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Laue HE, Bauer JA, Pathmasiri W, Sumner SCJ, McRitchie S, Palys TJ, Hoen AG, Madan JC, Karagas MR. Patterns of infant fecal metabolite concentrations and social behavioral development in toddlers. Pediatr Res 2024:10.1038/s41390-024-03129-z. [PMID: 38509226 DOI: 10.1038/s41390-024-03129-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 01/17/2024] [Accepted: 03/01/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUND Gut-derived metabolites, products of microbial and host co-metabolism, may inform mechanisms underlying children's neurodevelopment. We investigated whether infant fecal metabolites were related to toddler social behavior. METHODS Stool samples collected from 6-week-olds (n = 86) and 1-year-olds (n = 209) in the New Hampshire Birth Cohort Study (NHBCS) were analyzed using nuclear magnetic resonance spectroscopy metabolomics. Autism-related behavior in 3-year-olds was assessed by caregivers using the Social Responsiveness Scale (SRS-2). To assess the association between metabolites and SRS-2 scores, we used a traditional single-metabolite approach, quantitative metabolite set enrichment (QEA), and self-organizing maps (SOMs). RESULTS Using a single-metabolite approach and QEA, no individual fecal metabolite or metabolite set at either age was associated with SRS-2 scores. Using the SOM method, fecal metabolites of six-week-olds organized into four profiles, which were unrelated to SRS-2 scores. In 1-year-olds, one of twelve fecal metabolite profiles was associated with fewer autism-related behaviors, with SRS-2 scores 3.4 (95%CI: -7, 0.2) points lower than the referent group. This profile had higher concentrations of lactate and lower concentrations of short chain fatty acids than the reference. CONCLUSIONS We uncovered metabolic profiles in infant stool associated with subsequent social behavior, highlighting one potential mechanism by which gut bacteria may influence neurobehavior. IMPACT Differences in host and microbial metabolism may explain variability in neurobehavioral phenotypes, but prior studies do not have consistent results. We applied three statistical techniques to explore fecal metabolite differences related to social behavior, including self-organizing maps (SOMs), a novel machine learning algorithm. A 1-year-old fecal metabolite pattern characterized by high lactate and low short-chain fatty acid concentrations, identified using SOMs, was associated with social behavior less indicative of autism spectrum disorder. Our findings suggest that social behavior may be related to metabolite profiles and that future studies may uncover novel findings by applying the SOM algorithm.
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Affiliation(s)
- Hannah E Laue
- Department of Epidemiology, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA.
| | - Julia A Bauer
- Department of Epidemiology, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA
| | - Wimal Pathmasiri
- Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, NC, USA
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Susan C J Sumner
- Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, NC, USA
| | - Susan McRitchie
- Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, NC, USA
| | - Thomas J Palys
- Department of Epidemiology, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA
| | - Anne G Hoen
- Department of Epidemiology, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA
| | - Juliette C Madan
- Department of Epidemiology, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA
- Departments of Pediatrics and Psychiatry, Dartmouth Hitchcock Medical Center, Lebanon, NH, USA
| | - Margaret R Karagas
- Department of Epidemiology, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA
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2
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Vargas-Perez H, Grieder TE, van der Kooy D. Neural Plasticity in the Ventral Tegmental Area, Aversive Motivation during Drug Withdrawal and Hallucinogenic Therapy. J Psychoactive Drugs 2023; 55:62-72. [PMID: 35114904 DOI: 10.1080/02791072.2022.2033889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Aberrant glutamatergic signaling has been closely related to several pathologies of the central nervous system. Glutamatergic activity can induce an increase in neural plasticity mediated by brain-derived neurotrophic factor (BDNF) in the ventral tegmental area (VTA), a nodal point in the mesolimbic dopamine system. Recent studies have related BDNF dependent plasticity in the VTA with the modulation of aversive motivation to deal with noxious environmental stimuli. The disarray of these learning mechanisms would produce an abnormal augmentation in the representation of the emotional information related to aversion, sometimes even in the absence of external environmental trigger, inducing pathologies linked to mood disorders such as depression and drug addiction. Recent studies point out that serotonin (5-hydroxytryptamine, 5-HT) receptors, especially the 2a (5-HT2a) subtype, play an important role in BDNF-related neural plasticity in the VTA. It has been observed that a single administration of a 5HT2a agonist can both revert an animal to a nondependent state from a drug-dependent state (produced by the chronic administration of a substance of abuse). The 5HT2a agonist also reverted the BDNF-induced neural plasticity in the VTA, suggesting that the administration of 5-HT2a agonists could be used as effective therapeutic agents to treat drug addiction. These findings could explain the neurobiological correlate of the therapeutic use of 5HT2a agonists, which can be found in animals, plants and fungi during traditional medicine ceremonies and rituals to treat mood related disorders.
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Affiliation(s)
- Hector Vargas-Perez
- The Nierika Intercultural Medicine Institute, Ocuilan, México.,Postgrado En Ciencias Cognitivas, Universidad Autonoma Del Estado de Morelos, Cuernavaca, Mexico
| | - Taryn Elizabeth Grieder
- Institute of Medical Science and Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Derek van der Kooy
- Institute of Medical Science and Department of Molecular Genetics, University of Toronto, Toronto, Canada
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3
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Hui KK, Chater TE, Goda Y, Tanaka M. How Staying Negative Is Good for the (Adult) Brain: Maintaining Chloride Homeostasis and the GABA-Shift in Neurological Disorders. Front Mol Neurosci 2022; 15:893111. [PMID: 35875665 PMCID: PMC9305173 DOI: 10.3389/fnmol.2022.893111] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/10/2022] [Indexed: 01/27/2023] Open
Abstract
Excitatory-inhibitory (E-I) imbalance has been shown to contribute to the pathogenesis of a wide range of neurodevelopmental disorders including autism spectrum disorders, epilepsy, and schizophrenia. GABA neurotransmission, the principal inhibitory signal in the mature brain, is critically coupled to proper regulation of chloride homeostasis. During brain maturation, changes in the transport of chloride ions across neuronal cell membranes act to gradually change the majority of GABA signaling from excitatory to inhibitory for neuronal activation, and dysregulation of this GABA-shift likely contributes to multiple neurodevelopmental abnormalities that are associated with circuit dysfunction. Whilst traditionally viewed as a phenomenon which occurs during brain development, recent evidence suggests that this GABA-shift may also be involved in neuropsychiatric disorders due to the “dematuration” of affected neurons. In this review, we will discuss the cell signaling and regulatory mechanisms underlying the GABA-shift phenomenon in the context of the latest findings in the field, in particular the role of chloride cotransporters NKCC1 and KCC2, and furthermore how these regulatory processes are altered in neurodevelopmental and neuropsychiatric disorders. We will also explore the interactions between GABAergic interneurons and other cell types in the developing brain that may influence the GABA-shift. Finally, with a greater understanding of how the GABA-shift is altered in pathological conditions, we will briefly outline recent progress on targeting NKCC1 and KCC2 as a therapeutic strategy against neurodevelopmental and neuropsychiatric disorders associated with improper chloride homeostasis and GABA-shift abnormalities.
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Affiliation(s)
- Kelvin K. Hui
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, United States
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY, United States
- *Correspondence: Kelvin K. Hui,
| | - Thomas E. Chater
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Thomas E. Chater,
| | - Yukiko Goda
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Synapse Biology Unit, Okinawa Institute for Science and Technology Graduate University, Onna, Japan
| | - Motomasa Tanaka
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Japan
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4
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Song Y, Lally PJ, Yanez Lopez M, Oeltzschner G, Nebel MB, Gagoski B, Kecskemeti S, Hui SCN, Zöllner HJ, Shukla D, Arichi T, De Vita E, Yedavalli V, Thayyil S, Fallin D, Dean DC, Grant PE, Wisnowski JL, Edden RAE. Edited magnetic resonance spectroscopy in the neonatal brain. Neuroradiology 2022; 64:217-232. [PMID: 34654960 PMCID: PMC8887832 DOI: 10.1007/s00234-021-02821-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/20/2021] [Indexed: 10/20/2022]
Abstract
J-difference-edited spectroscopy is a valuable approach for the detection of low-concentration metabolites with magnetic resonance spectroscopy (MRS). Currently, few edited MRS studies are performed in neonates due to suboptimal signal-to-noise ratio, relatively long acquisition times, and vulnerability to motion artifacts. Nonetheless, the technique presents an exciting opportunity in pediatric imaging research to study rapid maturational changes of neurotransmitter systems and other metabolic systems in early postnatal life. Studying these metabolic processes is vital to understanding the widespread and rapid structural and functional changes that occur in the first years of life. The overarching goal of this review is to provide an introduction to edited MRS for neonates, including the current state-of-the-art in editing methods and editable metabolites, as well as to review the current literature applying edited MRS to the neonatal brain. Existing challenges and future opportunities, including the lack of age-specific reference data, are also discussed.
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Affiliation(s)
- Yulu Song
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Peter J Lally
- Department of Brain Sciences, Imperial College London, London, UK
| | - Maria Yanez Lopez
- Center for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Georg Oeltzschner
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Mary Beth Nebel
- Center for Neurodevelopmental and Imaging Research, Kennedy Krieger Institute, Baltimore, MD, 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Borjan Gagoski
- Department of Radiology, Division of Neuroradiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Boston, MA, USA
| | | | - Steve C N Hui
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Helge J Zöllner
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Deepika Shukla
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Tomoki Arichi
- Center for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.,Department of Bioengineering, Imperial College London, South Kensington Campus, London, UK
| | - Enrico De Vita
- Center for the Developing Brain, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.,Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, St Thomas's Hospital, Westminster Bridge Road, Lambeth Wing, 3rd Floor, London, SE1 7EH, UK
| | - Vivek Yedavalli
- Division of Neuroradiology, Park 367G, The Johns Hopkins University School of Medicine, 600 N. Wolfe St. B-112 D, Baltimore, MD, 21287, USA
| | - Sudhin Thayyil
- Centre for Perinatal Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Daniele Fallin
- Wendy Klag Center for Autism and Developmental Disabilities, Johns Hopkins University, Baltimore, USA.,Department of Mental Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, USA
| | - Douglas C Dean
- Waisman Center, University of WI-Madison, Madison, WI, 53705, USA.,Department of Pediatrics, Division of Neonatology and Newborn Nursery, University of WI-Madison, School of Medicine and Public Health, Madison, WI, 53705, USA.,Department of Medical Physics, University of WI-Madison, School of Medicine and Public Health, Madison, WI, 53705, USA
| | - P Ellen Grant
- Department of Radiology, Division of Neuroradiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Boston, MA, USA.,Department of Medicine, Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jessica L Wisnowski
- Children's Hospital Los Angeles, Los Angeles, CA, 90027, USA.,Department of Radiology and Fetal and Neonatal Institute, CHLA Division of Neonatology, Department of Pediatrics, Children's Hospital of Los Angeles, University of Southern California, Los Angeles, CA, 90033, USA
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA. .,Division of Neuroradiology, Park 367G, The Johns Hopkins University School of Medicine, 600 N. Wolfe St. B-112 D, Baltimore, MD, 21287, USA.
