brain Function, Brain Science InstituteKorea Institute of Science and Technology (KIST)SeoulRepublic of Korea
| | - Hocheol Kim
- Department of Herbal Pharmacology, College of Korean MedicineKyung Hee UniversitySeoulRepublic of Korea
| | - Min‐Ho Nam
- Center for Brain Function, Brain Science InstituteKorea Institute of Science and Technology (KIST)SeoulRepublic of Korea
- Department of KHU‐KIST Convergence Science and TechnologyKyung Hee UniversitySeoulRepublic of Korea
- Division of Bio‐Medical Science & Technology, KIST SchoolUniversity of Science and TechnologySeoulRepublic of Korea
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Cheng H, Chen D, Li X, Al-Sheikh U, Duan D, Fan Y, Zhu L, Zeng W, Hu Z, Tong X, Zhao G, Zhang Y, Zou W, Duan S, Kang L. Phasic/tonic glial GABA differentially transduce for olfactory adaptation and neuronal aging. Neuron 2024; 112:1473-1486.e6. [PMID: 38447577 DOI: 10.1016/j.neuron.2024.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 11/11/2023] [Accepted: 02/06/2024] [Indexed: 03/08/2024]
Abstract
Phasic (fast) and tonic (sustained) inhibition of γ-aminobutyric acid (GABA) are fundamental for regulating day-to-day activities, neuronal excitability, and plasticity. However, the mechanisms and physiological functions of glial GABA transductions remain poorly understood. Here, we report that the AMsh glia in Caenorhabditis elegans exhibit both phasic and tonic GABAergic signaling, which distinctively regulate olfactory adaptation and neuronal aging. Through genetic screening, we find that GABA permeates through bestrophin-9/-13/-14 anion channels from AMsh glia, which primarily activate the metabolic GABAB receptor GBB-1 in the neighboring ASH sensory neurons. This tonic action of glial GABA regulates the age-associated changes of ASH neurons and olfactory responses via a conserved signaling pathway, inducing neuroprotection. In addition, the calcium-evoked, vesicular glial GABA release acts upon the ionotropic GABAA receptor LGC-38 in ASH neurons to regulate olfactory adaptation. These findings underscore the fundamental significance of glial GABA in maintaining healthy aging and neuronal stability.
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Affiliation(s)
- Hankui Cheng
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China; MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China
| | - Du Chen
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China; MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China
| | - Xiao Li
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China; MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China
| | - Umar Al-Sheikh
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China; MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China
| | - Duo Duan
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China; MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China
| | - Yuedan Fan
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China; MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China
| | - Linhui Zhu
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China; MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China
| | - Wanxin Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Zhitao Hu
- Department of Neuroscience, City University of Hong Kong, Kowloon, China
| | - Xiajing Tong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Guohua Zhao
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Yongming Zhang
- Department of Ophthalmology of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Wenjuan Zou
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China; MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China
| | - Shumin Duan
- MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China
| | - Lijun Kang
- Department of Neurology of the Fourth Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Yiwu 322000, China; MOE Frontier Science Center for Brain Science and Brain machine Integration, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310053, China.
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Mitchell SJ, Phillips GD, Tench B, Li Y, Belelli D, Martin SJ, Swinny JD, Kelly L, Atack JR, Paradowski M, Lambert JJ. Neurosteroid Modulation of Synaptic and Extrasynaptic GABA A Receptors of the Mouse Nucleus Accumbens. Biomolecules 2024; 14:460. [PMID: 38672476 PMCID: PMC11048561 DOI: 10.3390/biom14040460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/29/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024] Open
Abstract
The recent approval of formulations of the endogenous neurosteroid allopregnanolone (brexanolone) and the synthetic neuroactive steroid SAGE-217 (zuranolone) to treat postpartum depression (PPD) has encouraged further research to elucidate why these potent enhancers of GABAAR function are clinically effective in this condition. Dopaminergic projections from the ventral tegmental area (VTA) to the nucleus accumbens are associated with reward/motivation and brain imaging studies report that individuals with PPD show reduced activity of this pathway in response to reward and infant engagement. However, the influence of neurosteroids on GABA-ergic transmission in the nucleus accumbens has received limited attention. Here, we investigate, in the medium spiny neurons (MSNs) of the mouse nucleus accumbens core, the effect of allopregnanolone, SAGE-217 and other endogenous and synthetic steroids of interest on fast phasic and tonic inhibition mediated by synaptic (α1/2βγ2) and extrasynaptic (α4βδ) GABAARs, respectively. We present evidence suggesting the resident tonic current results from the spontaneous opening of δ-GABAARs, where the steroid-enhanced tonic current is GABA-dependent. Furthermore, we demonstrate local neurosteroid synthesis in the accumbal slice preparation and reveal that GABA-ergic neurotransmission of MSNs is influenced by an endogenous neurosteroid tone. Given the dramatic fluctuations in allopregnanolone levels during pregnancy and postpartum, this neurosteroid-mediated local fine-tuning of GABAergic transmission in the MSNs will probably be perturbed.
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Affiliation(s)
- Scott J. Mitchell
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Grant D. Phillips
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Becks Tench
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Yunkai Li
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Delia Belelli
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Stephen J. Martin
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Jerome D. Swinny
- School of Pharmacy & Biomedical Sciences, St. Michael’s Building, University of Portsmouth, White Swan Road, Portsmouth PO1 2DT, UK; (J.D.S.); (L.K.)
| | - Louise Kelly
- School of Pharmacy & Biomedical Sciences, St. Michael’s Building, University of Portsmouth, White Swan Road, Portsmouth PO1 2DT, UK; (J.D.S.); (L.K.)
| | - John R. Atack
- Main Building, Medicines Discovery Institute, Park Place, Cardiff University, Cardiff, CF10 3AT, UK; (J.R.A.); (M.P.)
| | - Michael Paradowski
- Main Building, Medicines Discovery Institute, Park Place, Cardiff University, Cardiff, CF10 3AT, UK; (J.R.A.); (M.P.)
| | - Jeremy J. Lambert
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
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4
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Liddiard GT, Suryavanshi PS, Glykys J. Enhancing GABAergic Tonic Inhibition Reduces Seizure-Like Activity in the Neonatal Mouse Hippocampus and Neocortex. J Neurosci 2024; 44:e1342232023. [PMID: 38176909 PMCID: PMC10869160 DOI: 10.1523/jneurosci.1342-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/27/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024] Open
Abstract
Approximately one-third of neonatal seizures do not respond to first-line anticonvulsants, including phenobarbital, which enhances phasic inhibition. Whether enhancing tonic inhibition decreases seizure-like activity in the neonate when GABA is mainly depolarizing at this age is unknown. We evaluated if increasing tonic inhibition using THIP [4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol, gaboxadol], a δ-subunit-selective GABAA receptor agonist, decreases seizure-like activity in neonatal C57BL/6J mice (postnatal day P5-8, both sexes) using acute brain slices. Whole-cell patch-clamp recordings showed that THIP enhanced GABAergic tonic inhibitory conductances in layer V neocortical and CA1 pyramidal neurons and increased their rheobase without altering sEPSC characteristics. Two-photon calcium imaging demonstrated that enhancing the activity of extrasynaptic GABAARs decreased neuronal firing in both brain regions. In the 4-aminopyridine and the low-Mg2+ model of pharmacoresistant seizures, THIP reduced epileptiform activity in the neocortex and CA1 hippocampal region of neonatal and adult brain slices in a dose-dependent manner. We conclude that neocortical layer V and CA1 pyramidal neurons have tonic inhibitory conductances, and when enhanced, they reduce neuronal firing and decrease seizure-like activity. Therefore, augmenting tonic inhibition could be a viable approach for treating neonatal seizures.
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Affiliation(s)
- G T Liddiard
- Stead Family Department of Pediatrics, Iowa Neuroscience Institute, The University of Iowa, Iowa City 52242, Iowa
- Interdisciplinary Graduate Program in Neuroscience, The University of Iowa, Iowa City 52242, Iowa
| | - P S Suryavanshi
- Stead Family Department of Pediatrics, Iowa Neuroscience Institute, The University of Iowa, Iowa City 52242, Iowa
| | - J Glykys
- Stead Family Department of Pediatrics, Iowa Neuroscience Institute, The University of Iowa, Iowa City 52242, Iowa
- Interdisciplinary Graduate Program in Neuroscience, The University of Iowa, Iowa City 52242, Iowa
- Department of Neurology, The University of Iowa, Iowa City 52242, Iowa
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5
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Villalobos N. Disinhibition Is an Essential Network Motif Coordinated by GABA Levels and GABA B Receptors. Int J Mol Sci 2024; 25:1340. [PMID: 38279339 PMCID: PMC10816949 DOI: 10.3390/ijms25021340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/16/2024] [Accepted: 01/19/2024] [Indexed: 01/28/2024] Open
Abstract
Network dynamics are crucial for action and sensation. Changes in synaptic physiology lead to the reorganization of local microcircuits. Consequently, the functional state of the network impacts the output signal depending on the firing patterns of its units. Networks exhibit steady states in which neurons show various activities, producing many networks with diverse properties. Transitions between network states determine the output signal generated and its functional results. The temporal dynamics of excitation/inhibition allow a shift between states in an operational network. Therefore, a process capable of modulating the dynamics of excitation/inhibition may be functionally important. This process is known as disinhibition. In this review, we describe the effect of GABA levels and GABAB receptors on tonic inhibition, which causes changes (due to disinhibition) in network dynamics, leading to synchronous functional oscillations.
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Affiliation(s)
- Nelson Villalobos
- Academia de Fisiología, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de México 11340, Mexico;
- Sección de Estudios Posgrado e Investigación de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Colonia Casco de Santo Tomás, Ciudad de Mexico 11340, Mexico
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6
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Mangan KP, Nelson AB, Petrou S, Cirelli C, Jones MV. Cortical Tonic Inhibition Gates the Expression of Spike-and-Wave Discharges Associated with Absence Epilepsy. J Integr Neurosci 2024; 23:24. [PMID: 38287860 DOI: 10.31083/j.jin2301024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/27/2023] [Accepted: 10/26/2023] [Indexed: 01/31/2024] Open
Abstract
OBJECTIVE Absence seizures result from aberrant thalamocortical processing that confers synchronous, bilateral spike-and-wave discharges (SWDs) and behavioral arrest. Previous work has demonstrated that SWDs can result from enhanced thalamic tonic inhibition, consistent with the mechanism of first-line antiabsence drugs that target thalamic low-voltage-activated calcium channels. However, nearly half of patients with absence epilepsy are unresponsive to first-line medications. In this study we evaluated the role of cortical tonic inhibition and its manipulation on absence seizure expression. METHODS We used video-electroencephalogram (EEG) monitoring to show that mice with a γ-aminobutyric acid type A (GABAA) receptor mutation (γ2R43Q) display absence seizures. Voltage-clamp recordings in brain slices from wild type and γ2R43Q mice were used to evaluate the amount of tonic inhibition and its selective pharmacological modulation. Finally, we determined whether modulating tonic inhibition controls seizure expression. RESULTS γ2R43Q mice completely lack tonic inhibition in principal neurons of both layer 2/3 cortex and ventrobasal thalamus. Blocking cortical tonic inhibition in wild type mice is sufficient to elicit SWDs. Tonic inhibition in slices from γ2R43Q mice could be rescued in a dose-dependent fashion by the synthetic neurosteroid ganaxolone. Low-dose ganaxolone suppressed seizures in γ2R43Q mice. CONCLUSIONS Our data suggest that reduced cortical tonic inhibition promotes absence seizures and that normal function can be restored via selective pharmacological rescue. These results, together with previous findings, suggest that deviations of tonic inhibition either above or below an optimal set point can contribute to absence epilepsy. Returning the thalamocortical system to this set point may provide a novel treatment for refractory absence epilepsy.
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Affiliation(s)
- Kile P Mangan
- Neuroscience Training Program, University of Wisconsin, Madison, WI 53705, USA
- Department of Neuroscience, University of Wisconsin, Madison, WI 53705, USA
| | - Aaron B Nelson
- Neuroscience Training Program, University of Wisconsin, Madison, WI 53705, USA
- Department of Psychiatry, University of Wisconsin, Madison, WI 53719, USA
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - Chiara Cirelli
- Department of Psychiatry, University of Wisconsin, Madison, WI 53719, USA
| | - Mathew V Jones
- Department of Neuroscience, University of Wisconsin, Madison, WI 53705, USA
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Reddy DS. Neuroendocrine insights into neurosteroid therapy for postpartum depression. Trends Mol Med 2023; 29:979-982. [PMID: 37541828 PMCID: PMC10834837 DOI: 10.1016/j.molmed.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 07/09/2023] [Accepted: 07/13/2023] [Indexed: 08/06/2023]
Abstract
Postpartum depression (PPD) is associated with a decline in progesterone-derived anxiolytic-antidepressant neurosteroids after delivery. Neurosteroid replacement therapy (NRT) with GABA-A receptor-modulating allopregnanolone (brexanolone) shows promise as the first drug treatment for PPD. Here we describe the molecular insights of the neurosteroid approach for rapid relief of PPD symptoms compared with traditional antidepressants.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University School of Medicine, Bryan, TX 77807, USA; Texas A&M Health Institute of Pharmacology and Neurotherapeutics, Texas A&M University Health Science Center, Bryan, TX 77807, USA.
