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Marunaka Y. Physiological roles of chloride ions in bodily and cellular functions. J Physiol Sci 2023; 73:31. [PMID: 37968609 PMCID: PMC10717538 DOI: 10.1186/s12576-023-00889-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 10/31/2023] [Indexed: 11/17/2023]
Abstract
Physiological roles of Cl-, a major anion in the body, are not well known compared with those of cations. This review article introduces: (1) roles of Cl- in bodily and cellular functions; (2) the range of cytosolic Cl- concentration ([Cl-]c); (3) whether [Cl-]c could change with cell volume change under an isosmotic condition; (4) whether [Cl-]c could change under conditions where multiple Cl- transporters and channels contribute to Cl- influx and efflux in an isosmotic state; (5) whether the change in [Cl-]c could be large enough to act as signals; (6) effects of Cl- on cytoskeletal tubulin polymerization through inhibition of GTPase activity and tubulin polymerization-dependent biological activity; (7) roles of cytosolic Cl- in cell proliferation; (8) Cl--regulatory mechanisms of ciliary motility; (9) roles of Cl- in sweet/umami taste receptors; (10) Cl--regulatory mechanisms of with-no-lysine kinase (WNK); (11) roles of Cl- in regulation of epithelial Na+ transport; (12) relationship between roles of Cl- and H+ in body functions.
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Affiliation(s)
- Yoshinori Marunaka
- Medical Research Institute, Kyoto Industrial Health Association, General Incorporated Foundation, 67 Kitatsuboi-Cho, Nishinokyo, Nakagyo-Ku, Kyoto, 604-8472, Japan.
- Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, 525-8577, Japan.
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-Ku, Kyoto, 602-8566, Japan.
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2
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Furukawa T, Fukuda A. Maternal taurine as a modulator of Cl - homeostasis as well as of glycine/GABA A receptors for neocortical development. Front Cell Neurosci 2023; 17:1221441. [PMID: 37601283 PMCID: PMC10435090 DOI: 10.3389/fncel.2023.1221441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/20/2023] [Indexed: 08/22/2023] Open
Abstract
During brain and spinal cord development, GABA and glycine, the inhibitory neurotransmitters, cause depolarization instead of hyperpolarization in adults. Since glycine and GABAA receptors (GABAARs) are chloride (Cl-) ion channel receptor, the conversion of GABA/glycine actions during development is influenced by changes in the transmembrane Cl- gradient, which is regulated by Cl- transporters, NKCC1 (absorption) and KCC2 (expulsion). In immature neurons, inhibitory neurotransmitters are released in a non-vesicular/non-synaptic manner, transitioning to vesicular/synaptic release as the neuron matures. In other word, in immature neurons, neurotransmitters generally act tonically. Thus, the glycine/GABA system is a developmentally multimodal system that is required for neurogenesis, differentiation, migration, and synaptogenesis. The endogenous agonists for these receptors are not fully understood, we address taurine. In this review, we will discuss about the properties and function of taurine during development of neocortex. Taurine cannot be synthesized by fetuses or neonates, and is transferred from maternal blood through the placenta or maternal milk ingestion. In developing neocortex, taurine level is higher than GABA level, and taurine tonically activates GABAARs to control radial migration as a stop signal. In the marginal zone (MZ) of the developing neocortex, endogenous taurine modulates the spread of excitatory synaptic transmission, activating glycine receptors (GlyRs) as an endogenous agonist. Thus, taurine affects information processing and crucial developmental processes such as axonal growth, cell migration, and lamination in the developing cerebral cortex. Additionally, we also refer to the possible mechanism of taurine-regulating Cl- homeostasis. External taurine is uptake by taurine transporter (TauT) and regulates NKCC1 and KCC2 mediated by intracellular signaling pathway, with-no-lysine kinase 1 (WNK1) and its subsequent kinases STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) and oxidative stress response kinase-1 (OSR1). Through the regulation of NKCC1 and KCC2, mediated by the WNK-SPAK/OSR1 signaling pathway, taurine plays a role in maintaining Cl- homeostasis during normal brain development.
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Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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3
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Clark DN, Begg LR, Filiano AJ. Unique aspects of IFN-γ/STAT1 signaling in neurons. Immunol Rev 2022; 311:187-204. [PMID: 35656941 PMCID: PMC10120860 DOI: 10.1111/imr.13092] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/01/2022] [Accepted: 05/12/2022] [Indexed: 01/05/2023]
Abstract
The IFN-γ/STAT1 immune signaling pathway impacts many homeostatic and pathological aspects of neurons, beyond its canonical role in controlling intracellular pathogens. Well known for its potent pro-inflammatory and anti-viral functions in the periphery, the IFN-γ/STAT1 pathway is rapidly activated then deactivated to prevent excessive inflammation; however, neurons utilize unique IFN-γ/STAT1 activation patterns, which may contribute to the non-canonical neuron-specific downstream effects. Though it is now well-established that the immune system interacts and supports the CNS in health and disease, many aspects regarding IFN-γ production in the CNS and how neurons respond to IFN-γ are unclear. Additionally, it is not well understood how the diversity of the IFN-γ/STAT1 pathway is regulated in neurons to control homeostatic functions, support immune surveillance, and prevent pathologies. In this review, we discuss the neuron-specific mechanisms and kinetics of IFN-γ/STAT1 activation, the potential sources and entry sites of IFN-γ in the CNS, and the diverse set of homeostatic and pathological effects IFN-γ/STAT1 signaling in neurons has on CNS health and disease. We will also highlight the different contexts and conditions under which IFN-γ-induced STAT1 activation has been studied in neurons, and how various factors might contribute to the vast array of downstream effects observed.
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Affiliation(s)
- Danielle N. Clark
- Department of Immunology, Duke University, Durham, North Carolina, USA
- Marcus Center for Cellular Cures, Duke University, Durham, North Carolina, USA
| | - Lauren R. Begg
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Anthony J. Filiano
- Department of Immunology, Duke University, Durham, North Carolina, USA
- Marcus Center for Cellular Cures, Duke University, Durham, North Carolina, USA
- Department of Pathology, Duke University, Durham, North Carolina, USA
- Department of Neurosurgery, Duke University, Durham, North Carolina, USA
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Agrud A, Subburaju S, Goel P, Ren J, Kumar AS, Caldarone BJ, Dai W, Chavez J, Fukumura D, Jain RK, Kloner RA, Vasudevan A. Gabrb3 endothelial cell-specific knockout mice display abnormal blood flow, hypertension, and behavioral dysfunction. Sci Rep 2022; 12:4922. [PMID: 35318369 PMCID: PMC8941104 DOI: 10.1038/s41598-022-08806-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/04/2022] [Indexed: 11/17/2022] Open
Abstract
Our recent studies uncovered a novel GABA signaling pathway in embryonic forebrain endothelial cells that works independently from neuronal GABA signaling and revealed that disruptions in endothelial GABAA receptor-GABA signaling from early embryonic stages can directly contribute to the origin of psychiatric disorders. In the GABAA receptor β3 subunit endothelial cell conditional knockout (Gabrb3ECKO) mice, the β3 subunit is deleted selectively from endothelial cells, therefore endothelial GABAA receptors become inactivated and dysfunctional. There is a reduction in vessel densities and increased vessel morphology in the Gabrb3ECKO telencephalon that persists in the adult neocortex. Gabrb3ECKO mice show behavioral deficits such as impaired reciprocal social interactions, communication deficits, heightened anxiety, and depression. Here, we characterize the functional changes in Gabrb3ECKO mice by evaluating cortical blood flow, examine the consequences of loss of endothelial Gabrb3 on cardiac tissue, and define more in-depth altered behaviors. Red blood cell velocity and blood flow were increased in the cortical microcirculation of the Gabrb3ECKO mice. The Gabrb3ECKO mice had a reduction in vessel densities in the heart, similar to the brain; exhibited wavy, myocardial fibers, with elongated 'worm-like' nuclei in their cardiac histology, and developed hypertension. Additional alterations in behavioral function were observed in the Gabrb3ECKO mice such as increased spontaneous exploratory activity and rearing in an open field, reduced short term memory, decreased ambulatory activity in CLAMS testing, and altered prepulse inhibition to startle, an important biomarker of psychiatric diseases such as schizophrenia. Our results imply that vascular Gabrb3 is a key player in the brain as well as the heart, and its loss in both organs can lead to concurrent development of psychiatric and cardiac dysfunction.
