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Luppi AI, Rosas FE, Noonan MP, Mediano PAM, Kringelbach ML, Carhart-Harris RL, Stamatakis EA, Vernon AC, Turkheimer FE. Oxygen and the Spark of Human Brain Evolution: Complex Interactions of Metabolism and Cortical Expansion across Development and Evolution. Neuroscientist 2024; 30:173-198. [PMID: 36476177 DOI: 10.1177/10738584221138032] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Scientific theories on the functioning and dysfunction of the human brain require an understanding of its development-before and after birth and through maturation to adulthood-and its evolution. Here we bring together several accounts of human brain evolution by focusing on the central role of oxygen and brain metabolism. We argue that evolutionary expansion of human transmodal association cortices exceeded the capacity of oxygen delivery by the vascular system, which led these brain tissues to rely on nonoxidative glycolysis for additional energy supply. We draw a link between the resulting lower oxygen tension and its effect on cytoarchitecture, which we posit as a key driver of genetic developmental programs for the human brain-favoring lower intracortical myelination and the presence of biosynthetic materials for synapse turnover. Across biological and temporal scales, this protracted capacity for neural plasticity sets the conditions for cognitive flexibility and ongoing learning, supporting complex group dynamics and intergenerational learning that in turn enabled improved nutrition to fuel the metabolic costs of further cortical expansion. Our proposed model delineates explicit mechanistic links among metabolism, molecular and cellular brain heterogeneity, and behavior, which may lead toward a clearer understanding of brain development and its disorders.
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Affiliation(s)
- Andrea I Luppi
- Department of Clinical Neurosciences and Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Leverhulme Centre for the Future of Intelligence, University of Cambridge, Cambridge, UK
- The Alan Turing Institute, London, UK
| | - Fernando E Rosas
- Department of Informatics, University of Sussex, Brighton, UK
- Centre for Psychedelic Research, Department of Brain Science, Imperial College London, London, UK
- Centre for Complexity Science, Imperial College London, London, UK
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, UK
| | - MaryAnn P Noonan
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Pedro A M Mediano
- Department of Psychology, University of Cambridge, Cambridge, UK
- Department of Psychology, Queen Mary University of London, London, UK
- Department of Computing, Imperial College London, London, UK
| | - Morten L Kringelbach
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, UK
- Center for Music in the Brain, Aarhus University, Aarhus, Denmark
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Robin L Carhart-Harris
- Psychedelics Division-Neuroscape, Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Emmanuel A Stamatakis
- Department of Clinical Neurosciences and Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Anthony C Vernon
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Federico E Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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2
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Souza JR, Lima-Silveira L, Accorsi-Mendonça D, Machado BH. Enhancement of the Evoked Excitatory Transmission in the Nucleus Tractus Solitarius Neurons after Sustained Hypoxia in Mice Depends on A 2A Receptors. Neuroscience 2024; 536:57-71. [PMID: 37979842 DOI: 10.1016/j.neuroscience.2023.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 11/06/2023] [Accepted: 11/11/2023] [Indexed: 11/20/2023]
Abstract
The first synapses of the afferents of peripheral chemoreceptors are located in the Nucleus Tractus Solitarius (NTS) and there is evidence that short-term sustained hypoxia (SH - 24 h, FiO2 0.1) facilitates glutamatergic transmission in NTS neurons of rats. Adenosine is an important neuromodulator of synaptic transmission and hypoxia contributes to increase its extracellular concentration. The A2A receptors mediate the excitatory actions of adenosine and are active players in the modulation of neuronal networks in the NTS. Herein, we used knockout mice for A2A receptors (A2AKO) and electrophysiological recordings of NTS neurons were performed to evaluate the contribution of these receptors in the changes in synaptic transmission in NTS neurons of mice submitted to SH. The membrane passive properties and excitability of NTS neurons were not affected by SH and were similar between A2AKO and wild-type mice. The overall amplitude of spontaneous glutamatergic currents in NTS neurons of A2AKO mice was lower than in Balb/c WT mice. SH increased the amplitude of evoked glutamatergic currents of NTS neurons from WT mice by a non-presynaptic mechanism, but this enhancement was not observed in NTS neurons of A2AKO mice. Under normoxia, the amplitude of evoked glutamatergic currents was similar between WT and A2AKO mice. The data indicate that A2A receptors (a) modulate spontaneous glutamatergic currents, (b) do not modulate the evoked glutamatergic transmission in the NTS neurons under control conditions, and (c) are required for the enhancement of glutamatergic transmission observed in the NTS neurons of mice submitted to SH.