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5
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Toczylowska B, Zieminska E, Michałowska M, Chalimoniuk M, Fiszer U. Changes in the metabolic profiles of the serum and putamen in Parkinson's disease patients - In vitro and in vivo NMR spectroscopy studies. Brain Res 2020; 1748:147118. [PMID: 32931820 DOI: 10.1016/j.brainres.2020.147118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/01/2020] [Accepted: 09/06/2020] [Indexed: 10/23/2022]
Abstract
The aim of this study was to investigate the relationship between serum metabolomic biomarkers and brain in vivo magnetic resonance spectroscopy (MRS) biomarkers in patients with Parkinson's disease (PD) as well as to investigate compound concentration changes by comparing the results with healthy control subjects. Univariate statistical analysis of the serum showed significant differences in the levels of phenylalanine, tyrosine, lysine, glutamine, glutamate, acetone, acetate, 3-hydroxybutyrate, and 1-monoacylglycerol (1-MAG) between the PD patient group and the control group. Orthogonal partial least squares discriminant analysis showed significantly different compound concentrations of acetate, 3-hydroxybutyrate, glutamine, tyrosine, 1-MAG and testosterone. In vivo MRS of the putamen showed significantly higher concentrations of glutamine/glutamate complex and glutamine in patients with PD in comparison to control subjects. Following disrupted metabolic pathways in patients with PD were identified: dopamine synthesis, steroid hormone biosynthesis, fatty acid biosynthesis, the synthesis and degradation of ketone bodies, the metabolism of pyruvate, arginine, proline, alanine, aspartate, glutamate, tyrosine and phenylalanine. The obtained results may indicate changes in neurotransmission, disturbances in energy production and an altered cell membrane structure.
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Affiliation(s)
- Beata Toczylowska
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena st., 02-109 Warsaw, Poland
| | - Elzbieta Zieminska
- Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego st., 02-109 Warsaw, Poland.
| | - Małgorzata Michałowska
- Department of Neurology and Epileptology, Centre of Postgraduate Medical Education, Orlowski Hospital, 241 Czerniakowska st., 00-416 Warsaw, Poland
| | - Malgorzata Chalimoniuk
- Józef Piłsudski University of Physical Education in Warsaw Faculty in Biała Podlaska, 2 Akademicka st., 21-500 Biala Podlaska, Poland
| | - Urszula Fiszer
- Department of Neurology and Epileptology, Centre of Postgraduate Medical Education, Orlowski Hospital, 241 Czerniakowska st., 00-416 Warsaw, Poland
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6
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Hollnagel JO, Cesetti T, Schneider J, Vazetdinova A, Valiullina-Rakhmatullina F, Lewen A, Rozov A, Kann O. Lactate Attenuates Synaptic Transmission and Affects Brain Rhythms Featuring High Energy Expenditure. iScience 2020; 23:101316. [PMID: 32653807 PMCID: PMC7350153 DOI: 10.1016/j.isci.2020.101316] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/09/2020] [Accepted: 06/23/2020] [Indexed: 01/29/2023] Open
Abstract
Lactate shuttled from blood, astrocytes, and/or oligodendrocytes may serve as the major glucose alternative in brain energy metabolism. However, its effectiveness in fueling neuronal information processing underlying complex cortex functions like perception and memory is unclear. We show that sole lactate disturbs electrical gamma and theta-gamma oscillations in hippocampal networks by either attenuation or neural bursts. Bursting is suppressed by elevating the glucose fraction in substrate supply. By contrast, lactate does not affect electrical sharp wave-ripple activity featuring lower energy use. Lactate increases the oxygen consumption during the network states, reflecting enhanced oxidative ATP synthesis in mitochondria. Finally, lactate attenuates synaptic transmission in excitatory pyramidal cells and fast-spiking, inhibitory interneurons by reduced neurotransmitter release from presynaptic terminals, whereas action potential generation in the axon is regular. In conclusion, sole lactate is less effective and potentially harmful during gamma-band rhythms by omitting obligatory ATP delivery through fast glycolysis at the synapse. Lactate fuels network oscillations featuring low energy expenditure Lactate can disturb the neuronal excitation-inhibition balance Lactate attenuates neurotransmission at glutamatergic and GABAergic synapses Lactate increases oxygen consumption, whereas neural activity can even decrease
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Affiliation(s)
- Jan-Oliver Hollnagel
- Institute of Physiology and Pathophysiology, University of Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Tiziana Cesetti
- Institute of Physiology and Pathophysiology, University of Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Justus Schneider
- Institute of Physiology and Pathophysiology, University of Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Alina Vazetdinova
- OpenLab of Neurobiology, Kazan Federal University, 420008 Kazan, Russia
| | | | - Andrea Lewen
- Institute of Physiology and Pathophysiology, University of Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Andrei Rozov
- Institute of Physiology and Pathophysiology, University of Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany; OpenLab of Neurobiology, Kazan Federal University, 420008 Kazan, Russia
| | - Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany; Interdisciplinary Center for Neurosciences, University of Heidelberg, 69120 Heidelberg, Germany.
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7
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Levinson S, Tran CH, Barry J, Viker B, Levine MS, Vinters HV, Mathern GW, Cepeda C. Paroxysmal Discharges in Tissue Slices From Pediatric Epilepsy Surgery Patients: Critical Role of GABA B Receptors in the Generation of Ictal Activity. Front Cell Neurosci 2020; 14:54. [PMID: 32265658 PMCID: PMC7099654 DOI: 10.3389/fncel.2020.00054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 02/24/2020] [Indexed: 01/04/2023] Open
Abstract
In the present study, we characterized the effects of bath application of the proconvulsant drug 4-aminopyridine (4-AP) alone or in combination with GABAA and/or GABAB receptor antagonists, in cortical dysplasia (CD type I and CD type IIa/b), tuberous sclerosis complex (TSC), and non-CD cortical tissue samples from pediatric epilepsy surgery patients. Whole-cell patch clamp recordings in current and voltage clamp modes were obtained from cortical pyramidal neurons (CPNs), interneurons, and balloon/giant cells. In pyramidal neurons, bath application of 4-AP produced an increase in spontaneous synaptic activity as well as rhythmic membrane oscillations. In current clamp mode, these oscillations were generally depolarizing or biphasic and were accompanied by increased membrane conductance. In interneurons, membrane oscillations were consistently depolarizing and accompanied by bursts of action potentials. In a subset of balloon/giant cells from CD type IIb and TSC cases, respectively, 4-AP induced very low-amplitude, slow membrane oscillations that echoed the rhythmic oscillations from pyramidal neurons and interneurons. Bicuculline reduced the amplitude of membrane oscillations induced by 4-AP, indicating that they were mediated principally by GABAA receptors. 4-AP alone or in combination with bicuculline increased cortical excitability but did not induce seizure-like discharges. Ictal activity was observed in pyramidal neurons and interneurons from CD and TSC cases only when phaclofen, a GABAB receptor antagonist, was added to the 4-AP and bicuculline solution. These results emphasize the critical and permissive role of GABAB receptors in the transition to an ictal state in pediatric CD tissue and highlight the importance of these receptors as a potential therapeutic target in pediatric epilepsy.
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Affiliation(s)
- Simon Levinson
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Conny H Tran
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Joshua Barry
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Brett Viker
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Michael S Levine
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Harry V Vinters
- Section of Neuropathology, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Gary W Mathern
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Carlos Cepeda
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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8
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Voronina PP, Adamovich KV, Adamovich TV, Dubouskaya TG, Hrynevich SV, Waseem TV, Fedorovich SV. High Concentration of Ketone Body β-Hydroxybutyrate Modifies Synaptic Vesicle Cycle and Depolarizes Plasma Membrane of Rat Brain Synaptosomes. J Mol Neurosci 2019; 70:112-119. [PMID: 31643037 DOI: 10.1007/s12031-019-01406-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/27/2019] [Indexed: 12/14/2022]
Abstract
Ketoacidosis is a dangerous complication of diabetes mellitus in which plasma levels of ketone bodies can reach 20-25 mM. This condition is life-threatening. In contrast, a ketogenic diet, achieving plasma levels of ketone bodies of about 4-5 mM, can be used for treating different brain diseases. However, the factors leading to the conversion of the neuroprotective ketone bodies' action to the neurotoxic action during ketoacidosis are still unknown. We investigated the influence of high concentration (25 mM) of the main ketone body, β-hydroxybutyrate (BHB), on intrasynaptosomal pH (pHi), synaptic vesicle cycle, plasma membrane, and mitochondrial potentials. Using the fluorescent dye BCECF-AM, it was shown that BHB at concentrations of 8 and 25 mM did not influence pHi in synaptosomes. By means of the fluorescent dye acridine orange, it was demonstrated that 25 mM of BHB had no effect on exocytosis but inhibited compensatory endocytosis by 5-fold. Increasing buffer capacity with 25 mM HEPES did not affect endocytosis. Glucose abolished BHB-induced endocytosis inhibition. Using the fluorescent dye DiSC3(5), it was shown that 25 mM of BHB induced a significant plasma membrane depolarization. This effect was not impacted by glucose. Using the fluorescent dye rhodamine-123, it was shown that BHB alone (25 mМ) did not alter the potential of intrasynaptosomal mitochondria.Importantly, the high concentration of BHB (25 mМ) causes the depolarization of the plasma membrane and stronger inhibition of endocytosis compared with the intermediate concentration (8 mM).
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Affiliation(s)
- Polina P Voronina
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | - Ksenia V Adamovich
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | - Tatyana V Adamovich
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | - Tatsiana G Dubouskaya
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | - Sviatlana V Hrynevich
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | | | - Sergei V Fedorovich
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus. .,Department of Biochemistry, Belarusian State University, Minsk, Belarus.
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9
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Dubouskaya TG, Hrynevich SV, Fedorovich SV. The Combined Effect of Glucose and β-Hydroxybutyrate on the Membrane Potential of Synaptosomal Mitochondria. Biophysics (Nagoya-shi) 2019. [DOI: 10.1134/s0006350919030060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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10
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Magloire V, Cornford J, Lieb A, Kullmann DM, Pavlov I. KCC2 overexpression prevents the paradoxical seizure-promoting action of somatic inhibition. Nat Commun 2019; 10:1225. [PMID: 30874549 PMCID: PMC6420604 DOI: 10.1038/s41467-019-08933-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 02/01/2019] [Indexed: 11/09/2022] Open
Abstract
Although cortical interneurons are apparently well-placed to suppress seizures, several recent reports have highlighted a paradoxical role of perisomatic-targeting parvalbumin-positive (PV+) interneurons in ictogenesis. Here, we use an acute in vivo model of focal cortical seizures in awake behaving mice, together with closed-loop optogenetic manipulation of PV+ interneurons, to investigate their function during seizures. We show that photo-depolarization of PV+ interneurons rapidly switches from an anti-ictal to a pro-ictal effect within a few seconds of seizure initiation. The pro-ictal effect of delayed photostimulation of PV+ interneurons was not shared with dendrite-targeting somatostatin-positive (SOM+) interneurons. We also show that this switch can be prevented by overexpression of the neuronal potassium-chloride co-transporter KCC2 in principal cortical neurons. These results suggest that strategies aimed at improving the ability of principal neurons to maintain a trans-membrane chloride gradient in the face of excessive network activity can prevent interneurons from contributing to seizure perpetuation.