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Affiliation(s)
- Anass Agrud
- grid.280933.30000 0004 0452 8371Angiogenesis and Brain Development Laboratory, Huntington Medical Research Institutes (HMRI), 686 S Fair Oaks Avenue, Pasadena, CA 91105 USA
| | - Sivan Subburaju
- grid.280933.30000 0004 0452 8371Angiogenesis and Brain Development Laboratory, Huntington Medical Research Institutes (HMRI), 686 S Fair Oaks Avenue, Pasadena, CA 91105 USA ,grid.38142.3c000000041936754XDepartment of Psychiatry, Harvard Medical School, Boston, MA 02215 USA ,grid.240206.20000 0000 8795 072XDivision of Basic Neuroscience, McLean Hospital, 115 Mill Street, Belmont, MA 02478 USA
| | - Pranay Goel
- grid.280933.30000 0004 0452 8371Angiogenesis and Brain Development Laboratory, Huntington Medical Research Institutes (HMRI), 686 S Fair Oaks Avenue, Pasadena, CA 91105 USA
| | - Jun Ren
- grid.32224.350000 0004 0386 9924Edwin L. Steele Laboratories, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 USA
| | - Ashwin Srinivasan Kumar
- grid.32224.350000 0004 0386 9924Edwin L. Steele Laboratories, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 USA ,grid.116068.80000 0001 2341 2786Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Barbara J. Caldarone
- grid.38142.3c000000041936754XMouse Behavior Core, Department of Genetics, Harvard Medical School, Boston, MA USA
| | - Wangde Dai
- grid.280933.30000 0004 0452 8371Huntington Medical Research Institutes, Pasadena, CA USA ,grid.42505.360000 0001 2156 6853Division of Cardiovascular Medicine, Department of Medicine, Keck School of Medicine at University of Southern California, Los Angeles, CA USA
| | - Jesus Chavez
- grid.280933.30000 0004 0452 8371Huntington Medical Research Institutes, Pasadena, CA USA ,grid.42505.360000 0001 2156 6853Division of Cardiovascular Medicine, Department of Medicine, Keck School of Medicine at University of Southern California, Los Angeles, CA USA
| | - Dai Fukumura
- grid.32224.350000 0004 0386 9924Edwin L. Steele Laboratories, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 USA
| | - Rakesh K. Jain
- grid.32224.350000 0004 0386 9924Edwin L. Steele Laboratories, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 USA
| | - Robert A. Kloner
- grid.280933.30000 0004 0452 8371Huntington Medical Research Institutes, Pasadena, CA USA ,grid.42505.360000 0001 2156 6853Division of Cardiovascular Medicine, Department of Medicine, Keck School of Medicine at University of Southern California, Los Angeles, CA USA
| | - Anju Vasudevan
- Angiogenesis and Brain Development Laboratory, Huntington Medical Research Institutes (HMRI), 686 S Fair Oaks Avenue, Pasadena, CA, 91105, USA.
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Zizzo MG, Cicio A, Raimondo S, Alessandro R, Serio R. Age-related differences of γ-aminobutyric acid (GABA)ergic transmission in human colonic smooth muscle. Neurogastroenterol Motil 2022; 34:e14248. [PMID: 34432349 PMCID: PMC9285353 DOI: 10.1111/nmo.14248] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/10/2021] [Accepted: 08/10/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Enteric neurons undergo to functional changes during aging. We investigated the possible age-associated differences in enteric γ-aminobutyric acid (GABA)ergic transmission evaluating function and distribution of GABAergic receptors in human colon. METHODS Mechanical responses to GABA and GABA receptor agonists on slow phasic contractions were examined in vitro as changes in isometric tension in colonic muscle strips from young (<65 years old) and aged patients (>65 years old). GABAergic receptor expression was assessed by quantitative RT-PCR. KEY RESULTS In both preparations GABA induced an excitatory effect, consisting in an increase in the basal tone, antagonized by the GABAA receptor antagonist, bicuculline, and potentiated by phaclofen, GABAB receptor antagonist.Tetrodotoxin (TTX) and atropine-sensitive contractile responses to GABA and GABAA receptor agonist, muscimol, were more pronounced in old compared to young subjects. Baclofen, GABAB receptor agonist, induced a TTX-sensitive reduction of the amplitude of the spontaneous. Nω-nitro-l-arginine methyl ester (L-NAME), nitric oxide (NO) synthase inhibitor abolished the inhibitory responses in old preparations, but a residual responses persisted in young preparations, which in turn was abolished by suramin, purinergic receptor antagonist. α3-GABAA receptor subunit expression tends to change in an age-dependent manner. CONCLUSIONS AND INFERENCES Our results reveal age-related differences in GABAergic transmission in human colon. At all the age tested GABA regulates muscular contractility modulating the activity of the intrinsic neurons. Activation of GABAA receptor, through acetylcholine release, induces contraction, which increases in amplitude with age. GABAB receptor activation leads to neural release of NO and purines, being a loss of purinergic-component in aged group.
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Affiliation(s)
- Maria Grazia Zizzo
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF)University of PalermoViale delle Scienze,ed 16Palermo90128Italy,ATeN (Advanced Technologies Network) CenterUniversity of PalermoViale delle Scienze, ed 18Palermo90128Italy
| | - Adele Cicio
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF)University of PalermoViale delle Scienze,ed 16Palermo90128Italy
| | - Stefania Raimondo
- Department of Biomedicine, Neurosciences and Advanced Diagnostics (Bi.N.D)University of PalermoSection of Biology and GeneticsPalermo90133Italy
| | - Riccardo Alessandro
- Department of Biomedicine, Neurosciences and Advanced Diagnostics (Bi.N.D)University of PalermoSection of Biology and GeneticsPalermo90133Italy
| | - Rosa Serio
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF)University of PalermoViale delle Scienze,ed 16Palermo90128Italy
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Kilb W. When Are Depolarizing GABAergic Responses Excitatory? Front Mol Neurosci 2021; 14:747835. [PMID: 34899178 PMCID: PMC8651619 DOI: 10.3389/fnmol.2021.747835] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
The membrane responses upon activation of GABA(A) receptors critically depend on the intracellular Cl− concentration ([Cl−]i), which is maintained by a set of transmembrane transporters for Cl−. During neuronal development, but also under several pathophysiological conditions, the prevailing expression of the Cl− loader NKCC1 and the low expression of the Cl− extruder KCC2 causes elevated [Cl−]i, which result in depolarizing GABAergic membrane responses. However, depolarizing GABAergic responses are not necessarily excitatory, as GABA(A) receptors also reduces the input resistance of neurons and thereby shunt excitatory inputs. To summarize our knowledge on the effect of depolarizing GABA responses on neuronal excitability, this review discusses theoretical considerations and experimental studies illustrating the relation between GABA conductances, GABA reversal potential and neuronal excitability. In addition, evidences for the complex spatiotemporal interaction between depolarizing GABAergic and glutamatergic inputs are described. Moreover, mechanisms that influence [Cl−]i beyond the expression of Cl− transporters are presented. And finally, several in vitro and in vivo studies that directly investigated whether GABA mediates excitation or inhibition during early developmental stages are summarized. In summary, these theoretical considerations and experimental evidences suggest that GABA can act as inhibitory neurotransmitter even under conditions that maintain substantial depolarizing membrane responses.
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Affiliation(s)
- Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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Lombardi A, Luhmann HJ, Kilb W. Modelling the spatial and temporal constrains of the GABAergic influence on neuronal excitability. PLoS Comput Biol 2021; 17:e1009199. [PMID: 34767548 PMCID: PMC8612559 DOI: 10.1371/journal.pcbi.1009199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 11/24/2021] [Accepted: 10/24/2021] [Indexed: 11/21/2022] Open
Abstract
GABA (γ-amino butyric acid) is an inhibitory neurotransmitter in the adult brain that can mediate depolarizing responses during development or after neuropathological insults. Under which conditions GABAergic membrane depolarizations are sufficient to impose excitatory effects is hard to predict, as shunting inhibition and GABAergic effects on spatiotemporal filtering of excitatory inputs must be considered. To evaluate at which reversal potential a net excitatory effect was imposed by GABA (EGABAThr), we performed a detailed in-silico study using simple neuronal topologies and distinct spatiotemporal relations between GABAergic and glutamatergic inputs. These simulations revealed for GABAergic synapses located at the soma an EGABAThr close to action potential threshold (EAPThr), while with increasing dendritic distance EGABAThr shifted to positive values. The impact of GABA on AMPA-mediated inputs revealed a complex temporal and spatial dependency. EGABAThr depends on the temporal relation between GABA and AMPA inputs, with a striking negative shift in EGABAThr for AMPA inputs appearing after the GABA input. The spatial dependency between GABA and AMPA inputs revealed a complex profile, with EGABAThr being shifted to values negative to EAPThr for AMPA synapses located proximally to the GABA input, while for distally located AMPA synapses the dendritic distance had only a minor effect on EGABAThr. For tonic GABAergic conductances EGABAThr was negative to EAPThr over a wide range of gGABAtonic values. In summary, these results demonstrate that for several physiologically relevant situations EGABAThr is negative to EAPThr, suggesting that depolarizing GABAergic responses can mediate excitatory effects even if EGABA did not reach EAPThr. The neurotransmitter GABA mediates an inhibitory action in the mature brain, while it was found that GABA provokes depolarizations in the immature brain or after neurological insults. It is, however, not clear to which extend these GABAergic depolarizations can contribute to an excitatory effect. In the present manuscript we approached this question with a computational model of a simplified neurons to determine what amount of a GABAergic depolarizing effect, which we quantified by the so called GABA reversal potential (EGABA), was required to turn GABAergic inhibition to excitation. The results of our simulations revealed that if GABA was applied alone a GABAergic excitation was induced when EGABA was around the action potential threshold. When GABA was applied together with additional excitatory inputs, which is the physiological situation in the brain, only for spatially and temporally correlated inputs EGABA was close to the action potential threshold. For situations in which the additional excitatory inputs appear after the GABA input or are distant to the GABA input, an excitatory effect of GABA could be observed already at EGABA substantially negative to the action potential threshold. This results indicate that even slightly depolarizing GABA responses, which may be induced during or after neurological insults, can potentially turn GABAergic inhibition into GABAergic excitation.