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Bogaj K, Kaplon R, Urban-Ciecko J. GABAAR-mediated tonic inhibition differentially modulates intrinsic excitability of VIP- and SST- expressing interneurons in layers 2/3 of the somatosensory cortex. Front Cell Neurosci 2023; 17:1270219. [PMID: 37900589 PMCID: PMC10602639 DOI: 10.3389/fncel.2023.1270219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/25/2023] [Indexed: 10/31/2023] Open
Abstract
Extrasynaptic GABAA receptors (GABAARs) mediating tonic inhibition are thought to play an important role in the regulation of neuronal excitability. However, little is known about a cell type-specific tonic inhibition in molecularly distinctive types of GABAergic interneurons in the mammalian neocortex. Here, we used whole-cell patch-clamp techniques in brain slices prepared from transgenic mice expressing red fluorescent protein (TdTomato) in vasoactive intestinal polypeptide- or somatostatin- positive interneurons (VIP-INs and SST-INs, respectively) to investigate tonic and phasic GABAAR-mediated inhibition as well as effects of GABAA inhibition on intrinsic excitability of these interneurons in layers 2/3 (L2/3) of the somatosensory (barrel) cortex. We found that tonic inhibition was stronger in VIP-INs compared to SST-INs. Contrary to the literature data, tonic inhibition in SST-INs was comparable to pyramidal (Pyr) neurons. Next, tonic inhibition in both interneuron types was dependent on the activity of delta subunit-containing GABAARs. Finally, the GABAAR activity decreased intrinsic excitability of VIP-INs but not SST-INs. Altogether, our data indicate that GABAAR-mediated inhibition modulates neocortical interneurons in a type-specific manner. In contrast to L2/3 VIP-INs, intrinsic excitability of L2/3 SST-INs is immune to the GABAAR-mediated inhibition.
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Affiliation(s)
| | | | - Joanna Urban-Ciecko
- Laboratory of Electrophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland
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Huang TH, Lin YS, Hsiao CW, Wang LY, Ajibola MI, Abdulmajeed WI, Lin YL, Li YJ, Chen CY, Lien CC, Chiu CD, Cheng IHJ. Differential expression of GABA A receptor subunits δ and α6 mediates tonic inhibition in parvalbumin and somatostatin interneurons in the mouse hippocampus. Front Cell Neurosci 2023; 17:1146278. [PMID: 37545878 PMCID: PMC10397515 DOI: 10.3389/fncel.2023.1146278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 06/14/2023] [Indexed: 08/08/2023] Open
Abstract
Inhibitory γ-aminobutyric acid (GABA)-ergic interneurons mediate inhibition in neuronal circuitry and support normal brain function. Consequently, dysregulation of inhibition is implicated in various brain disorders. Parvalbumin (PV) and somatostatin (SST) interneurons, the two major types of GABAergic inhibitory interneurons in the hippocampus, exhibit distinct morpho-physiological properties and coordinate information processing and memory formation. However, the molecular mechanisms underlying the specialized properties of PV and SST interneurons remain unclear. This study aimed to compare the transcriptomic differences between these two classes of interneurons in the hippocampus using the ribosome tagging approach. The results revealed distinct expressions of genes such as voltage-gated ion channels and GABAA receptor subunits between PV and SST interneurons. Gabrd and Gabra6 were identified as contributors to the contrasting tonic GABAergic inhibition observed in PV and SST interneurons. Moreover, some of the differentially expressed genes were associated with schizophrenia and epilepsy. In conclusion, our results provide molecular insights into the distinct roles of PV and SST interneurons in health and disease.
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Affiliation(s)
- Tzu-Hsuan Huang
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Sian Lin
- Institute of Biomedical Informatics, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Program in Genetics and Genomics, Baylor College of Medicine, Houston, TX, United States
| | - Chiao-Wan Hsiao
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
| | - Liang-Yun Wang
- Institute of Biomedical Informatics, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Musa Iyiola Ajibola
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, College of Life Sciences, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
| | - Wahab Imam Abdulmajeed
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, College of Life Sciences, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Ilorin, Nigeria
| | - Yu-Ling Lin
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yu-Jui Li
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Cho-Yi Chen
- Institute of Biomedical Informatics, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Cheng-Chang Lien
- Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, College of Life Sciences, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Cheng-Di Chiu
- Department of Neurosurgery, China Medical University Hospital, Taichung, Taiwan
- Spine Center, China Medical University Hospital, Taichung, Taiwan
- Graduate Institute of Biomedical Science, China Medical University, Taichung, Taiwan
- School of Medicine, China Medical University, Taichung, Taiwan
| | - Irene Han-Juo Cheng
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
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10
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Wyroślak M, Dobrzański G, Mozrzymas JW. Bidirectional plasticity of GABAergic tonic inhibition in hippocampal somatostatin- and parvalbumin-containing interneurons. Front Cell Neurosci 2023; 17:1193383. [PMID: 37448697 PMCID: PMC10336215 DOI: 10.3389/fncel.2023.1193383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/05/2023] [Indexed: 07/15/2023] Open
Abstract
GABAA receptors present in extrasynaptic areas mediate tonic inhibition in hippocampal neurons regulating the performance of neural networks. In this study, we investigated the effect of NMDA-induced plasticity on tonic inhibition in somatostatin- and parvalbumin-containing interneurons. Using pharmacological methods and transgenic mice (SST-Cre/PV-Cre x Ai14), we induced the plasticity of GABAergic transmission in somatostatin- and parvalbumin-containing interneurons by a brief (3 min) application of NMDA. In the whole-cell patch-clamp configuration, we measured tonic currents enhanced by specific agonists (etomidate or gaboxadol). Furthermore, in both the control and NMDA-treated groups, we examined to what extent these changes depend on the regulation of distinct subtypes of GABAA receptors. Tonic conductance in the somatostatin-containing (SST+) interneurons is enhanced after NMDA application, and the observed effect is associated with an increased content of α5-containing GABAARs. Both fast-spiking and non-fast-spiking parvalbumin-positive (PV+) cells showed a reduction of tonic inhibition after plasticity induction. This effect was accompanied in both PV+ interneuron types by a strongly reduced proportion of δ-subunit-containing GABAARs and a relatively small increase in currents mediated by α5-containing GABAARs. Both somatostatin- and parvalbumin-containing interneurons show cell type-dependent and opposite sign plasticity of tonic inhibition. The underlying mechanisms depend on the cell-specific balance of plastic changes in the contents of α5 and δ subunit-containing GABAARs.
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Affiliation(s)
- Marcin Wyroślak
- Department of Biophysics and Neuroscience, Wroclaw Medical University, Wrocław, Poland
| | | | - Jerzy W. Mozrzymas
- Department of Biophysics and Neuroscience, Wroclaw Medical University, Wrocław, Poland
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11
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Yang J, Chen J, Liu Y, Chen KH, Baraban JM, Qiu Z. Ventral tegmental area astrocytes modulate cocaine reward by tonically releasing GABA. Neuron 2023; 111:1104-1117.e6. [PMID: 36681074 PMCID: PMC10079641 DOI: 10.1016/j.neuron.2022.12.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/30/2022] [Accepted: 12/27/2022] [Indexed: 01/21/2023]
Abstract
Addictive drugs increase ventral tegmental area (VTA) dopamine (DA) neuron activity through distinct cellular mechanisms, one of which involves disinhibition of DA neurons by inhibiting local GABA neurons. How drugs regulate VTA GABA neuron activity and drive addictive behaviors remains poorly understood. Here, we show that astrocytes control VTA GABA neuron activity in cocaine reward via tonic inhibition in mice. Repeated cocaine exposure potentiates astrocytic tonic GABA release through volume-regulated anion channels (VRACs) and augments tonic inhibition of VTA GABA neurons, thus downregulating their activities and disinhibiting nucleus accumbens (NAc) projecting DA neurons. Attenuation of tonic inhibition by either deleting Swell1 (Lrrc8a), the obligatory subunit of VRACs, in VTA astrocytes or disrupting δ subunit of GABAA receptors in VTA GABA neurons reduces cocaine-evoked changes in neuron activity, locomotion, and reward behaviors in mice. Together, our findings reveal the critical role of astrocytes in regulating the VTA local circuit and cocaine reward.
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Affiliation(s)
- Junhua Yang
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jianan Chen
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yongqing Liu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kevin Hong Chen
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jay M Baraban
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zhaozhu Qiu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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12
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Khodaei S, Wang DS, Lee Y, Chung W, Orser BA. Sevoflurane and lipopolysaccharide-induced inflammation differentially affect γ-aminobutyric acid type A receptor-mediated tonic inhibition in the hippocampus of male mice. Br J Anaesth 2023; 130:e7-e10. [PMID: 36336522 DOI: 10.1016/j.bja.2022.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 09/14/2022] [Indexed: 11/06/2022] Open
Affiliation(s)
- Shahin Khodaei
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Dian-Shi Wang
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Yulim Lee
- Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Republic of Korea
| | - Woosuk Chung
- Department of Physiology, University of Toronto, Toronto, ON, Canada; Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Republic of Korea; Department of Anesthesia and Pain Medicine, Chungnam National University School of Medicine, Daejeon, Republic of Korea
| | - Beverley A Orser
- Department of Physiology, University of Toronto, Toronto, ON, Canada; Department of Anesthesiology & Pain Medicine, University of Toronto, Toronto, ON, Canada; Department of Anesthesia, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
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13
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Deng PY, Kumar A, Cavalli V, Klyachko VA. FMRP regulates GABA A receptor channel activity to control signal integration in hippocampal granule cells. Cell Rep 2022; 39:110820. [PMID: 35584668 DOI: 10.1016/j.celrep.2022.110820] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/11/2022] [Accepted: 04/21/2022] [Indexed: 11/29/2022] Open
Abstract
Fragile X syndrome, the most common inherited form of intellectual disability, is caused by loss of fragile X mental retardation protein (FMRP). GABAergic system dysfunction is one of the hallmarks of FXS, yet the underlying mechanisms remain poorly understood. Here, we report that FMRP interacts with GABAA receptor (GABAAR) and modulates its single-channel activity. Specifically, FMRP regulates spontaneous GABAAR opening through modulating its single-channel conductance and open probability in dentate granule cells. FMRP loss reduces spontaneous GABAAR activity underlying tonic inhibition, while N-terminal FMRP fragment (aa 1-297) is sufficient to rapidly normalize tonic inhibition in Fmr1 knockout (KO) granule cells. FMRP-GABAAR interaction is supported by co-immunoprecipitation of FMRP with at least one GABAAR subunit, the α5. Functionally, FMRP-GABAAR interaction ensures accuracy of coincidence detection of granule cells, which is markedly reduced in Fmr1 KOs. Our study reveals a mechanism underlying FMRP regulation of the GABAergic system and information processing in the hippocampus.
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Affiliation(s)
- Pan-Yue Deng
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Ajeet Kumar
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Valeria Cavalli
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO 63110, USA; Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, MO 63110, USA; Center of Regenerative Medicine, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Vitaly A Klyachko
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO 63110, USA; Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, MO 63110, USA.
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14
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Paulsen RT, Burrell BD. Activity-Dependent Modulation of Tonic GABA Currents by Endocannabinoids in Hirudo verbana. Front Synaptic Neurosci 2022; 14:760330. [PMID: 35368247 PMCID: PMC8964407 DOI: 10.3389/fnsyn.2022.760330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 02/21/2022] [Indexed: 01/21/2023] Open
Abstract
Endocannabinoids are lipid neuromodulators that are synthesized on demand and primarily signal in a retrograde manner to elicit depression of excitatory and inhibitory synapses. Despite the considerable interest in their potential analgesic effects, there is evidence that endocannabinoids can have both pro-nociceptive and anti-nociceptive effects. The mechanisms contributing to the opposing effects of endocannabinoids in nociception need to be better understood before cannabinoid-based therapies can be effectively utilized to treat pain. Using the medicinal leech, Hirudo verbana, this work investigates whether endocannabinoids modulate tonic inhibition onto non-nociceptive afferents. In voltage clamp recordings, we analyzed changes in the tonic inhibition in pressure-sensitive (P) cells following pre-treatment with endocannabinoids, 2-arachidonoylglycerol (2-AG) or anandamide (AEA). We also tested whether high frequency stimulation (HFS) of nociceptive (N) cells could also modulate tonic inhibition. Both endocannabinoid application and N cell HFS depressed tonic inhibition in the P cell. Depression of tonic inhibition by N cell HFS was blocked by SB 366791 (a TRPV1 inhibitor). SB 366791 also prevented 2-AG-and AEA-induced depression of tonic inhibition. HFS-induced depression was not blocked by tetrahydrolipstatin (THL), which prevents 2-AG synthesis, nor AM 251 (a CB1 receptor inverse agonist). These results illustrate a novel activity-dependent modulation of tonic GABA currents that is mediated by endocannabinoid signaling and is likely to play an important role in sensitization of non-nociceptive afferent pathways.