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Affiliation(s)
- Vincent Magloire
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK.
| | - Jonathan Cornford
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Andreas Lieb
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Dimitri M Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Ivan Pavlov
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK.
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11
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Fedorovich SV, Voronina PP, Waseem TV. Ketogenic diet versus ketoacidosis: what determines the influence of ketone bodies on neurons? Neural Regen Res 2018; 13:2060-2063. [PMID: 30323121 PMCID: PMC6199956 DOI: 10.4103/1673-5374.241442] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 08/23/2018] [Indexed: 11/04/2022] Open
Abstract
Glucose is the main energy substrate for neurons, however, at certain conditions, e.g. in starvation, these cells could also use ketone bodies. This approach is used in clinical conditions as the ketogenic diet. The ketogenic diet is actually a biochemical model of fasting. It includes replacing carbohydrates by fats in daily meal. Synthesis of ketone bodies β-hydroxubutirate, acetoacetate and acetone begins once glycogen stores have depleted in the liver. The ketogenic diet can be used to treat clinical conditions, primarily epilepsy. The mechanism of neuroprotective action of ketogenic diet is not very clear. It is shown that ketone bodies influence neurons at three different levels, namely, metabolic, signaling and epigenetic levels. Ketone bodies are not always neuroprotective. Sometimes they can be toxic for the brain. Ketoacidosis which is a very dangerous complication of diabetes mellitus or alcoholism can be taken as an example. The exact mechanism of how neuroprotective properties of ketone bodies reverse to neurotoxic is yet to be established.
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12
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Reality of Inhibitory GABA in Neonatal Brain: Time to Rewrite the Textbooks? J Neurosci 2018; 36:10242-10244. [PMID: 27707962 DOI: 10.1523/jneurosci.2270-16.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 08/26/2016] [Indexed: 12/30/2022] Open
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13
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Metabolic regulation of synaptic activity. Rev Neurosci 2018; 29:825-835. [DOI: 10.1515/revneuro-2017-0090] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 03/16/2018] [Indexed: 12/20/2022]
Abstract
Abstract
Brain tissue is bioenergetically expensive. In humans, it composes approximately 2% of body weight and accounts for approximately 20% of calorie consumption. The brain consumes energy mostly for ion and neurotransmitter transport, a process that occurs primarily in synapses. Therefore, synapses are expensive for any living creature who has brain. In many brain diseases, synapses are damaged earlier than neurons start dying. Synapses may be considered as vulnerable sites on a neuron. Ischemic stroke, an acute disturbance of blood flow in the brain, is an example of a metabolic disease that affects synapses. The associated excessive glutamate release, called excitotoxicity, is involved in neuronal death in brain ischemia. Another example of a metabolic disease is hypoglycemia, a complication of diabetes mellitus, which leads to neuronal death and brain dysfunction. However, synapse function can be corrected with “bioenergetic medicine”. In this review, a ketogenic diet is discussed as a curative option. In support of a ketogenic diet, whereby carbohydrates are replaced for fats in daily meals, epileptic seizures can be terminated. In this review, we discuss possible metabolic sensors in synapses. These may include molecules that perceive changes in composition of extracellular space, for instance, ketone body and lactate receptors, or molecules reacting to changes in cytosol, for instance, KATP channels or AMP kinase. Inhibition of endocytosis is believed to be a universal synaptic mechanism of adaptation to metabolic changes.
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14
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Chen JY, Tran C, Hwang L, Deng G, Jung ME, Faull KF, Levine MS, Cepeda C. Partial Amelioration of Peripheral and Central Symptoms of Huntington's Disease via Modulation of Lipid Metabolism. J Huntingtons Dis 2016; 5:65-81. [PMID: 27031732 DOI: 10.3233/jhd-150181] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Huntington's disease (HD) is a fatal, inherited neurodegenerative disorder characterized by uncontrollable dance-like movements, as well as cognitive deficits and mood changes. A feature of HD is a metabolic disturbance that precedes neurological symptoms. In addition, brain cholesterol synthesis is significantly reduced, which could hamper synaptic transmission. OBJECTIVE Alterations in lipid metabolism as a potential target for therapeutic intervention in the R6/2 mouse model of HD were examined. METHODS Electrophysiological recordings in vitro examined the acute effects of cholesterol-modifying drugs. In addition, behavioral testing, effects on synaptic activity, and measurements of circulating and brain tissue concentrations of cholesterol and the ketone β-hydroxybutyrate (BHB), were examined in symptomatic R6/2 mice and littermate controls raised on normal chow or a ketogenic diet (KD). RESULTS Whole-cell voltage clamp recordings of striatal medium-sized spiny neurons (MSNs) from symptomatic R6/2 mice showed increased frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) compared with littermate controls. Incubation of slices in cholesterol reduced the frequency of large-amplitude sIPSCs. Addition of BHB or the Liver X Receptor (LXR) agonist T0901317 reduced the frequency and amplitude of sIPSCs. Surprisingly, incubation in simvastatin to reduce cholesterol levels also decreased the frequency of sIPSCs. HD mice fed the KD lost weight more gradually, performed better in an open field, had fewer stereotypies and lower brain levels of cholesterol than mice fed a regular diet. CONCLUSIONS Lipid metabolism represents a potential target for therapeutic intervention in HD. Modifying cholesterol or ketone levels acutely in the brain can partially rescue synaptic alterations, and the KD can prevent weight loss and improve some behavioral abnormalities.
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Affiliation(s)
- Jane Y Chen
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, CA, USA
| | - Conny Tran
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, CA, USA
| | - Lin Hwang
- Pasarow Mass Spectrometry Laboratory, David Geffen School of Medicine, University of California Los Angeles, CA, USA
| | - Gang Deng
- Department of Chemistry and Biochemistry, David Geffen School of Medicine, University of California Los Angeles, CA, USA
| | - Michael E Jung
- Department of Chemistry and Biochemistry, David Geffen School of Medicine, University of California Los Angeles, CA, USA
| | - Kym F Faull
- Pasarow Mass Spectrometry Laboratory, David Geffen School of Medicine, University of California Los Angeles, CA, USA.,Brain Research Institute, David Geffen School of Medicine, University of California Los Angeles, CA, USA
| | - Michael S Levine
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, CA, USA.,Brain Research Institute, David Geffen School of Medicine, University of California Los Angeles, CA, USA
| | - Carlos Cepeda
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, CA, USA
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15
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Riffault B, Kourdougli N, Dumon C, Ferrand N, Buhler E, Schaller F, Chambon C, Rivera C, Gaiarsa JL, Porcher C. Pro-Brain-Derived Neurotrophic Factor (proBDNF)-Mediated p75NTR Activation Promotes Depolarizing Actions of GABA and Increases Susceptibility to Epileptic Seizures. Cereb Cortex 2016; 28:510-527. [DOI: 10.1093/cercor/bhw385] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 11/17/2016] [Indexed: 12/16/2022] Open
Affiliation(s)
- Baptiste Riffault
- Aix-Marseille University, Département de Biologie, Parc Scientifique de Luminy, 13273 Marseille, France
- INSERM—Institut National de la Santé et de la Recherche Médicale, Unité 901, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED—Institut de Neurobiologie de la Méditerranée, Parc Scientifique de Luminy, 13273 Marseille, France
| | - Nazim Kourdougli
- Aix-Marseille University, Département de Biologie, Parc Scientifique de Luminy, 13273 Marseille, France
- INSERM—Institut National de la Santé et de la Recherche Médicale, Unité 901, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED—Institut de Neurobiologie de la Méditerranée, Parc Scientifique de Luminy, 13273 Marseille, France
| | - Camille Dumon
- Aix-Marseille University, Département de Biologie, Parc Scientifique de Luminy, 13273 Marseille, France
- INSERM—Institut National de la Santé et de la Recherche Médicale, Unité 901, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED—Institut de Neurobiologie de la Méditerranée, Parc Scientifique de Luminy, 13273 Marseille, France
| | - Nadine Ferrand
- Aix-Marseille University, Département de Biologie, Parc Scientifique de Luminy, 13273 Marseille, France
- INSERM—Institut National de la Santé et de la Recherche Médicale, Unité 901, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED—Institut de Neurobiologie de la Méditerranée, Parc Scientifique de Luminy, 13273 Marseille, France
| | - Emmanuelle Buhler
- Aix-Marseille University, Département de Biologie, Parc Scientifique de Luminy, 13273 Marseille, France
- Plateforme Post-Génomique, INMED, 13273 Marseille, France
| | - Fabienne Schaller
- Aix-Marseille University, Département de Biologie, Parc Scientifique de Luminy, 13273 Marseille, France
- Plateforme Post-Génomique, INMED, 13273 Marseille, France
| | - Caroline Chambon
- Aix-Marseille University, Département de Biologie, NIA, UMR 7260 CNRS, 13331 cedex 03, Marseille, France
| | - Claudio Rivera
- Aix-Marseille University, Département de Biologie, Parc Scientifique de Luminy, 13273 Marseille, France
- INSERM—Institut National de la Santé et de la Recherche Médicale, Unité 901, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED—Institut de Neurobiologie de la Méditerranée, Parc Scientifique de Luminy, 13273 Marseille, France
| | - Jean-Luc Gaiarsa
- Aix-Marseille University, Département de Biologie, Parc Scientifique de Luminy, 13273 Marseille, France
- INSERM—Institut National de la Santé et de la Recherche Médicale, Unité 901, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED—Institut de Neurobiologie de la Méditerranée, Parc Scientifique de Luminy, 13273 Marseille, France
| | - Christophe Porcher
- Aix-Marseille University, Département de Biologie, Parc Scientifique de Luminy, 13273 Marseille, France
- INSERM—Institut National de la Santé et de la Recherche Médicale, Unité 901, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED—Institut de Neurobiologie de la Méditerranée, Parc Scientifique de Luminy, 13273 Marseille, France
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16
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β-Hydroxybutyrate supports synaptic vesicle cycling but reduces endocytosis and exocytosis in rat brain synaptosomes. Neurochem Int 2016; 93:73-81. [PMID: 26748385 DOI: 10.1016/j.neuint.2015.12.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/28/2015] [Accepted: 12/29/2015] [Indexed: 01/04/2023]
Abstract
The ketogenic diet is used as a prophylactic treatment for different types of brain diseases, such as epilepsy or Alzheimer's disease. In such a diet, carbohydrates are replaced by fats in everyday food, resulting in an elevation of blood-borne ketone bodies levels. Despite clinical applications of this treatment, the molecular mechanisms by which the ketogenic diet exerts its beneficial effects are still uncertain. In this study, we investigated the effect of replacing glucose by the ketone body β-hydroxybutyrate as the main energy substrate on synaptic vesicle recycling in rat brain synaptosomes. First, we observed that exposing presynaptic terminals to nonglycolytic energy substrates instead of glucose did not alter the plasma membrane potential. Next, we found that synaptosomes were able to maintain the synaptic vesicle cycle monitored with the fluorescent dye acridine orange when glucose was replaced by β-hydroxybutyrate. However, in presence of β-hydroxybutyrate, synaptic vesicle recycling was modified with reduced endocytosis. Replacing glucose by pyruvate also led to a reduced endocytosis. Addition of β-hydroxybutyrate to glucose-containing incubation medium was without effect. Reduced endocytosis in presence of β-hydroxybutyrate as sole energy substrate was confirmed using the fluorescent dye FM2-10. Also we found that replacement of glucose by ketone bodies leads to inhibition of exocytosis, monitored by FM2-10. However this reduction was smaller than the effect on endocytosis under the same conditions. Using both acridine orange in synaptosomes and the genetically encoded sensor synaptopHluorin in cortical neurons, we observed that replacing glucose by β-hydroxybutyrate did not modify the pH gradient of synaptic vesicles. In conclusion, the nonglycolytic energy substrates β-hydroxybutyrate and pyruvate are able to support synaptic vesicle recycling. However, they both reduce endocytosis. Reduction of both endocytosis and exocytosis together with misbalance between endocytosis and exocytosis could be involved in the anticonvulsant activity of the ketogenic diet.