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Affiliation(s)
- Juliana R Souza
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Ludmila Lima-Silveira
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Daniela Accorsi-Mendonça
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil.
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3
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Souza JR, Machado BH. Cardiovascular and respiratory evaluation in adenosine A 2A receptor knockout mice submitted to short-term sustained hypoxia. Exp Physiol 2023; 108:1434-1445. [PMID: 37632713 PMCID: PMC10988442 DOI: 10.1113/ep091221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 08/03/2023] [Indexed: 08/28/2023]
Abstract
Sustained hypoxia (SH) in mice induces changes in the respiratory pattern and increase in the parasympathetic tone to the heart. Among adenosine G-protein-coupled receptors (GPCRs), the A2A receptors are especially important in mediating adenosine actions during hypoxia due to their expression in neurons involved with the generation and modulation of the autonomic and respiratory functions. Herein, we performed an in vivo evaluation of the baseline cardiovascular and respiratory parameters and their changes in response to SH in knockout mice for A2A receptors (A2A KO). SH produced similar and significant reductions in mean arterial pressure and heart rate in both wild-type (WT) and A2A KO mice when compared to their respective normoxic controls. Mice from WT and A2A KO groups submitted to normoxia or SH presented similar cardiovascular responses to peripheral chemoreflex activation (KCN). Under normoxic conditions A2A KO mice presented a respiratory frequency (fR ) significantly higher in relation to the WT group, which was reduced in response to SH. These data show that the lack of adenosine A2A receptors in mice does not affect the cardiovascular parameters and the autonomic responses to chemoreflex activation in control (normoxia) and SH mice. We conclude that the A2A receptors play a major role in the control of respiratory frequency and in the tachypnoeic response to SH in mice. NEW FINDINGS: What is the central question of this study? Are cardiovascular and respiratory parameters and their changes in response to sustained hypoxia (SH) altered in adenosine A2A receptor knockout mice? What is the main finding and its importance? Cardiovascular parameters and their changes in response to SH were not altered in A2A KO mice. The respiratory frequency in A2A KO was higher than in WT mice. In response to SH the respiratory frequency increased in WT, while it was reduced in A2A KO mice. A2A receptors play a major role in the modulation of respiratory frequency and in the tachypnoeic response to SH in mice.
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Affiliation(s)
- Juliana R. Souza
- Department of Physiology, School of Medicine of Ribeirão PretoUniversity of São PauloRibeirão PretoSPBrazil
| | - Benedito H. Machado
- Department of Physiology, School of Medicine of Ribeirão PretoUniversity of São PauloRibeirão PretoSPBrazil
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4
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Maina JN, Icardo JM, Zaccone G, Aragona M, Lauriano ER, Alesci A, Albano M, Guerrera MC, Germana A, Fernandes JMO, Kiron V, Capillo G. Immunohistochemical and ultrastructural study of the immune cell system and epithelial surfaces of the respiratory organs in the bimodally-breathing African sharptooth catfish (Clarias gariepinus Burchell, 1822). Anat Rec (Hoboken) 2022; 305:3212-3229. [PMID: 35142056 DOI: 10.1002/ar.24896] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/04/2022] [Accepted: 01/31/2022] [Indexed: 11/12/2022]
Abstract
Ach, represents the old neurotransmitter in central and peripheral nervous system. Its muscarinic and nicotinic receptors (mAChRs and nAChRs) constitute an independent cholinergic system that is found in immune cells and playsa key role in regulation of the immune function and cytokine production. Gas exchanging surfaces of the gills and air-breathing organs (ABOs) of the sharptooth catfish Clarias gariepinus were investigated using ultrastructural and confocal immunofluorescence techniques. This study was predominantly focused on the structure of the immune cell types, the expression of their neurotransmitters, including the antimicrobial peptide piscidin 1, and the functional significance of respiratory gas exchange epithelia. A network of immune cells (monocytes, eosinophils, and mast cells) was observed in the gill and theABO epithelia. Eosinophils containing 5HT immunoreactivity were seen in close association with mast cells expressing acetylcholine (Ach), 5HT, nNOS and piscidin 1. A rich and dense cholinergic innervation dispersing across the islet capillaries of the gas exchange barrier, and the localization of Ach in the squamous pavement cells covering the capillaries, were evidenced byVAChT antibodies.We report for the first time that piscidin 1(Pis 1) positive mast cells interact with Pis 1 positive nerves found in the epithelia of the respiratory organs.Pis 1 immunoreactivity was also observed in the covering respiratory epithelium of the ABOs and associated with a role in local mucosal immune defense . The above results anticipate future studies on the neuro-immune interactions at mucosal barrier surfaces, like the gill and the skin of fish, areas densely populated by different immune cells and sensory nerves that constantly sense and adapt to tissue-specific environmental challenges. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- John Ndegwa Maina