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15
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Roberts BM, Lambert E, Livesey JA, Wu Z, Li Y, Cragg SJ. Dopamine Release in Nucleus Accumbens Is under Tonic Inhibition by Adenosine A(1) Receptors Regulated by Astrocytic ENT1 and Dysregulated by Ethanol. J Neurosci 2022; 42:1738-51. [PMID: 35042768 DOI: 10.1523/JNEUROSCI.1548-21.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/20/2021] [Accepted: 11/23/2021] [Indexed: 11/21/2022] Open
Abstract
Striatal adenosine A1 receptor (A1R) activation can inhibit dopamine release. A1Rs on other striatal neurons are activated by an adenosine tone that is limited by equilibrative nucleoside transporter 1 (ENT1) that is enriched on astrocytes and is ethanol sensitive. We explored whether dopamine release in nucleus accumbens core is under tonic inhibition by A1Rs, and is regulated by astrocytic ENT1 and ethanol. In ex vivo striatal slices from male and female mice, A1R agonists inhibited dopamine release evoked electrically or optogenetically and detected using fast-scan cyclic voltammetry, most strongly for lower stimulation frequencies and pulse numbers, thereby enhancing the activity-dependent contrast of dopamine release. Conversely, A1R antagonists reduced activity-dependent contrast but enhanced evoked dopamine release levels, even for single optogenetic pulses indicating an underlying tonic inhibition. The ENT1 inhibitor nitrobenzylthioinosine reduced dopamine release and promoted A1R-mediated inhibition, and, conversely, virally mediated astrocytic overexpression of ENT1 enhanced dopamine release and relieved A1R-mediated inhibition. By imaging the genetically encoded fluorescent adenosine sensor [GPCR-activation based (GRAB)-Ado], we identified a striatal extracellular adenosine tone that was elevated by the ENT1 inhibitor and sensitive to gliotoxin fluorocitrate. Finally, we identified that ethanol (50 mm) promoted A1R-mediated inhibition of dopamine release, through diminishing adenosine uptake via ENT1. Together, these data reveal that dopamine output dynamics are gated by a striatal adenosine tone, limiting amplitude but promoting contrast, regulated by ENT1, and promoted by ethanol. These data add to the diverse mechanisms through which ethanol modulates striatal dopamine, and to emerging datasets supporting astrocytic transporters as important regulators of striatal function.SIGNIFICANCE STATEMENT Dopamine axons in the mammalian striatum are emerging as strategic sites where neuromodulators can powerfully influence dopamine output in health and disease. We found that ambient levels of the neuromodulator adenosine tonically inhibit dopamine release in nucleus accumbens core via adenosine A1 receptors (A1Rs), to a variable level that promotes the contrast in dopamine signals released by different frequencies of activity. We reveal that the equilibrative nucleoside transporter 1 (ENT1) on astrocytes limits this tonic inhibition, and that ethanol promotes it by diminishing adenosine uptake via ENT1. These findings support the hypotheses that A1Rs on dopamine axons inhibit dopamine release and, furthermore, that astrocytes perform important roles in setting the level of striatal dopamine output, in health and disease.
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16
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Reddy DS. Neurosteroid replacement therapy for catamenial epilepsy, postpartum depression and neuroendocrine disorders in women. J Neuroendocrinol 2022; 34:e13028. [PMID: 34506047 PMCID: PMC9247111 DOI: 10.1111/jne.13028] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/27/2021] [Accepted: 08/05/2021] [Indexed: 12/11/2022]
Abstract
Neurosteroids are involved in the pathophysiology of many neuroendocrine disorders in women. This review describes recent advancements in pharmacology of neurosteroids and emphasizes the benefits of neurosteroid replacement therapy for the management of neuroendocrine disorders such as catamenial epilepsy (CE), postpartum depression (PPD) and premenstrual brain conditions. Neurosteroids are endogenous modulators of neuronal excitability. A variety of neurosteroids are present in the brain including allopregnanolone (AP), allotetrahydro-deoxycorticosterone and androstanediol. Neurosteroids interact with synaptic and extrasynaptic GABAA receptors in the brain. AP and related neurosteroids, which are positive allosteric modulators of GABAA receptors, are powerful anticonvulsants, anxiolytic, antistress and neuroprotectant agents. In CE, seizures are most often clustered around a specific menstrual period in women. Neurosteroid withdrawal-linked plasticity in extrasynaptic receptors has been shown to play a key role in catamenial seizures, anxiety and other mood disorders. Based on our extensive research spanning two decades, we have proposed and championed neurosteroid replacement therapy as a rational strategy for treating disorders marked by neurosteroid-deficiency, such as CE and other related ovarian or menstrual disorders. In 2019, AP (renamed as brexanolone) was approved for treating PPD. A variety of synthetic neurosteroids are in clinical trials for epilepsy, depression and other brain disorders. Recent advancements in our understanding of neurosteroids have entered a new era of drug discovery and one that offers a high therapeutic potential for treating complex brain disorders.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University College of Medicine, Bryan, TX, USA
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17
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Konduru SS, Pan YZ, Wallace E, Pfammatter JA, Jones MV, Maganti RK. Sleep Deprivation Exacerbates Seizures and Diminishes GABAergic Tonic Inhibition. Ann Neurol 2021; 90:840-844. [PMID: 34476841 PMCID: PMC8530964 DOI: 10.1002/ana.26208] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 08/31/2021] [Accepted: 08/31/2021] [Indexed: 12/31/2022]
Abstract
Patients with epilepsy report that sleep deprivation is a common trigger for breakthrough seizures. The basic mechanism of this phenomenon is unknown. In the Kv1.1-/- mouse model of epilepsy, daily sleep deprivation indeed exacerbated seizures though these effects were lost after the third day. Sleep deprivation also accelerated mortality in ~ 52% of Kv1.1-/- mice, not observed in controls. Voltage-clamp experiments on the day after recovery from sleep deprivation showed reductions in GABAergic tonic inhibition in dentate granule cells in epileptic Kv1.1-/- mice. Our results suggest that sleep deprivation is detrimental to seizures and survival, possibly due to reductions in GABAergic tonic inhibition. ANN NEUROL 2021;90:840-844.
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Affiliation(s)
- Sai Surthi Konduru
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Yu-Zhen Pan
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Eli Wallace
- Department of Cellular and Molecular Pathology, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Jesse A Pfammatter
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Mathew V Jones
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Rama K Maganti
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI
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18
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Wyroślak M, Lebida K, Mozrzymas JW. Induction of Inhibitory Synaptic Plasticity Enhances Tonic Current by Increasing the Content of α5-Subunit Containing GABA A Receptors in Hippocampal Pyramidal Neurons. Neuroscience 2021; 467:39-46. [PMID: 34033868 DOI: 10.1016/j.neuroscience.2021.05.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 11/16/2022]
Abstract
It is known that besides synaptic inhibition, there is a persistent component of inhibitory drive mediated by tonic currents which is believed to mediate majority of the total inhibitory charge in hippocampal neurons. Tonic currents, depending on cell types, can be mediated by a variety of GABAA receptor (GABAAR) subtypes but in pyramidal neurons, α5-subunit containing receptors were found to be predominant. Importantly, α5-GABAARs were implicated in both inhibitory and excitatory synaptic plasticity as well as in a variety of cognitive tasks. In the present study, we asked whether the protocol that evokes NMDAR-dependent GABAergic inhibitory long-term potentiation (iLTP) also induces the plasticity of tonic inhibition in hippocampal pyramidal neurons. Our whole-cell patch-clamp recordings revealed that the induction of this type of iLTP is associated with a marked increase in tonic current. By using the specific inverse agonist of α5-containing GABAARs (L-655,709) we provide evidence that this plastic change in tonic current is correlated with an increased proportion of this type of GABAARs. On the contrary, the iLTP induction did not affect the tonic current potentiated by THIP, indicating that the pool of δ subunit-containing GABAARs receptors remains unaffected. We conclude that the α5-GABAARs-dependent plasticity of tonic inhibition is a novel dimension of the neuroplasticity of the inhibitory drive in the hippocampal principal neurons. Overall, α5-containing GABAARs emerge as key players in a variety of plasticity mechanisms operating over a large span of time and spatial scales.
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Affiliation(s)
- Marcin Wyroślak
- Department of Biophysics and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland.
| | - Katarzyna Lebida
- Department of Biophysics and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland
| | - Jerzy W Mozrzymas
- Department of Biophysics and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland
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19
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Rudolph S, Guo C, Pashkovski SL, Osorno T, Gillis WF, Krauss JM, Nyitrai H, Flaquer I, El-Rifai M, Datta SR, Regehr WG. Cerebellum-Specific Deletion of the GABA A Receptor δ Subunit Leads to Sex-Specific Disruption of Behavior. Cell Rep 2021; 33:108338. [PMID: 33147470 PMCID: PMC7700496 DOI: 10.1016/j.celrep.2020.108338] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 08/04/2020] [Accepted: 10/08/2020] [Indexed: 12/19/2022] Open
Abstract
Granule cells (GCs) of the cerebellar input layer express high-affinity δ GABAA subunit-containing GABAA receptors (δGABAARs) that respond to ambient GABA levels and context-dependent neuromodulators like steroids. We find that GC-specific deletion of δGABAA (cerebellar [cb] δ knockout [KO]) decreases tonic inhibition, makes GCs hyperexcitable, and in turn, leads to differential activation of cb output regions as well as many cortical and subcortical brain areas involved in cognition, anxiety-like behaviors, and the stress response. Cb δ KO mice display deficits in many behaviors, but motor function is normal. Strikingly, δGABAA deletion alters maternal behavior as well as spontaneous, stress-related, and social behaviors specifically in females. Our findings establish that δGABAARs enable the cerebellum to control diverse behaviors not previously associated with the cerebellum in a sex-dependent manner. These insights may contribute to a better understanding of the mechanisms that underlie behavioral abnormalities in psychiatric and neurodevelopmental disorders that display a gender bias. Rudolph et al. show that deletion of the neuromodulator and hormone-sensitive δGABAA receptor subunit from cerebellar granule cells results in anxiety-like behaviors and female-specific deficits in social behavior and maternal care. δGABAA deletion is associated with hyperexcitability of the cerebellar input layer and altered activation of many stress-related brain regions.
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Affiliation(s)
- Stephanie Rudolph
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Chong Guo
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Stan L Pashkovski
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Tomas Osorno
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Winthrop F Gillis
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jeremy M Krauss
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Hajnalka Nyitrai
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Isabella Flaquer
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Mahmoud El-Rifai
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Wade G Regehr
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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20
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Parga Becerra A, Logsdon AF, Banks WA, Ransom CB. Traumatic Brain Injury Broadly Affects GABAergic Signaling in Dentate Gyrus Granule Cells. eNeuro 2021; 8:ENEURO. [PMID: 33514602 DOI: 10.1523/ENEURO.0055-20.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 01/08/2021] [Accepted: 01/12/2021] [Indexed: 02/02/2023] Open
Abstract
Traumatic brain injury (TBI) causes cellular and molecular alterations that contribute to neuropsychiatric disease and epilepsy. GABAergic dysfunction figures prominently in the pathophysiology of TBI, yet the effects of TBI on tonic inhibition in hippocampus remain uncertain. We used a mouse model of severe TBI [controlled cortical impact (CCI)] to investigate GABAergic signaling in dentate gyrus granule cells (DGGCs). Basal tonic GABA currents were not affected by CCI. However, tonic currents induced by the δ subunit-selective GABAA receptor agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP; 10 μm) were reduced by 44% in DGGCs ipsilateral to CCI (CCI-ipsi), but not in contralateral DGGCs. Reduced THIP currents were apparent one week after injury and persisted up to 15 weeks. The frequency of spontaneous IPSCs (sIPSCs) was reduced in CCI-ipsi cells, but the amplitude and kinetics of sIPSCs were unaffected. Immunohistochemical analysis showed reduced expression of GABAA receptor δ subunits and GABAB receptor B2 subunits after CCI, by 43% and 40%, respectively. Activation of postsynaptic GABAB receptors caused a twofold increase in tonic currents, and this effect was markedly attenuated in CCI-ipsi cells (92% reduction). GABAB receptor-activated K+ currents in DGGCs were also significantly reduced in CCI-ipsi cells, confirming a functional deficit of GABAB receptors after CCI. Results indicate broad disruption of GABAergic signaling in DGGCs after CCI, with deficits in both phasic and tonic inhibition and GABAB receptor function. These changes are predicted to disrupt operation of hippocampal networks and contribute to sequelae of severe TBI, including epilepsy.
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21
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Roberts BM, Lopes EF, Cragg SJ. Axonal Modulation of Striatal Dopamine Release by Local γ-Aminobutyric Acid (GABA) Signalling. Cells 2021; 10:709. [PMID: 33806845 PMCID: PMC8004767 DOI: 10.3390/cells10030709] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 12/21/2022] Open
Abstract
Striatal dopamine (DA) release is critical for motivated actions and reinforcement learning, and is locally influenced at the level of DA axons by other striatal neurotransmitters. Here, we review a wealth of historical and more recently refined evidence indicating that DA output is inhibited by striatal γ-aminobutyric acid (GABA) acting via GABAA and GABAB receptors. We review evidence supporting the localisation of GABAA and GABAB receptors to DA axons, as well as the identity of the striatal sources of GABA that likely contribute to GABAergic modulation of DA release. We discuss emerging data outlining the mechanisms through which GABAA and GABAB receptors inhibit the amplitude as well as modulate the short-term plasticity of DA release. Furthermore, we highlight recent data showing that DA release is governed by plasma membrane GABA uptake transporters on striatal astrocytes, which determine ambient striatal GABA tone and, by extension, the tonic inhibition of DA release. Finally, we discuss how the regulation of striatal GABA-DA interactions represents an axis for dysfunction in psychomotor disorders associated with dysregulated DA signalling, including Parkinson's disease, and could be a novel therapeutic target for drugs to modify striatal DA output.
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Affiliation(s)
| | | | - Stephanie J. Cragg
- Department of Physiology, Anatomy and Genetics, Centre for Integrative Neuroscience and Oxford Parkinson’s Disease Centre, University of Oxford, Oxford OX1 3PT, UK
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22
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Abstract
Tonic inhibition mediated by extrasynaptic γ-aminobutyric acid type A receptors (GABAARs) critically regulates neuronal excitability and brain function. However, the mechanisms regulating tonic inhibition remain poorly understood. Here, we report that Shisa7 is critical for tonic inhibition regulation in hippocampal neurons. In juvenile Shisa7 knockout (KO) mice, α5-GABAAR-mediated tonic currents are significantly reduced. Mechanistically, Shisa7 is crucial for α5-GABAAR exocytosis. Additionally, Shisa7 regulation of tonic inhibition requires protein kinase A (PKA) that phosphorylates Shisa7 serine 405 (S405). Importantly, tonic inhibition undergoes activity-dependent regulation, and Shisa7 is required for homeostatic potentiation of tonic inhibition. Interestingly, in young adult Shisa7 KOs, basal tonic inhibition in hippocampal neurons is unaltered, largely due to the diminished α5-GABAAR component of tonic inhibition. However, at this stage, tonic inhibition oscillates during the daily sleep/wake cycle, a process requiring Shisa7. Together, these data demonstrate that intricate signaling mechanisms regulate tonic inhibition at different developmental stages and reveal a molecular link between sleep and tonic inhibition.
