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Korsak A, Kellett DO, Aziz Q, Anderson C, D’Souza A, Tinker A, Ackland GL, Gourine AV. Immediate and sustained increases in the activity of vagal preganglionic neurons during exercise and after exercise training. Cardiovasc Res 2023; 119:2329-2341. [PMID: 37516977 PMCID: PMC10597628 DOI: 10.1093/cvr/cvad115] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 03/31/2023] [Accepted: 05/12/2023] [Indexed: 08/01/2023] Open
Abstract
AIMS The brain controls the heart by dynamic recruitment and withdrawal of cardiac parasympathetic (vagal) and sympathetic activity. Autonomic control is essential for the development of cardiovascular responses during exercise, however, the patterns of changes in the activity of the two autonomic limbs, and their functional interactions in orchestrating physiological responses during exercise, are not fully understood. The aim of this study was to characterize changes in vagal parasympathetic drive in response to exercise and exercise training by directly recording the electrical activity of vagal preganglionic neurons in experimental animals (rats). METHODS AND RESULTS Single unit recordings were made using carbon-fibre microelectrodes from the populations of vagal preganglionic neurons of the nucleus ambiguus (NA) and the dorsal vagal motor nucleus of the brainstem. It was found that (i) vagal preganglionic neurons of the NA and the dorsal vagal motor nucleus are strongly activated during bouts of acute exercise, and (ii) exercise training markedly increases the resting activity of both populations of vagal preganglionic neurons and augments the excitatory responses of NA neurons during exercise. CONCLUSIONS These data show that central vagal drive increases during exercise and provide the first direct neurophysiological evidence that exercise training increases vagal tone. The data argue against the notion of exercise-induced central vagal withdrawal during exercise. We propose that robust increases in the activity of vagal preganglionic neurons during bouts of exercise underlie activity-dependent plasticity, leading to higher resting vagal tone that confers multiple health benefits associated with regular exercise.
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Affiliation(s)
- Alla Korsak
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Daniel O Kellett
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Qadeer Aziz
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
- Centre for Clinical Pharmacology and Precision Medicine, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Cali Anderson
- Division of Cardiovascular Sciences, University of Manchester, Manchester, UK
| | - Alicia D’Souza
- Division of Cardiovascular Sciences, University of Manchester, Manchester, UK
| | - Andrew Tinker
- Centre for Clinical Pharmacology and Precision Medicine, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Gareth L Ackland
- Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
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2
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Kopach O, Sylantyev S, Bard L, Michaluk P, Heller JP, Gutierrez del Arroyo A, Ackland GL, Gourine AV, Rusakov DA. Human neutrophils communicate remotely via calcium-dependent glutamate-induced glutamate release. iScience 2023; 26:107236. [PMID: 37496680 PMCID: PMC10366500 DOI: 10.1016/j.isci.2023.107236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/25/2023] [Accepted: 06/23/2023] [Indexed: 07/28/2023] Open
Abstract
Neutrophils are white blood cells that are critical to acute inflammatory and adaptive immune responses. Their swarming-pattern behavior is controlled by multiple cellular cascades involving calcium-dependent release of various signaling molecules. Previous studies have reported that neutrophils express glutamate receptors and can release glutamate but evidence of direct neutrophil-neutrophil communication has been elusive. Here, we hold semi-suspended cultured human neutrophils in patch-clamp whole-cell mode to find that calcium mobilization induced by stimulating one neutrophil can trigger an N-methyl-D-aspartate (NMDA) receptor-driven membrane current and calcium signal in neighboring neutrophils. We employ an enzymatic-based imaging assay to image, in real time, glutamate release from neutrophils induced by glutamate released from their neighbors. These observations provide direct evidence for a positive-feedback inter-neutrophil communication that could contribute to mechanisms regulating communal neutrophil behavior.
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Affiliation(s)
- Olga Kopach
- Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Sergyi Sylantyev
- Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
- Rowett Institute, University of Aberdeen, Ashgrove Road West, Aberdeen AB25 2ZD, UK
| | - Lucie Bard
- Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Piotr Michaluk
- Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
- BRAINCITY, Laboratory of Neurobiology, Nencki Institute of Experimental Biology PAS, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Janosch P. Heller
- Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
- School of Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Ana Gutierrez del Arroyo
- Translational Medicine and Therapeutics, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Gareth L. Ackland
- Translational Medicine and Therapeutics, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Alexander V. Gourine
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Dmitri A. Rusakov
- Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
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3
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Yackle K. Transformation of Our Understanding of Breathing Control by Molecular Tools. Annu Rev Physiol 2023; 85:93-113. [PMID: 36323001 PMCID: PMC9918693 DOI: 10.1146/annurev-physiol-021522-094142] [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: 02/12/2023]
Abstract
The rhythmicity of breath is vital for normal physiology. Even so, breathing is enriched with multifunctionality. External signals constantly change breathing, stopping it when under water or deepening it during exertion. Internal cues utilize breath to express emotions such as sighs of frustration and yawns of boredom. Breathing harmonizes with other actions that use our mouth and throat, including speech, chewing, and swallowing. In addition, our perception of breathing intensity can dictate how we feel, such as during the slow breathing of calming meditation and anxiety-inducing hyperventilation. Heartbeat originates from a peripheral pacemaker in the heart, but the automation of breathing arises from neural clusters within the brainstem, enabling interaction with other brain areas and thus multifunctionality. Here, we document how the recent transformation of cellular and molecular tools has contributed to our appreciation of the diversity of neuronal types in the breathing control circuit and how they confer the multifunctionality of breathing.
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Affiliation(s)
- Kevin Yackle
- Department of Physiology, University of California, San Francisco, California, USA;
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4
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Gourine AV, Dale N. Brain H + /CO 2 sensing and control by glial cells. Glia 2022; 70:1520-1535. [PMID: 35102601 DOI: 10.1002/glia.24152] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 01/04/2023]
Abstract
Maintenance of constant brain pH is critically important to support the activity of individual neurons, effective communication within the neuronal circuits, and, thus, efficient processing of information by the brain. This review article focuses on how glial cells detect and respond to changes in brain tissue pH and concentration of CO2 , and then trigger systemic and local adaptive mechanisms that ensure a stable milieu for the operation of brain circuits. We give a detailed account of the cellular and molecular mechanisms underlying sensitivity of glial cells to H+ and CO2 and discuss the role of glial chemosensitivity and signaling in operation of three key mechanisms that work in concert to keep the brain pH constant. We discuss evidence suggesting that astrocytes and marginal glial cells of the brainstem are critically important for central respiratory CO2 chemoreception-a fundamental physiological mechanism that regulates breathing in accord with changes in blood and brain pH and partial pressure of CO2 in order to maintain systemic pH homeostasis. We review evidence suggesting that astrocytes are also responsible for the maintenance of local brain tissue extracellular pH in conditions of variable acid loads associated with changes in the neuronal activity and metabolism, and discuss potential role of these glial cells in mediating the effects of CO2 on cerebral vasculature.
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Affiliation(s)
- Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, UK
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5
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Gourine AV, Spyer KM. Geoff Burnstock, purinergic signalling, and chemosensory control of breathing. Auton Neurosci 2021; 235:102839. [PMID: 34198056 DOI: 10.1016/j.autneu.2021.102839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/11/2021] [Accepted: 06/20/2021] [Indexed: 12/14/2022]
Abstract
This article is the authors' contribution to the tribute issue in honour of Geoffrey Burnstock, the founder of this journal and the field of purinergic signalling. We give a brief account of the results of experimental studies which at the beginning received valuable input from Geoff, who both directly and indirectly influenced our research undertaken over the last two decades. Research into the mechanisms controlling breathing identified ATP as the common mediator of the central and peripheral chemosensory transduction. Studies of the sources and mechanisms of chemosensory ATP release in the CNS suggested that this signalling pathway is universally engaged in conditions of increased metabolic demand by brain glial cells - astrocytes. Astrocytes appear to function as versatile CNS metabolic sensors that detect changes in brain tissue pH, CO2, oxygen, and cerebral perfusion pressure. Experimental studies on various aspects of astrocyte biology generated data indicating that the function of these omnipresent glial cells and communication between astrocytes and neurons are governed by purinergic signalling, - first discovered by Geoff Burnstock in the 70's and researched through his entire scientific career.
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Affiliation(s)
- Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London WC1E 6BT, UK.
| | - K Michael Spyer
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
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6
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Albaiceta GM, Brochard L, Dos Santos CC, Fernández R, Georgopoulos D, Girard T, Jubran A, López-Aguilar J, Mancebo J, Pelosi P, Skrobik Y, Thille AW, Wilcox ME, Blanch L. The central nervous system during lung injury and mechanical ventilation: a narrative review. Br J Anaesth 2021; 127:648-659. [PMID: 34340836 DOI: 10.1016/j.bja.2021.05.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/03/2021] [Accepted: 05/24/2021] [Indexed: 11/26/2022] Open
Abstract
Mechanical ventilation induces a number of systemic responses for which the brain plays an essential role. During the last decade, substantial evidence has emerged showing that the brain modifies pulmonary responses to physical and biological stimuli by various mechanisms, including the modulation of neuroinflammatory reflexes and the onset of abnormal breathing patterns. Afferent signals and circulating factors from injured peripheral tissues, including the lung, can induce neuronal reprogramming, potentially contributing to neurocognitive dysfunction and psychological alterations seen in critically ill patients. These impairments are ubiquitous in the presence of positive pressure ventilation. This narrative review summarises current evidence of lung-brain crosstalk in patients receiving mechanical ventilation and describes the clinical implications of this crosstalk. Further, it proposes directions for future research ranging from identifying mechanisms of multiorgan failure to mitigating long-term sequelae after critical illness.
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Affiliation(s)
- Guillermo M Albaiceta
- Unidad de Cuidados Intensivos Cardiológicos, Hospital Universitario Central de Asturias, Oviedo, Spain; Departamento de Biología Funcional, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain; Centro de Investigación Biomédica en Red-Enfermedades Respiratorias (CIBER)-Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.