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17
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Zilberter Y. Commentary: GABA Depolarizes Immature Neurons and Inhibits Network Activity in the Neonatal Neocortex In vivo. Front Pharmacol 2015; 6:294. [PMID: 26696892 PMCID: PMC4674808 DOI: 10.3389/fphar.2015.00294] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 11/23/2015] [Indexed: 11/24/2022] Open
Affiliation(s)
- Yuri Zilberter
- Institut de Neurosciences des Systèmes, Inserm UMR_S 1106, Aix-Marseille Université Marseille, France
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18
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Rodrigues AM, Santos LEC, Covolan L, Hamani C, de Almeida ACG. pH during non-synaptic epileptiform activity—computational simulations. Phys Biol 2015; 12:056007. [DOI: 10.1088/1478-3975/12/5/056007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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19
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Kirmse K, Kummer M, Kovalchuk Y, Witte OW, Garaschuk O, Holthoff K. GABA depolarizes immature neurons and inhibits network activity in the neonatal neocortex in vivo. Nat Commun 2015; 6:7750. [PMID: 26177896 DOI: 10.1038/ncomms8750] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 06/08/2015] [Indexed: 12/13/2022] Open
Abstract
A large body of evidence from in vitro studies suggests that GABA is depolarizing during early postnatal development. However, the mode of GABA action in the intact developing brain is unknown. Here we examine the in vivo effects of GABA in cells of the upper cortical plate using a combination of electrophysiological and Ca(2+)-imaging techniques. We report that at postnatal days (P) 3-4, GABA depolarizes the majority of immature neurons in the occipital cortex of anaesthetized mice. At the same time, GABA does not efficiently activate voltage-gated Ca(2+) channels and fails to induce action potential firing. Blocking GABA(A) receptors disinhibits spontaneous network activity, whereas allosteric activation of GABA(A) receptors has the opposite effect. In summary, our data provide evidence that in vivo GABA acts as a depolarizing neurotransmitter imposing an inhibitory control on network activity in the neonatal (P3-4) neocortex.
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Affiliation(s)
- Knut Kirmse
- Hans-Berger Department of Neurology, University Hospital Jena, D-07747 Jena, Germany
| | - Michael Kummer
- Hans-Berger Department of Neurology, University Hospital Jena, D-07747 Jena, Germany
| | - Yury Kovalchuk
- Institute of Physiology II, Eberhard-Karls University Tübingen, D-72074 Tübingen, Germany
| | - Otto W Witte
- Hans-Berger Department of Neurology, University Hospital Jena, D-07747 Jena, Germany
| | - Olga Garaschuk
- Institute of Physiology II, Eberhard-Karls University Tübingen, D-72074 Tübingen, Germany
| | - Knut Holthoff
- Hans-Berger Department of Neurology, University Hospital Jena, D-07747 Jena, Germany
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20
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Kaczor P, Rakus D, Mozrzymas JW. Neuron-astrocyte interaction enhance GABAergic synaptic transmission in a manner dependent on key metabolic enzymes. Front Cell Neurosci 2015; 9:120. [PMID: 25914620 PMCID: PMC4391237 DOI: 10.3389/fncel.2015.00120] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 03/17/2015] [Indexed: 11/21/2022] Open
Abstract
Gamma aminobutric acid (GABA) is the major inhibitory neurotransmitter in the adult brain and mechanisms of GABAergic inhibition have been intensely investigated in the past decades. Recent studies provided evidence for an important role of astrocytes in shaping GABAergic currents. One of the most obvious, but yet poorly understood, mechanisms of the cross-talk between GABAergic currents and astrocytes is metabolism including neurotransmitter homeostasis. In particular, how modulation of GABAergic currents by astrocytes depends on key enzymes involved in cellular metabolism remains largely unknown. To address this issue, we have considered two simple models of neuronal culture (NC): nominally astrocyte-free NC and neuronal-astrocytic co-cultures (ANCC). Miniature Inhibitory Postsynaptic Currents (mIPSCs) were recorded in control conditions and in the presence of different enzyme blockers. We report that enrichment of NC with astrocytes results in a marked increase in mIPSC frequency. This enhancement of GABAergic activity was accompanied by increased number of GAD65 and vGAT puncta, indicating that at least a part of the frequency enhancement was due to increased number of synaptic contacts. Inhibition of glutamine synthetase (Glns) (with MSO) strongly reduced mIPSC frequency in ANCC but had no effect in NC. Moreover, treatment of ANCC with inhibitor of glycogen phosphorylase (Gys) (BAYU6751) or with selective inhibitor of astrocytic Krebs cycle, fluoroacetate, resulted in a marked reduction of mIPSC frequency in ANCC having no effect in NC. We conclude that GABAergic synaptic transmission strongly depends on neuron-astrocyte interaction in a manner dependent on key metabolic enzymes as well as on the Krebs cycle.
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Affiliation(s)
- Przemysław Kaczor
- Department of Animal Molecular Physiology, Wroclaw University Wroclaw, Poland
| | - Dariusz Rakus
- Department of Animal Molecular Physiology, Wroclaw University Wroclaw, Poland
| | - Jerzy W Mozrzymas
- Department of Animal Molecular Physiology, Wroclaw University Wroclaw, Poland ; Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University Wroclaw, Poland
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21
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Rempe MJ, Wisor JP. Cerebral lactate dynamics across sleep/wake cycles. Front Comput Neurosci 2015; 8:174. [PMID: 25642184 PMCID: PMC4294128 DOI: 10.3389/fncom.2014.00174] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 12/23/2014] [Indexed: 12/17/2022] Open
Abstract
Cerebral metabolism varies dramatically as a function of sleep state. Brain concentration of lactate, the end product of glucose utilization via glycolysis, varies as a function of sleep state, and like slow wave activity (SWA) in the electroencephalogram (EEG), increases as a function of time spent awake or in rapid eye movement sleep and declines as a function of time spent in slow wave sleep (SWS). We sought to determine whether lactate concentration exhibits homeostatic dynamics akin to those of SWA in SWS. Lactate concentration in the cerebral cortex was measured by indwelling enzymatic biosensors. A set of equations based conceptually on Process S (previously used to quantify the homeostatic dynamics of SWA) was used to predict the sleep/wake state-dependent dynamics of lactate concentration in the cerebral cortex. Additionally, we applied an iterative parameter space-restricting algorithm (the Nelder-Mead method) to reduce computational time to find the optimal values of the free parameters. Compared to an exhaustive search, this algorithm reduced the computation time required by orders of magnitude. We show that state-dependent lactate concentration dynamics can be described by a homeostatic model, but that the optimal time constants for describing lactate dynamics are much smaller than those of SWA. This disconnect between lactate dynamics and SWA dynamics does not support the concept that lactate concentration is a biochemical mediator of sleep homeostasis. However, lactate synthesis in the cerebral cortex may nonetheless be informative with regard to sleep function, since the impact of glycolysis on sleep slow wave regulation is only just now being investigated.
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Affiliation(s)
- Michael J Rempe
- Mathematics and Computer Science, Whitworth University Spokane, WA, USA ; Department of Integrative Physiology and Neuroscience, College of Medical Sciences, Washington State University Spokane Spokane, WA, USA
| | - Jonathan P Wisor
- Department of Integrative Physiology and Neuroscience, College of Medical Sciences, Washington State University Spokane Spokane, WA, USA
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22
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Kumar V, Nag TC, Sharma U, Mewar S, Jagannathan NR, Wadhwa S. High resolution 1H NMR-based metabonomic study of the auditory cortex analogue of developing chick (Gallus gallus domesticus) following prenatal chronic loud music and noise exposure. Neurochem Int 2014; 76:99-108. [DOI: 10.1016/j.neuint.2014.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/16/2014] [Accepted: 07/04/2014] [Indexed: 02/07/2023]
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23
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The GABA excitatory/inhibitory developmental sequence: a personal journey. Neuroscience 2014; 279:187-219. [PMID: 25168736 DOI: 10.1016/j.neuroscience.2014.08.001] [Citation(s) in RCA: 194] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/17/2014] [Accepted: 08/01/2014] [Indexed: 12/11/2022]
Abstract
The developing brain is talkative but its language is not that of the adult. Most if not all voltage and transmitter-gated ionic currents follow a developmental sequence and network-driven patterns differ in immature and adult brains. This is best illustrated in studies engaged almost three decades ago in which we observed elevated intracellular chloride (Cl(-))i levels and excitatory GABA early during development and a perinatal excitatory/inhibitory shift. This sequence is observed in a wide range of brain structures and animal species suggesting that it has been conserved throughout evolution. It is mediated primarily by a developmentally regulated expression of the NKCC1 and KCC2 chloride importer and exporter respectively. The GABAergic depolarization acts in synergy with N-methyl-d-aspartate (NMDA) receptor-mediated and voltage-gated calcium currents to enhance intracellular calcium exerting trophic effects on neuritic growth, migration and synapse formation. These sequences can be deviated in utero by genetic or environmental insults leading to a persistence of immature features in the adult brain. This "neuroarcheology" concept paves the way to novel therapeutic perspectives based on the use of drugs that block immature but not adult currents. This is illustrated notably with the return to immature high levels of chloride and excitatory actions of GABA observed in many pathological conditions. This is due to the fact that in the immature brain a down regulation of KCC2 and an up regulation of NKCC1 are seen. Here, I present a personal history of how an unexpected observation led to novel concepts in developmental neurobiology and putative treatments of autism and other developmental disorders. Being a personal account, this review is neither exhaustive nor provides an update of this topic with all the studies that have contributed to this evolution. We all rely on previous inventors to allow science to advance. Here, I present a personal summary of this topic primarily to illustrate why we often fail to comprehend the implications of our own observations. They remind us - and policy deciders - why Science cannot be programed, requiring time, and risky investigations that raise interesting questions before being translated from bench to bed. Discoveries are always on sideways, never on highways.