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Affiliation(s)
- Kunwei Wu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wenyan Han
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Qingjun Tian
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yan Li
- Proteomics Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wei Lu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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van Nieuwenhuijzen PS, Parker K, Liao V, Houlton J, Kim HL, Johnston GAR, Hanrahan JR, Chebib M, Clarkson AN. Targeting GABA C Receptors Improves Post-Stroke Motor Recovery. Brain Sci 2021; 11:315. [PMID: 33801560 DOI: 10.3390/brainsci11030315] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 11/16/2022] Open
Abstract
Ischemic stroke remains a leading cause of disability worldwide, with limited treatment options available. This study investigates GABAC receptors as novel pharmacological targets for stroke recovery. The expression of ρ1 and ρ2 mRNA in mice were determined in peri-infarct tissue following photothrombotic motor cortex stroke. (R)-4-amino-cyclopent-1-enyl butylphosphinic acid (R)-4-ACPBPA and (S)-4-ACPBPA were assessed using 2-elecotrode voltage electrophysiology in Xenopus laevis oocytes. Stroke mice were treated for 4 weeks with either vehicle, the α5-selective negative allosteric modulator, L655,708, or the ρ1/2 antagonists, (R)-4-ACPBPA and (S)-4-ACPBPA respectively from 3 days post-stroke. Infarct size and expression levels of GAT3 and reactive astrogliosis were determined using histochemistry and immunohistochemistry respectively, and motor function was assessed using both the grid-walking and cylinder tasks. After stroke, significant increases in ρ1 and ρ2 mRNAs were observed on day 3, with ρ2 showing a further increase on day 7. (R)- and (S)-4-ACPBPA are both potent antagonists at ρ2 and only weak inhibitors of α5β2γ2 receptors. Treatment with either L655,708, (S)-4-ACPBPA (ρ1/2 antagonist; 5 mM only), or (R)-4-ACPBPA (ρ2 antagonist; 2.5 and 5 mM) from 3 days after stroke resulted in a significant improvement in motor recovery on the grid-walking task, with L655,708 and (R)-4-ACPBPA also showing an improvement in the cylinder task. Infarct size was unaffected, and only (R)-4-ACPBPA significantly increased peri-infarct GAT3 expression and decreased the level of reactive astrogliosis. Importantly, inhibiting GABAC receptors affords significant improvement in motor function after stroke. Targeting the ρ-subunit could provide a novel delayed treatment option for stroke recovery.
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Manzo MA, Wang DS, Li WW, Pinguelo A, Popa MO, Khodaei S, Atack JR, Ross RA, Orser BA. Inhibition of a tonic inhibitory conductance in mouse hippocampal neurones by negative allosteric modulators of α5 subunit-containing γ-aminobutyric acid type A receptors: implications for treating cognitive deficits. Br J Anaesth 2020; 126:674-683. [PMID: 33388140 DOI: 10.1016/j.bja.2020.11.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 10/30/2020] [Accepted: 11/16/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Multiple cognitive and psychiatric disorders are associated with an increased tonic inhibitory conductance that is generated by α5 subunit-containing γ-aminobutyric acid type A (α5 GABAA) receptors. Negative allosteric modulators that inhibit α5 GABAA receptors (α5-NAMs) are being developed as treatments for these disorders. The effects of α5-NAMs have been studied on recombinant GABAA receptors expressed in non-neuronal cells; however, no study has compared drug effects on the tonic conductance generated by native GABAA receptors in neurones, which was the goal of this study. METHODS The effects of five α5-NAMs (basmisanil, Ono-160, L-655,708, α5IA, and MRK-016) on tonic current evoked by a low concentration of GABA were studied using whole-cell recordings in cultured mouse hippocampal neurones. Drug effects on current evoked by a saturating concentration of GABA and on miniature inhibitory postsynaptic currents (mIPSCs) were also examined. RESULTS The α5-NAMs caused a concentration-dependent decrease in tonic current. The potencies varied as the inhibitory concentration for 50% inhibition (IC50) of basmisanil (127 nM) was significantly higher than those of the other compounds (0.4-0.8 nM). In contrast, the maximal efficacies of the drugs were similar (35.5-51.3% inhibition). The α5-NAMs did not modify current evoked by a saturating GABA concentration or mIPSCs. CONCLUSIONS Basmisanil was markedly less potent than the other α5-NAMs, an unexpected result based on studies of recombinant α5 GABAA receptors. Studying the effects of α5 GABAA receptor-selective drugs on the tonic inhibitory current in neurones could inform the selection of compounds for future clinical trials.
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Affiliation(s)
- Marc A Manzo
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Dian-Shi Wang
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Winston W Li
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Arsène Pinguelo
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Mariana O Popa
- Medicines Discovery Institute, Cardiff University, Cardiff, Wales
| | - Shahin Khodaei
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - John R Atack
- Medicines Discovery Institute, Cardiff University, Cardiff, Wales
| | - Ruth A Ross
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Beverley A Orser
- Department of Physiology, University of Toronto, Toronto, ON, Canada; Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada; Department of Anesthesia, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
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25
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Kwak H, Koh W, Kim S, Song K, Shin JI, Lee JM, Lee EH, Bae JY, Ha GE, Oh JE, Park YM, Kim S, Feng J, Lee SE, Choi JW, Kim KH, Kim YS, Woo J, Lee D, Son T, Kwon SW, Park KD, Yoon BE, Lee J, Li Y, Lee H, Bae YC, Lee CJ, Cheong E. Astrocytes Control Sensory Acuity via Tonic Inhibition in the Thalamus. Neuron 2020; 108:691-706.e10. [PMID: 32905785 DOI: 10.1016/j.neuron.2020.08.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 07/05/2020] [Accepted: 08/14/2020] [Indexed: 12/17/2022]
Abstract
Sensory discrimination is essential for survival. However, how sensory information is finely controlled in the brain is not well defined. Here, we show that astrocytes control tactile acuity via tonic inhibition in the thalamus. Mechanistically, diamine oxidase (DAO) and the subsequent aldehyde dehydrogenase 1a1 (Aldh1a1) convert putrescine into GABA, which is released via Best1. The GABA from astrocytes inhibits synaptically evoked firing at the lemniscal synapses to fine-tune the dynamic range of the stimulation-response relationship, the precision of spike timing, and tactile discrimination. Our findings reveal a novel role of astrocytes in the control of sensory acuity through tonic GABA release.
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Affiliation(s)
- Hankyul Kwak
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Wuhyun Koh
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea; Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea
| | - Sangwoo Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Kiyeong Song
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Jeong-Im Shin
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Jung Moo Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea; Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, South Korea
| | - Elliot H Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Jin Young Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 41566, South Korea
| | - Go Eun Ha
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Ju-Eun Oh
- Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Yongmin Mason Park
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea; Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea
| | - Sunpil Kim
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, South Korea
| | - Jiesi Feng
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China
| | - Seung Eun Lee
- Virus Facility, Research Animal Resource Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Ji Won Choi
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Ki Hun Kim
- Doping Control Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Yoo Sung Kim
- Department of Molecular Biology, College of Natural Science, Dankook University, Cheonan 31116, South Korea
| | - Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Dongsu Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Taehwang Son
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, South Korea
| | - Soon Woo Kwon
- Radiation Medicine Clinical Research Division, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Ki Duk Park
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul 02792, South Korea; KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, South Korea
| | - Bo-Eun Yoon
- Department of Molecular Biology, College of Natural Science, Dankook University, Cheonan 31116, South Korea
| | - Jaeick Lee
- Doping Control Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Hyunbeom Lee
- Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 41566, South Korea
| | - C Justin Lee
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea; Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea.
| | - Eunji Cheong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea; POSTECH Biotech Center, POSTECH, Pohang, South Korea.
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Dong Q, Kim J, Nguyen L, Bu Q, Chang Q. An Astrocytic Influence on Impaired Tonic Inhibition in Hippocampal CA1 Pyramidal Neurons in a Mouse Model of Rett Syndrome. J Neurosci 2020; 40:6250-61. [PMID: 32616668 DOI: 10.1523/JNEUROSCI.3042-19.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 05/13/2020] [Accepted: 06/10/2020] [Indexed: 01/28/2023] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disease caused by mutations in the methyl-CpG binding protein 2 (MECP2) gene. Although altered interneuron development and function are clearly demonstrated in RTT mice, a particular mode of inhibition, tonic inhibition, has not been carefully examined. We report here that tonic inhibition is significantly reduced in pyramidal neurons in the CA1 region of the hippocampus in mice where Mecp2 is deleted either in all cells or specifically in astrocytes. Since no change is detected in the level of GABA receptors, such a reduction in tonic inhibition is likely a result of decreased ambient GABA level in the extracellular space. Consistent with this explanation, we observed increased expression of a GABA transporter, GABA transporter 3 (GAT3), in the hippocampus of the Mecp2 KO mice, as well as a corresponding increase of GAT3 current in hippocampal astrocytes. These phenotypes are relevant to RTT because pharmacological blockage of GAT3 can normalize tonic inhibition and intrinsic excitability in CA1 pyramidal neurons, and rescue the phenotype of increased network excitability in acute hippocampal slices from the Mecp2 KO mice. Finally, chronic administration of a GAT3 antagonist improved a composite symptom score and extended lifespan in the Mecp2 KO mice. Only male mice were used in this study. These results not only advance our understanding of RTT etiology by defining a new neuronal phenotype and revealing how it can be influenced by astrocytic alterations, but also reveal potential targets for intervention.SIGNIFICANCE STATEMENT Our study reports a novel phenotype of reduced tonic inhibition in hippocampal CA1 pyramidal neurons in the Rett syndrome mice, reveal a potential mechanism of increased GABA transporter expression/activity in the neighboring astrocytes, describe a disease-relevant consequence in hyperexcitability, and provide preliminary evidence that targeting this phenotype may slow down disease progression in Rett syndrome mice. These results help our understanding of the disease etiology and identify a new therapeutic target for treating Rett syndrome.
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Dembitskaya Y, Wu YW, Semyanov A. Tonic GABA A Conductance Favors Spike-Timing-Dependent over Theta-Burst-Induced Long-Term Potentiation in the Hippocampus. J Neurosci 2020; 40:4266-76. [PMID: 32327534 DOI: 10.1523/JNEUROSCI.2118-19.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 03/21/2020] [Accepted: 04/15/2020] [Indexed: 11/21/2022] Open
Abstract
Synaptic plasticity is triggered by different patterns of network activity. Here, we investigated how LTP in CA3-CA1 synapses induced by different stimulation patterns is affected by tonic GABAA conductances in rat hippocampal slices. Spike-timing-dependent LTP was induced by pairing Schaffer collateral stimulation with antidromic stimulation of CA1 pyramidal neurons. Theta-burst-induced LTP was induced by theta-burst stimulation of Schaffer collaterals. We mimicked increased tonic GABAA conductance by bath application of 30 μm GABA. Surprisingly, tonic GABAA conductance selectively suppressed theta-burst-induced LTP but not spike-timing-dependent LTP. We combined whole-cell patch-clamp electrophysiology, two-photon Ca2+ imaging, glutamate uncaging, and mathematical modeling to dissect the mechanisms underlying these differential effects of tonic GABAA conductance. We found that Ca2+ transients during pairing of an action potential with an EPSP were less sensitive to tonic GABAA conductance-induced shunting inhibition than Ca2+ transients induced by EPSP burst. Our results may explain how different forms of memory are affected by increasing tonic GABAA conductances under physiological or pathologic conditions, as well as under the influence of substances that target extrasynaptic GABAA receptors (e.g., neurosteroids, sedatives, antiepileptic drugs, and alcohol).SIGNIFICANCE STATEMENT Brain activity is associated with neuronal firing and synaptic signaling among neurons. Synaptic plasticity represents a mechanism for learning and memory. However, some neurotransmitters that escape the synaptic cleft or are released by astrocytes can target extrasynaptic receptors. Extrasynaptic GABAA receptors mediate tonic conductances that reduce the excitability of neurons by shunting. This results in the decreased ability for neurons to fire action potentials, but when action potentials are successfully triggered, tonic conductances are unable to reduce them significantly. As such, tonic GABAA conductances have minimal effects on spike-timing-dependent synaptic plasticity while strongly attenuating the plasticity evoked by EPSP bursts. Our findings shed light on how changes in tonic conductances can selectively affect different forms of learning and memory.
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28
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Pan HQ, Zhang WH, Liao CZ, He Y, Xiao ZM, Qin X, Liu WZ, Wang N, Zou JX, Liu XX, Pan BX. Chronic Stress Oppositely Regulates Tonic Inhibition in Thy1-Expressing and Non-expressing Neurons in Amygdala. Front Neurosci 2020; 14:299. [PMID: 32362809 PMCID: PMC7180173 DOI: 10.3389/fnins.2020.00299] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 03/16/2020] [Indexed: 12/13/2022] Open
Abstract
Chronic or prolonged exposure to stress ranks among the most important socioenvironmental factors contributing to the development of neuropsychiatric diseases, a process generally associated with loss of inhibitory tone in amygdala. Recent studies have identified distinct neuronal circuits within the basolateral amygdala (BLA) engaged in different emotional processes. However, the potential circuit involved in stress-induced dysregulation of inhibitory tones in BLA remains elusive. Here, a transgenic mouse model expressing yellow fluorescent protein under control of the Thy1 promoter was used to differentiate subpopulations of projection neurons (PNs) within the BLA. We observed that the tonic inhibition in amygdala neurons expressing and not expressing Thy1 (Thy1+/-) was oppositely regulated by chronic social defeat stress (CSDS). In unstressed control mice, the tonic inhibitory currents were significantly stronger in Thy1- PNs than their Thy1+ counterparts. CSDS markedly reduced the currents in Thy1- projection neurons (PNs), but increased that in Thy1+ ones. By contrast, CSDS failed to affect both the phasic A-type γ-aminobutyric acid receptor (GABAAR) currents and GABABR currents in these two PN populations. Moreover, chronic corticosterone administration was sufficient to mimic the effect of CSDS on the tonic inhibition of Thy1+ and Thy1- PNs. As a consequence, the suppression of tonic GABAAR currents on the excitability of Thy1- PNs was weakened by CSDS, but enhanced in Thy1+ PNs. The differential regulation of chronic stress on the tonic inhibition in Thy1+ and Thy1- neurons may orchestrate cell-specific adaptation of amygdala neurons to chronic stress.