| | - Laurent Brochard
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
| | - Claudia C Dos Santos
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
| | - Rafael Fernández
- Centro de Investigación Biomédica en Red-Enfermedades Respiratorias (CIBER)-Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain; Critical Care Department, Althaia Xarxa Assistencial Universitaria de Manresa, Universitat Internacional de Catalunya, Manresa, Spain
| | - Dimitris Georgopoulos
- Intensive Care Medicine Department, University Hospital of Heraklion, School of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Timothy Girard
- Clinical Research, Investigation, and Systems Modeling of Acute Illness (CRISMA) Center, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Amal Jubran
- Division of Pulmonary and Critical Care Medicine, Hines VA Hospital, Hines, IL, USA; Loyola University of Chicago, Stritch School of Medicine, Maywood, IL, USA
| | - Josefina López-Aguilar
- Centro de Investigación Biomédica en Red-Enfermedades Respiratorias (CIBER)-Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain; Critical Care Center, Hospital Universitari Parc Taulí, Institut d'Investigació i Innovació Parc Taulí I3PT, Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Jordi Mancebo
- Servei Medicina Intensiva, University Hospital Sant Pau, Barcelona, Spain
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy; Anesthesia and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Genoa, Italy
| | - Yoanna Skrobik
- Department of Medicine, McGill University, Regroupement de Soins Critiques Respiratoires, Réseau de Soins Respiratoires FRQS, Montreal, QC, Canada
| | - Arnaud W Thille
- CHU de Poitiers, Médecine Intensive Réanimation, Poitiers, France; INSERM CIC 1402 ALIVE, Université de Poitiers, Poitiers, France
| | - Mary E Wilcox
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Department of Medicine, Division of Respirology (Critical Care Medicine), University Health Network, Toronto, ON, Canada
| | - Lluis Blanch
- Centro de Investigación Biomédica en Red-Enfermedades Respiratorias (CIBER)-Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain; Critical Care Center, Hospital Universitari Parc Taulí, Institut d'Investigació i Innovació Parc Taulí I3PT, Universitat Autònoma de Barcelona, Sabadell, Spain
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7
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Farmer AD, Strzelczyk A, Finisguerra A, Gourine AV, Gharabaghi A, Hasan A, Burger AM, Jaramillo AM, Mertens A, Majid A, Verkuil B, Badran BW, Ventura-Bort C, Gaul C, Beste C, Warren CM, Quintana DS, Hämmerer D, Freri E, Frangos E, Tobaldini E, Kaniusas E, Rosenow F, Capone F, Panetsos F, Ackland GL, Kaithwas G, O'Leary GH, Genheimer H, Jacobs HIL, Van Diest I, Schoenen J, Redgrave J, Fang J, Deuchars J, Széles JC, Thayer JF, More K, Vonck K, Steenbergen L, Vianna LC, McTeague LM, Ludwig M, Veldhuizen MG, De Couck M, Casazza M, Keute M, Bikson M, Andreatta M, D'Agostini M, Weymar M, Betts M, Prigge M, Kaess M, Roden M, Thai M, Schuster NM, Montano N, Hansen N, Kroemer NB, Rong P, Fischer R, Howland RH, Sclocco R, Sellaro R, Garcia RG, Bauer S, Gancheva S, Stavrakis S, Kampusch S, Deuchars SA, Wehner S, Laborde S, Usichenko T, Polak T, Zaehle T, Borges U, Teckentrup V, Jandackova VK, Napadow V, Koenig J. International Consensus Based Review and Recommendations for Minimum Reporting Standards in Research on Transcutaneous Vagus Nerve Stimulation (Version 2020). Front Hum Neurosci 2021; 14:568051. [PMID: 33854421 PMCID: PMC8040977 DOI: 10.3389/fnhum.2020.568051] [Citation(s) in RCA: 121] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 09/01/2020] [Indexed: 12/18/2022] Open
Abstract
Given its non-invasive nature, there is increasing interest in the use of transcutaneous vagus nerve stimulation (tVNS) across basic, translational and clinical research. Contemporaneously, tVNS can be achieved by stimulating either the auricular branch or the cervical bundle of the vagus nerve, referred to as transcutaneous auricular vagus nerve stimulation(VNS) and transcutaneous cervical VNS, respectively. In order to advance the field in a systematic manner, studies using these technologies need to adequately report sufficient methodological detail to enable comparison of results between studies, replication of studies, as well as enhancing study participant safety. We systematically reviewed the existing tVNS literature to evaluate current reporting practices. Based on this review, and consensus among participating authors, we propose a set of minimal reporting items to guide future tVNS studies. The suggested items address specific technical aspects of the device and stimulation parameters. We also cover general recommendations including inclusion and exclusion criteria for participants, outcome parameters and the detailed reporting of side effects. Furthermore, we review strategies used to identify the optimal stimulation parameters for a given research setting and summarize ongoing developments in animal research with potential implications for the application of tVNS in humans. Finally, we discuss the potential of tVNS in future research as well as the associated challenges across several disciplines in research and clinical practice.
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Affiliation(s)
- Adam D. Farmer
- Department of Gastroenterology, University Hospitals of North Midlands NHS Trust, Stoke on Trent, United Kingdom
| | - Adam Strzelczyk
- Department of Neurology, Epilepsy Center Frankfurt Rhine-Main, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | | | - Alexander V. Gourine
- Department of Neuroscience, Physiology and Pharmacology, Centre for Cardiovascular and Metabolic Neuroscience, University College London, London, United Kingdom
| | - Alireza Gharabaghi
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tuebingen, Tuebingen, Germany
| | - Alkomiet Hasan
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, University of Augsburg, Augsburg, Germany
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany
| | - Andreas M. Burger
- Laboratory for Biological Psychology, Faculty of Psychology and Educational Sciences, University of Leuven, Leuven, Belgium
| | | | - Ann Mertens
- Department of Neurology, Institute for Neuroscience, 4Brain, Ghent University Hospital, Gent, Belgium
| | - Arshad Majid
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Bart Verkuil
- Clinical Psychology and the Leiden Institute of Brain and Cognition, Leiden University, Leiden, Netherlands
| | - Bashar W. Badran
- Department of Psychiatry, Medical University of South Carolina, Charleston, SC, United States
| | - Carlos Ventura-Bort
- Department of Biological Psychology and Affective Science, Faculty of Human Sciences, University of Potsdam, Potsdam, Germany
| | - Charly Gaul
- Migraine and Headache Clinic Koenigstein, Königstein im Taunus, Germany
| | - Christian Beste
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Dresden, Germany
| | | | - Daniel S. Quintana
- NORMENT, Division of Mental Health and Addiction, University of Oslo and Oslo University Hospital, Oslo, Norway
- Department of Psychology, University of Oslo, Oslo, Norway
- KG Jebsen Centre for Neurodevelopmental Disorders, University of Oslo, Oslo, Norway
| | - Dorothea Hämmerer
- Medical Faculty, Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom
- Center for Behavioral Brain Sciences Magdeburg (CBBS), Otto-von-Guericke University, Magdeburg, Germany
| | - Elena Freri
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Eleni Frangos
- Pain and Integrative Neuroscience Branch, National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United States
| | - Eleonora Tobaldini
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Eugenijus Kaniusas
- Institute of Electrodynamics, Microwave and Circuit Engineering, TU Wien, Vienna, Austria
- SzeleSTIM GmbH, Vienna, Austria
| | - Felix Rosenow
- Department of Neurology, Epilepsy Center Frankfurt Rhine-Main, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Fioravante Capone
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Fivos Panetsos
- Faculty of Biology and Faculty of Optics, Complutense University of Madrid and Institute for Health Research, San Carlos Clinical Hospital (IdISSC), Madrid, Spain
| | - Gareth L. Ackland
- Translational Medicine and Therapeutics, Barts and The London School of Medicine and Dentistry, William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Gaurav Kaithwas
- Department of Pharmaceutical Sciences, School of Biosciences and Biotechnology, Babasaheb Bhimrao Ambedkar University (A Central University), Lucknow, India
| | - Georgia H. O'Leary
- Department of Psychiatry, Medical University of South Carolina, Charleston, SC, United States
| | - Hannah Genheimer
- Department of Biological Psychology, Clinical Psychology and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Heidi I. L. Jacobs
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
- Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Alzheimer Centre Limburg, Maastricht University, Maastricht, Netherlands
| | - Ilse Van Diest
- Research Group Health Psychology, Faculty of Psychology and Educational Sciences, University of Leuven, Leuven, Belgium
| | - Jean Schoenen
- Headache Research Unit, Department of Neurology-Citadelle Hospital, University of Liège, Liège, Belgium
| | - Jessica Redgrave
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Jiliang Fang
- Functional Imaging Lab, Department of Radiology, Guang An Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jim Deuchars
- School of Biomedical Science, Faculty of Biological Science, University of Leeds, Leeds, United Kingdom
| | - Jozsef C. Széles
- Division for Vascular Surgery, Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - Julian F. Thayer
- Department of Psychological Science, University of California, Irvine, Irvine, CA, United States
| | - Kaushik More
- Institute for Cognitive Neurology and Dementia Research, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
- Neuromodulatory Networks, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Kristl Vonck
- Department of Neurology, Institute for Neuroscience, 4Brain, Ghent University Hospital, Gent, Belgium
| | - Laura Steenbergen
- Clinical and Cognitive Psychology and the Leiden Institute of Brain and Cognition, Leiden University, Leiden, Netherlands
| | - Lauro C. Vianna
- NeuroV̇ASQ̇ - Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasilia, Brasilia, Brazil
| | - Lisa M. McTeague
- Department of Psychiatry, Medical University of South Carolina, Charleston, SC, United States
| | - Mareike Ludwig
- Department of Anatomy, Faculty of Medicine, Mersin University, Mersin, Turkey
| | - Maria G. Veldhuizen
- Mental Health and Wellbeing Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Marijke De Couck
- Faculty of Health Care, University College Odisee, Aalst, Belgium
- Division of Epileptology, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Marina Casazza
- Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Marius Keute
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tuebingen, Tuebingen, Germany
| | - Marom Bikson
- Department of Biomedical Engineering, City College of New York, New York, NY, United States
| | - Marta Andreatta
- Department of Biological Psychology, Clinical Psychology and Psychotherapy, University of Würzburg, Würzburg, Germany
- Department of Psychology, Education and Child Studies, Erasmus University Rotterdam, Rotterdam, Netherlands
| | - Martina D'Agostini
- Research Group Health Psychology, Faculty of Psychology and Educational Sciences, University of Leuven, Leuven, Belgium
| | - Mathias Weymar
- Department of Biological Psychology and Affective Science, Faculty of Human Sciences, University of Potsdam, Potsdam, Germany
- Faculty of Health Sciences Brandenburg, University of Potsdam, Potsdam, Germany
| | - Matthew Betts
- Department of Anatomy, Faculty of Medicine, Mersin University, Mersin, Turkey
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany
- Center for Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, Germany
| | - Matthias Prigge
- Neuromodulatory Networks, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Michael Kaess
- University Hospital of Child and Adolescent Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
- Section for Translational Psychobiology in Child and Adolescent Psychiatry, Department of Child and Adolescent Psychiatry, Centre for Psychosocial Medicine, University of Heidelberg, Heidelberg, Germany
| | - Michael Roden
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany
- German Center for Diabetes Research, Munich, Germany
| | - Michelle Thai
- Department of Psychology, College of Liberal Arts, University of Minnesota, Minneapolis, MN, United States
| | - Nathaniel M. Schuster
- Department of Anesthesiology, Center for Pain Medicine, University of California, San Diego Health System, La Jolla, CA, United States
| | - Nicola Montano
- Department of Internal Medicine, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Niels Hansen
- Department of Psychiatry and Psychotherapy, University of Göttingen, Göttingen, Germany
- Laboratory of Systems Neuroscience and Imaging in Psychiatry (SNIPLab), University of Göttingen, Göttingen, Germany
| | - Nils B. Kroemer
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Peijing Rong
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Rico Fischer
- Department of Psychology, University of Greifswald, Greifswald, Germany
| | - Robert H. Howland
- Department of Psychiatry, University of Pittsburgh School of Medicine, UPMC Western Psychiatric Hospital, Pittsburgh, PA, United States
| | - Roberta Sclocco
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States
- Department of Radiology, Logan University, Chesterfield, MO, United States
| | - Roberta Sellaro
- Cognitive Psychology Unit, Institute of Psychology, Leiden University, Leiden, Netherlands
- Leiden Institute for Brain and Cognition, Leiden, Netherlands
- Department of Developmental Psychology and Socialisation, University of Padova, Padova, Italy
| | - Ronald G. Garcia
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Sebastian Bauer
- Department of Neurology, Epilepsy Center Frankfurt Rhine-Main, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Sofiya Gancheva
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany
- Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Stavros Stavrakis
- Faculty of Biological Science, School of Biomedical Science, University of Leeds, Leeds, United Kingdom
| | - Stefan Kampusch
- Institute of Electrodynamics, Microwave and Circuit Engineering, TU Wien, Vienna, Austria
- SzeleSTIM GmbH, Vienna, Austria
| | - Susan A. Deuchars
- School of Biomedical Science, Faculty of Biological Science, University of Leeds, Leeds, United Kingdom
| | - Sven Wehner
- Department of Surgery, University Hospital Bonn, Bonn, Germany
| | - Sylvain Laborde
- Department of Performance Psychology, Institute of Psychology, Deutsche Sporthochschule, Köln, Germany
| | - Taras Usichenko
- Department of Anesthesiology, University Medicine Greifswald, Greifswald, Germany
- Department of Anesthesia, McMaster University, Hamilton, ON, Canada
| | - Thomas Polak
- Laboratory of Functional Neurovascular Diagnostics, AG Early Diagnosis of Dementia, Department of Psychiatry, Psychosomatics and Psychotherapy, University Clinic Würzburg, Würzburg, Germany
| | - Tino Zaehle
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany
| | - Uirassu Borges
- Department of Performance Psychology, Institute of Psychology, Deutsche Sporthochschule, Köln, Germany
- Department of Social and Health Psychology, Institute of Psychology, Deutsche Sporthochschule, Köln, Germany
| | - Vanessa Teckentrup
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Vera K. Jandackova
- Department of Epidemiology and Public Health, Faculty of Medicine, University of Ostrava, Ostrava, Czechia
- Department of Human Movement Studies, Faculty of Education, University of Ostrava, Ostrava, Czechia
| | - Vitaly Napadow
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States
- Department of Radiology, Logan University, Chesterfield, MO, United States
| | - Julian Koenig
- University Hospital of Child and Adolescent Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
- Section for Experimental Child and Adolescent Psychiatry, Department of Child and Adolescent Psychiatry, Centre for Psychosocial Medicine, University of Heidelberg, Heidelberg, Germany
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8
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Kamuf J, Garcia Bardon A, Ziebart A, Frauenknecht K, Folkert K, Schwab J, Ruemmler R, Renz M, Cana D, Thal SC, Hartmann EK. Experimental lung injury induces cerebral cytokine mRNA production in pigs. PeerJ 2020; 8:e10471. [PMID: 33354426 PMCID: PMC7733330 DOI: 10.7717/peerj.10471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 11/11/2020] [Indexed: 12/02/2022] Open
Abstract
Background Acute respiratory distress syndrome (ARDS) is an important disease with a high incidence among patients admitted to intensive care units. Over the last decades, the survival of critically ill patients has improved; however, cognitive deficits are among the long-term sequelae. We hypothesize that acute lung injury leads to upregulation of cerebral cytokine synthesis. Methods After approval of the institutional and animal care committee, 20 male pigs were randomized to one of three groups: (1) Lung injury by oleic acid injection (OAI), (2) ventilation only (CTR) or (3) untreated. We compared neuronal numbers, proportion of neurons with markers for apoptosis, activation state of Iba-1 stained microglia cells and cerebral mRNA levels of different cytokines between the groups 18 hours after onset of lung injury. Results We found an increase in hippocampal TNFalpha (p < 0.05) and IL-6 (p < 0.05) messenger RNA (mRNA) in the OAI compared to untreated group as well as higher hippocampal IL-6 mRNA compared to control (p < 0.05). IL-8 and IL-1beta mRNA showed no differences between the groups. We found histologic markers for beginning apoptosis in OAI compared to untreated (p < 0.05) and more active microglia cells in OAI and CTR compared to untreated (p < 0.001 each). Conclusion Hippocampal cytokine transcription increases within 18 hours after the induction of acute lung injury with histological evidence of neuronal damage. It remains to be elucidated if increased cytokine mRNA synthesis plays a role in the cognitive decline observed in survivors of ARDS.