- Department of Zoology, Auckland Park Campus, University of Johannesburg, Johannesburg, South Africa
| | - Jose Manuel Icardo
- Department of Anatomy and Cell Biology, Faculty of Medicine, University of Cantabria, Santander, Spain
| | - Giacomo Zaccone
- Department of Veterinary Sciences, Polo Universitario dell'Annunziata, University of Messina, Italy
| | - Marialuisa Aragona
- Department of Veterinary Sciences, Polo Universitario dell'Annunziata, University of Messina, Italy
| | - Eugenia Rita Lauriano
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Italy
| | - Alessio Alesci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Italy
| | - Marco Albano
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Italy
| | - Maria Cristina Guerrera
- Department of Veterinary Sciences, Polo Universitario dell'Annunziata, University of Messina, Italy
| | - Antonino Germana
- Department of Veterinary Sciences, Polo Universitario dell'Annunziata, University of Messina, Italy
| | | | - Viswanath Kiron
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Gioele Capillo
- Department of Veterinary Sciences, Polo Universitario dell'Annunziata, University of Messina, Italy.,Institute for Marine Biological Resources and Biotechnology (IRBIM) , National Research Council (CNR), Section of Messina, Messina, Italy
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Abstract
The carotid body (CB) is a bilateral arterial chemoreceptor located in the carotid artery bifurcation with an essential role in cardiorespiratory homeostasis. It is composed of highly perfused cell clusters, or glomeruli, innervated by sensory fibers. Glomus cells, the most abundant in each glomerulus, are neuron-like multimodal sensory elements able to detect and integrate changes in several physical and chemical parameters of the blood, in particular O2 tension, CO2 and pH, as well as glucose, lactate, or blood flow. Activation of glomus cells (e.g., during hypoxia or hypercapnia) stimulates the afferent fibers which impinge on brainstem neurons to elicit rapid compensatory responses (hyperventilation and sympathetic activation). This chapter presents an updated view of the structural organization of the CB and the mechanisms underlying the chemosensory responses of glomus cells, with special emphasis on the molecular processes responsible for acute O2 sensing. The properties of the glomus cell-sensory fiber synapse as well as the organization of CB output are discussed. The chapter includes the description of recently discovered CB stem cells and progenitor cells, and their role in CB growth during acclimatization to hypoxemia. Finally, the participation of the CB in the mechanisms of disease is briefly discussed.
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Affiliation(s)
- José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Seville, Spain; Biomedical Research Center for Neurodegenerative Diseases (CIBERNED), Madrid, Spain.
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Souza JR, Oliveira MD, Machado BH. Sustained hypoxia in mice increases parasympathetic but not sympathetic tone. Curr Res Physiol 2022; 5:361-368. [PMID: 36185816 PMCID: PMC9516409 DOI: 10.1016/j.crphys.2022.09.006] [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: 04/20/2022] [Revised: 08/22/2022] [Accepted: 09/20/2022] [Indexed: 11/18/2022] Open
Abstract
The autonomic profile of mice submitted to sustained hypoxia (SH) was not yet fully evaluated. Herein, we characterized the cardiovascular and autonomic profile of conscious freely moving mice submitted to SH using two sequential experimental protocols to evaluate the parasympathetic and sympathetic tone to the heart and the sympathetic tone to the vascular resistance. In the first protocol the sequence of antagonists was methyl-atropine followed by propranolol and then by prazosin, while in the second protocol the sequence was propranolol followed by methyl-atropine and then by prazosin. In SH the baseline heart rate was significantly lower than in control mice and the antagonism of the parasympathetic and sympathetic tone to the heart in both experimental protocols indicated an increased parasympathetic tone in SH mice and no changes in the sympathetic tone. Antagonism of the sympathetic tone to the vascular resistance with prazosin produced similar changes in arterial pressure in control and SH mice. Altogether these findings support the concept that mice submitted to SH present a significant increase in the parasympathetic but not in the sympathetic tone, which may explain why the baseline arterial pressure was not increased in SH mice. Autonomic profile of awake mice submitted to sustained hypoxia (SH) was evaluated by sequential pharmacological antagonists. Baseline heart rate in SH mice was lower and the tachycardic response to methyl-atropine was greater than in control mice. Fall in mean arterial pressure in response to prazosin was similar in control and SH mice. Parasympathetic tone to the heart of mice submitted to SH is increased while the overall sympathetic tone is not. These findings contribute to explain why mice, different of rats, are not hypertensive in response to SH.