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Affiliation(s)
- Aniello Lombardi
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Heiko J. Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- * E-mail:
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8
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Electrophysiology of ionotropic GABA receptors. Cell Mol Life Sci 2021; 78:5341-5370. [PMID: 34061215 PMCID: PMC8257536 DOI: 10.1007/s00018-021-03846-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/02/2021] [Accepted: 04/23/2021] [Indexed: 10/30/2022]
Abstract
GABAA receptors are ligand-gated chloride channels and ionotropic receptors of GABA, the main inhibitory neurotransmitter in vertebrates. In this review, we discuss the major and diverse roles GABAA receptors play in the regulation of neuronal communication and the functioning of the brain. GABAA receptors have complex electrophysiological properties that enable them to mediate different types of currents such as phasic and tonic inhibitory currents. Their activity is finely regulated by membrane voltage, phosphorylation and several ions. GABAA receptors are pentameric and are assembled from a diverse set of subunits. They are subdivided into numerous subtypes, which differ widely in expression patterns, distribution and electrical activity. Substantial variations in macroscopic neural behavior can emerge from minor differences in structure and molecular activity between subtypes. Therefore, the diversity of GABAA receptors widens the neuronal repertoire of responses to external signals and contributes to shaping the electrical activity of neurons and other cell types.
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Ryan RM, Ingram SL, Scimemi A. Regulation of Glutamate, GABA and Dopamine Transporter Uptake, Surface Mobility and Expression. Front Cell Neurosci 2021; 15:670346. [PMID: 33927596 PMCID: PMC8076567 DOI: 10.3389/fncel.2021.670346] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 03/15/2021] [Indexed: 01/31/2023] Open
Abstract
Neurotransmitter transporters limit spillover between synapses and maintain the extracellular neurotransmitter concentration at low yet physiologically meaningful levels. They also exert a key role in providing precursors for neurotransmitter biosynthesis. In many cases, neurons and astrocytes contain a large intracellular pool of transporters that can be redistributed and stabilized in the plasma membrane following activation of different signaling pathways. This means that the uptake capacity of the brain neuropil for different neurotransmitters can be dynamically regulated over the course of minutes, as an indirect consequence of changes in neuronal activity, blood flow, cell-to-cell interactions, etc. Here we discuss recent advances in the mechanisms that control the cell membrane trafficking and biophysical properties of transporters for the excitatory, inhibitory and modulatory neurotransmitters glutamate, GABA, and dopamine.
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Affiliation(s)
- Renae M. Ryan
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Susan L. Ingram
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, United States
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Bird LM, Ochoa-Lubinoff C, Tan WH, Heimer G, Melmed RD, Rakhit A, Visootsak J, During MJ, Holcroft C, Burdine RD, Kolevzon A, Thibert RL. The STARS Phase 2 Study: A Randomized Controlled Trial of Gaboxadol in Angelman Syndrome. Neurology 2020; 96:e1024-e1035. [PMID: 33443117 PMCID: PMC8055330 DOI: 10.1212/wnl.0000000000011409] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 10/12/2020] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To evaluate safety and tolerability and exploratory efficacy end points for gaboxadol (OV101) compared with placebo in individuals with Angelman syndrome (AS). METHODS Gaboxadol is a highly selective orthosteric agonist that activates δ-subunit-containing extrasynaptic γ-aminobutyric acid type A (GABAA) receptors. In a multicenter, double-blind, placebo-controlled, parallel-group trial, adolescent and adult individuals with a molecular diagnosis of AS were randomized (1:1:1) to 1 of 3 dosing regimens for a duration of 12 weeks: placebo morning dose and gaboxadol 15 mg evening dose (qd), gaboxadol 10 mg morning dose and 15 mg evening dose (bid), or placebo morning and evening dose. Safety and tolerability were monitored throughout the study. Prespecified exploratory efficacy end points included adapted Clinical Global Impression-Severity and Clinical Global Impression-Improvement (CGI-I) scales, which documented the clinical severity at baseline and change after treatment, respectively. RESULTS Eighty-eight individuals were randomized. Of 87 individuals (aged 13-45 years) who received at least 1 dose of study drug, 78 (90%) completed the study. Most adverse events (AEs) were mild to moderate, and no life-threatening AEs were reported. Efficacy of gaboxadol, as measured by CGI-I improvement in an exploratory analysis, was observed in gaboxadol qd vs placebo (p = 0.0006). CONCLUSION After 12 weeks of treatment, gaboxadol was found to be generally well-tolerated with a favorable safety profile. The efficacy as measured by the AS-adapted CGI-I scale warrants further studies. CLINICALTRIALSGOV IDENTIFIER NCT02996305. CLASSIFICATION OF EVIDENCE This study provides Class I evidence that, for individuals with AS, gaboxadol is generally safe and well-tolerated.
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Affiliation(s)
- Lynne M Bird
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Cesar Ochoa-Lubinoff
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Wen-Hann Tan
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Gali Heimer
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Raun D Melmed
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Amit Rakhit
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Jeannie Visootsak
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Matthew J During
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Christina Holcroft
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Rebecca D Burdine
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
| | - Alexander Kolevzon
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston.
| | - Ronald L Thibert
- From the University of California, San Diego (L.M.B.); Rady Children's Hospital (L.M.B.), San Diego, CA; Division of Developmental-Behavioral Pediatrics (C.O.-L.), Rush University Medical Center, Chicago, IL; Division of Genetics and Genomics (W.-H.T.), Boston Children's Hospital, Harvard Medical School, MA; Pediatric Neurology Unit (G.H.), Safra Children's Hospital, the Sheba Medical Center, Ramat Gan; The Sackler School of Medicine (G.H.), Tel Aviv University, Israel; Southwest Autism Research and Resource Center (R.D.M.), Phoenix, AZ; Ovid Therapeutics Inc. (A.R., M.J.D.); Neurogene (J.V.), New York, NY; Prometrika, LLC (C.H.), Cambridge, MA; Department of Molecular Biology (R.D.B.), Princeton University, NJ; Seaver Autism Center for Research and Treatment, Department of Psychiatry (A.K.), Icahn School of Medicine at Mount Sinai, New York, NY; and Angelman Syndrome Clinic, Department of Neurology (R.L.T.), Massachusetts General Hospital, Boston
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11
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Gholaminejad A, Gholamipour-Badie H, Nasehi M, Naghdi N. Prelimbic of Medial Prefrontal Cortex GABA Modulation through Testosterone on Spatial Learning and Memory. IRANIAN JOURNAL OF PHARMACEUTICAL RESEARCH : IJPR 2020; 18:1429-1444. [PMID: 32641952 PMCID: PMC6934985 DOI: 10.22037/ijpr.2019.1100745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Prefrontal cortex (PFC) is involved in multiple functions including attentional processes, spatial orientation, short-term memory, and long-term memory. Our previous study indicated that microinjection of testosterone in CA1 impaired spatial learning and memory. Some evidence suggests that impairment effect of testosterone is mediated by GABAergic system. In the present study, we investigated the interaction of testosterone (androgenic receptor agonist) and bicuculline (GABAA receptor antagonist) on spatial learning and memory performance in the prelimbic (PL) of male Wistar rats. Cannulae were bilaterally implanted into the PL region of PFC and drugs were daily microinjected for two minutes in each side. There are 4 experiments. In the first experiment, three sham groups were operated (solvent of testosterone, bicuculline, testosterone plus bicuculline). In the second experiment, different doses of testosterone (40, 80 μg /0.5 μL DMSO/each side) were injected into the PL before each session. In the third experiment, intra PL injections of bicuculline (2, 4 μg/0.5 μL DMSO/each side) were given before every session. In the last experiment, testosterone (80μg/0.5 μL DMSO/each side) along with bicuculline (2 μg/0.5 μL DMSO/each side) was injected into the PL. The results showed there is no difference between control group and sham operated group. Testosterone 80 μg and bicuculline 2 μg, each given separately, and also in combination increased escape latency to find the platform compared to the sham operated and cause to impaired spatial learning and memory. It is shown that intra PL microinjection of bicuculline after testosterone treatment could not rescue the spatial learning and memory impaired induced by testosterone.