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Decreased astroglial monocarboxylate transporter 4 expression in temporal lobe epilepsy. Mol Neurobiol 2014; 50:327-38. [PMID: 24464262 DOI: 10.1007/s12035-013-8619-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/12/2013] [Indexed: 10/25/2022]
Abstract
Efflux of monocaroxylates like lactate, pyruvate, and ketone bodies from astrocytes through monocarboxylate transporter 4 (MCT4) supplies the local neuron population with metabolic intermediates to meet energy requirements under conditions of increased demand. Disruption of this astroglial-neuron metabolic coupling pathway may contribute to epileptogenesis. We measured MCT4 expression in temporal lobe epileptic foci excised from patients with intractable epilepsy and in rats injected with pilocarpine, an animal model of temporal lobe epilepsy (TLE). Cortical MCT4 expression levels were significantly lower in TLE patients compared with controls, due at least partially to MCT4 promoter methylation. Expression of MCT4 also decreased progressively in pilocarpine-treated rats from 12 h to 14 days post-administration. Underexpression of MCT4 in cultured astrocytes induced by a short hairpin RNA promoted apoptosis. Knockdown of astrocyte MCT4 also suppressed excitatory amino acid transporter 1 (EAAT1) expression. Reduced MCT4 and EAAT1 expression by astrocytes may lead to neuronal hyperexcitability and epileptogenesis in the temporal lobe by reducing the supply of metabolic intermediates and by allowing accumulation of extracellular glutamate.
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Rivera-Angulo AJ, Peña-Ortega F. Isocitrate supplementation promotes breathing generation, gasping, and autoresuscitation in neonatal mice. J Neurosci Res 2013; 92:375-88. [DOI: 10.1002/jnr.23330] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 10/15/2013] [Accepted: 10/25/2013] [Indexed: 02/01/2023]
Affiliation(s)
- Ana-Julia Rivera-Angulo
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto de Neurobiología; Universidad Nacional Autónoma de México-Campus Juriquilla; Querétaro México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto de Neurobiología; Universidad Nacional Autónoma de México-Campus Juriquilla; Querétaro México
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26
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Löscher W, Puskarjov M, Kaila K. Cation-chloride cotransporters NKCC1 and KCC2 as potential targets for novel antiepileptic and antiepileptogenic treatments. Neuropharmacology 2013; 69:62-74. [PMID: 22705273 DOI: 10.1016/j.neuropharm.2012.05.045] [Citation(s) in RCA: 200] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/22/2012] [Accepted: 05/28/2012] [Indexed: 12/31/2022]
Abstract
In cortical and hippocampal neurons, cation-chloride cotransporters (CCCs) control the reversal potential (EGABA) of GABAA receptor-mediated current and voltage responses and, consequently, they modulate the efficacy of GABAergic inhibition. Two members of the CCC family, KCC2 (the major neuron-specific K-Cl cotransporter; KCC isoform 2) and NKCC1 (the Na-K-2Cl cotransporter isoform 1 which is expressed in both neurons and glial cells) have attracted much interest in studies on GABAergic signaling under both normal and pathophysiological conditions, such as epilepsy. There is tentative evidence that loop diuretic compounds such as furosemide and bumetanide may have clinically relevant antiepileptic actions, especially when administered in combination with conventional GABA-mimetic drugs such as phenobarbital. Furosemide is a non-selective inhibitor of CCCs while at low concentrations bumetanide is selective for NKCCs. Search for novel antiepileptic drugs (AEDs) is highly motivated especially for the treatment of neonatal seizures which are often resistant to, or even aggravated by conventional AEDs. This review shows that the antiepileptic effects of loop diuretics described in the pertinent literature are based on widely heterogeneous mechanisms ranging from actions on both neuronal NKCC1 and KCC2 to modulation of the brain extracellular volume fraction. A promising strategy for the development of novel CCC-blocking AEDs is based on prodrugs that are activated following their passage across the blood-brain barrier. This article is part of the Special Issue entitled 'New Targets and Approaches to the Treatment of Epilepsy'.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany.
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Effects of intensive cognitive-behavioral therapy on cingulate neurochemistry in obsessive-compulsive disorder. J Psychiatr Res 2013; 47:494-504. [PMID: 23290560 PMCID: PMC3672238 DOI: 10.1016/j.jpsychires.2012.11.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 10/31/2012] [Accepted: 11/16/2012] [Indexed: 11/23/2022]
Abstract
The neurophysiological bases of cognitive-behavioral therapy (CBT) for obsessive-compulsive disorder (OCD) are incompletely understood. Previous studies, though sparse, implicate metabolic changes in pregenual anterior cingulate cortex (pACC) and anterior middle cingulate cortex (aMCC) as neural correlates of response to CBT. The goal of this pilot study was to determine the relationship between levels of the neurochemically interlinked metabolites glutamate + glutamine (Glx) and N-acetyl-aspartate + N-acetyl-aspartyl-glutamate (tNAA) in pACC and aMCC to pretreatment OCD diagnostic status and OCD response to CBT. Proton magnetic resonance spectroscopic imaging ((1)H MRSI) was acquired from pACC and aMCC in 10 OCD patients at baseline, 8 of whom had a repeat scan after 4 weeks of intensive CBT. pACC was also scanned (baseline only) in 8 age-matched healthy controls. OCD symptoms improved markedly in 8/8 patients after CBT. In right pACC, tNAA was significantly lower in OCD patients than controls at baseline and then increased significantly after CBT. Baseline tNAA also correlated with post-CBT change in OCD symptom severity. In left aMCC, Glx decreased significantly after intensive CBT. These findings add to evidence implicating the pACC and aMCC as loci of the metabolic effects of CBT in OCD, particularly effects on glutamatergic and N-acetyl compounds. Moreover, these metabolic responses occurred after just 4 weeks of intensive CBT, compared to 3 months for standard weekly CBT. Baseline levels of tNAA in the pACC may be associated with response to CBT for OCD. Lateralization of metabolite effects of CBT, previously observed in subcortical nuclei and white matter, may also occur in cingulate cortex. Tentative mechanisms for these effects are discussed. Comorbid depressive symptoms in OCD patients may have contributed to metabolite effects, although baseline and post-CBT change in depression ratings varied with choline-compounds and myo-inositol rather than Glx or tNAA.
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28
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Pavlov I, Kaila K, Kullmann DM, Miles R. Cortical inhibition, pH and cell excitability in epilepsy: what are optimal targets for antiepileptic interventions? J Physiol 2013; 591:765-74. [PMID: 22890709 PMCID: PMC3591695 DOI: 10.1113/jphysiol.2012.237958] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/10/2012] [Indexed: 12/14/2022] Open
Abstract
Epilepsy is characterised by the propensity of the brain to generate spontaneous recurrent bursts of excessive neuronal activity, seizures. GABA-mediated inhibition is critical for restraining neuronal excitation in the brain, and therefore potentiation of GABAergic neurotransmission is commonly used to prevent seizures. However, data obtained in animal models of epilepsy and from human epileptic tissue suggest that GABA-mediated signalling contributes to interictal and ictal activity. Prolonged activation of GABA(A) receptors during epileptiform bursts may even initiate a shift in GABAergic neurotransmission from inhibitory to excitatory and so have a proconvulsant action. Direct targeting of the membrane mechanisms that reduce spiking in glutamatergic neurons may better control neuronal excitability in epileptic tissue. Manipulation of brain pH may be a promising approach and recent advances in gene therapy and optogenetics seem likely to provide further routes to effective therapeutic intervention.
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Affiliation(s)
- Ivan Pavlov
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London WC1N 3BG, UK.
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29
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Zilberter M, Ivanov A, Ziyatdinova S, Mukhtarov M, Malkov A, Alpár A, Tortoriello G, Botting CH, Fülöp L, Osypov AA, Pitkänen A, Tanila H, Harkany T, Zilberter Y. Dietary energy substrates reverse early neuronal hyperactivity in a mouse model of Alzheimer's disease. J Neurochem 2013; 125:157-71. [PMID: 23241062 DOI: 10.1111/jnc.12127] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/10/2012] [Accepted: 12/11/2012] [Indexed: 01/25/2023]
Abstract
Deficient energy metabolism and network hyperactivity are the early symptoms of Alzheimer's disease (AD). In this study, we show that administration of exogenous oxidative energy substrates (OES) corrects neuronal energy supply deficiency that reduces the amyloid-beta-induced abnormal neuronal activity in vitro and the epileptic phenotype in AD model in vivo. In vitro, acute application of protofibrillar amyloid-β1-42 (Aβ1-42) induced aberrant network activity in wild-type hippocampal slices that was underlain by depolarization of both the neuronal resting membrane potential and GABA-mediated current reversal potential. Aβ1-42 also impaired synaptic function and long-term potentiation. These changes were paralleled by clear indications of impaired energy metabolism, as indicated by abnormal NAD(P)H signaling induced by network activity. However, when glucose was supplemented with OES pyruvate and 3-beta-hydroxybutyrate, Aβ1-42 failed to induce detrimental changes in any of the above parameters. We administered the same OES as chronic supplementation to a standard diet to APPswe/PS1dE9 transgenic mice displaying AD-related epilepsy phenotype. In the ex-vivo slices, we found neuronal subpopulations with significantly depolarized resting and GABA-mediated current reversal potentials, mirroring abnormalities we observed under acute Aβ1-42 application. Ex-vivo cortex of transgenic mice fed with standard diet displayed signs of impaired energy metabolism, such as abnormal NAD(P)H signaling and strongly reduced tolerance to hypoglycemia. Transgenic mice also possessed brain glycogen levels twofold lower than those of wild-type mice. However, none of the above neuronal and metabolic dysfunctions were observed in transgenic mice fed with the OES-enriched diet. In vivo, dietary OES supplementation abated neuronal hyperexcitability, as the frequency of both epileptiform discharges and spikes was strongly decreased in the APPswe/PS1dE9 mice placed on the diet. Altogether, our results suggest that early AD-related neuronal malfunctions underlying hyperexcitability and energy metabolism deficiency can be prevented by dietary supplementation with native energy substrates.