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Affiliation(s)
- Han-Qing Pan
- Department of Biological Science, School of Life Sciences, Nanchang University, Nanchang, China.,Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang, China
| | - Wen-Hua Zhang
- Department of Biological Science, School of Life Sciences, Nanchang University, Nanchang, China.,Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang, China
| | - Cai-Zhi Liao
- Department of Biological Science, School of Life Sciences, Nanchang University, Nanchang, China.,Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang, China
| | - Ye He
- Center for Medical Experiments, Nanchang University, Nanchang, China
| | - Zhi-Ming Xiao
- Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang, China
| | - Xia Qin
- Department of Biological Science, School of Life Sciences, Nanchang University, Nanchang, China.,Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang, China
| | - Wei-Zhu Liu
- Department of Biological Science, School of Life Sciences, Nanchang University, Nanchang, China.,Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang, China
| | - Na Wang
- Department of Physiology, Mudanjiang Medical University, Mudanjiang, China
| | - Jia-Xin Zou
- Department of Biological Science, School of Life Sciences, Nanchang University, Nanchang, China.,Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang, China
| | - Xiao-Xuan Liu
- Department of Biological Science, School of Life Sciences, Nanchang University, Nanchang, China.,Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang, China
| | - Bing-Xing Pan
- Department of Biological Science, School of Life Sciences, Nanchang University, Nanchang, China.,Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang, China
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29
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Pati D, Harden SW, Sheng W, Kelly KB, de Kloet AD, Krause EG, Frazier CJ. Endogenous oxytocin inhibits hypothalamic corticotrophin-releasing hormone neurones following acute hypernatraemia. J Neuroendocrinol 2020; 32:e12839. [PMID: 32133707 PMCID: PMC7384450 DOI: 10.1111/jne.12839] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 01/24/2020] [Accepted: 02/06/2020] [Indexed: 12/12/2022]
Abstract
Significant prior evidence indicates that centrally acting oxytocin robustly modulates stress responsiveness and anxiety-like behaviour, although the neural mechanisms behind these effects are not entirely understood. A plausible neural basis for oxytocin-mediated stress reduction is via inhibition of corticotrophin-releasing hormone (CRH) neurones in the paraventricular nucleus of the hypothalamus (PVN) that regulate activation of the hypothalamic-pituitary-adrenal axis. Previously, we have shown that, following s.c. injection of 2.0 mol L-1 NaCl, oxytocin synthesising neurones are activated in the rat PVN, an oxytocin receptor (Oxtr)-dependent inhibitory tone develops on a subset of parvocellular neurones and stress-mediated increases in plasma corticosterone levels are blunted. In the present study, we utilised transgenic male CRH-reporter mice to selectively target PVN CRH neurones for whole-cell recordings. These experiments reveal that acute salt loading produces tonic inhibition of PVN CRH neurones through a mechanism that is largely independent of synaptic activity. Further studies reveal that a subset of CRH neurones within the PVN synthesise mRNA for Oxtr(s). Salt induced Oxtr-dependent inhibitory tone was eliminated in individual PVN CRH neurones filled with GDP-β-S. Additional electrophysiological studies suggest that reduced excitability of PVN CRH neurones in salt-loaded animals is associated with increased activation of inwardly rectifying potassium channels. Nevertheless, substantial effort to recapitulate the core effects of salt loading by activating Oxtr(s) with an exogenous agonist produced mixed results. Collectively, these results enhance our understanding of how oxytocin receptor-mediated signalling modulates the function of CRH neurones in the PVN.
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Affiliation(s)
- Dipanwita Pati
- Department of Pharmacodynamics, College of Pharmacy,
University of Florida
| | - Scott W. Harden
- Department of Pharmacodynamics, College of Pharmacy,
University of Florida
| | | | - Kyle B. Kelly
- Department of Pharmacodynamics, College of Pharmacy,
University of Florida
| | - Annette D. de Kloet
- Department of Physiology and Functional Genomics, College
of Medicine, University of Florida
| | - Eric G. Krause
- Department of Pharmacodynamics, College of Pharmacy,
University of Florida
| | - Charles J. Frazier
- Department of Pharmacodynamics, College of Pharmacy,
University of Florida
- Department of Neuroscience, College of Medicine, University
of Florida
- Corresponding author: Charles J.
Frazier, Ph.D., Associate Professor and University of Florida Term Professor,
Department of Pharmacodynamics, College of Pharmacy, University of Florida,
JHMHC Box 100487, Room P1-20, 1345 Center Drive, Gainesville, FL 32610, USA,
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30
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Bryson A, Hatch RJ, Zandt BJ, Rossert C, Berkovic SF, Reid CA, Grayden DB, Hill SL, Petrou S. GABA-mediated tonic inhibition differentially modulates gain in functional subtypes of cortical interneurons. Proc Natl Acad Sci U S A 2020; 117:3192-202. [PMID: 31974304 DOI: 10.1073/pnas.1906369117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The binding of GABA (γ-aminobutyric acid) to extrasynaptic GABAA receptors generates tonic inhibition that acts as a powerful modulator of cortical network activity. Despite GABA being present throughout the extracellular space of the brain, previous work has shown that GABA may differentially modulate the excitability of neuron subtypes according to variation in chloride gradient. Here, using biophysically detailed neuron models, we predict that tonic inhibition can differentially modulate the excitability of neuron subtypes according to variation in electrophysiological properties. Surprisingly, tonic inhibition increased the responsiveness (or gain) in models with features typical for somatostatin interneurons but decreased gain in models with features typical for parvalbumin interneurons. Patch-clamp recordings from cortical interneurons supported these predictions, and further in silico analysis was then performed to seek a putative mechanism underlying gain modulation. We found that gain modulation in models was dependent upon the magnitude of tonic current generated at depolarized membrane potential-a property associated with outward rectifying GABAA receptors. Furthermore, tonic inhibition produced two biophysical changes in models of relevance to neuronal excitability: 1) enhanced action potential repolarization via increased current flow into the dendritic compartment, and 2) reduced activation of voltage-dependent potassium channels. Finally, we show theoretically that reduced potassium channel activation selectively increases gain in models possessing action potential dynamics typical for somatostatin interneurons. Potassium channels in parvalbumin-type models deactivate rapidly and are unavailable for further modulation. These findings show that GABA can differentially modulate interneuron excitability and suggest a mechanism through which this occurs in silico via differences of intrinsic electrophysiological properties.
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31
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Lu X, Zorumski CF, Mennerick S. Lack of Neurosteroid Selectivity at δ vs. γ2-Containing GABA A Receptors in Dentate Granule Neurons. Front Mol Neurosci 2020; 13:6. [PMID: 32038169 PMCID: PMC6989425 DOI: 10.3389/fnmol.2020.00006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/09/2020] [Indexed: 11/17/2022] Open
Abstract
GABAA receptors mediate a large fraction of inhibitory neurotransmission in the central nervous system. Two major classes of GABAA receptors are γ2-containing receptors and δ-containing receptors, which are largely located synaptically and extrasynaptically, respectively. Neuroactive steroids such as allopregnanolone (3α5αP) and allotetrahydrodeoxycorticosterone (THDOC) are hypothesized to selectively affect δ-containing receptors over γ2-containing receptors. However, the selectivity of neurosteroids on GABAA receptor classes is controversial. In this study, we re-examined this issue using mice with picrotoxin resistance associated with either the δ or γ2 subunit. Our results show that 3α5αP potentiated phasic inhibition of GABAA receptors, and this is mainly through γ2-containing receptors. 3α5αP, with or without exogenous GABA, potentiated tonic inhibition through GABAA receptors. Surprisingly, potentiation arose from both γ2- and δ-containing receptors, even when a δ selective agonist THIP was used to activate current. Although ethanol has been proposed to act through neurosteroids and to act selectively at δ receptors, we found no evidence for ethanol potentiation of GABAA receptor function at 50 mM under our experimental conditions. Finally, we found that the actions of pentobarbital exhibited very similar effects on tonic current as 3α5αP, emphasizing the broad spectrum nature of neurosteroid potentiation. Overall, using chemogenetic analysis, our evidence suggests that in a cell population enriched for δ-containing receptors, neurosteroids act through both δ-containing and non-δ-containing receptors.
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Affiliation(s)
- Xinguo Lu
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States
| | - Charles F Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States.,Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States.,Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, United States
| | - Steven Mennerick
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States.,Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States.,Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, United States
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32
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Heo JY, Nam MH, Yoon HH, Kim J, Hwang YJ, Won W, Woo DH, Lee JA, Park HJ, Jo S, Lee MJ, Kim S, Shim JE, Jang DP, Kim KI, Huh SH, Jeong JY, Kowall NW, Lee J, Im H, Park JH, Jang BK, Park KD, Lee HJ, Shin H, Cho IJ, Hwang EM, Kim Y, Kim HY, Oh SJ, Lee SE, Paek SH, Yoon JH, Jin BK, Kweon GR, Shim I, Hwang O, Ryu H, Jeon SR, Lee CJ. Aberrant Tonic Inhibition of Dopaminergic Neuronal Activity Causes Motor Symptoms in Animal Models of Parkinson's Disease. Curr Biol 2020; 30:276-291.e9. [PMID: 31928877 DOI: 10.1016/j.cub.2019.11.079] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/19/2019] [Accepted: 11/26/2019] [Indexed: 01/12/2023]
Abstract
Current pharmacological treatments for Parkinson's disease (PD) are focused on symptomatic relief, but not on disease modification, based on the strong belief that PD is caused by irreversible dopaminergic neuronal death. Thus, the concept of the presence of dormant dopaminergic neurons and its possibility as the disease-modifying therapeutic target against PD have not been explored. Here we show that optogenetic activation of substantia nigra pars compacta (SNpc) neurons alleviates parkinsonism in acute PD animal models by recovering tyrosine hydroxylase (TH) from the TH-negative dormant dopaminergic neurons, some of which still express DOPA decarboxylase (DDC). The TH loss depends on reduced dopaminergic neuronal firing under aberrant tonic inhibition, which is attributed to excessive astrocytic GABA. Blocking the astrocytic GABA synthesis recapitulates the therapeutic effect of optogenetic activation. Consistently, SNpc of postmortem PD patients shows a significant population of TH-negative/DDC-positive dormant neurons surrounded by numerous GABA-positive astrocytes. We propose that disinhibiting dormant dopaminergic neurons by blocking excessive astrocytic GABA could be an effective therapeutic strategy against PD.