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Affiliation(s)
- Azadeh Gholaminejad
- Department of Physiology and Pharmacology, Pasteur Institute of Iran (IPI), Tehran, Iran.,Department of Cognitive Neuroscience, Institute for Cognitive Science Studies (ICSS), Tehran, Iran
| | | | - Mohammad Nasehi
- Department of Cognitive Neuroscience, Institute for Cognitive Science Studies (ICSS), Tehran, Iran.,Cognitive and neuroscience research center (CNRC), Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Nasser Naghdi
- Department of Physiology and Pharmacology, Pasteur Institute of Iran (IPI), Tehran, Iran.,Department of Cognitive Neuroscience, Institute for Cognitive Science Studies (ICSS), Tehran, Iran
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12
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Baez A, Van Brunt T, Moody G, Wollmuth LP, Hsieh H. Voltage dependent allosteric modulation of IPSCs by benzodiazepines. Brain Res 2020; 1736:146699. [PMID: 32027866 DOI: 10.1016/j.brainres.2020.146699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 01/04/2020] [Accepted: 02/02/2020] [Indexed: 10/25/2022]
Abstract
GABAA receptors (GABAAR) are inhibitory ion channels ubiquitously expressed in the central nervous system and play critical roles in brain development and function. Benzodiazepines are positive allosteric modulators of GABAAR, enhancing channel opening frequency when GABA is bound to the receptor. Midazolam is a commonly used benzodiazepine. It is frequently used for premature infants, but the long-term consequences of its use in this patient population are not well established. Here, we studied the acute effects of midazolam on immature synapses. Using a rodent organotypic hippocampal slice preparation, we evaluated how midazolam affects inhibitory synaptic transmission onto CA1 pyramidal neurons. We found that 1 μM midazolam enhances evoked inhibitory post synaptic currents (eIPSCs) at a holding potential of -60 mV. Similarly, 1 μM midazolam enhances miniature IPSCs (mIPSCs) in CA1 pyramidal neurons at holding potentials of -60 mV and -30 mV. At depolarized holding potentials, however, midazolam no longer enhances mIPSCs. Depolarization of the postsynaptic cell by itself increases mIPSC decay, which occludes the allosteric effects of midazolam. These results provide insight into how a benzodiazepine and membrane voltage may modulate GABAAR function in developing circuits.
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Affiliation(s)
- Alexander Baez
- Medical Scientist Training Program (MSTP), Stony Brook University, Stony Brook, NY 11794, USA
| | - Trevor Van Brunt
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY 11794, USA
| | - Gabrielle Moody
- Department of Molecular and Cellular Pharmacology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Lonnie P Wollmuth
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY 11794, USA; Department of Biochemistry & Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA; Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY 11794-5230, USA
| | - Helen Hsieh
- Department of Surgery, Stony Brook Medicine, Stony Brook, NY 11794-8191, USA; Department of Pediatrics, Stony Brook Medicine, Stony Brook, NY 11794-8191, USA.
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13
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Tesic V, Joksimovic SM, Quillinan N, Krishnan K, Covey DF, Todorovic SM, Jevtovic-Todorovic V. Neuroactive steroids alphaxalone and CDNC24 are effective hypnotics and potentiators of GABA A currents, but are not neurotoxic to the developing rat brain. Br J Anaesth 2020; 124:603-613. [PMID: 32151384 DOI: 10.1016/j.bja.2020.01.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 01/01/2020] [Accepted: 01/20/2020] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND The most currently used general anaesthetics are potent potentiators of γ-aminobutyric acid A (GABAA) receptors and are invariably neurotoxic during the early stages of brain development in preclinical animal models. As causality between GABAA potentiation and anaesthetic-induced developmental neurotoxicity has not been established, the question remains whether GABAergic activity is crucial for promoting/enhancing neurotoxicity. Using the neurosteroid analogue, (3α,5α)-3-hydroxy-13,24-cyclo-18,21-dinorchol-22-en-24-ol (CDNC24), which potentiates recombinant GABAA receptors, we examined whether this potentiation is the driving force in inducing neurotoxicity during development. METHODS The neurotoxic potential of CDNC24 was examined vis-à-vis propofol (2,6-diisopropylphenol) and alphaxalone (5α-pregnan-3α-ol-11,20-dione) at the peak of rat synaptogenesis. In addition to the morphological neurotoxicity studies of the subiculum and medial prefrontal cortex (mPFC), we assessed the extra-, pre-, and postsynaptic effects of these agents on GABAergic neurotransmission in acute subicular slices from rat pups. RESULTS CDNC24, like alphaxalone and propofol, caused dose-dependent hypnosis in vivo, with a higher therapeutic index. CDNC24 and alphaxalone, unlike propofol, did not cause developmental neuroapoptosis in the subiculum and mPFC. Propofol potentiated post- and extrasynaptic GABAA currents as evidenced by increased spontaneous inhibitory postsynaptic current (sIPSC) decay time and prominent tonic currents, respectively. CDNC24 and alphaxalone had a similar postsynaptic effect, but also displayed a strong presynaptic effect as evidenced by decreased frequency of sIPSCs and induced moderate tonic currents. CONCLUSIONS The lack of neurotoxicity of CDNC24 and alphaxalone may be at least partly related to suppression of presynaptic GABA release in the developing brain.
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Affiliation(s)
- Vesna Tesic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Srdjan M Joksimovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Nidia Quillinan
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO, USA
| | - Douglas F Covey
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, MO, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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14
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Fukuda A. Chloride homeodynamics underlying modal shifts in cellular and network oscillations. Neurosci Res 2020; 156:14-23. [PMID: 32105770 DOI: 10.1016/j.neures.2020.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 11/22/2019] [Accepted: 02/21/2020] [Indexed: 11/16/2022]
Abstract
γ-Aminobutyric acid (GABA) generally induces hyperpolarization and inhibition in the adult brain, but causes depolarization (and can be excitatory) in the immature brain. Depolarizing GABA actions are necessary for neurogenesis, differentiation, migration, and synaptogenesis. Additionally, the conversion of GABA responses from inhibition to excitation can be induced in adults by pathological conditions. Because GABAA receptors are Cl- channels, alternating GABA actions between hyperpolarization (Cl- influx) and depolarization (Cl- efflux) are induced by changes in the Cl- gradient, which is regulated by C- transporters. Thus, the dynamics of neural functions are modulated by active Cl- homeostasis (Cl- homeodynamics), alternating inhibition and excitation, and could underlie the modal shifts in cellular and network oscillations. Such a modal shift in GABA actions is required for normal development. Thus disturbances in this developmental GABA modal shift and/or the induction of excitatory GABA action in adult could underlie the pathogenesis of diverse neurological diseases (so-called network diseases).
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Affiliation(s)
- Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan; Advanced Research Facilities and Services, Preeminent Medical Photonics Education and Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan.
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15
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GABA-mediated tonic inhibition differentially modulates gain in functional subtypes of cortical interneurons. Proc Natl Acad Sci U S A 2020; 117:3192-3202. [PMID: 31974304 DOI: 10.1073/pnas.1906369117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [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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16
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Mechanistic insights into autocrine and paracrine roles of endothelial GABA signaling in the embryonic forebrain. Sci Rep 2019; 9:16256. [PMID: 31700116 PMCID: PMC6838150 DOI: 10.1038/s41598-019-52729-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/18/2019] [Indexed: 12/24/2022] Open
Abstract
The developing cerebral cortex uses a complex developmental plan involving angiogenesis, neurogenesis and neuronal migration. Our recent studies have highlighted the importance of endothelial cell secreted GABA signaling in the embryonic forebrain and established novel autonomous links between blood vessels and the origin of neuropsychiatric diseases. A GABA pathway operates in both endothelial cells and GABAergic neurons of the embryonic telencephalon; however, while the neuronal GABA pathway has been extensively studied, little is known about the endothelial GABA pathway. Our recently generated Vgat endothelial cell knockout mouse model that blocks GABA release from endothelial cells, serves as a new tool to study how endothelial GABA signaling shapes angiogenesis and neurovascular interactions during prenatal development. Quantitative gene expression profiling reveals that the endothelial GABA signaling pathway influences genes connected to specific processes like endothelial cell proliferation, differentiation, migration, tight junction formation, vascular sprouting and integrity. It also shows how components of the neuronal GABA pathway, for instance receptor mediated signaling, cell cycle related components and transcription factors are affected in the absence of endothelial GABA release. Taken together, our findings delineate the close relationship between vascular and nervous systems that begin early in embryogenesis establishing their future interactions and interdependence.
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17
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Choi YK, Vasudevan A. Endothelial GABA signaling: a phoenix awakened. Aging (Albany NY) 2019; 10:859-860. [PMID: 29846173 PMCID: PMC5990386 DOI: 10.18632/aging.101457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/21/2018] [Indexed: 11/25/2022]
Affiliation(s)
- Yong Kee Choi
- Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA.,Angiogenesis and Brain Development Laboratory, Division of Basic Neuroscience, McLean Hospital, Belmont, MA 02478, USA
| | - Anju Vasudevan
- Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA.,Angiogenesis and Brain Development Laboratory, Division of Basic Neuroscience, McLean Hospital, Belmont, MA 02478, USA
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18
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Jiang XM, Wang WP, Liu ZH, Yin HJ, Ma H, Feng N, Wang L, Huang HH, Wang XL. 2-(4-methyl-thiazol-5-yl) ethyl nitrate maleate-potentiated GABA A receptor response in hippocampal neurons. CNS Neurosci Ther 2018; 24:1231-1240. [PMID: 30039924 DOI: 10.1111/cns.13033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/15/2018] [Accepted: 06/25/2018] [Indexed: 12/31/2022] Open
Abstract
AIMS 2-(4-methyl-thiazol-5-yl) ethyl nitrate maleate (NMZM), a derivative of clomethiazole (CMZ), had been investigated for the treatment of Alzheimer's disease (AD). The beneficial effects of NMZM in AD included reversing cognitive deficit, improving learning and memory as well as neuroprotection. The pharmacological effects of NMZM on GABAA receptors were reported previously; however, the mechanisms were unclear and were explored therefore. RESULTS In this study, we demonstrated that NMZM improved learning and memory by alleviating scopolamine-induced long-term potentiation (LTP) suppression in the dentate gyrus of rats, indicating that NMZM had protective effects against scopolamine-induced depression of LTP. Next, we investigated the action of NMZM on GABAA receptors in hippocampal neurons and the binding site of NMZM on GABAA receptors. NMZM directly activated GABAA receptors in hippocampal neurons in a weak manner. However, NMZM could potentiate the response of GABAA receptors to GABA and NMZM positively modulated GABAA receptors with an EC50 value of 465 μmol/L at 3 μmol/L GABA while this potentiation at low concentration of GABA (1, 3 μmol/L) was more significant than that at high concentration (10, 30 μmol/L). In addition, NMZM could enhance GABA currents after using diazepam and pentobarbital, the positive modulators of GABAA receptors. NMZM could not affect the etomidate-potentiated GABAA current. It suggested that the binding site of NMZM on GABAA receptors is the same as etomidate. CONCLUSIONS These results provided support for the neuroprotective effect of NMZM, which was partly dependent on the potentiation of GABAA receptors. The etomidate binding site might be a new target for neuronal protection and for drug development.