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Affiliation(s)
- Jens Kamuf
- Department of Anesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Andreas Garcia Bardon
- Department of Anesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Alexander Ziebart
- Department of Anesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Katrin Frauenknecht
- Institute of Neuropathology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Konstantin Folkert
- Department of Anesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Johannes Schwab
- Department of Anesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Robert Ruemmler
- Department of Anesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Miriam Renz
- Department of Anesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Denis Cana
- Institute of Neuropathology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Serge C Thal
- Department of Anesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
| | - Erik K Hartmann
- Department of Anesthesiology, Medical Centre of the Johannes Gutenberg-University, Mainz, Germany
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9
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Booth LC, Yao ST, Korsak A, Farmer DGS, Hood SG, McCormick D, Boesley Q, Connelly AA, McDougall SJ, Korim WS, Guild SJ, Mastitskaya S, Le P, Teschemacher AG, Kasparov S, Ackland GL, Malpas SC, McAllen RM, Allen AM, May CN, Gourine AV. Selective optogenetic stimulation of efferent fibers in the vagus nerve of a large mammal. Brain Stimul 2020; 14:88-96. [PMID: 33217609 PMCID: PMC7836098 DOI: 10.1016/j.brs.2020.11.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/26/2020] [Accepted: 11/11/2020] [Indexed: 12/26/2022] Open
Abstract
Background Electrical stimulation applied to individual organs, peripheral nerves, or specific brain regions has been used to treat a range of medical conditions. In cardiovascular disease, autonomic dysfunction contributes to the disease progression and electrical stimulation of the vagus nerve has been pursued as a treatment for the purpose of restoring the autonomic balance. However, this approach lacks selectivity in activating function- and organ-specific vagal fibers and, despite promising results of many preclinical studies, has so far failed to translate into a clinical treatment of cardiovascular disease. Objective Here we report a successful application of optogenetics for selective stimulation of vagal efferent activity in a large animal model (sheep). Methods and results Twelve weeks after viral transduction of a subset of vagal motoneurons, strong axonal membrane expression of the excitatory light-sensitive ion channel ChIEF was achieved in the efferent projections innervating thoracic organs and reaching beyond the level of the diaphragm. Blue laser or LED light (>10 mW mm−2; 1 ms pulses) applied to the cervical vagus triggered precisely timed, strong bursts of efferent activity with evoked action potentials propagating at speeds of ∼6 m s−1. Conclusions These findings demonstrate that in species with a large, multi-fascicled vagus nerve, it is possible to stimulate a specific sub-population of efferent fibers using light at a site remote from the vector delivery, marking an important step towards eventual clinical use of optogenetic technology for autonomic neuromodulation. Described is a method of selective efferent vagus nerve stimulation using light. Vagal preganglionic neurons are targeted to express light-sensitive channels. Specific efferent VNS by light delivery to the cervical vagus is achieved in a large animal model. Demonstrates feasibility of using optogenetic technology for autonomic neuromodulation.
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Affiliation(s)
- Lindsea C Booth
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Song T Yao
- Florey Department of Neuroscience and Mental Health, MDHS, University of Melbourne, Melbourne, Australia
| | - Alla Korsak
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - David G S Farmer
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia; Department of Physiology, The University of Melbourne, Melbourne, Australia
| | - Sally G Hood
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Daniel McCormick
- Department of Physiology and Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Quinn Boesley
- Department of Physiology and Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Angela A Connelly
- Department of Physiology, The University of Melbourne, Melbourne, Australia
| | - Stuart J McDougall
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Willian S Korim
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Sarah-Jane Guild
- Department of Physiology and Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Svetlana Mastitskaya
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Phuong Le
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Anja G Teschemacher
- Physiology, Neuroscience and Pharmacology, University of Bristol, Bristol, UK
| | - Sergey Kasparov
- Physiology, Neuroscience and Pharmacology, University of Bristol, Bristol, UK; Baltic Federal University, Kaliningrad, Russian Federation
| | - Gareth L Ackland
- Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Simon C Malpas
- Department of Physiology and Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Robin M McAllen
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Andrew M Allen
- Department of Physiology, The University of Melbourne, Melbourne, Australia
| | - Clive N May
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia.
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK.
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10
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Theparambil SM, Hosford PS, Ruminot I, Kopach O, Reynolds JR, Sandoval PY, Rusakov DA, Barros LF, Gourine AV. Astrocytes regulate brain extracellular pH via a neuronal activity-dependent bicarbonate shuttle. Nat Commun 2020; 11:5073. [PMID: 33033238 PMCID: PMC7545092 DOI: 10.1038/s41467-020-18756-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 09/09/2020] [Indexed: 12/19/2022] Open
Abstract
Brain cells continuously produce and release protons into the extracellular space, with the rate of acid production corresponding to the levels of neuronal activity and metabolism. Efficient buffering and removal of excess H+ is essential for brain function, not least because all the electrogenic and biochemical machinery of synaptic transmission is highly sensitive to changes in pH. Here, we describe an astroglial mechanism that contributes to the protection of the brain milieu from acidification. In vivo and in vitro experiments conducted in rodent models show that at least one third of all astrocytes release bicarbonate to buffer extracellular H+ loads associated with increases in neuronal activity. The underlying signalling mechanism involves activity-dependent release of ATP triggering bicarbonate secretion by astrocytes via activation of metabotropic P2Y1 receptors, recruitment of phospholipase C, release of Ca2+ from the internal stores, and facilitated outward HCO3- transport by the electrogenic sodium bicarbonate cotransporter 1, NBCe1. These results show that astrocytes maintain local brain extracellular pH homeostasis via a neuronal activity-dependent release of bicarbonate. The data provide evidence of another important metabolic housekeeping function of these glial cells.
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Affiliation(s)
- Shefeeq M Theparambil
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Patrick S Hosford
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Iván Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - Olga Kopach
- Institute of Neurology, University College London, London, UK
| | | | | | | | | | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK.
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11
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Machhada A, Hosford PS, Dyson A, Ackland GL, Mastitskaya S, Gourine AV. Optogenetic Stimulation of Vagal Efferent Activity Preserves Left Ventricular Function in Experimental Heart Failure. JACC Basic Transl Sci 2020; 5:799-810. [PMID: 32875170 PMCID: PMC7452237 DOI: 10.1016/j.jacbts.2020.06.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 06/05/2020] [Accepted: 06/06/2020] [Indexed: 12/21/2022]
Abstract
This study was designed to determine the effect of selective optogenetic simulation of vagal efferent activity on left ventricular function in an animal (rat) model of MI-induced heart failure. Optogenetic stimulation of dorsal brainstem vagal pre-ganglionic neurons transduced to express light-sensitive channels preserved LV function and exercise capacity in animals with MI. The data suggest that activation of vagal efferents is critically important to deliver the therapeutic benefit of VNS in chronic heart failure.
Large clinical trials designed to test the efficacy of vagus nerve stimulation (VNS) in patients with heart failure did not demonstrate benefits with respect to the primary endpoints. The nonselective nature of VNS may account for the failure to translate promising results of preclinical and earlier clinical studies. This study showed that optogenetic stimulation of vagal pre-ganglionic neurons transduced to express light-sensitive channels preserved left ventricular function and exercise capacity in a rat model of myocardial infarction−induced heart failure. These data suggested that stimulation of vagal efferent activity is critically important to deliver the therapeutic benefit of VNS in heart failure.
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Key Words
- ABP, arterial blood pressure
- DVMN, dorsal motor nucleus of the vagus nerve
- GRK2, G-protein−coupled receptor kinase 2
- LAD, left anterior descending coronary artery
- LV dP/dtMAX, maximum rate of rise of left ventricular pressure
- LV, left ventricle
- LVEDP, left ventricular end-diastolic pressure
- LVESP, left ventricular end-systolic pressure
- LVP, left ventricular pressure
- LVV, lentiviral vector
- MI, myocardial infarction
- VNS, vagus nerve stimulation
- autonomic nervous system
- eGFP, enhanced green fluorescent protein
- heart failure
- myocardial infarction
- neuromodulation
- vagus nerve stimulation
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Affiliation(s)
- Asif Machhada
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Patrick S Hosford
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.,Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Alex Dyson
- Clinical Physiology, Division of Medicine, University College London, London, United Kingdom
| | - Gareth L Ackland
- Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Svetlana Mastitskaya
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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12
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Hadjihambi A, Karagiannis A, Theparambil SM, Ackland GL, Gourine AV. The effect of general anaesthetics on brain lactate release. Eur J Pharmacol 2020; 881:173188. [PMID: 32439258 PMCID: PMC7456770 DOI: 10.1016/j.ejphar.2020.173188] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 05/04/2020] [Accepted: 05/10/2020] [Indexed: 12/17/2022]
Abstract
The effects of anaesthetic agents on brain energy metabolism may explain their shared neurophysiological actions but remain poorly understood. The brain lactate shuttle hypothesis proposes that lactate, provided by astrocytes, is an important neuronal energy substrate. Here we tested the hypothesis that anaesthetic agents impair the brain lactate shuttle by interfering with astrocytic glycolysis. Lactate biosensors were used to record changes in lactate release by adult rat brainstem and cortical slices in response to thiopental, propofol and etomidate. Changes in cytosolic nicotinamide adenine dinucleotide reduced (NADH) and oxidized (NAD+) ratio as a measure of glycolytic rate were recorded in cultured astrocytes. It was found that in brainstem slices thiopental, propofol and etomidate reduced lactate release by 7.4 ± 3.6% (P < 0.001), 9.7 ± 6.6% (P < 0.001) and 8.0 ± 7.8% (P = 0.04), respectively. In cortical slices, thiopental reduced lactate release by 8.2 ± 5.6% (P = 0.002) and propofol by 6.0 ± 4.5% (P = 0.009). Lactate release in cortical slices measured during the light phase (period of sleep/low activity) was ~25% lower than that measured during the dark phase (period of wakefulness) (326 ± 83 μM vs 430 ± 118 μM, n = 10; P = 0.04). Thiopental and etomidate induced proportionally similar decreases in cytosolic [NADH]:[NAD+] ratio in astrocytes, indicative of a reduction in glycolytic rate. These data suggest that anaesthetic agents inhibit astrocytic glycolysis and reduce the level of extracellular lactate in the brain. Similar reductions in brain lactate release occur during natural state of sleep, suggesting that general anaesthesia may recapitulate some of the effects of sleep on brain energy metabolism.