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7
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Abstract
Oxygen (O2) is essential for life and therefore the supply of sufficient O2 to the tissues is a major physiological challenge. In mammals, a deficit of O2 (hypoxia) triggers rapid cardiorespiratory reflexes (e.g. hyperventilation and increased heart output) that within a few seconds increase the uptake of O2 by the lungs and its distribution throughout the body. The prototypical acute O2-sensing organ is the carotid body (CB), which contains sensory glomus cells expressing O2-regulated ion channels. In response to hypoxia, glomus cells depolarize and release transmitters which activate afferent fibers terminating at the brainstem respiratory and autonomic centers. In this review, we summarize the basic properties of CB chemoreceptor cells and the essential role played by their specialized mitochondria in acute O2 sensing and signaling. We focus on recent data supporting a "mitochondria-to-membrane signaling" model of CB chemosensory transduction. The possibility that the differential expression of specific subunit isoforms and enzymes could allow mitochondria to play a generalized adaptive O2-sensing and signaling role in a wide variety of cells is also discussed.
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Affiliation(s)
- José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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8
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Anand H, Ende V, Singh G, Qureshi I, Duong TQ, Mehler MF. Nervous System-Systemic Crosstalk in SARS-CoV-2/COVID-19: A Unique Dyshomeostasis Syndrome. Front Neurosci 2021; 15:727060. [PMID: 34512253 PMCID: PMC8430330 DOI: 10.3389/fnins.2021.727060] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/30/2021] [Indexed: 01/05/2023] Open
Abstract
SARS-CoV-2 infection is associated with a spectrum of acute neurological syndromes. A subset of these syndromes promotes higher in-hospital mortality than is predicted by traditional parameters defining critical care illness. This suggests that deregulation of components of the central and peripheral nervous systems compromises the interplay with systemic cellular, tissue and organ interfaces to mediate numerous atypical manifestations of COVID-19 through impairments in organismal homeostasis. This unique dyshomeostasis syndrome involves components of the ACE-2/1 lifecycles, renin-angiotensin system regulatory axes, integrated nervous system functional interactions and brain regions differentially sculpted by accelerated evolutionary processes and more primordial homeostatic functions. These biological contingencies suggest a mechanistic blueprint to define long-term neurological sequelae and systemic manifestations such as premature aging phenotypes, including organ fibrosis, tissue degeneration and cancer. Therapeutic initiatives must therefore encompass innovative combinatorial agents, including repurposing FDA-approved drugs targeting components of the autonomic nervous system and recently identified products of SARS-CoV-2-host interactions.
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Affiliation(s)
- Harnadar Anand
- The Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Victoria Ende
- Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, United States
| | - Gurinder Singh
- Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, United States
| | - Irfan Qureshi
- The Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY, United States
- Biohaven Pharmaceuticals, New Haven, CT, United States
| | - Tim Q. Duong
- Department of Radiology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, United States
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Mark F. Mehler
- The Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY, United States
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, NY, United States
- Institute for Brain Disorders and Neural Regeneration, Albert Einstein College of Medicine, Bronx, NY, United States
- Rose F. Kennedy Center for Intellectual and Developmental Disabilities, Albert Einstein College of Medicine, Bronx, NY, United States
- Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, United States
- Gottesman Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY, United States
- Center for Epigenomics, Albert Einstein College of Medicine, Bronx, NY, United States
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Ogoh S, Washio T, Stacey BS, Tsukamoto H, Iannetelli A, Owens TS, Calverley TA, Fall L, Marley CJ, Saito S, Watanabe H, Hashimoto T, Ando S, Miyamoto T, Bailey DM. Integrated respiratory chemoreflex-mediated regulation of cerebral blood flow in hypoxia: Implications for oxygen delivery and acute mountain sickness. Exp Physiol 2021; 106:1922-1938. [PMID: 34318560 DOI: 10.1113/ep089660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/20/2021] [Indexed: 12/30/2022]
Abstract