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Affiliation(s)
- Jun Young Heo
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea; Infection Control Convergence Research Center, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Min-Ho Nam
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; Department of Science in Korean Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea
| | - Hyung Ho Yoon
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Jeongyeon Kim
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; Emotion, Cognition and Behavior Research Group, Korea Brain Research Institute, Daegu 41062, Korea
| | - Yu Jin Hwang
- Center for Neuro-Medicine, Brain Science Institute, KIST, Seoul 02792, Korea
| | - Woojin Won
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; KU-KIST Graduate School of Converging Science of Technology, Korea University, Seoul 02841, Korea
| | - Dong Ho Woo
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Ji Ae Lee
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Hyun-Jung Park
- Department of Science in Korean Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea
| | - Seonmi Jo
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; Department of Genetic Resources Research, National Marine Biodiversity Institute of Korea, Seocheon 33662, Korea
| | - Min Joung Lee
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea; Infection Control Convergence Research Center, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Sunpil Kim
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; KU-KIST Graduate School of Converging Science of Technology, Korea University, Seoul 02841, Korea
| | - Jeong-Eun Shim
- Department of Biomedical Engineering, Hanyang University, Seoul 04763, Korea
| | - Dong-Pyo Jang
- Department of Biomedical Engineering, Hanyang University, Seoul 04763, Korea
| | - Kyoung I Kim
- Department of Biochemistry & Molecular Biology, Department of Neuroscience, Neurodegeneration Control Research Center, School of Medicine, Kyung Hee University, Seoul 02447, Korea
| | - Sue H Huh
- Department of Biochemistry & Molecular Biology, Department of Neuroscience, Neurodegeneration Control Research Center, School of Medicine, Kyung Hee University, Seoul 02447, Korea
| | - Jae Y Jeong
- Department of Biochemistry & Molecular Biology, Department of Neuroscience, Neurodegeneration Control Research Center, School of Medicine, Kyung Hee University, Seoul 02447, Korea
| | - Neil W Kowall
- Boston University Alzheimer's Disease Center, Boston University School of Medicine, Boston, MA 02118, USA; Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA; VA Boston Healthcare System, Boston, MA 02132, USA
| | - Junghee Lee
- Boston University Alzheimer's Disease Center, Boston University School of Medicine, Boston, MA 02118, USA; Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA; VA Boston Healthcare System, Boston, MA 02132, USA
| | - Hyeonjoo Im
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; Center for Neuro-Medicine, Brain Science Institute, KIST, Seoul 02792, Korea
| | - Jong Hyun Park
- Convergence Research Center for Dementia, KIST, Seoul 02792, Korea
| | - Bo Ko Jang
- Convergence Research Center for Dementia, KIST, Seoul 02792, Korea
| | - Ki Duk Park
- Convergence Research Center for Dementia, KIST, Seoul 02792, Korea
| | - Hyunjoo J Lee
- Center for BioMicrosystems, Brain Science Institute, KIST, Seoul 02792, Korea
| | - Hyogeun Shin
- Center for BioMicrosystems, Brain Science Institute, KIST, Seoul 02792, Korea
| | - Il-Joo Cho
- Center for BioMicrosystems, Brain Science Institute, KIST, Seoul 02792, Korea
| | - Eun Mi Hwang
- Center for Functional Connectomics, KIST, Seoul 02792, Korea
| | - YoungSoo Kim
- Center for Neuro-Medicine, Brain Science Institute, KIST, Seoul 02792, Korea; Department of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, and Integrated Science and Engineering Division, Yonsei University, Incheon 21983, Korea
| | - Hye Yun Kim
- Department of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, and Integrated Science and Engineering Division, Yonsei University, Incheon 21983, Korea
| | - Soo-Jin Oh
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; Convergence Research Center for Dementia, KIST, Seoul 02792, Korea
| | - Seung Eun Lee
- Virus Facility, Research Animal Resource Center, KIST, Seoul 02792, Korea
| | - Sun Ha Paek
- Department of Neurosurgery, Seoul National University Hospital, Seoul 03080, Korea
| | - Jong Hyuk Yoon
- Neurodegenerative Diseases Research Group, Korea Brain Research Institute, Daegu 41062, Korea
| | - Byung K Jin
- Department of Biochemistry & Molecular Biology, Department of Neuroscience, Neurodegeneration Control Research Center, School of Medicine, Kyung Hee University, Seoul 02447, Korea
| | - Gi Ryang Kweon
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea; Infection Control Convergence Research Center, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Insop Shim
- Department of Science in Korean Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea
| | - Onyou Hwang
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Hoon Ryu
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; Center for Neuro-Medicine, Brain Science Institute, KIST, Seoul 02792, Korea; Boston University Alzheimer's Disease Center, Boston University School of Medicine, Boston, MA 02118, USA; Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA; VA Boston Healthcare System, Boston, MA 02132, USA.
| | - Sang Ryong Jeon
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea.
| | - C Justin Lee
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea; KU-KIST Graduate School of Converging Science of Technology, Korea University, Seoul 02841, Korea; Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.
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33
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Adams NE, Hughes LE, Phillips HN, Shaw AD, Murley AG, Nesbitt D, Cope TE, Bevan-Jones WR, Passamonti L, Rowe JB. GABA-ergic Dynamics in Human Frontotemporal Networks Confirmed by Pharmaco-Magnetoencephalography. J Neurosci 2020; 40:1640-9. [PMID: 31915255 DOI: 10.1523/JNEUROSCI.1689-19.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/25/2019] [Accepted: 12/25/2019] [Indexed: 12/15/2022] Open
Abstract
To bridge the gap between preclinical cellular models of disease and in vivo imaging of human cognitive network dynamics, there is a pressing need for informative biophysical models. Here we assess dynamic causal models (DCM) of cortical network responses, as generative models of magnetoencephalographic observations during an auditory oddball roving paradigm in healthy adults. This paradigm induces robust perturbations that permeate frontotemporal networks, including an evoked 'mismatch negativity' response and transiently induced oscillations. Here, we probe GABAergic influences in the networks using double-blind placebo-controlled randomized-crossover administration of the GABA reuptake inhibitor, tiagabine (oral, 10 mg) in healthy older adults. We demonstrate the facility of conductance-based neural mass mean-field models, incorporating local synaptic connectivity, to investigate laminar-specific and GABAergic mechanisms of the auditory response. The neuronal model accurately recapitulated the observed magnetoencephalographic data. Using parametric empirical Bayes for optimal model inversion across both drug sessions, we identify the effect of tiagabine on GABAergic modulation of deep pyramidal and interneuronal cell populations. We found a transition of the main GABAergic drug effects from auditory cortex in standard trials to prefrontal cortex in deviant trials. The successful integration of pharmaco- magnetoencephalography with dynamic causal models of frontotemporal networks provides a potential platform on which to evaluate the effects of disease and pharmacological interventions.SIGNIFICANCE STATEMENT Understanding human brain function and developing new treatments require good models of brain function. We tested a detailed generative model of cortical microcircuits that accurately reproduced human magnetoencephalography, to quantify network dynamics and connectivity in frontotemporal cortex. This approach identified the effect of a test drug (GABA-reuptake inhibitor, tiagabine) on neuronal function (GABA-ergic dynamics), opening the way for psychopharmacological studies in health and disease with the mechanistic precision afforded by generative models of the brain.
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34
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Chazalon M, Paredes-Rodriguez E, Morin S, Martinez A, Cristóvão-Ferreira S, Vaz S, Sebastiao A, Panatier A, Boué-Grabot E, Miguelez C, Baufreton J. GAT-3 Dysfunction Generates Tonic Inhibition in External Globus Pallidus Neurons in Parkinsonian Rodents. Cell Rep 2019; 23:1678-1690. [PMID: 29742425 DOI: 10.1016/j.celrep.2018.04.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/08/2018] [Accepted: 04/02/2018] [Indexed: 12/26/2022] Open
Abstract
The external globus pallidus (GP) is a key GABAergic hub in the basal ganglia (BG) circuitry, a neuronal network involved in motor control. In Parkinson's disease (PD), the rate and pattern of activity of GP neurons are profoundly altered and contribute to the motor symptoms of the disease. In rodent models of PD, the striato-pallidal pathway is hyperactive, and extracellular GABA concentrations are abnormally elevated in the GP, supporting the hypothesis of an alteration of neuronal and/or glial clearance of GABA. Here, we discovered the existence of persistent GABAergic tonic inhibition in GP neurons of dopamine-depleted (DD) rodent models. We showed that glial GAT-3 transporters are downregulated while neuronal GAT-1 function remains normal in DD rodents. Finally, we showed that blocking GAT-3 activity in vivo alters the motor coordination of control rodents, suggesting that GABAergic tonic inhibition in the GP contributes to the pathophysiology of PD.
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Affiliation(s)
- Marine Chazalon
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | | | - Stéphanie Morin
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | - Audrey Martinez
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | - Sofia Cristóvão-Ferreira
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neuroscience, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Sandra Vaz
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neuroscience, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Ana Sebastiao
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neuroscience, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Aude Panatier
- INSERM U1215, Neurocentre Magendie, 33000 Bordeaux, France; Université de Bordeaux, 33000 Bordeaux, France
| | - Eric Boué-Grabot
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | - Cristina Miguelez
- Department of Pharmacology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain
| | - Jérôme Baufreton
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France.
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35
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Christian CA. Nucleus-specific modulation of phasic and tonic inhibition by endogenous neurosteroidogenesis in the murine thalamus. Synapse 2019; 74:e22144. [PMID: 31736138 DOI: 10.1002/syn.22144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 10/30/2019] [Accepted: 11/14/2019] [Indexed: 11/08/2022]
Abstract
Neurosteroids are potent allosteric modulators of GABAA receptors (GABAA Rs). Although the effects of exogenous neurosteroids on GABAA R function are well documented, less is known about effects of neurosteroids produced by local endogenous biosynthesis. The neurosteroidogenic enzymes 5α-reductase and 3α-hydroxysteroid dehydrogenase are expressed in two nuclei of somatosensory thalamus, the thalamic reticular nucleus (nRT) and ventrobasal nucleus (VB). Here, the effects of acute blockade of neurosteroidogenesis by the 5α-reductase inhibitor finasteride on phasic and tonic GABAA R-mediated currents were examined in nRT and VB of mice. In nRT, finasteride altered the decay and amplitude, but not the frequency, of phasic currents, with no effect on tonic inhibition. In VB neurons, by contrast, finasteride reduced both the size and frequency of phasic currents, and also reduced the degree of tonic inhibition. These studies thus provide novel evidence for endogenous modulation of GABAA R function by 5α-reduced neurosteroids in the mature thalamus.
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Affiliation(s)
- Catherine A Christian
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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36
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Parakala ML, Zhang Y, Modgil A, Chadchankar J, Vien TN, Ackley MA, Doherty JJ, Davies PA, Moss SJ. Metabotropic, but not allosteric, effects of neurosteroids on GABAergic inhibition depend on the phosphorylation of GABA A receptors. J Biol Chem 2019; 294:12220-12230. [PMID: 31239352 PMCID: PMC6690684 DOI: 10.1074/jbc.ra119.008875] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/28/2019] [Indexed: 11/06/2022] Open
Abstract
Neuroactive steroids (NASs) are synthesized within the brain and exert profound effects on behavior. These effects are primarily believed to arise from the activities of NASs as positive allosteric modulators (PAMs) of the GABA-type A receptor (GABAAR). NASs also activate a family of G protein-coupled receptors known as membrane progesterone receptors (mPRs). Here, using surface-biotinylation assays and electrophysiology techniques, we examined mPRs' role in mediating the effects of NAS on the efficacy of GABAergic inhibition. Selective mPR activation enhanced phosphorylation of Ser-408 and Ser-409 (Ser-408/9) within the GABAAR β3 subunit, which depended on the activity of cAMP-dependent protein kinase A (PKA) and protein kinase C (PKC). mPR activation did not directly modify GABAAR activity and had no acute effects on phasic or tonic inhibition. Instead, mPR activation induced a sustained elevation in tonic current, which was blocked by PKA and PKC inhibition. Substitution of Ser-408/9 to alanine residues also prevented the effects of mPR activation on tonic current. Furthermore, this substitution abolished the effects of sustained NAS exposure on tonic inhibition. Interestingly, the allosteric effects of NAS on GABAergic inhibition were independent of Ser-408/9 in the β3 subunit. Additionally, although allosteric effects of NAS on GABAergic inhibition were sensitive to a recently developed "NAS antagonist," the sustained effects of NAS on tonic inhibition were not. We conclude that metabotropic effects of NAS on GABAergic inhibition are mediated by mPR-dependent modulation of GABAAR phosphorylation. We propose that this mechanism may contribute to the varying behavioral effects of NAS.
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Affiliation(s)
- Manasa L Parakala
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Yihui Zhang
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Amit Modgil
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Jayashree Chadchankar
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Thuy N Vien
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | | | | | - Paul A Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111; Department of Neuroscience, Physiology, and Pharmacology, University College, London WC1E 6BT, United Kingdom.
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37
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Clarkson AN, Boothman-Burrell L, Dósa Z, Nagaraja RY, Jin L, Parker K, van Nieuwenhuijzen PS, Neumann S, Gowing EK, Gavande N, Ahring PK, Holm MM, Hanrahan JR, Nicolazzo JA, Jensen K, Chebib M. The flavonoid, 2'-methoxy-6-methylflavone, affords neuroprotection following focal cerebral ischaemia. J Cereb Blood Flow Metab 2019; 39:1266-1282. [PMID: 29376464 PMCID: PMC6668512 DOI: 10.1177/0271678x18755628] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Tonic inhibitory currents, mediated by extrasynaptic GABAA receptors, are elevated at a delay following stroke. Flavonoids minimise the extent of cellular damage following stroke, but little is known about their mode of action. We demonstrate that the flavonoid, 2'-methoxy-6-methylflavone (0.1-10 µM; 2'MeO6MF), increases GABAA receptor tonic currents presumably via δ-containing GABAA receptors. Treatment with 2'MeO6MF 1-6 h post focal ischaemia dose dependently decreases infarct volume and improves functional recovery. The effect of 2'MeO6MF was attenuated in δ-/- mice, indicating that the effects of the flavonoid were mediated via δ-containing GABAA receptors. Further, as flavonoids have been shown to have multiple modes of action, we investigated the anti-inflammatory effects of 2'MeO6MF. Using a macrophage cell line, we show that 2'MeO6MF can dampen an LPS-induced elevation in NFkB activity. Assessment of vehicle-treated stroke animals revealed a significant increase in circulating IL1β, TNFα and IFγ levels. Treatment with 2'MeO6MF dampened the stroke-induced increase in circulating cytokines, which was blocked in the presence of the pan-AKT inhibitor, GSK690693. These studies support the hypothesis that compounds that potentiate tonic inhibition via δ-containing GABAA receptors soon after stroke can afford neuroprotection.