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Affiliation(s)
- Anna Hadjihambi
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK; Department of Biomedical Sciences, University of Lausanne, Lausanne, 1005, Switzerland.
| | - Anastassios Karagiannis
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
| | - Shefeeq M Theparambil
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
| | - Gareth L Ackland
- Translational Medicine & Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
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13
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Mastitskaya S, Turovsky E, Marina N, Theparambil SM, Hadjihambi A, Kasparov S, Teschemacher AG, Ramage AG, Gourine AV, Hosford PS. Astrocytes Modulate Baroreflex Sensitivity at the Level of the Nucleus of the Solitary Tract. J Neurosci 2020; 40:3052-3062. [PMID: 32132265 PMCID: PMC7141885 DOI: 10.1523/jneurosci.1438-19.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 12/16/2019] [Accepted: 01/12/2020] [Indexed: 11/21/2022] Open
Abstract
Maintenance of cardiorespiratory homeostasis depends on autonomic reflexes controlled by neuronal circuits of the brainstem. The neurophysiology and neuroanatomy of these reflex pathways are well understood, however, the mechanisms and functional significance of autonomic circuit modulation by glial cells remain largely unknown. In the experiments conducted in male laboratory rats we show that astrocytes of the nucleus of the solitary tract (NTS), the brain area that receives and integrates sensory information from the heart and blood vessels, respond to incoming afferent inputs with [Ca2+]i elevations. Astroglial [Ca2+]i responses are triggered by transmitters released by vagal afferents, glutamate acting at AMPA receptors and 5-HT acting at 5-HT2A receptors. In conscious freely behaving animals blockade of Ca2+-dependent vesicular release mechanisms in NTS astrocytes by virally driven expression of a dominant-negative SNARE protein (dnSNARE) increased baroreflex sensitivity by 70% (p < 0.001). This effect of compromised astroglial function was specific to the NTS as expression of dnSNARE in astrocytes of the ventrolateral brainstem had no effect. ATP is considered the principle gliotransmitter and is released by vesicular mechanisms blocked by dnSNARE expression. Consistent with this hypothesis, in anesthetized rats, pharmacological activation of P2Y1 purinoceptors in the NTS decreased baroreflex gain by 40% (p = 0.031), whereas blockade of P2Y1 receptors increased baroreflex gain by 57% (p = 0.018). These results suggest that glutamate and 5-HT, released by NTS afferent terminals, trigger Ca2+-dependent astroglial release of ATP to modulate baroreflex sensitivity via P2Y1 receptors. These data add to the growing body of evidence supporting an active role of astrocytes in brain information processing.SIGNIFICANCE STATEMENT Cardiorespiratory reflexes maintain autonomic balance and ensure cardiovascular health. Impaired baroreflex may contribute to the development of cardiovascular disease and serves as a robust predictor of cardiovascular and all-cause mortality. The data obtained in this study suggest that astrocytes are integral components of the brainstem mechanisms that process afferent information and modulate baroreflex sensitivity via the release of ATP. Any condition associated with higher levels of "ambient" ATP in the NTS would be expected to decrease baroreflex gain by the mechanism described here. As ATP is the primary signaling molecule of glial cells (astrocytes, microglia), responding to metabolic stress and inflammatory stimuli, our study suggests a plausible mechanism of how the central component of the baroreflex is affected in pathological conditions.
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Affiliation(s)
- Svetlana Mastitskaya
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Egor Turovsky
- Institute of Cell Biophysics, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Pushchino 142290, Russian Federation
| | - Nephtali Marina
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Shefeeq M Theparambil
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Anna Hadjihambi
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Sergey Kasparov
- Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol BS8 1TD, United Kingdom
- Baltic Federal University, Kaliningrad 236041, Russian Federation, and
| | - Anja G Teschemacher
- Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Andrew G Ramage
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom,
| | - Patrick S Hosford
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom,
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, United Kingdom
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14
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Mazzone GL, Nistri A. Modulation of extrasynaptic GABAergic receptor activity influences glutamate release and neuronal survival following excitotoxic damage to mouse spinal cord neurons. Neurochem Int 2019; 128:175-185. [PMID: 31051211 DOI: 10.1016/j.neuint.2019.04.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/08/2019] [Accepted: 04/30/2019] [Indexed: 12/14/2022]
Abstract
Excitotoxic levels of released glutamate trigger a cascade of deleterious cellular events leading to delayed neuronal death. This phenomenon implies extensive dysregulation in the balance between network excitation and inhibition. Our hypothesis was that enhancing network inhibition should prevent excitotoxicity and provide neuroprotection. To test this notion, we used mouse organotypic spinal slice cultures and explored if excitotoxicity caused by the potent glutamate analogue kainate was blocked by pharmacological increase in GABAA receptor activity. To this end we monitored (with a biosensor) real-time glutamate release following 1 h kainate application and quantified neuronal survival 24 h later. Glutamate release evoked by kainate was strongly decreased by the allosteric GABAA modulator midazolam (10 nM) or the GABA agonist THIP (10 μM), leading to neuroprotection. On the contrary, much higher glutamate release was induced by the GABA antagonist bicuculline (20 μM) that inhibits synaptic and extrasynaptic GABAA receptors. Gabazine (20 μM), an antagonist of synaptic GABAA receptors, had no effect on glutamate release or neuroprotection. No effect was observed with the glycine antagonist strychnine or the glycine agonist L-alanine. These findings indicate that enhancement of GABA receptor activity was an effective tool to counteract excitotoxic death in spinal networks. In view of the potent activity by THIP, preferentially acting on extrasynaptic GABAA receptors, the present data imply a significant role for extrasynaptic GABAA receptors in sparing spinal cord neurons from injury.
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Affiliation(s)
- Graciela L Mazzone
- Instituto de Investigaciones en Medicina Traslacional (IIMT), CONICET-Universidad Austral, Derqui-Pilar, Buenos Aires, Argentina.
| | - Andrea Nistri
- Neuroscience Dept., International School for Advanced Studies (SISSA), Trieste, Italy
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15
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Yamamoto K, Mifflin S. Inhibition of glial glutamate transporter GLT1 in the nucleus of the solitary tract attenuates baroreflex control of sympathetic nerve activity and heart rate. Physiol Rep 2018; 6:e13877. [PMID: 30230240 PMCID: PMC6144441 DOI: 10.14814/phy2.13877] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/22/2018] [Accepted: 08/31/2018] [Indexed: 02/02/2023] Open
Abstract
The astrocytic glutamate transporter (GLT1) plays an important role in the maintenance of extracellular glutamate concentration below neurotoxic levels in brain. However, the functional role of GLT1 within the nucleus of the solitary tract (NTS) in the regulation of cardiovascular function remains unclear. We examined the effect of inhibiting GLT1 in the subpostremal NTS on mean arterial pressure (MAP), renal sympathetic nerve activity (RSNA) and heart rate (HR) in anesthetized, artificially ventilated rats. It was found that dihydrokainate (DHK; inhibitor of GLT1, 5 mmol/L, 100 nL) injections into the NTS (n = 6) decreased MAP (50 ± 10 mmHg, mean ± SD), RSNA (89 ± 14%) and HR (37 ± 6 bpm). Pretreatment with kynurenate (KYN; glutamate receptor antagonist, 5 mmol/L, 30 μL) topically applied to the dorsal surface of the brainstem (n = 4) attenuated the responses to NTS injections of DHK (P < 0.01). The effect of DHK on arterial baroreflex function was examined using i.v. infusions of phenylephrine and nitroprusside. DHK reduced baroreflex response range (maximum-minimum) of RSNA by 91 ± 2% and HR by 83 ± 5% (n = 6, P < 0.001). These results indicate that inhibition of GLT1 within the NTS decreases MAP, RSNA, and HR by the activation of ionotropic glutamate receptors. As a result, baroreflex control of RSNA and HR was dramatically attenuated. The astrocytic glutamate transporter in the NTS plays an important role in the maintenance and regulation of cardiovascular function.
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Affiliation(s)
- Kenta Yamamoto
- Department of Physiology and AnatomyUniversity of North Texas Health Science CentreFort WorthTexas
- Faculty of Pharmaceutical SciencesTeikyo Heisei UniversityTokyoJapan
| | - Steve Mifflin
- Department of Physiology and AnatomyUniversity of North Texas Health Science CentreFort WorthTexas
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Marina N, Turovsky E, Christie IN, Hosford PS, Hadjihambi A, Korsak A, Ang R, Mastitskaya S, Sheikhbahaei S, Theparambil SM, Gourine AV. Brain metabolic sensing and metabolic signaling at the level of an astrocyte. Glia 2018; 66:1185-1199. [PMID: 29274121 PMCID: PMC5947829 DOI: 10.1002/glia.23283] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 10/04/2017] [Accepted: 11/29/2017] [Indexed: 12/18/2022]
Abstract
Astrocytes support neuronal function by providing essential structural and nutritional support, neurotransmitter trafficking and recycling and may also contribute to brain information processing. In this article we review published results and report new data suggesting that astrocytes function as versatile metabolic sensors of central nervous system (CNS) milieu and play an important role in the maintenance of brain metabolic homeostasis. We discuss anatomical and functional features of astrocytes that allow them to detect and respond to changes in the brain parenchymal levels of metabolic substrates (oxygen and glucose), and metabolic waste products (carbon dioxide). We report data suggesting that astrocytes are also sensitive to circulating endocrine signals-hormones like ghrelin, glucagon-like peptide-1 and leptin, that have a major impact on the CNS mechanisms controlling food intake and energy balance. We discuss signaling mechanisms that mediate communication between astrocytes and neurons and consider how these mechanisms are recruited by astrocytes activated in response to various metabolic challenges. We review experimental data suggesting that astrocytes modulate the activities of the respiratory and autonomic neuronal networks that ensure adaptive changes in breathing and sympathetic drive in order to support the physiological and behavioral demands of the organism in ever-changing environmental conditions. Finally, we discuss evidence suggesting that altered astroglial function may contribute to the pathogenesis of disparate neurological, respiratory and cardiovascular disorders such as Rett syndrome and systemic arterial hypertension.
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Affiliation(s)
- Nephtali Marina
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
- Research Department of Metabolism and Experimental Therapeutics, Division of MedicineUniversity College LondonLondonWC1E 6JJUnited Kingdom
| | - Egor Turovsky
- Laboratory of Intracellular SignallingInstitute of Cell Biophysics, Russian Academy of SciencesPushchinoRussia
| | - Isabel N Christie
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
| | - Patrick S Hosford
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
| | - Anna Hadjihambi
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
| | - Alla Korsak
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
| | - Richard Ang
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
| | - Svetlana Mastitskaya
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
| | - Shahriar Sheikhbahaei
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
| | - Shefeeq M Theparambil
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonWC1E 6BTUnited Kingdom
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Ferreira CB, Cravo SL, Stocker SD. Airway obstruction produces widespread sympathoexcitation: role of hypoxia, carotid chemoreceptors, and NTS neurotransmission. Physiol Rep 2018; 6:e13536. [PMID: 29388357 PMCID: PMC5817833 DOI: 10.14814/phy2.13536] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/05/2017] [Accepted: 11/11/2017] [Indexed: 02/07/2023] Open
Abstract
Obstructive sleep apnea (OSA) is the most common respiratory disturbance of sleep and is closely associated to cardiovascular diseases. In humans, apnea increases respiratory effort and elevates muscle sympathetic nerve activity (SNA), but the primary stimulus for the SNA activation has not been identified. We recently developed a model of apnea in rodents using acute airway obstruction. In this study, we employed this model to test whether the elevation in SNA was mediated by hypoxia, carotid chemoreceptors, or neurotransmission in the nucleus tractus solitarius (NTS). In anesthetized, male Sprague-Dawley rats, airway obstruction (20s) increased phrenic nerve activity (PNA), arterial blood pressure (ABP), and lumbar, renal, and splanchnic SNA. The changes in SNA were similar across all three sympathetic nerves. Inactivation of chemoreceptors by hyperoxia (100% O2 ) or surgical denervation of carotid chemoreceptors attenuated, but did not eliminate, the changes in SNA and ABP produced by airway obstruction. To interrupt afferent information from carotid chemoreceptor and extracarotid afferents to the hindbrain, airway obstruction was performed before and after NTS microinjection of the GABAA agonist muscimol or a cocktail of NMDA and non-NMDA antagonists. Inhibition of NTS neurons or blockade of glutamatergic receptors attenuated the increase in lumbar SNA, splanchnic SNA, renal SNA, and PNA. Collectively, these findings suggest that PNA and SNA responses induced by airway obstruction depend, in part, on chemoreceptors afferents and glutamatergic neurotransmission in the NTS.