NEW FINDINGS What is the central question of this study? To what extent do hypoxia-induced changes in the peripheral and central respiratory chemoreflex modulate anterior and posterior cerebral oxygen delivery, with corresponding implications for susceptibility to acute mountain sickness? What is the main finding and its importance? We provide evidence for site-specific regulation of cerebral blood flow in hypoxia that preserves oxygen delivery in the posterior but not the anterior cerebral circulation, with minimal contribution from the central respiratory chemoreflex. External carotid artery vasodilatation might prove to be an alternative haemodynamic risk factor that predisposes to acute mountain sickness. ABSTRACT The aim of the present study was to determine the extent to which hypoxia-induced changes in the peripheral and central respiratory chemoreflex modulate anterior and posterior cerebral blood flow (CBF) and oxygen delivery (CDO2 ), with corresponding implications for the pathophysiology of the neurological syndrome, acute mountain sickness (AMS). Eight healthy men were randomly assigned single blind to 7 h of passive exposure to both normoxia (21% O2 ) and hypoxia (12% O2 ). The peripheral and central respiratory chemoreflex, internal carotid artery, external carotid artery (ECA) and vertebral artery blood flow (duplex ultrasound) and AMS scores (questionnaires) were measured throughout. A reduction in internal carotid artery CDO2 was observed during hypoxia despite a compensatory elevation in perfusion. In contrast, vertebral artery and ECA CDO2 were preserved, and the former was attributable to a more marked increase in perfusion. Hypoxia was associated with progressive activation of the peripheral respiratory chemoreflex (P < 0.001), whereas the central respiratory chemoreflex remained unchanged (P > 0.05). Symptom severity in participants who developed clinical AMS was positively related to ECA blood flow (Lake Louise score, r = 0.546-0.709, P = 0.004-0.043; Environmental Symptoms Questionnaires-Cerebral symptoms score, r = 0.587-0.771, P = 0.001-0.027, n = 4). Collectively, these findings highlight the site-specific regulation of CBF in hypoxia that maintains CDO2 selectively in the posterior but not the anterior cerebral circulation, with minimal contribution from the central respiratory chemoreflex. Furthermore, ECA vasodilatation might represent a hitherto unexplored haemodynamic risk factor implicated in the pathophysiology of AMS.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan.,Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Hayato Tsukamoto
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK.,Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Angelo Iannetelli
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Thomas S Owens
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Thomas A Calverley
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Lewis Fall
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Christopher J Marley
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan
| | - Takeshi Hashimoto
- Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Soichi Ando
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | | | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
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10
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Batista LA, Lopes JB, Brianis RC, Haibara AS, Moreira FA. Intravenous doxapram administration as a potential model of panic attacks in rats. Behav Pharmacol 2021; 32:182-193. [PMID: 33136614 DOI: 10.1097/fbp.0000000000000594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Panic disorder can be categorized into the nonrespiratory or the respiratory subtypes, the latter comprising dyspnea, shortness of breath, chest pain, feelings of suffocation, and paresthesias. Doxapram is an analeptic capable of inducing panic attacks with respiratory symptoms in individuals diagnosed with the disorder; however, its neuroanatomical targets and its effects on experimental animals remain uncharacterized. One of the brain regions proposed to trigger panic attacks is the midbrain periaqueductal gray (PAG). Therefore, in this study, we evaluated the effects of doxapram in Fos (c-Fos) protein expression in the PAG and characterized its cardiorespiratory and behavioral effects on the elevated T maze and in the conditioned place aversion (CPA) paradigms. Doxapram increased Fos expression in different columns of the PAG, increased respiratory frequency, decreased heart rate, and increased arterial pressure when injected via intravenous route. Alprazolam, a panicolytic benzodiazepine, injected via intraperitoneal route, decreased respiratory frequency, whereas URB597, an anandamide hydrolysis inhibitor injected via intraperitoneal route, was ineffective. Doxapram injected via intraperitoneal route induced an anxiogenic-like effect in the elevated T-maze model; however, it failed to induce CPA. This study suggests that the cardiorespiratory and behavioral effects of doxapram in rodents serve as an experimental model that can provide insights into the neurobiology of panic attacks.