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Affiliation(s)
- Xiao-Mei Jiang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of MateriaMedica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Wei-Ping Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of MateriaMedica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhi-Hui Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of MateriaMedica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Hua-Jing Yin
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of MateriaMedica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Hao Ma
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of MateriaMedica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Nan Feng
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of MateriaMedica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Ling Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of MateriaMedica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Hai-Hong Huang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of MateriaMedica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xiao-Liang Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of MateriaMedica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
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19
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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] [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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20
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Monesson-Olson B, McClain JJ, Case AE, Dorman HE, Turkewitz DR, Steiner AB, Downes GB. Expression of the eight GABAA receptor α subunits in the developing zebrafish central nervous system. PLoS One 2018; 13:e0196083. [PMID: 29702678 PMCID: PMC5922542 DOI: 10.1371/journal.pone.0196083] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/05/2018] [Indexed: 11/26/2022] Open
Abstract
GABA is a robust regulator of both developing and mature neural networks. It exerts many of its effects through GABAA receptors, which are heteropentamers assembled from a large array of subunits encoded by distinct genes. In mammals, there are 19 different GABAA subunit types, which are divided into the α, β, γ, δ, ε, π, θ and ρ subfamilies. The immense diversity of GABAA receptors is not fully understood. However, it is known that specific isoforms, with their distinct biophysical properties and expression profiles, tune responses to GABA. Although larval zebrafish are well-established as a model system for neural circuit analysis, little is known about GABAA receptors diversity and expression in this system. Here, using database analysis, we show that the zebrafish genome contains at least 23 subunits. All but the mammalian θ and ε subunits have at least one zebrafish ortholog, while five mammalian GABAA receptor subunits have two zebrafish orthologs. Zebrafish contain one subunit, β4, which does not have a clear mammalian ortholog. Similar to mammalian GABAA receptors, the zebrafish α subfamily is the largest and most diverse of the subfamilies. In zebrafish there are eight α subunits, and RNA in situ hybridization across early zebrafish development revealed that they demonstrate distinct patterns of expression in the brain, spinal cord, and retina. Some subunits were very broadly distributed, whereas others were restricted to small populations of cells. Subunit-specific expression patterns in zebrafish resembled were those found in frogs and rodents, which suggests that the roles of different GABAA receptor isoforms are largely conserved among vertebrates. This study provides a platform to examine isoform specific roles of GABAA receptors within zebrafish neural circuits and it highlights the potential of this system to better understand the remarkable heterogeneity of GABAA receptors.
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Affiliation(s)
- Bryan Monesson-Olson
- Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA, United States of America
- Biology Department, University of Massachusetts, Amherst, MA, United States of America
| | - Jon J. McClain
- Biology Department, University of Massachusetts, Amherst, MA, United States of America
| | - Abigail E. Case
- Biology Department, University of Massachusetts, Amherst, MA, United States of America
| | - Hanna E. Dorman
- Biology Department, University of Massachusetts, Amherst, MA, United States of America
| | - Daniel R. Turkewitz
- Department of Biology and Health Sciences, Pace University, Pleasantville, NY, United States of America
| | - Aaron B. Steiner
- Department of Biology and Health Sciences, Pace University, Pleasantville, NY, United States of America
| | - Gerald B. Downes
- Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA, United States of America
- Biology Department, University of Massachusetts, Amherst, MA, United States of America
- * E-mail:
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21
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Fueta Y, Sekino Y, Yoshida S, Kanda Y, Ueno S. Prenatal exposure to valproic acid alters the development of excitability in the postnatal rat hippocampus. Neurotoxicology 2018; 65:1-8. [DOI: 10.1016/j.neuro.2018.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 12/03/2017] [Accepted: 01/04/2018] [Indexed: 11/16/2022]
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22
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Yakoub K, Jung S, Sattler C, Damerow H, Weber J, Kretzschmann A, Cankaya AS, Piel M, Rösch F, Haugaard AS, Frølund B, Schirmeister T, Lüddens H. Structure–Function Evaluation of Imidazopyridine Derivatives Selective for δ-Subunit-Containing γ-Aminobutyric Acid Type A (GABAA) Receptors. J Med Chem 2018; 61:1951-1968. [DOI: 10.1021/acs.jmedchem.7b01484] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Kirsten Yakoub
- Department of Psychiatry and Psychotherapy, Faculty of Health and Medical Sciences, University Medical Center Mainz, D-55131 Mainz, Germany
| | | | - Christian Sattler
- Department of Psychiatry and Psychotherapy, Faculty of Health and Medical Sciences, University Medical Center Mainz, D-55131 Mainz, Germany
| | | | | | | | | | | | | | - Anne S. Haugaard
- Department of Drug Design and Pharmacology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | | | - Hartmut Lüddens
- Department of Psychiatry and Psychotherapy, Faculty of Health and Medical Sciences, University Medical Center Mainz, D-55131 Mainz, Germany
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23
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Feng HJ, Forman SA. Comparison of αβδ and αβγ GABA A receptors: Allosteric modulation and identification of subunit arrangement by site-selective general anesthetics. Pharmacol Res 2017; 133:289-300. [PMID: 29294355 DOI: 10.1016/j.phrs.2017.12.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 12/28/2017] [Accepted: 12/29/2017] [Indexed: 12/27/2022]
Abstract
GABAA receptors play a dominant role in mediating inhibition in the mature mammalian brain, and defects of GABAergic neurotransmission contribute to the pathogenesis of a variety of neurological and psychiatric disorders. Two types of GABAergic inhibition have been described: αβγ receptors mediate phasic inhibition in response to transient high-concentrations of synaptic GABA release, and αβδ receptors produce tonic inhibitory currents activated by low-concentration extrasynaptic GABA. Both αβδ and αβγ receptors are important targets for general anesthetics, which induce apparently different changes both in GABA-dependent receptor activation and in desensitization in currents mediated by αβγ vs. αβδ receptors. Many of these differences are explained by correcting for the high agonist efficacy of GABA at most αβγ receptors vs. much lower efficacy at αβδ receptors. The stoichiometry and subunit arrangement of recombinant αβγ receptors are well established as β-α-γ-β-α, while those of αβδ receptors remain controversial. Importantly, some potent general anesthetics selectively bind in transmembrane inter-subunit pockets of αβγ receptors: etomidate acts at β+/α- interfaces, and the barbiturate R-5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl) barbituric acid (R-mTFD-MPAB) acts at α+/β- and γ+/β- interfaces. Thus, these drugs are useful as structural probes in αβδ receptors formed from free subunits or concatenated subunit assemblies designed to constrain subunit arrangement. Although a definite conclusion cannot be drawn, studies using etomidate and R-mTFD-MPAB support the idea that recombinant α1β3δ receptors may share stoichiometry and subunit arrangement with α1β3γ2 receptors.
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Affiliation(s)
- Hua-Jun Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, and Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA.
| | - Stuart A Forman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, and Department of Anesthesia, Harvard Medical School, Boston, MA 02114, USA.
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24
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Li S, Kumar T P, Joshee S, Kirschstein T, Subburaju S, Khalili JS, Kloepper J, Du C, Elkhal A, Szabó G, Jain RK, Köhling R, Vasudevan A. Endothelial cell-derived GABA signaling modulates neuronal migration and postnatal behavior. Cell Res 2017; 28:221-248. [PMID: 29086765 PMCID: PMC5799810 DOI: 10.1038/cr.2017.135] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/06/2017] [Accepted: 09/07/2017] [Indexed: 01/27/2023] Open
Abstract
The cerebral cortex is essential for integration and processing of information
that is required for most behaviors. The exquisitely precise laminar
organization of the cerebral cortex arises during embryonic development when
neurons migrate successively from ventricular zones to coalesce into specific
cortical layers. While radial glia act as guide rails for projection neuron
migration, pre-formed vascular networks provide support and guidance cues for
GABAergic interneuron migration. This study provides novel conceptual and
mechanistic insights into this paradigm of vascular-neuronal interactions,
revealing new mechanisms of GABA and its receptor-mediated signaling via
embryonic forebrain endothelial cells. With the use of two new endothelial cell
specific conditional mouse models of the GABA pathway
(Gabrb3ΔTie2-Cre and
VgatΔTie2-Cre), we show that partial or
complete loss of GABA release from endothelial cells during embryogenesis
results in vascular defects and impairs long-distance migration and positioning
of cortical interneurons. The downstream effects of perturbed endothelial
cell-derived GABA signaling are critical, leading to lasting changes to cortical
circuits and persistent behavioral deficits. Furthermore, we illustrate new
mechanisms of activation of GABA signaling in forebrain endothelial cells that
promotes their migration, angiogenesis and acquisition of blood-brain barrier
properties. Our findings uncover and elucidate a novel endothelial GABA
signaling pathway in the CNS that is distinct from the classical neuronal GABA
signaling pathway and shed new light on the etiology and pathophysiology of
neuropsychiatric diseases, such as autism spectrum disorders, epilepsy, anxiety,
depression and schizophrenia.