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Affiliation(s)
| | - Sergio L. Cravo
- Department of PhysiologyFederal University of São PauloSão PauloSão PauloBrazil
| | - Sean D. Stocker
- Department of MedicineDivision of Renal‐ElectrolyteUniversity of Pittsburgh School of MedicinePittsburghPennsylvania
- University of Pittsburgh Hypertension CenterUniversity of Pittsburgh School of MedicinePittsburghPennsylvania
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18
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Rocha JN. Extracellular adenosine 5'-triphosphate concentrations changes in rat spinal cord associated with the activation of urinary bladder afferents. A microdialysis study. EINSTEIN-SAO PAULO 2017; 14:541-546. [PMID: 28076603 PMCID: PMC5221382 DOI: 10.1590/s1679-45082016ao3794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/25/2016] [Indexed: 11/22/2022] Open
Abstract
Objective To determine adenosine 5’-triphosphate levels in the interstice of spinal cord L6-S1 segment, under basal conditions or during mechanical and chemical activation of urinary bladder afferents. Methods A microdialysis probe was transversally implanted in the dorsal half of spinal cord L6-S1 segment in female rats. Microdialysate was collected at 15 minutes intervals during 135 minutes, in anesthetized animals. Adenosine 5’-triphosphate concentrations were determined with a bioluminescent assay. In one group of animals (n=7) microdialysate samples were obtained with an empty bladder during a 10-minutes bladder distension to 20 or 40cmH2O with either saline, saline with acetic acid or saline with capsaicin. In another group of animals (n=6) bladder distention was performed and the microdialysis solution contained the ectonucleotidase inhibitor ARL 67156. Results Basal extracellular adenosine triphosphate levels were 110.9±35.34fmol/15 minutes, (mean±SEM, n=13), and bladder distention was associated with a significant increase in adenosine 5’-triphosphate levels which was not observed after bladder distention with saline solution containing capsaicin (10µM). Microdialysis with solution containing ARL 67156 (1mM) was associated with significantly higher extracellular adenosine 5’-triphosphate levels and no further increase in adenosine 5’-triphosphate was observed during bladder distension. Conclusion Adenosine 5’-triphosphate was present in the interstice of L6-S1 spinal cord segments, was degraded by ectonucleotidase, and its concentration increased following the activation of bladder mechanosensitive but not of the chemosensitive afferents fibers. Adenosine 5’-triphosphate may originate either from the central endings of bladder mechanosensitive primary afferent neurons, or most likely from intrinsic spinal neurons, or glial cells and its release appears to be modulated by capsaicin activated bladder primary afferent or by adenosine 5’-triphosphate itself.
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Affiliation(s)
- Jeová Nina Rocha
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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19
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Cutsforth-Gregory JK, Benarroch EE. Nucleus of the solitary tract, medullary reflexes, and clinical implications. Neurology 2017; 88:1187-1196. [PMID: 28202704 DOI: 10.1212/wnl.0000000000003751] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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20
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Newton AJH, Wall MJ, Richardson MJE. Modeling microelectrode biosensors: free-flow calibration can substantially underestimate tissue concentrations. J Neurophysiol 2016; 117:937-949. [PMID: 27927788 PMCID: PMC5338626 DOI: 10.1152/jn.00788.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/05/2016] [Indexed: 12/11/2022] Open
Abstract
Microelectrode biosensors are typically calibrated in a free-flow environment where the concentrations at the biosensor surface are constant. However, when in tissue, the analyte reaches the biosensor via diffusion and so analyte breakdown by the biosensor results in a concentration gradient and consequently a lower concentration around the biosensor. This effect means that naive free-flow calibration will underestimate tissue concentration. We develop mathematical models to better quantify the discrepancy between the calibration and tissue environment and experimentally verify our key predictions. Microelectrode amperometric biosensors are widely used to measure concentrations of analytes in solution and tissue including acetylcholine, adenosine, glucose, and glutamate. A great deal of experimental and modeling effort has been directed at quantifying the response of the biosensors themselves; however, the influence that the macroscopic tissue environment has on biosensor response has not been subjected to the same level of scrutiny. Here we identify an important issue in the way microelectrode biosensors are calibrated that is likely to have led to underestimations of analyte tissue concentrations. Concentration in tissue is typically determined by comparing the biosensor signal to that measured in free-flow calibration conditions. In a free-flow environment the concentration of the analyte at the outer surface of the biosensor can be considered constant. However, in tissue the analyte reaches the biosensor surface by diffusion through the extracellular space. Because the enzymes in the biosensor break down the analyte, a density gradient is set up resulting in a significantly lower concentration of analyte near the biosensor surface. This effect is compounded by the diminished volume fraction (porosity) and reduction in the diffusion coefficient due to obstructions (tortuosity) in tissue. We demonstrate this effect through modeling and experimentally verify our predictions in diffusive environments. NEW & NOTEWORTHY Microelectrode biosensors are typically calibrated in a free-flow environment where the concentrations at the biosensor surface are constant. However, when in tissue, the analyte reaches the biosensor via diffusion and so analyte breakdown by the biosensor results in a concentration gradient and consequently a lower concentration around the biosensor. This effect means that naive free-flow calibration will underestimate tissue concentration. We develop mathematical models to better quantify the discrepancy between the calibration and tissue environment and experimentally verify our key predictions.
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Affiliation(s)
- Adam J H Newton
- Warwick Mathematics Institute, University of Warwick, Coventry, United Kingdom; and
| | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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21
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Karagiannis A, Sylantyev S, Hadjihambi A, Hosford PS, Kasparov S, Gourine AV. Hemichannel-mediated release of lactate. J Cereb Blood Flow Metab 2016; 36:1202-11. [PMID: 26661210 PMCID: PMC4900446 DOI: 10.1177/0271678x15611912] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 09/21/2015] [Indexed: 11/16/2022]
Abstract
In the central nervous system lactate contributes to the extracellular pool of readily available energy substrates and may also function as a signaling molecule which mediates communication between glial cells and neurons. Monocarboxylate transporters are believed to provide the main pathway for lactate transport across the membranes. Here we tested the hypothesis that lactate could also be released via opening of pannexin and/or functional connexin hemichannels. In acute slices prepared from the brainstem, hippocampus, hypothalamus and cortex of adult rats, enzymatic amperometric biosensors detected significant tonic lactate release inhibited by compounds, which block pannexin/connexin hemichannels and facilitated by lowering extracellular [Ca(2+)] or increased PCO2 Enhanced lactate release triggered by hypoxia was reduced by ∼50% by either connexin or monocarboxylate transporter blockers. Stimulation of Schaffer collateral fibers triggered lactate release in CA1 area of the hippocampus, which was facilitated in conditions of low extracellular [Ca(2+)], markedly reduced by blockade of connexin hemichannels and abolished by lactate dehydrogenase inhibitor oxamate. These results indicate that lactate transport across the membranes may occur via mechanisms other than monocarboxylate transporters. In the central nervous system, hemichannels may function as a conduit of lactate release, and this mechanism is recruited during hypoxia and periods of enhanced neuronal activity.
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Affiliation(s)
- Anastassios Karagiannis
- Department of Neuroscience, Physiology and Pharmacology, Centre for Cardiovascular and Metabolic Neuroscience, University College London (UCL), London, UK
| | - Sergiy Sylantyev
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Anna Hadjihambi
- Department of Neuroscience, Physiology and Pharmacology, Centre for Cardiovascular and Metabolic Neuroscience, University College London (UCL), London, UK
| | - Patrick S Hosford
- Department of Neuroscience, Physiology and Pharmacology, Centre for Cardiovascular and Metabolic Neuroscience, University College London (UCL), London, UK
| | - Sergey Kasparov
- Department of Physiology and Pharmacology, University of Bristol, Bristol, UK
| | - Alexander V Gourine
- Department of Neuroscience, Physiology and Pharmacology, Centre for Cardiovascular and Metabolic Neuroscience, University College London (UCL), London, UK
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Rajani V, Zhang Y, Revill A, Funk G. The role of P2Y1 receptor signaling in central respiratory control. Respir Physiol Neurobiol 2016; 226:3-10. [DOI: 10.1016/j.resp.2015.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 10/06/2015] [Indexed: 12/24/2022]
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Calik MW, Carley DW. Intracerebroventricular injections of dronabinol, a cannabinoid receptor agonist, does not attenuate serotonin-induced apnea in Sprague-Dawley rats. J Negat Results Biomed 2016; 15:8. [PMID: 27133202 PMCID: PMC4852437 DOI: 10.1186/s12952-016-0052-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/02/2016] [Indexed: 12/16/2022] Open
Abstract
Background Evidence suggests that vagal nerve activity may play a role in sleep apnea induction. In anesthetized rats, dronabinol, a cannabinoid (CB) receptor agonist, injected into the nodose ganglia attenuates reflex apnea and increases genioglossus activity, and reflex apnea attenuation is blocked by systemic pre-treatment with cannabinoid type 1 and/or type 2 receptor antagonists. However, it is unclear whether dronabinol has similar effects in the central nervous system; CB receptors are widely distributed in the brain, especially on neuronal circuitry important for respiration and upper airway activation. Here, we examine the effects of intracerebroventricular (ICV) injection of dronabinol on serotonin (5-HT)-induced apnea. Methods Adult male Sprague-Dawley rats were anesthetized and instrumented with bilateral electrodes to monitor genioglossi EMG and with a piezoelectric strain gauge to monitor respiratory pattern. Serotonin was intravenously infused into a femoral vein to induce reflex apnea. After baseline recordings, rats were placed in a stereotaxic apparatus. A unilateral osteotomy was made to allow access for injection to the right lateral ventricle, and the dura were carefully removed. Dronabinol (100, 10, 1, or 0.1 μg/3 μl DMSO) or control (3 μl DMSO) was injected into the right lateral ventricle and 5-HT infusion was repeated. Data (mean ± SEM) were analyzed using a mixed model analysis with a repeated/fixed measure. Results There was no main effect in 5-HT-induced apnea or breath duration, or in breath instability, between ICV dronabinol injected and ICV vehicle control injected groups. Moreover, there was no main effect in phasic or tonic genioglossus activity between ICV dronabinol injected and ICV vehicle control injected groups. Conclusion Our data show that ICV injection of dronabinol did not decrease 5-HT-induced apneas, and did not increase genioglossus activity. This in contrast to published results of dronabinol’s effect on apnea via the vagus nerve. Our results suggest that the effects of dronabinol on reflex apneas are peripherally mediated via suppression of vagal nerve activity.