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Affiliation(s)
| | | | | | - Andrea S Haibara
- Departament of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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11
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Rodrigues KL, Souza JR, Bazilio DS, de Oliveira M, Moraes MPS, Moraes DJA, Machado BH. Changes in the autonomic and respiratory patterns in mice submitted to short-term sustained hypoxia. Exp Physiol 2021; 106:759-770. [PMID: 33501717 DOI: 10.1113/ep089323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/20/2021] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of this study? Do mice submitted to sustained hypoxia present autonomic and respiratory changes similarly to rats? What is the main finding and its importance? Arterial pressure in the normal range, reduced baseline heart rate and tachypnoea were observed in behaving sustained hypoxia mice. Recordings in the in situ preparation of mice submitted to sustained hypoxia show an increase in cervical vagus nerve activity and a simultaneous reduction in thoracic sympathetic nerve activity correlated with changes in the respiratory cycle. Therefore, mice are an important model for studies on the modulation of sympathetic activity to the cardiovascular system and the vagus innervation of the upper airways due to changes in the respiratory network induced by sustained hypoxia. ABSTRACT Short-term sustained hypoxia (SH) in rats induces sympathetic overactivity and hypertension due to changes in sympathetic-respiratory coupling. However, there are no consistent data about the effect of SH on mice due to the different protocols of hypoxia and difficulties associated with the handling of these rodents under different experimental conditions. In situ recordings of autonomic and respiratory nerves in SH mice have not been performed yet. Herein, we evaluated the effects of SH ( F i O 2 = 0.1 for 24 h) on baseline mean arterial pressure (MAP), heart rate (HR), respiratory frequency (fR ) and responses to chemoreflex activation in behaving SH mice. A characterization of changes in cervical vagus (cVN), thoracic sympathetic (tSN), phrenic (PN) and abdominal (AbN) nerves in SH mice using the in situ working heart-brainstem preparation was also performed. SH mice presented normal MAP, significant reduction in baseline HR, increase in baseline fR , as well as increase in the magnitude of bradycardic response to chemoreflex activation. In in situ preparations, SH mice presented a reduction in PN discharge frequency, and increases in the time of expiration and incidence of late-expiratory bursts in AbN activity. Nerve recordings also indicated a significant increase in cVN activity and a significant reduction in tSN activity during expiration in SH mice. These findings make SH mice an important experimental model for better understanding how changes in the respiratory network may impact on the modulation of vagal control to the upper airways, as well as in the sympathetic activity to the cardiovascular system.
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Affiliation(s)
- Karla L Rodrigues
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Juliana R Souza
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Darlan S Bazilio
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Mauro de Oliveira
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Melina P S Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Davi J A Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
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Bazilio DS, Rodrigues KL, Moraes DJA, Machado BH. Distinct cardiovascular and respiratory responses to short-term sustained hypoxia in juvenile Sprague Dawley and Wistar Hannover rats. Auton Neurosci 2020; 230:102746. [PMID: 33260056 DOI: 10.1016/j.autneu.2020.102746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 12/01/2022]
Abstract
Short-term sustained hypoxia (SH) elicits active expiration, augmented late-expiratory (late-E) sympathetic activity, increased arterial pressure and ventilation, and amplified sympathetic and abdominal expiratory responses to chemoreflex activation in rats of the Wistar-Ribeirão Preto (WRP) strain. Herein, we investigated whether SH can differentially affect the cardiovascular and respiratory outcomes of Sprague-Dawley (SD) and Wistar Hannover (WH) rats and compared the results with previous data using WRP rats. For this, we exposed SD and WH rats to SH (FiO2 = 0.1) for 24 h and evaluated arterial pressure, sympathetic activity, and respiratory pattern. SD rats presented increased arterial pressure, respiratory rate and tidal volume, as well as augmented late-E expiratory motor output and increased sympathetic outflow due to post-inspiratory and late-E sympathetic overactivity. WH rats presented reduced changes, suggesting lower responsiveness of this strain to this SH protocol. The magnitudes of changes in sympathetic and abdominal expiratory motor activities to chemoreflex activation in SD rats were reduced by SH. Pressor responses to chemoreflex activation were shown to be blunted in SD and WH rats after SH. The data are showing that SD, WH, and WRP rat strains exhibit marked differences in their cardiovascular, autonomic and respiratory responses to 24-h SH and draw attention to the importance of rat strain for studies exploring the underlying mechanisms involved in the neuronal changes induced by the experimental model of SH.
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Affiliation(s)
- Darlan S Bazilio
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Karla L Rodrigues
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Davi J A Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil.