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Affiliation(s)
- Andrew N Clarkson
- 1 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand.,2 Faculty of Pharmacy, The University of Sydney, Sydney, Australia
| | - Lily Boothman-Burrell
- 1 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Zita Dósa
- 3 Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Raghavendra Y Nagaraja
- 1 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Liang Jin
- 4 Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Kim Parker
- 1 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | | | - Silke Neumann
- 1 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand.,5 Department of Pathology, University of Otago, Dunedin, New Zealand
| | - Emma K Gowing
- 1 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Navnath Gavande
- 2 Faculty of Pharmacy, The University of Sydney, Sydney, Australia
| | - Philip K Ahring
- 2 Faculty of Pharmacy, The University of Sydney, Sydney, Australia
| | - Mai M Holm
- 3 Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Jane R Hanrahan
- 2 Faculty of Pharmacy, The University of Sydney, Sydney, Australia
| | - Joseph A Nicolazzo
- 4 Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Kimmo Jensen
- 3 Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Mary Chebib
- 2 Faculty of Pharmacy, The University of Sydney, Sydney, Australia
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38
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Trent S, Hall J, Connelly WM, Errington AC. Cyfip1 Haploinsufficiency Does Not Alter GABA A Receptor δ-Subunit Expression and Tonic Inhibition in Dentate Gyrus PV + Interneurons and Granule Cells. eNeuro 2019; 6:ENEURO.0364-18.2019. [PMID: 31209152 PMCID: PMC6635810 DOI: 10.1523/eneuro.0364-18.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 05/28/2019] [Accepted: 05/31/2019] [Indexed: 12/01/2022] Open
Abstract
Copy number variation (CNV) at chromosomal region 15q11.2 is linked to increased risk of neurodevelopmental disorders including autism and schizophrenia. A significant gene at this locus is cytoplasmic fragile X mental retardation protein (FMRP) interacting protein 1 (CYFIP1). CYFIP1 protein interacts with FMRP, whose monogenic absence causes fragile X syndrome (FXS). Fmrp knock-out has been shown to reduce tonic GABAergic inhibition by interacting with the δ-subunit of the GABAA receptor (GABAAR). Using in situ hybridization (ISH), qPCR, Western blotting techniques, and patch clamp electrophysiology in brain slices from a Cyfip1 haploinsufficient mouse, we examined δ-subunit mediated tonic inhibition in the dentate gyrus (DG). In wild-type (WT) mice, DG granule cells (DGGCs) responded to the δ-subunit-selective agonist THIP with significantly increased tonic currents. In heterozygous mice, no significant difference was observed in THIP-evoked currents in DGGCs. Phasic GABAergic inhibition in DGGC was also unaltered with no difference in properties of spontaneous IPSCs (sIPSCs). Additionally, we demonstrate that DG granule cell layer (GCL) parvalbumin-positive interneurons (PV+-INs) have functional δ-subunit-mediated tonic GABAergic currents which, unlike DGGC, are also modulated by the α1-selective drug zolpidem. Similar to DGGC, both IPSCs and THIP-evoked currents in PV+-INs were not different between Cyfip1 heterozygous and WT mice. Supporting our electrophysiological data, we found no significant change in hippocampal δ-subunit mRNA expression or protein level and no change in α1/α4-subunit mRNA expression. Thus, Cyfip1 haploinsufficiency, mimicking human 15q11.2 microdeletion syndrome, does not alter hippocampal phasic or tonic GABAergic inhibition, substantially differing from the Fmrp knock-out mouse model.
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Affiliation(s)
- Simon Trent
- Neuroscience and Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Jeremy Hall
- Neuroscience and Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - William M Connelly
- School of Medicine, University of Tasmania, Hobart, Tasmania 7000, Australia
| | - Adam C Errington
- Neuroscience and Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
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39
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Reddy DS, Carver CM, Clossen B, Wu X. Extrasynaptic γ-aminobutyric acid type A receptor-mediated sex differences in the antiseizure activity of neurosteroids in status epilepticus and complex partial seizures. Epilepsia 2019; 60:730-743. [PMID: 30895610 DOI: 10.1111/epi.14693] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Sex differences are evident in the antiseizure activity of neurosteroids; however, the potential mechanisms remain unclear. In this study, we sought to determine whether differences in target extrasynaptic δ-subunit γ-aminobutyric acid type A (GABA-A) receptor expression and function underlie the sex differences in seizure susceptibility and the antiseizure activity of neurosteroids. METHODS Sex differences in seizure susceptibility and protective activity of three distinct neurosteroids-allopregnanolone (AP), androstanediol (AD), and ganaxolone-were evaluated in the pilocarpine model of status epilepticus (SE) and kindling seizure test in mice. Immunocytochemistry was used for δGABA-A receptor expression analysis, and patch-clamp recordings in brain slices evaluated its functional currents. RESULTS Sex differences were apparent in kindling epileptogenic seizures, with males exhibiting a faster progression to a fully kindled state. Neurosteroids AP, AD, or ganaxolone produced dose-dependent protection against SE and acute partial seizures. However, female mice exhibited strikingly enhanced sensitivity to the antiseizure activity of neurosteroids compared to males. Sex differences in neurosteroid protection were unrelated to pharmacokinetic factors, as plasma levels of neurosteroids associated with seizure protection were similar between sexes. Mice lacking extrasynaptic δGABA-A receptors did not exhibit sex differences in neurosteroid protection. Consistent with a greater abundance of extrasynaptic δGABA-A receptors, AP produced a significantly greater potentiation of tonic currents in dentate gyrus granule cells in females than males; however, such enhanced AP sensitivity was diminished in δGABA-A receptor knockout female mice. SIGNIFICANCE Neurosteroids exhibit greater antiseizure potency in females than males, likely due to a greater abundance of extrasynaptic δGABA-A receptors that mediate neurosteroid-sensitive tonic currents and seizure protection. These findings indicate the potential to develop personalized gender-specific neurosteroid treatments for SE and epilepsy in men and women, including catamenial epilepsy.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Chase Matthew Carver
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center San Antonio, San Antonio, Texas
| | - Bryan Clossen
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Xin Wu
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
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40
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Modgil A, Vien TN, Ackley MA, Doherty JJ, Moss SJ, Davies PA. Neuroactive Steroids Reverse Tonic Inhibitory Deficits in Fragile X Syndrome Mouse Model. Front Mol Neurosci 2019; 12:15. [PMID: 30804752 PMCID: PMC6371020 DOI: 10.3389/fnmol.2019.00015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/16/2019] [Indexed: 12/15/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability. A reduction in neuronal inhibition mediated by γ-aminobutyric acid type A receptors (GABAARs) has been implicated in the pathophysiology of FXS. Neuroactive steroids (NASs) are known allosteric modulators of GABAAR channel function, but recent studies from our laboratory have revealed that NASs also exert persistent metabotropic effects on the efficacy of tonic inhibition by increasing the protein kinase C (PKC)-mediated phosphorylation of the α4 and β3 subunits which increase the membrane expression and boosts tonic inhibition. We have assessed the GABAergic signaling in the hippocampus of fragile X mental retardation protein (FMRP) knock-out (Fmr1KO) mouse. The GABAergic tonic current in dentate gyrus granule cells (DGGCs) from 3- to 5-week-old (p21–35) Fmr1KO mice was significantly reduced compared to WT mice. Additionally, spontaneous inhibitory post synaptic inhibitory current (sIPSC) amplitudes were increased in DGGCs from Fmr1 KO mice. While sIPSCs decay in both genotypes was prolonged by the prototypic benzodiazepine diazepam, those in Frm1-KO mice were selectively potentiated by RO15-4513. Consistent with this altered pharmacology, modifications in the expression levels and phosphorylation of receptor GABAAR subtypes that mediate tonic inhibition were seen in Fmr1 KO mice. Significantly, exposure to NASs induced a sustained elevation in tonic current in Fmr1 KO mice which was prevented with PKC inhibition. Likewise, exposure reduced elevated membrane excitability seen in the mutant mice. Collectively, our results suggest that NAS act to reverse the deficits of tonic inhibition seen in FXS, and thereby reduce aberrant neuronal hyperexcitability seen in this disorder.
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Affiliation(s)
- Amit Modgil
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Thuy N Vien
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | | | | | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States.,Department of Neuroscience, Physiology and Pharmacology, University College, London, United Kingdom
| | - Paul A Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
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Lie ME, Gowing EK, Johansen NB, Dalby NO, Thiesen L, Wellendorph P, Clarkson AN. GAT3 selective substrate l-isoserine upregulates GAT3 expression and increases functional recovery after a focal ischemic stroke in mice. J Cereb Blood Flow Metab 2019; 39:74-88. [PMID: 29160736 PMCID: PMC6311676 DOI: 10.1177/0271678x17744123] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ischemic stroke triggers an elevation in tonic GABA inhibition that impairs the ability of the brain to form new structural and functional cortical circuits required for recovery. This stroke-induced increase in tonic inhibition is caused by impaired GABA uptake via the glial GABA transporter GAT3, highlighting GAT3 as a novel target in stroke recovery. Using a photothrombotic stroke mouse model, we show that GAT3 protein levels are decreased in peri-infarct tissue from 6 h to 42 days post-stroke. Prior studies have shown that GAT substrates can increase GAT surface expression. Therefore, we aimed to assess whether the GAT3 substrate, L-isoserine, could increase post-stroke functional recovery. L-Isoserine (38 µM or 380 µM) administered directly into the infarct from day 5 to 32 post-stroke, significantly increased motor performance in the grid-walking and cylinder tasks in a concentration-dependent manner, without affecting infarct volumes. Additionally, L-isoserine induced a lasting increase in GAT3 expression in peri-infarct regions accompanied by a small decrease in GFAP expression. This study is the first to show that a GAT3 substrate can increase GAT3 expression and functional recovery after focal ischemic stroke following a delayed long-term treatment. We propose that enhancing GAT3-mediated uptake dampens tonic inhibition and promotes functional recovery after stroke.
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Affiliation(s)
- Maria Ek Lie
- 1 Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,2 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Emma K Gowing
- 2 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Nina B Johansen
- 1 Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Nils Ole Dalby
- 1 Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Louise Thiesen
- 1 Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- 1 Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Andrew N Clarkson
- 2 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand.,3 Faculty of Pharmacy, The University of Sydney, Sydney, New South Wales, Australia
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42
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Kammel LG, Wei W, Jami SA, Voskuhl RR, O'Dell TJ. Enhanced GABAergic Tonic Inhibition Reduces Intrinsic Excitability of Hippocampal CA1 Pyramidal Cells in Experimental Autoimmune Encephalomyelitis. Neuroscience 2018; 395:89-100. [PMID: 30447391 DOI: 10.1016/j.neuroscience.2018.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 11/03/2018] [Accepted: 11/05/2018] [Indexed: 11/24/2022]
Abstract
Cognitive impairment (CI), a debilitating and pervasive feature of multiple sclerosis (MS), is correlated with hippocampal atrophy. Findings from postmortem MS hippocampi indicate that expression of genes involved in both excitatory and inhibitory neurotransmission are altered in MS, and although deficits in excitatory neurotransmission have been reported in the MS model experimental autoimmune encephalomyelitis (EAE), the functional consequence of altered inhibitory neurotransmission remains poorly understood. In this study, we used electrophysiological and biochemical techniques to examine inhibitory neurotransmission in the CA1 region of the hippocampus in EAE. We find that tonic, GABAergic inhibition is enhanced in CA1 pyramidal cells from EAE mice. Although plasma membrane expression of the GABA transporter GAT-3 was decreased in the EAE hippocampus, an increased surface expression of α5 subunit-containing GABAA receptors appears to be primarily responsible for the increase in tonic inhibition during EAE. Enhanced tonic inhibition during EAE was associated with decreased CA1 pyramidal cell excitability and inhibition of α5 subunit-containing GABAA receptors with the negative allosteric modulator L-655,708 enhanced pyramidal cell excitability in EAE mice. Together, our results suggest that altered GABAergic neurotransmission may underlie deficits in hippocampus-dependent cognitive function in EAE and MS.
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43
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AOKI C, CHEN YW, CHOWDHURY TG, PIPER W. α4βδ-GABA A receptors in dorsal hippocampal CA1 of adolescent female rats traffic to the plasma membrane of dendritic spines following voluntary exercise and contribute to protection of animals from activity-based anorexia through localization at excitatory synapses. J Neurosci Res 2018; 96:1450-1466. [PMID: 28218471 PMCID: PMC5563482 DOI: 10.1002/jnr.24035] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 01/17/2017] [Accepted: 01/18/2017] [Indexed: 01/22/2023]
Abstract
In hippocampal CA1 of adolescent female rodents, α4βδ-GABAA receptors (α4βδ-GABAA Rs) suppress excitability of pyramidal neurons through shunting inhibition at excitatory synapses. This contributes to anxiolysis of stressed animals. Socially isolated adolescent female rats with 8 days of wheel access, the last 4 days of which entail restricted food access, have been shown to exhibit excessive exercise, choosing to run instead of eat (activity-based anorexia [ABA]). Upregulation of α4βδ-GABAA Rs in the dorsal hippocampal CA1 (DH), seen among some ABA animals, correlates with suppression of excessive exercise. We used electron microscopic immunocytochemistry to show that exercise alone (EX), but not food restriction alone (FR), also augments α4βδ-GABAA R expression at axospinous excitatory synapses of the DH (67%, P = 0.027), relative to socially isolated controls without exercise or food restriction (CON). Relative to CON, ABA animals' synaptic α4βδ-GABAA R elevation was modestly elevated (37%), but this level correlated strongly and negatively with individual differences in ABA vulnerability-i.e., food restriction-evoked hyperactivity (Pearson R = -0.902, P = 0.002) and weight changes (R = 0.822, P = 0.012). These correlations were absent from FR and EX brains or ventral hippocampus of ABA brains. Comparison to CON of α4βδ-GABAA R location in the DH indicated that ABA induces trafficking of α4βδ-GABAA R from reserve pools in spine cytoplasm to excitatory synapses. Pair-housing CON animals reduced cytoplasmic α4βδ-GABAA R without reducing synaptic α4βδ-GABAA R. Thus, exercise induces trafficking of α4βδ-GABAA Rs to excitatory synapses, while individual differences in ABA vulnerability are linked most strongly to trafficking of α4βδ-GABAA Rs in the reverse direction-from excitatory synapses to the reserve pool during co-occurring food restriction. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Chiye AOKI
- Center for Neural Sci., New York University, New York, NY, 10003
| | - Yi-Wen CHEN
- Center for Neural Sci., New York University, New York, NY, 10003
| | | | - Walter PIPER
- Center for Neural Sci., New York University, New York, NY, 10003
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44
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Pan G, Chen Z, Zheng H, Zhang Y, Xu H, Bu G, Zheng H, Li Y. Compensatory Mechanisms Modulate the Neuronal Excitability in a Kainic Acid-Induced Epilepsy Mouse Model. Front Neural Circuits 2018; 12:48. [PMID: 30008664 PMCID: PMC6034068 DOI: 10.3389/fncir.2018.00048] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/05/2018] [Indexed: 01/28/2023] Open
Abstract
Epilepsy is one of the most common neurological disorders affecting millions of people. Due to the complicated and unclear mechanisms of epilepsy, still a significant proportion of epilepsy patients remain poorly controlled. Epilepsy is characterized by convulsive seizures that are caused by increased excitability. In this study, by using kainic acid (KA)-induced epilepsy mice, we investigated the neuronal activities and revealed the neuronal compensatory mechanisms after KA-induced toxic hyperexcitability. The results indicate that both phasic inhibition induced by enhanced inhibitory synaptic activity and tonic inhibition mediated by activated astrocytes participate in the compensatory mechanisms. Compensatory mechanisms were already found in various neuronal disorders and were considered important in protecting nervous system from toxic hyperexcitability. This study hopefully will provide valuable clues in understanding the complex neuronal mechanisms of epilepsy, and exploring potential clinical treatment of the disease.