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Affiliation(s)
- Misha Zilberter
- Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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30
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Recent progress in GABAergic excitation from mature brain. Arch Pharm Res 2012; 35:2035-44. [PMID: 23263799 DOI: 10.1007/s12272-012-1202-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/23/2012] [Accepted: 11/27/2012] [Indexed: 01/15/2023]
Abstract
The excitatory effect of γ-Aminobutyric acid (GABA) has been recognized in very young animals and in seizure generation, but not so much in animals after weaning age or in adults. The existence of this phenomenon in mature brain is still controversial. In the course of debate, creative studies have identified and characterized the phenomenon in suprachiasmatic nucleus, cortex, hippocampus and basolateral amygdala, albeit mostly in single neurons. In neural circuit activity, presumed GABAergic excitation was observed in basolateral amygdala during the study of a neuropeptide, cholecystokinin. Though the functional meaning of this phenomenon in vivo remains to be uncovered, it may be implicated in epilepsy or anxiety in the adult brain.
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31
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Egorov AV, Draguhn A. Development of coherent neuronal activity patterns in mammalian cortical networks: common principles and local hetereogeneity. Mech Dev 2012; 130:412-23. [PMID: 23032193 DOI: 10.1016/j.mod.2012.09.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 09/18/2012] [Accepted: 09/21/2012] [Indexed: 11/19/2022]
Abstract
Many mammals are born in a very immature state and develop their rich repertoire of behavioral and cognitive functions postnatally. This development goes in parallel with changes in the anatomical and functional organization of cortical structures which are involved in most complex activities. The emerging spatiotemporal activity patterns in multi-neuronal cortical networks may indeed form a direct neuronal correlate of systemic functions like perception, sensorimotor integration, decision making or memory formation. During recent years, several studies--mostly in rodents--have shed light on the ontogenesis of such highly organized patterns of network activity. While each local network has its own peculiar properties, some general rules can be derived. We therefore review and compare data from the developing hippocampus, neocortex and--as an intermediate region--entorhinal cortex. All cortices seem to follow a characteristic sequence starting with uncorrelated activity in uncoupled single neurons where transient activity seems to have mostly trophic effects. In rodents, before and shortly after birth, cortical networks develop weakly coordinated multineuronal discharges which have been termed synchronous plateau assemblies (SPAs). While these patterns rely mostly on electrical coupling by gap junctions, the subsequent increase in number and maturation of chemical synapses leads to the generation of large-scale coherent discharges. These patterns have been termed giant depolarizing potentials (GDPs) for predominantly GABA-induced events or early network oscillations (ENOs) for mostly glutamatergic bursts, respectively. During the third to fourth postnatal week, cortical areas reach their final activity patterns with distinct network oscillations and highly specific neuronal discharge sequences which support adult behavior. While some of the mechanisms underlying maturation of network activity have been elucidated much work remains to be done in order to fully understand the rules governing transition from immature to mature patterns of network activity.
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Affiliation(s)
- Alexei V Egorov
- Institute of Physiology and Pathophysiology, University of Heidelberg and Bernstein Center for Computational Neuroscience-BCCN Heidelberg/Mannheim, D-69120 Heidelberg, Germany.
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32
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Ben-Ari Y, Woodin MA, Sernagor E, Cancedda L, Vinay L, Rivera C, Legendre P, Luhmann HJ, Bordey A, Wenner P, Fukuda A, van den Pol AN, Gaiarsa JL, Cherubini E. Refuting the challenges of the developmental shift of polarity of GABA actions: GABA more exciting than ever! Front Cell Neurosci 2012; 6:35. [PMID: 22973192 PMCID: PMC3428604 DOI: 10.3389/fncel.2012.00035] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 07/29/2012] [Indexed: 12/12/2022] Open
Abstract
During brain development, there is a progressive reduction of intracellular chloride associated with a shift in GABA polarity: GABA depolarizes and occasionally excites immature neurons, subsequently hyperpolarizing them at later stages of development. This sequence, which has been observed in a wide range of animal species, brain structures and preparations, is thought to play an important role in activity-dependent formation and modulation of functional circuits. This sequence has also been considerably reinforced recently with new data pointing to an evolutionary preserved rule. In a recent “Hypothesis and Theory Article,” the excitatory action of GABA in early brain development is suggested to be “an experimental artefact” (Bregestovski and Bernard, 2012). The authors suggest that the excitatory action of GABA is due to an inadequate/insufficient energy supply in glucose-perfused slices and/or to the damage produced by the slicing procedure. However, these observations have been repeatedly contradicted by many groups and are inconsistent with a large body of evidence including the fact that the developmental shift is neither restricted to slices nor to rodents. We summarize the overwhelming evidence in support of both excitatory GABA during development, and the implications this has in developmental neurobiology.
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Affiliation(s)
- Yehezkel Ben-Ari
- INSERM Unité 901, Université de la Méditerranée, UMR S901 Aix-Marseille 2 and INMED Marseille, France
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Wisor JP, Rempe MJ, Schmidt MA, Moore ME, Clegern WC. Sleep slow-wave activity regulates cerebral glycolytic metabolism. Cereb Cortex 2012; 23:1978-87. [PMID: 22767634 DOI: 10.1093/cercor/bhs189] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Non-rapid eye movement sleep (NREMS) onset is characterized by a reduction in cerebral metabolism and an increase in slow waves, 1-4-Hz oscillations between relatively depolarized and hyperpolarized states in the cerebral cortex. The metabolic consequences of slow-wave activity (SWA) at the cellular level remain uncertain. We sought to determine whether SWA modulates the rate of glycolysis within the cerebral cortex. The real-time measurement of lactate concentration in the mouse cerebral cortex demonstrates that it increases during enforced wakefulness. In spontaneous sleep/wake cycles, lactate concentration builds during wakefulness and rapid eye movement sleep and declines during NREMS. The rate at which lactate concentration declines during NREMS is proportional to the magnitude of electroencephalographic (EEG) activity at frequencies of <10 Hz. The induction of 1-Hz oscillations, but not 10-Hz oscillations, in the electroencephalogram by optogenetic stimulation of cortical pyramidal cells during wakefulness triggers a decline in lactate concentration. We conclude that cerebral SWA promotes a decline in the rate of glycolysis in the cerebral cortex. These results demonstrate a cellular energetic function for sleep SWA, which may contribute to its restorative effects on brain function.
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Affiliation(s)
- Jonathan P Wisor
- WWAMI Medical Education Program, Department of Veterinary Comparative Anatomy, Pharmacology and Physiology, Washington State University, Spokane, WA 99210-1945, USA.
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Ben-Ari Y, Khalilov I, Kahle KT, Cherubini E. The GABA excitatory/inhibitory shift in brain maturation and neurological disorders. Neuroscientist 2012; 18:467-86. [PMID: 22547529 DOI: 10.1177/1073858412438697] [Citation(s) in RCA: 407] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ionic currents and the network-driven patterns they generate differ in immature and adult neurons: The developing brain is not a "small adult brain." One of the most investigated examples is the developmentally regulated shift of actions of the transmitter GABA that inhibit adult neurons but excite immature ones because of an initially higher intracellular chloride concentration [Cl(-)](i), leading to depolarizing and often excitatory actions of GABA instead of hyperpolarizing and inhibitory actions. The levels of [Cl(-)](i) are also highly labile, being readily altered transiently or persistently by enhanced episodes of activity in relation to synaptic plasticity or a variety of pathological conditions, including seizures and brain insults. Among the plethora of channels, transporters, and other devices involved in controlling [Cl(-)](i), two have emerged as playing a particularly important role: the chloride importer NKCC1 and the chloride exporter KCC2. Here, the authors stress the importance of determining how [Cl(-)](i) is dynamically regulated and how this affects brain operation in health and disease. In a clinical perspective, agents that control [Cl(-)](i) and reinstate inhibitory actions of GABA open novel therapeutic perspectives in many neurological disorders, including infantile epilepsies, autism spectrum disorders, and other developmental disorders.
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35
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Lauritzen F, Heuser K, de Lanerolle NC, Lee TSW, Spencer DD, Kim JH, Gjedde A, Eid T, Bergersen LH. Redistribution of monocarboxylate transporter 2 on the surface of astrocytes in the human epileptogenic hippocampus. Glia 2012; 60:1172-81. [PMID: 22535546 DOI: 10.1002/glia.22344] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 03/30/2012] [Indexed: 01/05/2023]
Abstract
Emerging evidence points to monocarboxylates as key players in the pathophysiology of temporal lobe epilepsy (TLE) with hippocampal sclerosis (mesial temporal lobe epilepsy, MTLE). Monocarboxylate transporters (MCTs) 1 and 2, which are abundantly present on brain endothelial cells and perivascular astrocyte endfeet, respectively, facilitate the transport of monocarboxylates and protons across cell membranes. Recently, we reported that the density of MCT1 protein is reduced on endothelial cells and increased on astrocyte plasma membranes in the hippocampal formation in patients with MTLE and in several animal models of the disorder. Because the perivascular astrocyte endfeet comprise an important part of the neurovascular unit, we now assessed the distribution of the MCT2 in hippocampal formations in TLE patients with (MTLE) or without hippocampal sclerosis (non-MTLE). Light microscopic immunohistochemistry revealed significantly less perivascular MCT2 immunoreactivity in the hippocampal formation in MTLE (n = 6) than in non-MTLE (n = 6) patients, and to a lesser degree in non-MTLE than in nonepilepsy patients (n = 4). Immunogold electron microscopy indicated that the loss of MCT2 protein occurred on perivascular astrocyte endfeet. Interestingly, the loss of MCT2 on astrocyte endfeet in MTLE (n = 3) was accompanied by an upregulation of the protein on astrocyte membranes facing synapses in the neuropil, when compared with non-MTLE (n = 3). We propose that the altered distribution of MCT1 and MCT2 in TLE (especially MTLE) limits the flux of monocarboxylates across the blood-brain barrier and enhances the exchange of monocarboxylates within the brain parenchyma.
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Affiliation(s)
- Fredrik Lauritzen
- The Brain and Muscle Energy Group, Department of Anatomy and Centre for Molecular Biology and Neuroscience, University of Oslo, Blindern, NO-0317 Oslo, Norway
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36
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Bregestovski P, Bernard C. Excitatory GABA: How a Correct Observation May Turn Out to be an Experimental Artifact. Front Pharmacol 2012; 3:65. [PMID: 22529813 PMCID: PMC3329772 DOI: 10.3389/fphar.2012.00065] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 04/02/2012] [Indexed: 12/04/2022] Open
Abstract
The concept of the excitatory action of GABA during early development is based on data obtained mainly in brain slice recordings. However, in vivo measurements as well as observations made in intact hippocampal preparations indicate that GABA is in fact inhibitory in rodents at early neonatal stages. The apparent excitatory action of GABA seems to stem from cellular injury due to the slicing procedure, which leads to accumulation of intracellular Cl− in injured neurons. This procedural artifact was shown to be attenuated through various manipulations such as addition of energy substrates more relevant to the in vivo situation. These observations question the very concept of excitatory GABA in immature neuronal networks.