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Affiliation(s)
- Suyan Li
- Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA.,Angiogenesis and Brain Development Laboratory, Division of Basic Neuroscience, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA
| | - Peeyush Kumar T
- Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA.,Angiogenesis and Brain Development Laboratory, Division of Basic Neuroscience, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA
| | - Sampada Joshee
- Angiogenesis and Brain Development Laboratory, Division of Basic Neuroscience, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA
| | - Timo Kirschstein
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstrasse 9, 18057 Rostock, Germany
| | - Sivan Subburaju
- Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA.,Program in Structural and Molecular Neuroscience, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA
| | | | - Jonas Kloepper
- Edwin L. Steele Laboratories, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Chuang Du
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02148, USA
| | - Abdallah Elkhal
- Department of Surgery, Harvard Medical School, Boston, MA 02115, USA.,Division of Transplantation, Brigham and Women's Hospital, 221 Longwood Avenue, EBRC 309, Boston, MA 02115, USA
| | - Gábor Szabó
- Laboratory of Molecular Biology and Genetics, Department of Gene Technology and Developmental Neurobiology, Institute of Experimental Medicine, 1083 Budapest, Hungary
| | - Rakesh K Jain
- Edwin L. Steele Laboratories, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Rüdiger Köhling
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstrasse 9, 18057 Rostock, Germany
| | - Anju Vasudevan
- Department of Psychiatry, Harvard Medical School, Boston, MA 02215, USA.,Angiogenesis and Brain Development Laboratory, Division of Basic Neuroscience, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA
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25
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McMenamin CA, Travagli RA, Browning KN. Inhibitory neurotransmission regulates vagal efferent activity and gastric motility. Exp Biol Med (Maywood) 2017; 241:1343-50. [PMID: 27302177 DOI: 10.1177/1535370216654228] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The gastrointestinal tract receives extrinsic innervation from both the sympathetic and parasympathetic nervous systems, which regulate and modulate the function of the intrinsic (enteric) nervous system. The stomach and upper gastrointestinal tract in particular are heavily influenced by the parasympathetic nervous system, supplied by the vagus nerve, and disruption of vagal sensory or motor functions results in disorganized motility patterns, disrupted receptive relaxation and accommodation, and delayed gastric emptying, amongst others. Studies from several laboratories have shown that the activity of vagal efferent motoneurons innervating the upper GI tract is inhibited tonically by GABAergic synaptic inputs from the adjacent nucleus tractus solitarius. Disruption of this influential central GABA input impacts vagal efferent output, hence gastric functions, significantly. The purpose of this review is to describe the development, physiology, and pathophysiology of this functionally dominant inhibitory synapse and its role in regulating vagally determined gastric functions.
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Affiliation(s)
- Caitlin A McMenamin
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, USA
| | - R Alberto Travagli
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, USA
| | - Kirsteen N Browning
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, USA
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26
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Centanni SW, Burnett EJ, Trantham-Davidson H, Chandler LJ. Loss of δ-GABA A receptor-mediated tonic currents in the adult prelimbic cortex following adolescent alcohol exposure. Addict Biol 2017; 22:616-628. [PMID: 26804056 DOI: 10.1111/adb.12353] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 10/29/2015] [Accepted: 11/24/2015] [Indexed: 11/30/2022]
Abstract
Delayed maturation of the adolescent prefrontal cortex may render it particularly vulnerable to insults, including those associated with drugs of abuse. Using a rat model of binge alcohol exposure, the present study examined the effect of adolescent intermittent ethanol (AIE) exposure during postnatal days 28-42 on γ-aminobutyric acid (GABA)ergic neurotransmission in the prelimbic cortex. In control rats, patch-clamp electrophysiology in acute slices obtained at different postnatal ages revealed a developmental increase in the GABAA receptor-mediated tonic current in layer V pyramidal neurons but no change in layers II/III when measured in the adult. In slices from AIE-exposed rats, the amplitude of the tonic current was significantly reduced compared with controls when tested at postnatal days 45, 60 and 90-120. This AIE-induced reduction in tonic current was found to reflect attenuation of currents mediated by δ-subunit containing receptors. Consistent with this, facilitation of the tonic current by bath application of either ethanol or allopregnanolone was attenuated in slices from AIE-exposed adult rats compared with control rats. However, expression of this facilitation as a percent of the amplitude of the total current mediated by δ-GABAA receptors revealed that AIE did not alter their sensitivity to either agonist. Lastly, immunohistochemistry and Western blot analysis revealed no change in the expression of δ-GABAA subunits or their surface expression. Taken together, these studies reveal that AIE exposure results in persistent deficits in δ-GABAA tonic currents in the adult prelimbic cortex that may contribute to deficits in decision-making and behavioral control in adulthood.
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Affiliation(s)
- Samuel W. Centanni
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
| | - Elizabeth J. Burnett
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
| | | | - L. Judson Chandler
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
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27
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Developmental control of spike-timing-dependent plasticity by tonic GABAergic signaling in striatum. Neuropharmacology 2017; 121:261-277. [PMID: 28408325 DOI: 10.1016/j.neuropharm.2017.04.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 03/20/2017] [Accepted: 04/07/2017] [Indexed: 11/20/2022]
Abstract
Activity-dependent long-term potentiation (LTP) and depression (LTD) of synaptic strength underlie multiple forms of learning and memory. Spike-timing-dependent plasticity (STDP) has been described as a Hebbian synaptic learning rule that could account for experience-dependent changes in neural networks, but little is known about whether and how STDP evolves during development. We previously showed that GABAergic signaling governs STDP polarity and thus operates as a Hebbian/anti-Hebbian switch in the striatum. Although GABAergic networks are subject to important developmental maturation, it remains unclear whether STDP is developmentally shaped by GABAergic signaling. Here, we investigated whether STDP rules are developmentally regulated at corticostriatal synapses in the dorsolateral striatum. We found that striatal STDP displays unidirectional plasticity (Hebbian tLTD) in young rats (P7-10) whereas STDP is bidirectional and anti-Hebbian in juvenile (P20-25) and adult (P60-90) rats. We also provide evidence that the appearance of tonic (extrasynaptic) GABAergic signaling from the juvenile stage is a crucial factor in shaping STDP rules during development, establishing bidirectional anti-Hebbian STDP in the adult striatum. Thus, developmental maturation of GABAergic signaling tightly drives the polarity of striatal plasticity.
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28
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Whissell PD, Avramescu S, Wang DS, Orser BA. δGABAA Receptors Are Necessary for Synaptic Plasticity in the Hippocampus. Anesth Analg 2016; 123:1247-1252. [DOI: 10.1213/ane.0000000000001373] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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29
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Hydrogen peroxide modulates neuronal excitability and membrane properties in ventral horn neurons of the rat spinal cord. Neuroscience 2016; 331:206-20. [DOI: 10.1016/j.neuroscience.2016.06.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/27/2016] [Accepted: 06/17/2016] [Indexed: 01/29/2023]
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30
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Kakizawa K, Watanabe M, Mutoh H, Okawa Y, Yamashita M, Yanagawa Y, Itoi K, Suda T, Oki Y, Fukuda A. A novel GABA-mediated corticotropin-releasing hormone secretory mechanism in the median eminence. SCIENCE ADVANCES 2016; 2:e1501723. [PMID: 27540587 PMCID: PMC4988769 DOI: 10.1126/sciadv.1501723] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 07/19/2016] [Indexed: 05/13/2023]
Abstract
Corticotropin-releasing hormone (CRH), which is synthesized in the paraventricular nucleus (PVN) of the hypothalamus, plays an important role in the endocrine stress response. The excitability of CRH neurons is regulated by γ-aminobutyric acid (GABA)-containing neurons projecting to the PVN. We investigated the role of GABA in the regulation of CRH release. The release of CRH was impaired, accumulating in the cell bodies of CRH neurons in heterozygous GAD67-GFP (green fluorescent protein) knock-in mice (GAD67(+/GFP)), which exhibited decreased GABA content. The GABAA receptor (GABAAR) and the Na(+)-K(+)-2Cl(-) cotransporter (NKCC1), but not the K(+)-Cl(-) cotransporter (KCC2), were expressed in the terminals of the CRH neurons at the median eminence (ME). In contrast, CRH neuronal somata were enriched with KCC2 but not with NKCC1. Thus, intracellular Cl(-) concentrations ([Cl(-)]i) may be increased at the terminals of CRH neurons compared with concentrations in the cell body. Moreover, GABAergic terminals projecting from the arcuate nucleus were present in close proximity to CRH-positive nerve terminals. Furthermore, a GABAAR agonist increased the intracellular calcium (Ca(2+)) levels in the CRH neuron terminals but decreased the Ca(2+) levels in their somata. In addition, the increases in Ca(2+) concentrations were prevented by an NKCC1 inhibitor. We propose a novel mechanism by which the excitatory action of GABA maintains a steady-state CRH release from axon terminals in the ME.