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Spiller PF, da Silva MP, Moraes DJA. Lactate does not activate the carotid body of Wistar rat. Respir Physiol Neurobiol 2020; 285:103593. [PMID: 33276092 DOI: 10.1016/j.resp.2020.103593] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/06/2020] [Accepted: 11/26/2020] [Indexed: 12/19/2022]
Abstract
The carotid body's glomus cells are the primary sensors of hypoxia in mammals. Previous studies suggested that the glomus cells' hypoxia sensitivity is mediated by lactate in mice. This molecule increases the intracellular [Ca2+] and induces exocytosis in glomus cells, activating the carotid sinus nerve (the axons of chemoreceptive petrosal neurons). On the other hand, how lactate affects the activity of carotid body of rats is still unknown. We hypothesized that lactate activates the carotid body of rats. In Wistar rats, we measured the changes in the electrical properties of isolated glomus cells and petrosal chemoreceptive neurons in in situ preparations in response to different concentrations of lactate. Superfusion of both physiological and supraphysiological concentrations of lactate did not affect the membrane conductance and potential of glomus cells. Moreover, lactate injected into the carotid body did not activate the anatomically and physiologically identified chemoreceptive petrosal neurons. We conclude that the carotid body of Wistar rats is not sensitive to lactate.
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Affiliation(s)
- Pedro F Spiller
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Melina P da Silva
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Davi J A Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
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14
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Prasad A, Prasad M. Single Virus Targeting Multiple Organs: What We Know and Where We Are Heading? Front Med (Lausanne) 2020; 7:370. [PMID: 32850890 PMCID: PMC7419463 DOI: 10.3389/fmed.2020.00370] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/17/2020] [Indexed: 12/14/2022] Open
Abstract
COVID-19 caused by SARS-CoV-2 has already infected more than 6. 3 million people worldwide as of 1st June 2020 and caused a global medical emergency. Healthcare professionals have been struggling to devise appropriate therapeutic strategies against the virus mainly due to the diverse range of symptoms and multiple-organ failure in infected patients. Several broad-spectrum antiviral drugs are being used for treatment; however, there is yet no specific drug or vaccine against the virus. Multiple-organ failure due to hyperactivity of the immune system resulting in cytokine storms is a major reason for death among the 5% critically ill patients. In this article, we have discussed the damage caused by COVID-19 on different organs of the human body.
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Rocha MP, Campos MO, Mattos JD, Mansur DE, Rocha HNM, Secher NH, Nóbrega ACL, Fernandes IA. K ATP channels modulate cerebral blood flow and oxygen delivery during isocapnic hypoxia in humans. J Physiol 2020; 598:3343-3356. [PMID: 32463117 DOI: 10.1113/jp279751] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/11/2020] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS ATP-sensitive K+ (KATP ) channels mediate hypoxia-induced cerebral vasodilatation and hyperperfusion in animals. We tested whether KATP channels blockade affects the increase in human cerebral blood flow (CBF) and the maintenance of oxygen delivery (CDO2 ) during hypoxia. Hypoxia-induced increases in the anterior circulation and total cerebral perfusion were attenuated under KATP channels blockade affecting the relative changes of brain oxygen delivery. Therefore, in humans, KATP channels activation modulates the vascular tone in the anterior circulation of the brain, contributing to CBF and CDO2 responses to hypoxia. ABSTRACT ATP-sensitive K+ (KATP ) channels mediate hypoxia-induced cerebral vasodilatation and hyperperfusion in animals. We tested whether KATP channels blockade affects the increase in cerebral blood flow (CBF) and the maintenance of oxygen delivery (CDO2 ) during hypoxia in humans. Nine healthy men were exposed to 5-min trials of normoxia and isocapnic hypoxia (IHX, 10% O2 ) before (BGB) and 3 h after glibenclamide ingestion (AGB). Mean arterial pressure (MAP), arterial saturation ( S a O 2 ), partial pressure of oxygen ( P a O 2 ) and carbon dioxide ( P aC O 2 ), internal carotid artery blood flow (ICABF), vertebral artery blood flow (VABF), total (t)CBF (Doppler ultrasound) and CDO2 were quantified during the trials. IHX provoked similar reductions in S a O 2 and P a O 2 , while MAP was not affected by oxygen desaturation or KATP blockade. A smaller increase in ICABF (ΔBGB: 36 ± 23 vs. ΔAGB 11 ± 18%, p = 0.019) but not in VABF (∆BGB 26 ± 21 vs. ∆AGB 27 ± 27%, p = 0.893) was observed during the hypoxic trial under KATP channels blockade. Thus, IHX-induced increases in tCBF (∆BGB 32 ± 19 vs. ∆AGB 14 ± 13%, p = 0.012) and CDO2 relative changes (∆BGB 7 ± 13 vs. ∆AGB -6 ± 14%, p = 0.048) were attenuated during the AGB hypoxic trial. In a separate protocol, 6 healthy men (5 from protocol 1) underwent a 5-min exposure to normoxia and IHX before and 3 h after placebo (5 mg of cornstarch) ingestion. IHX reduced S a O 2 and P a O 2 , but placebo did not affect the ICABF, VABF, tCBF, or CDO2 responses. Therefore, in humans, KATP channels activation modulates vascular tone in the anterior rather than the posterior circulation of the brain, contributing to tCBF and CDO2 responses to hypoxia.