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Affiliation(s)
- Michael W Calik
- Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago, 845 South Damen Avenue (M/C 802), Chicago, IL, 60612, USA. .,Department of Biobehavioral Health Science, University of Illinois at Chicago, 845 South Damen Avenue (M/C 802), Chicago, IL, 60612, USA.
| | - David W Carley
- Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago, 845 South Damen Avenue (M/C 802), Chicago, IL, 60612, USA.,Department of Biobehavioral Health Science, University of Illinois at Chicago, 845 South Damen Avenue (M/C 802), Chicago, IL, 60612, USA.,Department of Medicine, University of Illinois at Chicago, 1853 West Polk Street (M/C 784), Chicago, IL, 60612, USA
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Frenguelli BG, Wall MJ. Combined electrophysiological and biosensor approaches to study purinergic regulation of epileptiform activity in cortical tissue. J Neurosci Methods 2015; 260:202-14. [PMID: 26381061 DOI: 10.1016/j.jneumeth.2015.09.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 09/05/2015] [Accepted: 09/07/2015] [Indexed: 12/16/2022]
Abstract
BACKGROUND Cortical brain slices offer a readily accessible experimental model of a region of the brain commonly affected by epilepsy. The diversity of recording techniques, seizure-promoting protocols and mutant mouse models provides a rich diversity of avenues of investigation, which is facilitated by the regular arrangement of distinct neuronal populations and afferent fibre pathways, particularly in the hippocampus. NEW METHOD AND RESULTS We have been interested in the regulation of seizure activity in hippocampal and neocortical slices by the purines, adenosine and ATP. Via the use of microelectrode biosensors we have been able to measure the release of these important neuroactive compounds simultaneously with on-going epileptiform activity, even of brief durations. In addition, detailed numerical analysis and computational modelling has produced new insights into the kinetics and spatial distribution of elevations in purine concentration that occur during seizure activity. COMPARISON AND CONCLUSIONS Such an approach allows the spatio-temporal characteristics of neurotransmitter/neuromodulator release to be directly correlated with electrophysiological measures of synaptic and seizure activity, and can provide greater insight into the role of purines in epilepsy.
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Affiliation(s)
| | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
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25
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A critical role for purinergic signalling in the mechanisms underlying generation of BOLD fMRI responses. J Neurosci 2015; 35:5284-92. [PMID: 25834053 DOI: 10.1523/jneurosci.3787-14.2015] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The mechanisms of neurovascular coupling underlying generation of BOLD fMRI signals remain incompletely understood. It has been proposed that release of vasoactive substances by astrocytes couples neuronal activity to changes in cerebrovascular blood flow. However, the role of astrocytes in fMRI responses remains controversial. Astrocytes communicate via release of ATP, and here we tested the hypothesis that purinergic signaling plays a role in the mechanisms underlying fMRI. An established fMRI paradigm was used to trigger BOLD responses in the forepaw region of the somatosensory cortex (SSFP) of an anesthetized rat. Forepaw stimulation induced release of ATP in the SSFP region. To interfere with purinergic signaling by promoting rapid breakdown of the vesicular and/or released ATP, a lentiviral vector was used to express a potent ectonucleotidase, transmembrane prostatic acid phosphatase (TMPAP), in the SSFP region. TMPAP expression had no effect on resting cerebral blood flow, cerebrovascular reactivity, and neuronal responses to sensory stimulation. However, TMPAP catalytic activity markedly reduced the magnitude of BOLD fMRI responses triggered in the SSFP region by forepaw stimulation. Facilitated ATP breakdown could result in accumulation of adenosine. However, blockade of A1 receptors had no effect on BOLD responses and did not reverse the effect of TMPAP. These results suggest that purinergic signaling plays a significant role in generation of BOLD fMRI signals. We hypothesize that astrocytes activated during periods of enhanced neuronal activity release ATP, which propagates astrocytic activation, stimulates release of vasoactive substances and dilation of cerebral vasculature.
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Abstract
In conscious mammals, hypoxia or hypercapnia stimulates breathing while theoretically exerting opposite effects on central respiratory chemoreceptors (CRCs). We tested this theory by examining how hypoxia and hypercapnia change the activity of the retrotrapezoid nucleus (RTN), a putative CRC and chemoreflex integrator. Archaerhodopsin-(Arch)-transduced RTN neurons were reversibly silenced by light in anesthetized rats. We bilaterally transduced RTN and nearby C1 neurons with Arch (PRSx8-ArchT-EYFP-LVV) and measured the cardiorespiratory consequences of Arch activation (10 s) in conscious rats during normoxia, hypoxia, or hyperoxia. RTN photoinhibition reduced breathing equally during non-REM sleep and quiet wake. Compared with normoxia, the breathing frequency reduction (Δf(R)) was larger in hyperoxia (65% FiO2), smaller in 15% FiO2, and absent in 12% FiO2. Tidal volume changes (ΔV(T)) followed the same trend. The effect of hypoxia on Δf(R) was not arousal-dependent but was reversed by reacidifying the blood (acetazolamide; 3% FiCO2). Δf(R) was highly correlated with arterial pH up to arterial pH (pHa) 7.5 with no frequency inhibition occurring above pHa 7.53. Blood pressure was minimally reduced suggesting that C1 neurons were very modestly inhibited. In conclusion, RTN neurons regulate eupneic breathing about equally during both sleep and wake. RTN neurons are the first putative CRCs demonstrably silenced by hypocapnic hypoxia in conscious mammals. RTN neurons are silent above pHa 7.5 and increasingly active below this value. During hyperoxia, RTN activation maintains breathing despite the inactivity of the carotid bodies. Finally, during hypocapnic hypoxia, carotid body stimulation increases breathing frequency via pathways that bypass RTN.
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27
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Zoccal DB, Furuya WI, Bassi M, Colombari DSA, Colombari E. The nucleus of the solitary tract and the coordination of respiratory and sympathetic activities. Front Physiol 2014; 5:238. [PMID: 25009507 PMCID: PMC4070480 DOI: 10.3389/fphys.2014.00238] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 06/09/2014] [Indexed: 12/15/2022] Open
Abstract
It is well known that breathing introduces rhythmical oscillations in the heart rate and arterial pressure levels. Sympathetic oscillations coupled to the respiratory activity have been suggested as an important homeostatic mechanism optimizing tissue perfusion and blood gas uptake/delivery. This respiratory-sympathetic coupling is strengthened in conditions of blood gas challenges (hypoxia and hypercapnia) as a result of the synchronized activation of brainstem respiratory and sympathetic neurons, culminating with the emergence of entrained cardiovascular and respiratory reflex responses. Studies have proposed that the ventrolateral region of the medulla oblongata is a major site of synaptic interaction between respiratory and sympathetic neurons. However, other brainstem regions also play a relevant role in the patterning of respiratory and sympathetic motor outputs. Recent findings suggest that the neurons of the nucleus of the solitary tract (NTS), in the dorsal medulla, are essential for the processing and coordination of respiratory and sympathetic responses to hypoxia. The NTS is the first synaptic station of the cardiorespiratory afferent inputs, including peripheral chemoreceptors, baroreceptors and pulmonary stretch receptors. The synaptic profile of the NTS neurons receiving the excitatory drive from afferent inputs is complex and involves distinct neurotransmitters, including glutamate, ATP and acetylcholine. In the present review we discuss the role of the NTS circuitry in coordinating sympathetic and respiratory reflex responses. We also analyze the neuroplasticity of NTS neurons and their contribution for the development of cardiorespiratory dysfunctions, as observed in neurogenic hypertension, obstructive sleep apnea and metabolic disorders.
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Affiliation(s)
- Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
| | - Werner I Furuya
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
| | - Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
| | - Débora S A Colombari
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
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Sims RE, Dale N. Activity-dependent adenosine release may be linked to activation of Na(+)-K(+) ATPase: an in vitro rat study. PLoS One 2014; 9:e87481. [PMID: 24489921 PMCID: PMC3906196 DOI: 10.1371/journal.pone.0087481] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 12/23/2013] [Indexed: 01/06/2023] Open
Abstract
In the brain, extracellular adenosine increases as a result of neuronal activity. The mechanisms by which this occurs are only incompletely understood. Here we investigate the hypothesis that the Na+ influxes associated with neuronal signalling activate the Na+-K+ ATPase which, by consuming ATP, generates intracellular adenosine that is then released via transporters. By measuring adenosine release directly with microelectrode biosensors, we have demonstrated that AMPA-receptor evoked adenosine release in basal forebrain and cortex depends on extracellular Na+. We have simultaneously imaged intracellular Na+ and measured adenosine release. The accumulation of intracellular Na+ during AMPA receptor activation preceded adenosine release by some 90 s. By removing extracellular Ca2+, and thus preventing indiscriminate neuronal activation, we used ouabain to test the role of the Na+-K+ ATPase in the release of adenosine. Under conditions which caused a Na+ influx, brief applications of ouabain increased the accumulation of intracellular Na+ but conversely rapidly reduced extracellular adenosine levels. In addition, ouabain greatly reduced the amount of adenosine released during application of AMPA. Our data therefore suggest that activity of the Na+-K+ ATPase is directly linked to the efflux of adenosine and could provide a universal mechanism that couples adenosine release to neuronal activity. The Na+-K+ ATPase-dependent adenosine efflux is likely to provide adenosine-mediated activity-dependent negative feedback that will be important in many diverse functional contexts including the regulation of sleep.
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Affiliation(s)
- Robert Edward Sims
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- * E-mail:
| | - Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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Sobrinho CR, Wenker IC, Poss EM, Takakura AC, Moreira TS, Mulkey DK. Purinergic signalling contributes to chemoreception in the retrotrapezoid nucleus but not the nucleus of the solitary tract or medullary raphe. J Physiol 2014; 592:1309-23. [PMID: 24445316 DOI: 10.1113/jphysiol.2013.268490] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Several brain regions are thought to function as important sites of chemoreception including the nucleus of the solitary tract (NTS), medullary raphe and retrotrapezoid nucleus (RTN). In the RTN, mechanisms of chemoreception involve direct H(+)-mediated activation of chemosensitive neurons and indirect modulation of chemosensitive neurons by purinergic signalling. Evidence suggests that RTN astrocytes are the source of CO2-evoked ATP release. However, it is not clear whether purinergic signalling also influences CO2/H(+) responsiveness of other putative chemoreceptors. The goals of this study are to determine if CO2/H(+)-sensitive neurons in the NTS and medullary raphe respond to ATP, and whether purinergic signalling in these regions influences CO2 responsiveness in vitro and in vivo. In brain slices, cell-attached recordings of membrane potential show that CO2/H(+)-sensitive NTS neurons are activated by focal ATP application; however, purinergic P2-receptor blockade did not affect their CO2/H(+) responsiveness. CO2/H(+)-sensitive raphe neurons were unaffected by ATP or P2-receptor blockade. In vivo, ATP injection into the NTS increased cardiorespiratory activity; however, injection of a P2-receptor blocker into this region had no effect on baseline breathing or CO2/H(+) responsiveness. Injections of ATP or a P2-receptor blocker into the medullary raphe had no effect on cardiorespiratory activity or the chemoreflex. As a positive control we confirmed that ATP injection into the RTN increased breathing and blood pressure by a P2-receptor-dependent mechanism. These results suggest that purinergic signalling is a unique feature of RTN chemoreception.
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Affiliation(s)
- Cleyton R Sobrinho
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, 1524, Prof. Lineu Prestes Avenue, 05508-000, São Paulo, SP, Brazil. ; D. K. Mulkey: Department of Physiology and Neurobiology, University of Connecticut, 75 N Eagleville Rd, Unit 3156, Storrs, CT 06269-3156, USA.
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Stone AJ, Evanson KW, Kluess HA. ATP metabolism in skeletal muscle arterioles. Physiol Rep 2014; 2:e00207. [PMID: 24744886 PMCID: PMC3967690 DOI: 10.1002/phy2.207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 01/04/2014] [Accepted: 01/07/2014] [Indexed: 11/15/2022] Open
Abstract
The purpose of this study was to investigate the metabolism of Adenosine triphosphate (ATP) in skeletal muscle resistance arterioles and to determine whether this metabolism is altered during the rapid growth phase of the rat. We attempted to quantify ATP metabolism in gastrocnemius first‐order arterioles from 8‐, 10‐, and 12‐week‐old rats. We measured ATP metabolism using an ATPase/GTPase assay with whole vessel segments as well as using a real‐time adenosine biosensor following electric field stimulation. Our first method of measuring ATP metabolism allowed us to measure the amount of free phosphate produced with ATP as a substrate. When ecto‐nucleotidase activity was inhibited by ARL67156, pyridoxal phosphate‐6‐azophenly‐2′, 4′‐disulfonic acid (PPADS), or suramin prior to adding ATP, we found that the rate of phosphate production was significantly reduced by 27%, 21%, and 22%, respectively (P < 0.05). Our second method of measuring ATP metabolism allowed us to measure the amount of adenosine produced following electric field stimulation of the arteriole with and without nucleotidase inhibitors. Surprisingly, we found that adenosine overflow was not attenuated by nucleotidase inhibitors. We concluded that ecto‐phosphodieterase/phyrophophatase (E‐NPP), ecto‐diadenosine polyphosphatase (ApnA), NTPDase1 and 2, and E5NT may be present on the gastrocnemius 1A arteriole and do play a role in ATP metabolism. Between the ages of 8 weeks and 12 weeks, however, overall ATP metabolism may not change. The purpose of this study was to investigate the metabolism of Adenosine triphosphate (ATP) in skeletal muscle resistance arterioles and whether it is altered during the rapid growth phase of the rat. We concluded that ecto‐phosphodieterase/phyrophophatase (E‐NPP), ecto‐diadenosine polyphosphatase (ApnA), NTPDase1 and 2, and E5NT may be present on the gastrocnemius 1A arteriole and do play a role in ATP metabolism. Between the ages of 8 weeks and 12 weeks, however, overall ATP metabolism may not change.