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Affiliation(s)
- Keisuke Kakizawa
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
- Second Division, Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Hiroki Mutoh
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Yuta Okawa
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
- Second Division, Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Miho Yamashita
- Second Division, Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
| | - Keiichi Itoi
- Laboratory of Information Biology, Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Takafumi Suda
- Second Division, Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Yutaka Oki
- Department of Family and Community Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
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31
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High and low GABA sensitivity α4β2δ GABAA receptors are expressed in Xenopus laevis oocytes with divergent stoichiometries. Biochem Pharmacol 2016; 103:98-108. [DOI: 10.1016/j.bcp.2015.12.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/29/2015] [Indexed: 12/11/2022]
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32
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Kim J, Son Y, Kim J, Lee S, Kang S, Park K, Kim SH, Kim JC, Kim J, Takayama C, Im HI, Yang M, Shin T, Moon C. Developmental and degenerative modulation of GABAergic transmission in the mouse hippocampus. Int J Dev Neurosci 2015; 47:320-32. [PMID: 26394279 DOI: 10.1016/j.ijdevneu.2015.08.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/05/2015] [Accepted: 08/21/2015] [Indexed: 11/30/2022] Open
Abstract
γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter involved in synaptic plasticity. GABAergic transmission is also implicated in developmental and degenerative processes in the brain. The goal of the present study was to understand the developmental and degenerative regulation of GABAergic transmission in the mouse hippocampus by examining changes in GABA receptor subunit mRNA levels and GABA-related protein expression during postnatal development of the hippocampus and trimethyltin (TMT)-induced neurodegeneration in the juvenile (postnatal day [PD] 24) and adult hippocampus (PD 56). During postnatal development, the mRNA levels of GABA A receptor (GABAAR) subunits, including α1, α4, β1, β2, and δ; GABA B receptor (GABABR) subunit 2; and the expression of GABA-related proteins, including glutamic acid decarboxylase, vesicular GABA transporter (VGAT), and potassium chloride cotransporter 2 increased gradually in the mouse hippocampus. The results of seizure scoring and histopathological findings in the hippocampus revealed a more pronounced response to the same administered TMT dose in juvenile mice, compared with that in adult mice. The mRNA levels of most GABA receptor subunits in the juvenile hippocampus, excluding GABAAR subunit β3, were dynamically altered after TMT treatment. The mRNA levels of GABAAR subunits γ2 and δ decreased significantly in the adult hippocampus following TMT treatment, whereas the level of GABABR subunit 1 mRNA increased significantly. Among the GABA-related proteins, only VGAT decreased significantly in the juvenile and adult mouse hippocampus after TMT treatment. In conclusion, regulation of GABAergic signaling in the mouse hippocampus may be related to maturation of the central nervous system and the degree of neurodegeneration during postnatal development and TMT-induced neurodegeneration in the experimental animals.
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Affiliation(s)
- Jinwook Kim
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Yeonghoon Son
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Juhwan Kim
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea; Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 136-791, South Korea
| | - Sueun Lee
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Sohi Kang
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Kyunghwan Park
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Sung-Ho Kim
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Jong-Choon Kim
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Jeongtae Kim
- Department of Molecular Anatomy, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan
| | - Chitoshi Takayama
- Department of Molecular Anatomy, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan
| | - Heh-In Im
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 136-791, South Korea
| | - Miyoung Yang
- Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, South Korea
| | - Taekyun Shin
- Department of Veterinary Anatomy, College of Veterinary Medicine, Jeju National University, Jeju 690-756, South Korea.
| | - Changjong Moon
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea.
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Watanabe M, Fukuda A. Development and regulation of chloride homeostasis in the central nervous system. Front Cell Neurosci 2015; 9:371. [PMID: 26441542 PMCID: PMC4585146 DOI: 10.3389/fncel.2015.00371] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/04/2015] [Indexed: 12/22/2022] Open
Abstract
γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter of the mature central nervous system (CNS). The developmental switch of GABAergic transmission from excitation to inhibition is induced by changes in Cl− gradients, which are generated by cation-Cl− co-transporters. An accumulation of Cl− by the Na+-K+-2Cl− co-transporter (NKCC1) increases the intracellular Cl− concentration ([Cl−]i) such that GABA depolarizes neuronal precursors and immature neurons. The subsequent ontogenetic switch, i.e., upregulation of the Cl−-extruder KCC2, which is a neuron-specific K+-Cl− co-transporter, with or without downregulation of NKCC1, results in low [Cl−]i levels and the hyperpolarizing action of GABA in mature neurons. Development of Cl− homeostasis depends on developmental changes in NKCC1 and KCC2 expression. Generally, developmental shifts (decreases) in [Cl−]i parallel the maturation of the nervous system, e.g., early in the spinal cord, hypothalamus and thalamus, followed by the limbic system, and last in the neocortex. There are several regulators of KCC2 and/or NKCC1 expression, including brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF), and cystic fibrosis transmembrane conductance regulator (CFTR). Therefore, regionally different expression of these regulators may also contribute to the regional developmental shifts of Cl− homeostasis. KCC2 and NKCC1 functions are also regulated by phosphorylation by enzymes such as PKC, Src-family tyrosine kinases, and WNK1–4 and their downstream effectors STE20/SPS1-related proline/alanine-rich kinase (SPAK)-oxidative stress responsive kinase-1 (OSR1). In addition, activation of these kinases is modulated by humoral factors such as estrogen and taurine. Because these transporters use the electrochemical driving force of Na+ and K+ ions, topographical interaction with the Na+-K+ ATPase and its modulators such as creatine kinase (CK) should modulate functions of Cl− transporters. Therefore, regional developmental regulation of these regulators and modulators of Cl− transporters may also play a pivotal role in the development of Cl− homeostasis.
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Affiliation(s)
- Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
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Hellsten K, Linden AM, Korpi E. Paradoxical widespread c-Fos expression induced by a GABA agonist in the forebrain of transgenic mice with ectopic expression of the GABAA α6 subunit. Neuroscience 2015; 293:123-35. [DOI: 10.1016/j.neuroscience.2015.02.052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/30/2015] [Accepted: 02/28/2015] [Indexed: 10/23/2022]
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Cheron G, Márquez-Ruiz J, Kishino T, Dan B. Disruption of the LTD dialogue between the cerebellum and the cortex in Angelman syndrome model: a timing hypothesis. Front Syst Neurosci 2014; 8:221. [PMID: 25477791 PMCID: PMC4237040 DOI: 10.3389/fnsys.2014.00221] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/25/2014] [Indexed: 12/11/2022] Open
Abstract
Angelman syndrome (AS) is a genetic neurodevelopmental disorder in which cerebellar functioning impairment has been documented despite the absence of gross structural abnormalities. Characteristically, a spontaneous 160 Hz oscillation emerges in the Purkinje cells network of the Ube3a (m-/p+) Angelman mouse model. This abnormal oscillation is induced by enhanced Purkinje cell rhythmicity and hypersynchrony along the parallel fiber beam. We present a pathophysiological hypothesis for the neurophysiology underlying major aspects of the clinical phenotype of AS, including cognitive, language and motor deficits, involving long-range connection between the cerebellar and the cortical networks. This hypothesis states that the alteration of the cerebellar rhythmic activity impinges cerebellar long-term depression (LTD) plasticity, which in turn alters the LTD plasticity in the cerebral cortex. This hypothesis was based on preliminary experiments using electrical stimulation of the whiskers pad performed in alert mice showing that after a 8 Hz LTD-inducing protocol, the cerebellar LTD accompanied by a delayed response in the wild type (WT) mice is missing in Ube3a (m-/p+) mice and that the LTD induced in the barrel cortex following the same peripheral stimulation in wild mice is reversed into a LTP in the Ube3a (m-/p+) mice. The control exerted by the cerebellum on the excitation vs. inhibition balance in the cerebral cortex and possible role played by the timing plasticity of the Purkinje cell LTD on the spike-timing dependent plasticity (STDP) of the pyramidal neurons are discussed in the context of the present hypothesis.