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Affiliation(s)
- Piotr Bregestovski
- INSERM URM 1106, Institut de Neuroscience des Systèmes, Aix-Marseille Université Marseille, France
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37
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Khakhalin AS, Aizenman CD. GABAergic transmission and chloride equilibrium potential are not modulated by pyruvate in the developing optic tectum of Xenopus laevis tadpoles. PLoS One 2012; 7:e34446. [PMID: 22496804 PMCID: PMC3319581 DOI: 10.1371/journal.pone.0034446] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 03/05/2012] [Indexed: 11/19/2022] Open
Abstract
In the developing mammalian brain, gamma-aminobutyric acid (GABA) is thought to play an excitatory rather than an inhibitory role due to high levels of intracellular Cl(-) in immature neurons. This idea, however, has been questioned by recent studies which suggest that glucose-based artificial cerebrospinal fluid (ACSF) may be inadequate for experiments on immature and developing brains. These studies suggest that immature neurons may require alternative energy sources, such as lactate or pyruvate. Lack of these other energy sources is thought to result in artificially high intracellular Cl(-) concentrations, and therefore a more depolarized GABA receptor (GABAR) reversal potential. Since glucose metabolism can vary widely among different species, it is important to test the effects of these alternative energy sources on different experimental preparations. We tested whether pyruvate affects GABAergic transmission in isolated brains of developing wild type Xenopus tadpoles in vitro by recording the responsiveness of tectal neurons to optic nerve stimulation, and by measuring currents evoked by local GABA application in a gramicidin perforated patch configuration. We found that, in contrast with previously reported results, the reversal potential for GABAR-mediated currents does not change significantly between developmental stages 45 and 49. Partial substitution of glucose by pyruvate had only minor effects on both the GABA reversal potential, and the responsiveness of tectal neurons at stages 45 and 49. Total depletion of energy sources from the ACSF did not affect neural responsiveness. We also report a strong spatial gradient in GABA reversal potential, with immature cells adjacent to the lateral and caudal proliferative zones having more positive reversal potentials. We conclude that in this experimental preparation standard glucose-based ACSF is an appropriate extracellular media for in vitro experiments.
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Affiliation(s)
| | - Carlos D. Aizenman
- Department of Neuroscience, Brown University, Providence, Rhode Island, United States of America
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38
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Bos R, Vinay L. Glucose is an adequate energy substrate for the depolarizing action of GABA and glycine in the neonatal rat spinal cord in vitro. J Neurophysiol 2012; 107:3107-15. [PMID: 22457452 DOI: 10.1152/jn.00571.2011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In vitro studies have repeatedly demonstrated that the neurotransmitters γ-aminobutyric acid (GABA) and glycine depolarize immature neurons in many areas of the CNS, including the spinal cord. This widely accepted phenomenon was recently challenged by experiments showing that the depolarizing action of GABA on neonatal hippocampus and neocortex in vitro was prevented by adding energy substrates (ES), such as the ketone body metabolite dl-β-hydroxybutyric acid (DL-BHB), lactate, or pyruvate to the artificial cerebrospinal fluid (ACSF). It was suggested that GABA-induced depolarizations in vitro might be an artifact due to inadequate energy supply when glucose is the sole energy source, consistent with the energy metabolism of neonatal rat brain being largely dependent on ESs other than glucose. Here we examined the effects of these ESs (DL-BHB, lactate, pyruvate) on inhibitory postsynaptic potentials (IPSPs) recorded from neonatal rat lumbar spinal cord motoneurons (MNs), in vitro. We report that supplementing the ACSF with physiologic concentrations of DL-BHB, lactate, or pyruvate does not alter the reversal potential of IPSPs (E(IPSP)). Only high concentrations of pyruvate hyperpolarized E(IPSP). In addition, the depolarizing action of GABA on primary afferent terminals was not affected by supplementing the ACSF with ES at physiologic concentrations. We conclude that depolarizing IPSPs in immature MNs and the primary afferent depolarizations are not caused by inadequate energy supply. Glucose at its standard concentration appears to be an adequate ES for the neonatal spinal cord in vitro.
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Affiliation(s)
- Rémi Bos
- Institut de Neurosciences de la Timone, Unité Mixte Recherche 7289, Centre National de la Recherche Scientifique, and Aix-Marseille Université, Marseille, France
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Shetty PK, Galeffi F, Turner DA. Cellular Links between Neuronal Activity and Energy Homeostasis. Front Pharmacol 2012; 3:43. [PMID: 22470340 PMCID: PMC3308331 DOI: 10.3389/fphar.2012.00043] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/24/2012] [Indexed: 12/20/2022] Open
Abstract
Neuronal activity, astrocytic responses to this activity, and energy homeostasis are linked together during baseline, conscious conditions, and short-term rapid activation (as occurs with sensory or motor function). Nervous system energy homeostasis also varies during long-term physiological conditions (i.e., development and aging) and with adaptation to pathological conditions, such as ischemia or low glucose. Neuronal activation requires increased metabolism (i.e., ATP generation) which leads initially to substrate depletion, induction of a variety of signals for enhanced astrocytic function, and increased local blood flow and substrate delivery. Energy generation (particularly in mitochondria) and use during ATP hydrolysis also lead to considerable heat generation. The local increases in blood flow noted following neuronal activation can both enhance local substrate delivery but also provides a heat sink to help cool the brain and removal of waste by-products. In this review we highlight the interactions between short-term neuronal activity and energy metabolism with an emphasis on signals and factors regulating astrocyte function and substrate supply.
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Affiliation(s)
- Pavan K Shetty
- Neurosurgery and Neurobiology, Research and Surgery Services, Durham VA Medical Center, Duke University Durham, NC, USA
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Abstract
Neuronal excitability in the adult brain is controlled by a balance between synaptic excitation and inhibition mediated by glutamate and GABA, respectively. While generally inhibitory in the adult brain, GABA(A) receptor activation is excitatory under certain conditions in which the GABA reversal potential is shifted positive due to intracellular Cl(-) accumulation, such as during early postnatal development and brain injury. However, the conditions under which GABA is excitatory are generally either transitory or pathological. Here, we reveal GABAergic synaptic inputs to be uniformly excitatory in vasopressin (VP)-secreting magnocellular neurons in the adult hypothalamus under normal conditions. The GABA reversal potential (E(GABA)) was positive to resting potential and spike threshold in VP neurons, but not in oxytocin (OT)-secreting neurons. The VP neurons lacked expression of the K(+)-Cl(-) cotransporter 2 (KCC2), the predominant Cl(-) exporter in the adult brain. The E(GABA) was unaffected by inhibition of KCC2 in VP neurons, but was shifted positive in OT neurons, which express KCC2. Alternatively, inhibition of the Na(+)-K(+)-Cl(-) cotransporter 1 (NKCC1), a Cl(-) importer expressed in most cell types mainly during postnatal development, caused a negative shift in E(GABA) in VP neurons, but had no effect on GABA currents in OT neurons. GABA(A) receptor blockade caused a decrease in the firing rate of VP neurons, but an increase in firing in OT neurons. Our findings demonstrate that GABA is excitatory in adult VP neurons, suggesting that the classical excitation/inhibition paradigm of synaptic glutamate and GABA control of neuronal excitability does not apply to VP neurons.
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Song N, Shi H, Li C, Yin S. Differences in developmental changes in GABAergic response between bushy and stellate cells in the rat anteroventral cochlear nucleus. Int J Dev Neurosci 2012; 30:397-403. [DOI: 10.1016/j.ijdevneu.2012.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 09/08/2011] [Accepted: 02/14/2012] [Indexed: 11/29/2022] Open
Affiliation(s)
- Ning‐ying Song
- Department of OtorhinolaryngologyAffiliated Sixth People's Hospital of Shanghai Jiaotong University600 Yishan RoadShanghai200233China
| | - Hai‐bo Shi
- Department of OtorhinolaryngologyAffiliated Sixth People's Hospital of Shanghai Jiaotong University600 Yishan RoadShanghai200233China
| | - Chun‐yan Li
- Department of OtorhinolaryngologyAffiliated Sixth People's Hospital of Shanghai Jiaotong University600 Yishan RoadShanghai200233China
| | - Shan‐kai Yin
- Department of OtorhinolaryngologyAffiliated Sixth People's Hospital of Shanghai Jiaotong University600 Yishan RoadShanghai200233China
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Abstract
Seizures that are resistant to standard medications remain a major clinical problem. One underutilized option for patients with medication-resistant seizures is the high-fat, low-carbohydrate ketogenic diet. The diet received its name based on the observation that patients consuming this diet produce ketone bodies (e.g., acetoacetate, β-hydroxybutyrate, and acetone). Although the exact mechanisms of the diet are unknown, ketone bodies have been hypothesized to contribute to the anticonvulsant and antiepileptic effects. In this review, anticonvulsant properties of ketone bodies and the ketogenic diet are discussed (including GABAergic and glutamatergic effects). Because of the importance of ketone body metabolism in the early stages of life, the effects of ketone bodies on developing neurons in vitro also are discussed. Understanding how ketone bodies exert their effects will help optimize their use in treating epilepsy and other neurological disorders.
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Nociceptive stimuli enhance anesthetic-induced neuroapoptosis in the rat developing brain. Neurobiol Dis 2012; 45:743-50. [DOI: 10.1016/j.nbd.2011.10.021] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 10/04/2011] [Accepted: 10/22/2011] [Indexed: 11/22/2022] Open
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Ivanov A, Zilberter Y. Critical state of energy metabolism in brain slices: the principal role of oxygen delivery and energy substrates in shaping neuronal activity. FRONTIERS IN NEUROENERGETICS 2011; 3:9. [PMID: 22232599 PMCID: PMC3247678 DOI: 10.3389/fnene.2011.00009] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 12/10/2011] [Indexed: 12/22/2022]
Abstract
The interactive vasculo-neuro-glial system controlling energy supply in the brain is absent in vitro where energy provision is determined by experimental conditions. Despite the fact that neuronal activity is extremely energy demanding, little has been reported on the state of energy metabolism in submerged brain slices. Without this information, the arbitrarily chosen oxygenation and metabolic provisions make questionable the efficient oxidative metabolism in slices. We show that in mouse hippocampal slices (postnatal day 19–44), evoked neuronal discharges, spontaneous network activity (initiated by 4-aminopyridine), and synaptic stimulation-induced NAD(P)H autofluorescence depend strongly on the oxygen availability. Only the rate of perfusion as high as ~15 ml/min (95% O2) provided appropriate oxygenation of a slice. Lower oxygenation resulted in the decrease of both local field potentials and spontaneous network activity as well as in significant modulation of short-term synaptic plasticity. The reduced oxygen supply considerably inhibited the oxidation phase of NAD(P)H signaling indicating that the changes in neuronal activity were paralleled by the decrease in aerobic energy metabolism. Interestingly, the dependence of neuronal activity on oxygen tension was clearly shifted toward considerably larger pO2 values in slices when compared to in vivo conditions. With sufficient pO2 provided by a high perfusion rate, partial substitution of glucose in ACSF for β-hydroxybutyrate, pyruvate, or lactate enhanced both oxidative metabolism and synaptic function. This suggests that the high pO2 in brain slices is compulsory for maintaining oxidative metabolism, and glucose alone is not sufficient in fulfilling energy requirements during neuronal activity. Altogether, our results demonstrate that energy metabolism determines the functional state of neuronal network, highlighting the need for the adequate metabolic support to be insured in the in vitro experiments.