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Affiliation(s)
- Audrey J. Stone
- Department of Health Science, Kinesiology, Recreation and Dance; University of Arkansas; Fayetteville Arkansas
- Pennsylvania State University College of Medicine; Hershey Pennsylvania
| | - Kirk W. Evanson
- Department of Health Science, Kinesiology, Recreation and Dance; University of Arkansas; Fayetteville Arkansas
| | - Heidi A. Kluess
- Department of Health Science, Kinesiology, Recreation and Dance; University of Arkansas; Fayetteville Arkansas
- School of Kinesiology; Auburn University; Auburn Alabama
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Abstract
The main functions of the respiratory neural network are to produce a coordinated, efficient, rhythmic motor behavior and maintain homeostatic control over blood oxygen and CO2/pH levels. Purinergic (ATP) signaling features prominently in these homeostatic reflexes. The signaling actions of ATP are produced through its binding to a diversity of ionotropic P2X and metabotropic P2Y receptors. However, its net effect on neuronal and network excitability is determined by the interaction between the three limbs of a complex system comprising the signaling actions of ATP at P2Rs, the distribution of multiple ectonucleotidases that differentially metabolize ATP into ADP, AMP, and adenosine (ADO), and the signaling actions of ATP metabolites, especially ADP at P2YRs and ADO at P1Rs. Understanding the significance of purinergic signaling is further complicated by the fact that neurons, glia, and the vasculature differentially express P2 and P1Rs, and that both neurons and glia release ATP. This article reviews at cellular, synaptic, and network levels, current understanding and emerging concepts about the diverse roles played by this three-part signaling system in: mediating the chemosensitivity of respiratory networks to hypoxia and CO2/pH; modulating the activity of rhythm generating networks and inspiratory motoneurons, and; controlling blood flow through the cerebral vasculature.
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Affiliation(s)
- Gregory D Funk
- Department of Physiology, Centre for Neuroscience, Women & Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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González-López A, López-Alonso I, Aguirre A, Amado-Rodríguez L, Batalla-Solís E, Astudillo A, Tomás-Zapico C, Fueyo A, dos Santos CC, Talbot K, Albaiceta GM. Mechanical ventilation triggers hippocampal apoptosis by vagal and dopaminergic pathways. Am J Respir Crit Care Med 2013; 188:693-702. [PMID: 23962032 DOI: 10.1164/rccm.201304-0691oc] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Critically ill patients frequently develop neuropsychological disturbances including acute delirium or memory impairment. The need for mechanical ventilation is a risk factor for these adverse events, but a mechanism that links lung stretch and brain injury has not been identified. OBJECTIVES To identify the mechanisms that lead to brain dysfunction during mechanical ventilation. METHODS Brains from mechanically ventilated mice were harvested, and signals of apoptosis and alterations in the Akt survival pathway were studied. These measurements were repeated in vagotomized or haloperidol-treated mice, and in animals intracerebroventricularly injected with selective dopamine-receptor blockers. Hippocampal slices were cultured and treated with micromolar concentrations of dopamine, with or without dopamine receptor blockers. Last, levels of dysbindin, a regulator of the membrane availability of dopamine receptors, were assessed in the experimental model and in brain samples from ventilated patients. MEASUREMENTS AND MAIN RESULTS Mechanical ventilation triggers hippocampal apoptosis as a result of type 2 dopamine receptor activation in response to vagal signaling. Activation of these receptors blocks the Akt/GSK3β prosurvival pathway and activates the apoptotic cascade, as demonstrated in vivo and in vitro. Vagotomy, systemic haloperidol, or intracerebroventricular raclopride (a type 2 dopamine receptor blocker) ameliorated this effect. Moreover, ventilation induced a concomitant change in the expression of dysbindin-1C. These results were confirmed in brain samples from ventilated patients. CONCLUSIONS These results prove the existence of a pathogenic mechanism of lung stretch-induced hippocampal apoptosis that could explain the neurological changes in ventilated patients and may help to identify novel therapeutic approaches.
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Affiliation(s)
- Adrián González-López
- 1 Departamento de Biología Funcional, Área de Fisiología, Instituto Universitario de Oncología del Principado de Asturias, and
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Smith SMC, Mitchell GS, Friedle SA, Sibigtroth CM, Vinit S, Watters JJ. Hypoxia Attenuates Purinergic P2X Receptor-Induced Inflammatory Gene Expression in Brainstem Microglia. HYPOXIA 2013; 2013. [PMID: 24377098 PMCID: PMC3873144 DOI: 10.2147/hp.s45529] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hypoxia and increased extracellular nucleotides are frequently coincident in the brainstem. Extracellular nucleotides are potent modulators of microglial inflammatory gene expression via P2X purinergic receptor activation. Although hypoxia is also known to modulate inflammatory gene expression, little is known about how hypoxia or P2X receptor activation alone affects inflammatory molecule production in brainstem microglia, nor how hypoxia and P2X receptor signaling interact when they occur together. In the study reported here, we investigated the ability of a brief episode of hypoxia (2 hours) in the presence and absence of the nonselective P2X receptor agonist 2′(3′)-O-(4-benzoylbenzoyl)adenosine-5′-triphosphate (BzATP) to promote inflammatory gene expression in brainstem microglia in adult rats. We evaluated inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNFα), and interleukin (IL)-6 messenger RNA levels in immunomagnetically isolated brainstem microglia. While iNOS and IL-6 gene expression increased with hypoxia and BzATP alone, TNFα expression was unaffected. Surprisingly, BzATP-induced inflammatory effects were lost after hypoxia, suggesting that hypoxia impairs proinflammatory P2X-receptor signaling. We also evaluated the expression of key P2X receptors activated by BzATP, namely P2X1, P2X4, and P2X7. While hypoxia did not alter their expression, BzATP upregulated P2X4 and P2X7 mRNAs; these effects were ablated in hypoxia. Although both P2X4 and P2X7 receptor expression correlated with increased microglial iNOS and IL-6 levels in microglia from normoxic rats, in hypoxia, P2X7 only correlated with IL-6, and P2X4 correlated only with iNOS. In addition, correlations between P2X7 and P2X4 were lost following hypoxia, suggesting that P2X4 and P2X7 receptor signaling differs in normoxia and hypoxia. Together, these data suggest that hypoxia suppresses P2X receptor-induced inflammatory gene expression, indicating a potentially immunosuppressive role of extracellular nucleotides in brainstem microglia following exposure to hypoxia.
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Affiliation(s)
- Stephanie M C Smith
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA 53706 ; Comparative Biomedical Sciences Training Program, University of Wisconsin, Madison, WI, USA 53706
| | - Gordon S Mitchell
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA 53706 ; Comparative Biomedical Sciences Training Program, University of Wisconsin, Madison, WI, USA 53706
| | - Scott A Friedle
- Program in Cellular and Molecular Biology, University of Wisconsin, Madison, WI, USA 53706
| | | | - Stéphane Vinit
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA 53706
| | - Jyoti J Watters
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA 53706 ; Comparative Biomedical Sciences Training Program, University of Wisconsin, Madison, WI, USA 53706 ; Program in Cellular and Molecular Biology, University of Wisconsin, Madison, WI, USA 53706
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Vasylieva N, Marinesco S. Enzyme Immobilization on Microelectrode Biosensors. NEUROMETHODS 2013. [DOI: 10.1007/978-1-62703-370-1_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Wakabayashi KT, Kiyatkin EA. Rapid changes in extracellular glutamate induced by natural arousing stimuli and intravenous cocaine in the nucleus accumbens shell and core. J Neurophysiol 2012; 108:285-99. [PMID: 22496525 DOI: 10.1152/jn.01167.2011] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Glutamate (Glu) is a major excitatory neurotransmitter, playing a crucial role in the functioning of the nucleus accumbens (NAc), a critical area implicated in somatosensory integration and regulation of motivated behavior. In this study, high-speed amperometry with enzyme-based biosensors was used in freely moving rats to examine changes in extracellular Glu in the NAc shell and core induced by a tone, tail pinch (TP), social interaction with a male conspecific (SI), and intravenous (iv) cocaine (1 mg/kg). To establish the contribution of Glu to electrochemical signal changes, similar recordings were conducted with null (Glu(0)) sensors, which were exposed to the same chemical and physical environment but were insensitive to Glu. TP, SI, and cocaine, but not a tone, induced relatively large and prolonged current increases detected by both Glu and Glu(0) sensors. However, current differentials revealed very rapid, much smaller, and transient increases in extracellular Glu levels, more predominantly in the NAc shell than core. In contrast to monophasic responses with natural stimuli, cocaine induced a biphasic Glu increase in the shell, with a transient peak during the injection and a slower postinjection peak. Therefore, Glu is phasically released in the NAc after exposure to natural arousing stimuli and cocaine; this release is rapid, stimulus dependent, and structure specific, suggesting its role in triggering neural and behavioral activation induced by these stimuli. This study also demonstrates the need for multiple in vitro and in vivo controls to reveal relatively small, highly phasic, and transient fluctuations in Glu levels occurring under behaviorally relevant conditions.
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Affiliation(s)
- Ken T Wakabayashi
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
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Jin Z, Choi MJ, Park CS, Park YS, Jin YH. Propofol facilitated excitatory postsynaptic currents frequency on nucleus tractus solitarii (NTS) neurons. Brain Res 2012; 1432:1-6. [DOI: 10.1016/j.brainres.2011.11.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 10/12/2011] [Accepted: 11/04/2011] [Indexed: 12/01/2022]
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Measurement of purine release with microelectrode biosensors. Purinergic Signal 2011; 8:27-40. [PMID: 22095158 DOI: 10.1007/s11302-011-9273-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 09/19/2011] [Indexed: 12/22/2022] Open
Abstract
Purinergic signalling departs from traditional paradigms of neurotransmission in the variety of release mechanisms and routes of production of extracellular ATP and adenosine. Direct real-time measurements of these purinergic agents have been of great value in understanding the functional roles of this signalling system in a number of diverse contexts. Here, we review the methods for measuring purine release, introduce the concept of microelectrode biosensors for ATP and adenosine and explain how these have been used to provide new mechanistic insight in respiratory chemoreception, synaptic physiology, eye development and purine salvage. We finish by considering the association of purine release with pathological conditions and examine the possibilities that biosensors for purines may one day be a standard part of the clinical diagnostic tool chest.