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Affiliation(s)
- Guy Cheron
- Laboratory of Electrophysiology, Université de MonsMons, Belgium
- Laboratory of Neurophysiology and Movement Biomechanics, ULB Neuroscience Institut, Université Libre de BruxellesBrussels, Belgium
| | | | - Tatsuya Kishino
- Division of Functional Genomics, Center for Frontier Life Sciences, Nagasaki UniversityNagasaki, Japan
| | - Bernard Dan
- Department of Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de BruxellesBrussels, Belgium
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Ando N, Sugasawa Y, Inoue R, Aosaki T, Miura M, Nishimura K. Effects of the volatile anesthetic sevoflurane on tonic GABA currents in the mouse striatum during postnatal development. Eur J Neurosci 2014; 40:3147-57. [PMID: 25139222 DOI: 10.1111/ejn.12691] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 07/04/2014] [Accepted: 07/11/2014] [Indexed: 11/28/2022]
Abstract
The volatile anesthetic sevoflurane, which is widely used in pediatric surgery, has proposed effects on GABAA receptor-mediated extrasynaptic tonic inhibition. In the developing striatum, medium-sized spiny projection neurons have tonic GABA currents, which function in the excitatory/inhibitory balance and maturation of striatal neural circuits. In this study, we examined the effects of sevoflurane on the tonic GABA currents of medium spiny neurons in developing striatal slices. Sevoflurane strongly increased GABAA receptor-mediated tonic conductance at postnatal days 3-35. The antagonist of the GABA transporter-1, 1-[2-[[(diphenylmethylene)imino]oxy]ethyl]-1,2,5,6-tetrahydro-3-pyridinecarboxylic acid hydrochloride further increased tonic GABA conductance during the application of sevoflurane, thereby increasing the total magnitude of tonic currents. Both GABA (5 μM) and 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-3-ol hydrochloride, the δ-subunit-containing GABAA receptor agonist, induced tonic GABA currents in medium spiny neurons but not in cholinergic neurons. However, sevoflurane additively potentiated the tonic GABA currents in both cells. Interestingly, 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-3-ol hydrochloride-sensitive neurons made a large current response to sevoflurane, indicating the contribution of the δ-subunit on sevoflurane-enhanced tonic GABA currents. Our findings suggest that sevoflurane can affect the tone of tonic GABA inhibition in a developing striatal neural network.
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Affiliation(s)
- Nozomi Ando
- Department of Anesthesiology and Pain Management, Juntendo University School of Medicine, Tokyo, Japan; Neurophysiology Research Group, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
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Altered expression of δGABAA receptors in health and disease. Neuropharmacology 2014; 88:24-35. [PMID: 25128850 DOI: 10.1016/j.neuropharm.2014.08.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 07/28/2014] [Accepted: 08/03/2014] [Indexed: 01/08/2023]
Abstract
γ-Aminobutyric acid type A receptors that contain the δ subunit (δGABAA receptors) are expressed in multiple types of neurons throughout the central nervous system, where they generate a tonic conductance that shapes neuronal excitability and synaptic plasticity. These receptors regulate a variety of important behavioral functions, including memory, nociception and anxiety, and may also modulate neurogenesis. Given their functional significance, δGABAA receptors are considered to be novel therapeutic targets for the treatment of memory dysfunction, pain, insomnia and mood disorders. These receptors are highly responsive to sedative-hypnotic drugs, general anesthetics and neuroactive steroids. A further remarkable feature of δGABAA receptors is that their expression levels are highly dynamic and fluctuate substantially during development and in response to physiological changes including stress and the reproductive cycle. Furthermore, the expression of these receptors varies in pathological conditions such as alcoholism, fragile X syndrome, epilepsy, depression, schizophrenia, mood disorders and traumatic brain injury. Such fluctuations in receptor expression have significant consequences for behavior and may alter responsiveness to therapeutic drugs. This review considers the alterations in the expression of δGABAA receptors associated with various states of health and disease and the implications of these changes.
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Abstract
Intracranial self-stimulation (ICSS) is a behavioral procedure in which operant responding is maintained by pulses of electrical brain stimulation. In research to study abuse-related drug effects, ICSS relies on electrode placements that target the medial forebrain bundle at the level of the lateral hypothalamus, and experimental sessions manipulate frequency or amplitude of stimulation to engender a wide range of baseline response rates or response probabilities. Under these conditions, drug-induced increases in low rates/probabilities of responding maintained by low frequencies/amplitudes of stimulation are interpreted as an abuse-related effect. Conversely, drug-induced decreases in high rates/probabilities of responding maintained by high frequencies/amplitudes of stimulation can be interpreted as an abuse-limiting effect. Overall abuse potential can be inferred from the relative expression of abuse-related and abuse-limiting effects. The sensitivity and selectivity of ICSS to detect abuse potential of many classes of abused drugs is similar to the sensitivity and selectivity of drug self-administration procedures. Moreover, similar to progressive-ratio drug self-administration procedures, ICSS data can be used to rank the relative abuse potential of different drugs. Strengths of ICSS in comparison with drug self-administration include 1) potential for simultaneous evaluation of both abuse-related and abuse-limiting effects, 2) flexibility for use with various routes of drug administration or drug vehicles, 3) utility for studies in drug-naive subjects as well as in subjects with controlled levels of prior drug exposure, and 4) utility for studies of drug time course. Taken together, these considerations suggest that ICSS can make significant contributions to the practice of abuse potential testing.
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Affiliation(s)
- S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Laurence L Miller
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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Furukawa T, Yamada J, Akita T, Matsushima Y, Yanagawa Y, Fukuda A. Roles of taurine-mediated tonic GABAA receptor activation in the radial migration of neurons in the fetal mouse cerebral cortex. Front Cell Neurosci 2014; 8:88. [PMID: 24734001 PMCID: PMC3975117 DOI: 10.3389/fncel.2014.00088] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 03/10/2014] [Indexed: 11/15/2022] Open
Abstract
γ-Aminobutyric acid (GABA) depolarizes embryonic cerebrocortical neurons and continuous activation of the GABAA receptor (GABAAR) contributes to their tonic depolarization. Although multiple reports have demonstrated a role of GABAAR activation in neocortical development, including in migration, most of these studies have used pharmacological blockers. Herein, we performed in utero electroporation in GABA synthesis-lacking homozygous GAD67-GFP knock-in mice (GAD67GFP/GFP) to label neurons born in the ventricular zone. Three days after electroporation, there were no differences in the distribution of labeled cells between the genotypes. The dose–response properties of labeled cells to GABA were equivalent among genotypes. However, continuous blockade of GABAAR with the GABAAR antagonist SR95531 accelerated radial migration. This effect of GABAAR blockade in GAD67GFP/GFP mice suggested a role for alternative endogenous GABAAR agonists. Thus, we tested the role of taurine, which is derived from maternal blood but is abundant in the fetal brain. The taurine-evoked currents in labeled cells were mediated by GABAAR. Taurine uptake was blocked by a taurine transporter inhibitor, 2-(guanidino)ethanesulfonic acid (GES), and taurine release was blocked by a volume-sensitive anion channel blocker, 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid, as examined through high-performance liquid chromatography. GES increased the extracellular taurine concentration and induced an inward shift of the holding current, which was reversed by SR95531. In a taurine-deficient mouse model, the GABAAR-mediated tonic currents were greatly reduced, and radial migration was accelerated. As the tonic currents were equivalent among the genotypes of GAD67-GFP knock-in mice, taurine, rather than GABA, might play a major role as an endogenous agonist of embryonic tonic GABAAR conductance, regulating the radial migration of neurons in the developing neocortex.
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Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Junko Yamada
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan ; Department of Neurophysiology, Hirosaki University Graduate School of Medicine Hirosaki, Aomori, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Yoshitaka Matsushima
- Department of Chemistry, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine Maebashi, Gunma, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
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Uchida T, Furukawa T, Iwata S, Yanagawa Y, Fukuda A. Selective loss of parvalbumin-positive GABAergic interneurons in the cerebral cortex of maternally stressed Gad1-heterozygous mouse offspring. Transl Psychiatry 2014; 4:e371. [PMID: 24618690 PMCID: PMC3966041 DOI: 10.1038/tp.2014.13] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/05/2014] [Accepted: 01/30/2014] [Indexed: 12/14/2022] Open
Abstract
Exposure to maternal stress (MS) and mutations in GAD1, which encodes the γ-aminobutyric acid (GABA) synthesizing enzyme glutamate decarboxylase (GAD) 67, are both risk factors for psychiatric disorders. However, the relationship between these risk factors remains unclear. Interestingly, the critical period of MS for psychiatric disorders in offspring corresponds to the period of GABAergic neuron neurogenesis and migration in the fetal brain, that is, in the late stage of gestation. Indeed, decrement of parvalbumin (PV)-positive GABAergic interneurons in the medial prefrontal cortex (mPFC) and hippocampus (HIP) has often been observed in schizophrenia patients. In the present study, we used GAD67-green fluorescent protein (GFP) knock-in mice (that is, mice in which the Gad1 gene is heterozygously deleted; GAD67(+/GFP)) that underwent prenatal stress from embryonic day 15.0 to 17.5 and monitored PV-positive GABAergic neurons to address the interaction between Gad1 disruption and stress. Administration of 5-bromo-2-deoxyuridine revealed that neurogenesis of GFP-positive GABAergic neurons, but not cortical plate cells, was significantly diminished in fetal brains during MS. Differential expression of glucocorticoid receptors by different progenitor cell types may underlie this differential outcome. Postnatally, the density of PV-positive, but not PV-negative, GABAergic neurons was significantly decreased in the mPFC, HIP and somatosensory cortex but not in the motor cortex of GAD67(+/GFP) mice. By contrast, these findings were not observed in wild-type (GAD67(+/+)) offspring. These results suggest that prenatal stress, in addition to heterozygous deletion of Gad1, could specifically disturb the proliferation of neurons destined to be PV-positive GABAergic interneurons.
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Affiliation(s)
- T Uchida
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - T Furukawa
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - S Iwata
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Y Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - A Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan,Department of Neurophysiology, Hamamatsu University School of Medicine, 20-1 Handayama 1-chome, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan. E-mail:
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