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Affiliation(s)
- Anton Ivanov
- INSERM UMR751, Université de la Méditerranée Marseille, France
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Wang LC, Tang ZQ, Lu Y. Synaptic activity-induced Ca(2+) signaling in avian cochlear nucleus magnocellularis neurons. Neurosci Res 2011; 72:129-39. [PMID: 22134051 DOI: 10.1016/j.neures.2011.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 10/05/2011] [Accepted: 11/10/2011] [Indexed: 01/08/2023]
Abstract
Neurons of the avian cochlear nucleus magnocellularis (NM) receive glutamatergic inputs from the spiral ganglion cells via the auditory nerve and feedback GABAergic inputs primarily from the superior olivary nucleus. We investigated regulation of Ca(2+) signaling in NM neurons with ratiometric Ca(2+) imaging in chicken brain slices. Application of exogenous glutamate or GABA increased the intracellular Ca(2+) concentration ([Ca(2+)](i)) in NM neurons. Interestingly, GABA-induced Ca(2+) responses persisted into neuronal maturation, in both standard and energy substrate enriched artificial cerebrospinal fluid. More importantly, we found that electrical stimulation applied to the glutamatergic and GABAergic afferent fibers innervating the NM was able to elicit transient [Ca(2+)](i) increases in NM neurons, and the amplitude of the Ca(2+) responses increased with increasing frequency and duration of the electrical stimulation. Antagonists for ionotropic glutamate receptors significantly blocked these [Ca(2+)](i) increases, whereas blocking GABA(A) receptors did not affect the Ca(2+) responses, suggesting that synaptically released glutamate but not GABA induced the Ca(2+) signaling in vitro. Furthermore, activation of GABA(A) receptors with exogenous agonists inhibited synaptic activity-induced [Ca(2+)](i) increases in NM neurons, suggesting a role of GABA(A) receptors in the regulation of Ca(2+) homeostasis in the avian cochlear nucleus neurons.
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Affiliation(s)
- Lie-Cheng Wang
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, PO Box 95, Rootstown, OH 44272, USA
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Chronic hyperosmotic stress converts GABAergic inhibition into excitation in vasopressin and oxytocin neurons in the rat. J Neurosci 2011; 31:13312-22. [PMID: 21917814 DOI: 10.1523/jneurosci.1440-11.2011] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In mammals, the increased secretion of arginine-vasopressin (AVP) (antidiuretic hormone) and oxytocin (natriuretic hormone) is a key physiological response to hyperosmotic stress. In this study, we examined whether chronic hyperosmotic stress weakens GABA(A) receptor-mediated synaptic inhibition in rat hypothalamic magnocellular neurosecretory cells (MNCs) secreting these hormones. Gramicidin-perforated recordings of MNCs in acute hypothalamic slices prepared from control rats and ones subjected to the chronic hyperosmotic stress revealed that this challenge not only attenuated the GABAergic inhibition but actually converted it into excitation. The hyperosmotic stress caused a profound depolarizing shift in the reversal potential of GABAergic response (E(GABA)) in MNCs. This E(GABA) shift was associated with increased expression of Na(+)-K(+)-2Cl(-) cotransporter 1 (NKCC1) in MNCs and was blocked by the NKCC inhibitor bumetanide as well as by decreasing NKCC activity through a reduction of extracellular sodium. Blocking central oxytocin receptors during the hyperosmotic stress prevented the switch to GABAergic excitation. Finally, intravenous injection of the GABA(A) receptor antagonist bicuculline lowered the plasma levels of AVP and oxytocin in rats under the chronic hyperosmotic stress. We conclude that the GABAergic responses of MNCs switch between inhibition and excitation in response to physiological needs through the regulation of transmembrane Cl(-) gradients.
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Abstract
Anesthesia kills neurons in the brain of infantile animals, including primates, and causes permanent and progressive neurocognitive decline. The anesthesia community and regulatory authorities alike are concerned that is also true in humans. In this review, I summarize what we currently know about the risks of pediatric anesthesia to long-term cognitive function. If anesthesia is discovered to cause cognitive decline in humans, we need to know how to prevent and treat it. Prevention requires knowledge of the mechanisms of anesthesia-induced cognitive decline. This review gives an overview of some of the mechanisms that have been proposed for anesthesia-induced cognitive decline and discusses possible treatment options. If anesthesia induces cognitive decline in humans, we need to know what type and duration of anesthetic is safe, and which, if any, is not safe. This review discusses early results of comparative animal studies of anesthetic neurotoxicity. Until we know if and how pediatric anesthesia affects cognition in humans, a change in anesthetic practice would be premature, not guided by evidence of better alternatives, and therefore potentially dangerous. The SmartTots initiative jointly supported by the International Anesthesia Research Society and the Food and Drug Administration aims to fund research designed to shed light on these issues that are of high priority to the anesthesia community and the public alike and therefore deserves the full support of these interest groups.
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Affiliation(s)
- Greg Stratmann
- Department of Anesthesia and Perioperative Care, University of California San Francisco, Box 0464, Room U286, 513 Parnassus Ave., San Francisco, CA 94143, USA.
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Friauf E, Rust MB, Schulenborg T, Hirtz JJ. Chloride cotransporters, chloride homeostasis, and synaptic inhibition in the developing auditory system. Hear Res 2011; 279:96-110. [PMID: 21683130 DOI: 10.1016/j.heares.2011.05.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 05/11/2011] [Indexed: 01/24/2023]
Abstract
The role of glycine and GABA as inhibitory neurotransmitters in the adult vertebrate nervous system has been well characterized in a variety of model systems, including the auditory, which is particularly well suited for analyzing inhibitory neurotransmission. However, a full understanding of glycinergic and GABAergic transmission requires profound knowledge of how the precise organization of such synapses emerges. Likewise, the role of glycinergic and GABAergic signaling during development, including the dynamic changes in regulation of cytosolic chloride via chloride cotransporters, needs to be thoroughly understood. Recent literature has elucidated the developmental expression of many of the molecular components that comprise the inhibitory synaptic phenotype. An equally important focus of research has revealed the critical role of glycinergic and GABAergic signaling in sculpting different developmental aspects in the auditory system. This review examines the current literature detailing the expression patterns and function (chapter 1), as well as the regulation and pharmacology of chloride cotransporters (chapter 2). Of particular importance is the ontogeny of glycinergic and GABAergic transmission (chapter 3). The review also surveys the recent work on the signaling role of these two major inhibitory neurotransmitters in the developing auditory system (chapter 4) and concludes with an overview of areas for further research (chapter 5).
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Affiliation(s)
- Eckhard Friauf
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, POB 3049, D-67653 Kaiserslautern, Germany.
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Doyon N, Prescott SA, Castonguay A, Godin AG, Kröger H, De Koninck Y. Efficacy of synaptic inhibition depends on multiple, dynamically interacting mechanisms implicated in chloride homeostasis. PLoS Comput Biol 2011; 7:e1002149. [PMID: 21931544 PMCID: PMC3169517 DOI: 10.1371/journal.pcbi.1002149] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 06/11/2011] [Indexed: 11/19/2022] Open
Abstract
Chloride homeostasis is a critical determinant of the strength and robustness of inhibition mediated by GABA(A) receptors (GABA(A)Rs). The impact of changes in steady state Cl(-) gradient is relatively straightforward to understand, but how dynamic interplay between Cl(-) influx, diffusion, extrusion and interaction with other ion species affects synaptic signaling remains uncertain. Here we used electrodiffusion modeling to investigate the nonlinear interactions between these processes. Results demonstrate that diffusion is crucial for redistributing intracellular Cl(-) load on a fast time scale, whereas Cl(-)extrusion controls steady state levels. Interaction between diffusion and extrusion can result in a somato-dendritic Cl(-) gradient even when KCC2 is distributed uniformly across the cell. Reducing KCC2 activity led to decreased efficacy of GABA(A)R-mediated inhibition, but increasing GABA(A)R input failed to fully compensate for this form of disinhibition because of activity-dependent accumulation of Cl(-). Furthermore, if spiking persisted despite the presence of GABA(A)R input, Cl(-) accumulation became accelerated because of the large Cl(-) driving force that occurs during spikes. The resulting positive feedback loop caused catastrophic failure of inhibition. Simulations also revealed other feedback loops, such as competition between Cl(-) and pH regulation. Several model predictions were tested and confirmed by [Cl(-)](i) imaging experiments. Our study has thus uncovered how Cl(-) regulation depends on a multiplicity of dynamically interacting mechanisms. Furthermore, the model revealed that enhancing KCC2 activity beyond normal levels did not negatively impact firing frequency or cause overt extracellular K(-) accumulation, demonstrating that enhancing KCC2 activity is a valid strategy for therapeutic intervention.
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Affiliation(s)
- Nicolas Doyon
- Division of Cellular and Molecular Neuroscience, Centre de recherche Université Laval Robert-Giffard, Québec, Québec, Canada
- Department of Psychiatry & Neuroscience, Université Laval, Québec, Québec, Canada
| | - Steven A. Prescott
- Department of Neurobiology and Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Annie Castonguay
- Division of Cellular and Molecular Neuroscience, Centre de recherche Université Laval Robert-Giffard, Québec, Québec, Canada
- Department of Psychiatry & Neuroscience, Université Laval, Québec, Québec, Canada
| | - Antoine G. Godin
- Division of Cellular and Molecular Neuroscience, Centre de recherche Université Laval Robert-Giffard, Québec, Québec, Canada
| | - Helmut Kröger
- Department of Physics, Université Laval, Québec, Québec, Canada
| | - Yves De Koninck
- Division of Cellular and Molecular Neuroscience, Centre de recherche Université Laval Robert-Giffard, Québec, Québec, Canada
- Department of Psychiatry & Neuroscience, Université Laval, Québec, Québec, Canada
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