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Mazzone GL, Nistri A. Electrochemical detection of endogenous glutamate release from rat spinal cord organotypic slices as a real-time method to monitor excitotoxicity. J Neurosci Methods 2011; 197:128-32. [DOI: 10.1016/j.jneumeth.2011.01.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 01/27/2011] [Accepted: 01/28/2011] [Indexed: 01/28/2023]
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Yamamoto K, Noguchi J, Yamada C, Watabe AM, Kato F. Distinct target cell-dependent forms of short-term plasticity of the central visceral afferent synapses of the rat. BMC Neurosci 2010; 11:134. [PMID: 20961403 PMCID: PMC2978217 DOI: 10.1186/1471-2202-11-134] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 10/20/2010] [Indexed: 11/25/2022] Open
Abstract
Background The visceral afferents from various cervico-abdominal sensory receptors project to the dorsal vagal complex (DVC), which is composed of the nucleus of the solitary tract (NTS), the area postrema and the dorsal motor nucleus of the vagus nerve (DMX), via the vagus and glossopharyngeal nerves and then the solitary tract (TS) in the brainstem. While the excitatory transmission at the TS-NTS synapses shows strong frequency-dependent suppression in response to repeated stimulation of the afferents, the frequency dependence and short-term plasticity at the TS-DMX synapses, which also transmit monosynaptic information from the visceral afferents to the DVC neurons, remain largely unknown. Results Recording of the EPSCs activated by paired or repeated TS stimulation in the brainstem slices of rats revealed that, unlike NTS neurons whose paired-pulse ratio (PPR) is consistently below 0.6, the distribution of the PPR of DMX neurons shows bimodal peaks that are composed of type I (PPR, 0.6-1.5; 53% of 120 neurons recorded) and type II (PPR, < 0.6; 47%) neurons. Some of the type I DMX neurons showed paired-pulse potentiation. The distinction of these two types depended on the presynaptic release probability and the projection target of the postsynaptic cells; the distinction was not dependent on the location or soma size of the cell, intensity or site of the stimulation, the latency, standard deviation of latency or the quantal size. Repeated stimulation at 20 Hz resulted in gradual and potent decreases in EPSC amplitude in the NTS and type II DMX neurons, whereas type I DMX neurons displayed only slight decreases, which indicates that the DMX neurons of this type could be continuously activated by repeated firing of primary afferent fibers at a high (~10 Hz) frequency. Conclusions These two general types of short-term plasticity might contribute to the differential activation of distinct vago-vagal reflex circuits, depending on the firing frequency and type of visceral afferents.
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Affiliation(s)
- Kiyofumi Yamamoto
- Laboratory of Neurophysiology, Department of Neuroscience, Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan
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Huckstepp RTR, id Bihi R, Eason R, Spyer KM, Dicke N, Willecke K, Marina N, Gourine AV, Dale N. Connexin hemichannel-mediated CO2-dependent release of ATP in the medulla oblongata contributes to central respiratory chemosensitivity. J Physiol 2010; 588:3901-20. [PMID: 20736421 DOI: 10.1113/jphysiol.2010.192088] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Arterial PCO2, a major determinant of breathing, is detected by chemosensors located in the brainstem. These are important for maintaining physiological levels of PCO2 in the blood and brain, yet the mechanisms by which the brain senses CO(2) remain controversial. As ATP release at the ventral surface of the brainstem has been causally linked to the adaptive changes in ventilation in response to hypercapnia, we have studied the mechanisms of CO(2)-dependent ATP release in slices containing the ventral surface of the medulla oblongata. We found that CO(2)-dependent ATP release occurs in the absence of extracellular acidification and correlates directly with the level of PCO2. ATP release is independent of extracellular Ca(2+) and may occur via the opening of a gap junction hemichannel. As agents that act on connexin channels block this release, but compounds selective for pannexin-1 have no effect, we conclude that a connexin hemichannel is involved in CO(2)-dependent ATP release. We have used molecular, genetic and immunocytochemical techniques to demonstrate that in the medulla oblongata connexin 26 (Cx26) is preferentially expressed near the ventral surface. The leptomeninges, subpial astrocytes and astrocytes ensheathing penetrating blood vessels at the ventral surface of the medulla can be loaded with dye in a CO(2)-dependent manner, suggesting that gating of a hemichannel is involved in ATP release. This distribution of CO(2)-dependent dye loading closely mirrors that of Cx26 expression and colocalizes to glial fibrillary acidic protein (GFAP)-positive cells. In vivo, blockers with selectivity for Cx26 reduce hypercapnia-evoked ATP release and the consequent adaptive enhancement of breathing. We therefore propose that Cx26-mediated release of ATP in response to changes in PCO2 is an important mechanism contributing to central respiratory chemosensitivity.
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Huckstepp RTR, Eason R, Sachdev A, Dale N. CO2-dependent opening of connexin 26 and related β connexins. J Physiol 2010; 588:3921-31. [PMID: 20736419 DOI: 10.1113/jphysiol.2010.192096] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We have previously shown connexin mediated CO(2)-dependent ATP release from the surface of the medulla oblongata. Given the localization of connexin 26 (Cx26) to the chemosensing areas of the medulla, we have tested in a heterologous expression system (HeLa cells) whether Cx26 may be sensitive to changes in PCO2. Cx26 responded to an increase in PCO2 at constant extracellular pH by opening and to a decrease in PCO2 by closing. Furthermore, Cx26 was partially activated at a physiological PCO2 of around 40 mmHg. Cx26 in isolated patches responded to changes in PCO2, suggesting direct CO(2) sensitivity of the hemichannel to CO(2). Heterologous expression of Cx26 in HeLa cells was sufficient to endow them with the capacity to release ATP in a CO(2)-sensitive manner. We have examined other heterologously expressed connexins for their ability to respond to changes in PCO2. The closely related β connexins Cx30 and Cx32 also displayed sensitivity to changes in PCO2, but with slightly different characteristics from Cx26. The more distant Cx43 exhibited CO(2)-dependent closing (possibly mediated through intracellular acidification), while Cx36 displayed no CO(2) sensitivity. These surprising findings suggest that connexins may play a hitherto unappreciated variety of signalling roles, and that Cx26 and related β connexins may impart direct sensitivity to CO(2) throughout the brain.
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Dean JB, Putnam RW. The caudal solitary complex is a site of central CO(2) chemoreception and integration of multiple systems that regulate expired CO(2). Respir Physiol Neurobiol 2010; 173:274-87. [PMID: 20670695 DOI: 10.1016/j.resp.2010.07.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 06/30/2010] [Accepted: 07/01/2010] [Indexed: 12/16/2022]
Abstract
The solitary complex is comprised of the nucleus tractus solitarius (NTS, sensory) and dorsal motor nucleus of the vagus (DMV, motor), which functions as an integrative center for neural control of multiple systems including the respiratory, cardiovascular and gastroesophageal systems. The caudal NTS-DMV is one of the several sites of central CO(2) chemoreception in the brain stem. CO(2) chemosensitive neurons are fully responsive to CO(2) at birth and their responsiveness seems to depend on pH-sensitive K(+) channels. In addition, chemosensitive neurons are highly sensitive to conditions such as hypoxia (e.g., neural plasticity) and hyperoxia (e.g., stimulation), suggesting they employ redox and nitrosative signaling mechanisms. Here we review the cellular and systems physiological evidence supporting our hypothesis that the caudal NTS-DMV is a site for integration of respiratory, cardiovascular and gastroesophageal systems that work together to eliminate CO(2) during acute and chronic respiratory acidosis to restore pH homeostasis.
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Affiliation(s)
- Jay B Dean
- Dept. of Molecular Pharmacology & Physiology, Hyperbaric Biomedical Research Laboratory, University of South Florida, Tampa, FL 33612, USA.
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Inyushkina EM, Merkulova NA, Inyushkin AN. Mechanisms of the respiratory activity of leptin at the level of the solitary tract nucleus. ACTA ACUST UNITED AC 2010; 40:707-13. [PMID: 20635220 DOI: 10.1007/s11055-010-9316-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/15/2009] [Indexed: 12/20/2022]
Abstract
Acute experiments on anesthetized laboratory rats were performed to study the effects microinjections of 10(-4) M leptin into the solitary tract nucleus on the extent of the Hering-Breuer inflation reflex in ventilatory reactions to hypercapnia. Local administration of leptin into this area led to inhibition of the Hering-Breuer reflex. The extent of ventilatory responses to hypercapnia, conversely, increased, which may provide evidence that leptin has a modulatory influence on central chemoreceptors. These physiological mechanisms of action probably play a leading role in mediating the stimulatory respiratory effects of leptin at the level of the solitary tract nucleus.
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Affiliation(s)
- E M Inyushkina
- Samara State University, 1 Academician Pavlov St., 443016, Samara, Russia
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Abstract
The purpose of this study was to investigate the sources of ATP in the 1A arteriole, and to investigate age-related changes in ATP overflow. Arterioles (1A) from the red portion of the gastrocnemius muscle were isolated, cannulated and pressurized in a microvessel chamber with field stimulation electrodes. ATP overflow was determined using probes specific for ATP and null probes that were constructed similar to the ATP probes, but did not contain the enzyme coating. ATP concentrations were determined using a normal curve (0.78 to 25 micromol l(-1) ATP). ATP overflow occurred in two phases. Phase one began in the first 20 s following stimulation and phase two started 35 s after field stimulation. Tetrodotoxin, a potent neurotoxin that blocks action potential generation in nerves, abolished both phases of ATP overflow. alpha1-Receptor blockade resulted in a small decrease in ATP overflow in phase two, but endothelial removal resulted in an increase in ATP overflow. ATP overflow was lowest in 6-month-old rats and highest in 12- and 2-month-old rats (P<0.05). ATP overflow measured via biosensors was of neural origin with a small contribution from the vascular smooth muscle. The endothelium seems to play an important role in attenuating ATP overflow in 1A arterioles.
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Affiliation(s)
- Heidi A Kluess
- Department of Health Science, Kinesiology, Recreation and Dance, 308V HPER Building, 1 University of Arkansas, Fayetteville, AR 72701, USA.
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Masino SA, Kawamura M, Wasser CD, Wasser CA, Pomeroy LT, Ruskin DN. Adenosine, ketogenic diet and epilepsy: the emerging therapeutic relationship between metabolism and brain activity. Curr Neuropharmacol 2010; 7:257-68. [PMID: 20190967 PMCID: PMC2769009 DOI: 10.2174/157015909789152164] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 05/01/2009] [Accepted: 05/06/2009] [Indexed: 12/12/2022] Open
Abstract
For many years the neuromodulator adenosine has been recognized as an endogenous anticonvulsant molecule and termed a “retaliatory metabolite.” As the core molecule of ATP, adenosine forms a unique link between cell energy and neuronal excitability. In parallel, a ketogenic (high-fat, low-carbohydrate) diet is a metabolic therapy that influences neuronal activity significantly, and ketogenic diets have been used successfully to treat medically-refractory epilepsy, particularly in children, for decades. To date the key neural mechanisms underlying the success of dietary therapy are unclear, hindering development of analogous pharmacological solutions. Similarly, adenosine receptor–based therapies for epilepsy and myriad other disorders remain elusive. In this review we explore the physiological regulation of adenosine as an anticonvulsant strategy and suggest a critical role for adenosine in the success of ketogenic diet therapy for epilepsy. While the current focus is on the regulation of adenosine, ketogenic metabolism and epilepsy, the therapeutic implications extend to acute and chronic neurological disorders as diverse as brain injury, inflammatory and neuropathic pain, autism and hyperdopaminergic disorders. Emerging evidence for broad clinical relevance of the metabolic regulation of adenosine will be discussed.
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Affiliation(s)
- S A Masino
- Psychology Department, Trinity College, 300 Summit St., Hartford, CT, USA.
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Purinergic signalling in autonomic control. Trends Neurosci 2009; 32:241-8. [PMID: 19359051 DOI: 10.1016/j.tins.2009.03.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 03/16/2009] [Accepted: 03/17/2009] [Indexed: 02/07/2023]
Abstract
Intercellular purinergic signalling, which utilizes ATP as a transmitter, is fundamental for the operation of the autonomic nervous system. ATP is released together with 'classical' transmitters from sympathetic and parasympathetic nerves supplying various peripheral targets, modulates neurotransmission in autonomic ganglia, has an important role in local enteric neural control and coordination of intestinal secretion and motility, and acts as a common mediator for several distinct sensory modalities. Recently, the role of ATP-mediated signalling in the central nervous control of autonomic function has been addressed. Emerging data demonstrate that in the brain ATP is involved in the operation of several key cardiorespiratory reflexes, contributes to central processing of viscerosensory information, mediates central CO(2) chemosensory transduction and triggers adaptive changes in breathing, and modulates the activities of the brainstem vagal preganglionic, presympathetic and respiratory neural networks.
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Braga VA, Zoccal DB, Accorsi-Mendonca D. Are ATP and glutamate released from slowly adapting pulmonary stretch receptor afferents in the NTS? J Physiol 2008; 586:4791-2. [PMID: 18703575 DOI: 10.1113/jphysiol.2008.160549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Valdir A Braga
- Department of Medicine, The Universitof Chicago, Chicago, IL, USA.
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