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Affiliation(s)
- Gaojie Pan
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| | - Zhicai Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| | - Honghua Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| | - Yunwu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China.,Neurodegenerative Disease Research Program, Sanford-Burnham Medical Research Institute, La Jolla, CA, United States
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China.,Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Hui Zheng
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX, United States
| | - Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
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45
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Baker SA, Drumm BT, Cobine CA, Keef KD, Sanders KM. Inhibitory Neural Regulation of the Ca 2+ Transients in Intramuscular Interstitial Cells of Cajal in the Small Intestine. Front Physiol 2018; 9:328. [PMID: 29686622 PMCID: PMC5900014 DOI: 10.3389/fphys.2018.00328] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 03/15/2018] [Indexed: 01/03/2023] Open
Abstract
Gastrointestinal motility is coordinated by enteric neurons. Both inhibitory and excitatory motor neurons innervate the syncytium consisting of smooth muscle cells (SMCs) interstitial cells of Cajal (ICC) and PDGFRα+ cells (SIP syncytium). Confocal imaging of mouse small intestines from animals expressing GCaMP3 in ICC were used to investigate inhibitory neural regulation of ICC in the deep muscular plexus (ICC-DMP). We hypothesized that Ca2+ signaling in ICC-DMP can be modulated by inhibitory enteric neural input. ICC-DMP lie in close proximity to the varicosities of motor neurons and generate ongoing Ca2+ transients that underlie activation of Ca2+-dependent Cl- channels and regulate the excitability of SMCs in the SIP syncytium. Electrical field stimulation (EFS) caused inhibition of Ca2+ for the first 2-3 s of stimulation, and then Ca2+ transients escaped from inhibition. The NO donor (DEA-NONOate) inhibited Ca2+ transients and Nω-Nitro-L-arginine (L-NNA) or a guanylate cyclase inhibitor (ODQ) blocked inhibition induced by EFS. Purinergic neurotransmission did not affect Ca2+ transients in ICC-DMP. Purinergic neurotransmission elicits hyperpolarization of the SIP syncytium by activation of K+ channels in PDGFRα+ cells. Generalized hyperpolarization of SIP cells by pinacidil (KATP agonist) or MRS2365 (P2Y1 agonist) also had no effect on Ca2+ transients in ICC-DMP. Peptidergic transmitter receptors (VIP and PACAP) are expressed in ICC and can modulate ICC-DMP Ca2+ transients. In summary Ca2+ transients in ICC-DMP are blocked by enteric inhibitory neurotransmission. ICC-DMP lack a voltage-dependent mechanism for regulating Ca2+ release, and this protects Ca2+ handling in ICC-DMP from membrane potential changes in other SIP cells.
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Affiliation(s)
| | | | | | | | - Kenton M. Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno, NV, United States
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46
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Ge Y, Kang Y, Cassidy RM, Moon KM, Lewis R, Wong ROL, Foster LJ, Craig AM. Clptm1 Limits Forward Trafficking of GABA A Receptors to Scale Inhibitory Synaptic Strength. Neuron 2018; 97:596-610.e8. [PMID: 29395912 DOI: 10.1016/j.neuron.2017.12.038] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 11/17/2017] [Accepted: 12/22/2017] [Indexed: 12/11/2022]
Abstract
In contrast with numerous studies of glutamate receptor-associated proteins and their involvement in the modulation of excitatory synapses, much less is known about mechanisms controlling postsynaptic GABAA receptor (GABAAR) numbers. Using tandem affinity purification from tagged GABAAR γ2 subunit transgenic mice and proteomic analysis, we isolated several GABAAR-associated proteins, including Cleft lip and palate transmembrane protein 1 (Clptm1). Clptm1 interacted with all GABAAR subunits tested and promoted GABAAR trapping in the endoplasmic reticulum. Overexpression of Clptm1 reduced GABAAR-mediated currents in a recombinant system, in cultured hippocampal neurons, and in brain, with no effect on glycine or AMPA receptor-mediated currents. Conversely, knockdown of Clptm1 increased phasic and tonic inhibitory transmission with no effect on excitatory synaptic transmission. Furthermore, altering the expression level of Clptm1 mimicked activity-induced inhibitory synaptic scaling. Thus, in complement to other GABAAR-associated proteins that promote receptor surface expression, Clptm1 limits GABAAR forward trafficking and regulates inhibitory homeostatic plasticity.
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Affiliation(s)
- Yuan Ge
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Yunhee Kang
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Robert M Cassidy
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Kyung-Mee Moon
- Department of Biochemistry and Molecular Biology and Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Renate Lewis
- Department of Anatomy and Neurobiology, Washington University, St. Louis, MO 63110, USA
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology and Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
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47
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Lie ME, Gowing EK, Clausen RP, Wellendorph P, Clarkson AN. Inhibition of GABA transporters fails to afford significant protection following focal cerebral ischemia. J Cereb Blood Flow Metab 2018; 38:166-173. [PMID: 29148909 PMCID: PMC5757447 DOI: 10.1177/0271678x17743669] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Brain ischemia triggers excitotoxicity and cell death, yet no neuroprotective drugs have made it to the clinic. While enhancing GABAergic signaling to counterbalance excitotoxicity has shown promise in animal models, clinical studies have failed. Blockade of GABA transporters (GATs) offers an indirect approach to increase GABA inhibition to lower the excitation threshold of neurons. Among the GATs, GAT1 is known to promote neuroprotection, while the protective role of the extrasynaptic transporters GAT3 and BGT1 is elusive. A focal lesion was induced in the motor cortex in two to four-month-old C57BL/6 J male mice by photothrombosis. The GAT1 inhibitor, tiagabine (1 and 10 mg/kg), the GAT2/3 inhibitor, ( S)-SNAP-5114 (5 and 30 mg/kg) and the GAT1/BGT1 inhibitor, EF-1502 (1 and 10 mg/kg) were given i.p. 1 and 6 h post-stroke to assess their impact on infarct volume and motor performance seven days post-stroke. One mg/kg tiagabine improved motor performance, while 10 mg/kg tiagabine, ( S)-SNAP-5114 and EF-1502 had no effect. None of the compounds affected infarct volume. Interestingly, treatment with tiagabine induced seizures and ( S)-SNAP-5114 led to increased mortality. Although we show that tiagabine can promote protection, our findings indicate that caution should be had when using GAT1 and GAT3 inhibitors for conditions of brain ischemia.
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Affiliation(s)
- Maria Ek Lie
- 1 Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,2 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Emma K Gowing
- 2 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Rasmus P Clausen
- 1 Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- 1 Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Andrew N Clarkson
- 2 Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand.,3 Faculty of Pharmacy, The University of Sydney, Sydney, New South Wales, Australia
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48
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Bridi MS, Park SM, Huang S. Developmental Disruption of GABA AR-Meditated Inhibition in Cntnap2 KO Mice. eNeuro 2017; 4:ENEURO. [PMID: 28966979 DOI: 10.1523/ENEURO.0162-17.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 12/24/2022] Open
Abstract
GABA released from presynaptic sites induces short-lived phasic inhibition mediated by synaptic GABAA receptors (GABAARs) and longer-duration tonic inhibition mediated by extrasynaptic GABAA or GABAB receptors (GABABRs). A number of studies have found that contactin-associated protein 2 (Cntnap2) knockout (KO) mice, a well-established mouse model of autism, exhibit reduced interneuron numbers and aberrant phasic inhibition. However, little is known about whether tonic inhibition is disrupted in Cntnap2 KO mice and when the disruption of inhibition begins to occur during postnatal development. We examined tonic and phasic inhibition in layer 2/3 pyramidal cells of primary visual cortex of Cntnap2 KO at two different developmental stages, three to four and six to eight weeks of age. We found that both phasic inhibition and GABAAR but not GABABR-mediated tonic inhibition was reduced in pyramidal cells from six- to eight-week-old Cntnap2 KO mice, while in three- to four-week-old mice, no significant effects of genotype on tonic or phasic inhibition was observed. We further found that activation of tonic currents mediated by δ-subunit-containing GABAARs reduced neural excitability, an effect that was attenuated by loss of Cntnap2. While the relative contribution of tonic versus phasic inhibition to autism-related symptoms remains unclear, our data suggest that reduced tonic inhibition may play an important role, and δ-subunit-containing GABAARs may be a useful target for therapeutic intervention in autism.
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49
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Canto-Bustos M, Loeza-Alcocer E, Cuellar CA, Osuna P, Elias-Viñas D, Granados-Soto V, Manjarrez E, Felix R, Delgado-Lezama R. Tonically Active α 5GABA A Receptors Reduce Motoneuron Excitability and Decrease the Monosynaptic Reflex. Front Cell Neurosci 2017; 11:283. [PMID: 28970784 PMCID: PMC5609539 DOI: 10.3389/fncel.2017.00283] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 08/31/2017] [Indexed: 11/19/2022] Open
Abstract
Motoneurons, the final common path of the Central Nervous System (CNS), are under a complex control of its excitability in order to precisely translate the interneuronal pattern of activity into skeletal muscle contraction and relaxation. To fulfill this relevant function, motoneurons are provided with a vast repertoire of receptors and channels, including the extrasynaptic GABAA receptors which have been poorly investigated. Here, we confirmed that extrasynaptic α5 subunit-containing GABAA receptors localize with choline acetyltransferase (ChAT) positive cells, suggesting that these receptors are expressed in turtle motoneurons as previously reported in rodents. In these cells, α5GABAA receptors are activated by ambient GABA, producing a tonic shunt that reduces motoneurons’ membrane resistance and affects their action potential firing properties. In addition, α5GABAA receptors shunted the synaptic excitatory inputs depressing the monosynaptic reflex (MSR) induced by activation of primary afferents. Therefore, our results suggest that α5GABAA receptors may play a relevant physiological role in motor control.
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Affiliation(s)
- Martha Canto-Bustos
- Department of Neuroscience, Center for the Neural Basis of Cognition, University of PittsburghPittsburgh, PA, United States
| | - Emanuel Loeza-Alcocer
- Department of Neurobiology, University of Pittsburgh School of MedicinePittsburgh, PA, United States
| | - Carlos A Cuellar
- Laboratory of Neuronal Engineering, Mayo Clinic MinnesotaRochester, MN, United States
| | - Paulina Osuna
- Departamento de Fisiología, Biofísica y Neurociencias, CinvestavMexico City, Mexico
| | | | | | - Elías Manjarrez
- Instituto de Fisiología, Benemérita Universidad Autónoma de PueblaPuebla, Mexico
| | - Ricardo Felix
- Departamento de Biología Celular, CinvestavMexico City, Mexico
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50
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Kim YS, Woo J, Lee CJ, Yoon BE. Decreased Glial GABA and Tonic Inhibition in Cerebellum of Mouse Model for Attention-Deficit/Hyperactivity Disorder (ADHD). Exp Neurobiol 2017; 26:206-212. [PMID: 28912643 PMCID: PMC5597551 DOI: 10.5607/en.2017.26.4.206] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/23/2017] [Accepted: 08/23/2017] [Indexed: 01/19/2023] Open
Abstract
About 5~12% of school-aged children suffer from the Attention-Deficit/Hyperactivity Disorder (ADHD). However, the core mechanism of ADHD remains unclear. G protein-coupled receptor kinase-interacting protein-1 (GIT1) has recently been reported to be associated with ADHD in human and the genetic deletion of GIT1 result in ADHD-like behaviors in mice. Mice lacking GIT1 shows a shift in neuronal excitation/inhibition (E/I) balance. However, the pricise mechanism for E/I imbalance and the role of neuron-glia interaction in GIT1 knockout (KO) mice have not been studied. Especially, a possible contribution of glial GABA and tonic inhibition mediated by astrocytic GABA release in the mouse model for ADHD remains unexplored. Therefore, we investigated the changes in the amount of GABA and degree of tonic inhibition in GIT1 KO mice. We observed a decreased glial GABA intensity in GIT1 KO mice compared to wild type (WT) mice and an attenuation of tonic current from cerebellar granule cells in GIT1 KO mice. Our study identifies the previously unknown mechanism of reduced astrocytic GABA and tonic inhibition in GIT1 lacking mice as a potential cause of hyperactivity disorder.
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Affiliation(s)
- Yoo Sung Kim
- Department of Molecular biology, Dankook University, Cheonan, Chungnam 31116, Korea
| | - Junsung Woo
- Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Neuroscience Program, University of Science and Technology (UST), Daejeon 34113, Korea
| | - C Justin Lee
- Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Neuroscience Program, University of Science and Technology (UST), Daejeon 34113, Korea.,KU-KIST Graduate School of Converging Sciences and Technologies, Korea University, Seoul 02841, Korea
| | - Bo-Eun Yoon
- Department of Molecular biology, Dankook University, Cheonan, Chungnam 31116, Korea
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