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Affiliation(s)
- Marcos P Rocha
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Helena N M Rocha
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Niels H Secher
- Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Igor A Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brazil
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16
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Yadav AK, Yadav PK, Chaudhary GR, Tiwari M, Gupta A, Sharma A, Pandey AN, Pandey AK, Chaube SK. Autophagy in hypoxic ovary. Cell Mol Life Sci 2019; 76:3311-3322. [PMID: 31062072 PMCID: PMC11105528 DOI: 10.1007/s00018-019-03122-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 03/30/2019] [Accepted: 04/29/2019] [Indexed: 12/19/2022]
Abstract
Oxygen deprivation affects human health by modulating system as well as cellular physiology. Hypoxia generates reactive oxygen species (ROS), causes oxidative stress and affects female reproductive health by altering ovarian as well as oocyte physiology in mammals. Hypoxic conditions lead to several degenerative changes by inducing various cell death pathways like autophagy, apoptosis and necrosis in the follicle of mammalian ovary. The encircling somatic cell death interrupts supply of nutrients to the oocyte and nutrient deprivation may result in the generation of ROS. Increased level of ROS could induce granulosa cells as well as oocyte autophagy. Although autophagy removes damaged proteins and subcellular organelles to maintain the cell survival, irreparable damages could induce cell death within intra-follicular microenvironment. Hypoxia-induced autophagy is operated through 5' AMP activated protein kinase-mammalian target of rapamycin, endoplasmic reticulum stress/unfolded protein response and protein kinase C delta-c-junN terminal kinase 1 pathways in a wide variety of somatic cell types. Similar to somatic cells, we propose that hypoxia may induce granulosa cell as well as oocyte autophagy and it could be responsible at least in part for germ cell elimination from mammalian ovary. Hypoxia-mediated germ cell depletion may cause several reproductive impairments including early menopause in mammals.
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Affiliation(s)
- Anil Kumar Yadav
- Cell Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Pramod K Yadav
- Cell Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Govind R Chaudhary
- Cell Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Meenakshi Tiwari
- Cell Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Anumegha Gupta
- Cell Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Alka Sharma
- Cell Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Ashutosh N Pandey
- Cell Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Ajai K Pandey
- Department of Kayachikitsa, Faculty of Ayurveda, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 221005, India
| | - Shail K Chaube
- Cell Physiology Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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17
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Talal S, Ayali A, Gefen E. Respiratory gas levels interact to control ventilatory motor patterns in isolated locust ganglia. ACTA ACUST UNITED AC 2019; 222:jeb.195388. [PMID: 30910833 DOI: 10.1242/jeb.195388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 03/19/2019] [Indexed: 11/20/2022]
Abstract
Large insects actively ventilate their tracheal system even at rest, using abdominal pumping movements, which are controlled by a central pattern generator (CPG) in the thoracic ganglia. We studied the effects of respiratory gases on the ventilatory rhythm by isolating the thoracic ganglia and perfusing its main tracheae with various respiratory gas mixtures. Fictive ventilation activity was recorded from motor nerves controlling spiracular and abdominal ventilatory muscles. Both hypoxia and hypercapnia increased the ventilation rate, with the latter being much more potent. Sub-threshold hypoxic and hypercapnic levels were still able to modulate the rhythm as a result of interactions between the effects of the two respiratory gases. Additionally, changing the oxygen levels in the bathing saline affected ventilation rate, suggesting a modulatory role for haemolymph oxygen. Central sensing of both respiratory gases as well as interactions of their effects on the motor output of the ventilatory CPG reported here indicate convergent evolution of respiratory control among terrestrial animals of distant taxa.
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Affiliation(s)
- Stav Talal
- School of Zoology, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Amir Ayali
- School of Zoology, Tel Aviv University, Tel Aviv 6997801, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv-Yafo 6997801, Israel
| | - Eran Gefen
- Department of Biology, University of Haifa-Oranim, Tivon 3600600, Israel
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18
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Accorsi-Mendonça D, Bonagamba LGH, Machado BH. Astrocytic modulation of glutamatergic synaptic transmission is reduced in NTS of rats submitted to short-term sustained hypoxia. J Neurophysiol 2019; 121:1822-1830. [PMID: 30892977 DOI: 10.1152/jn.00279.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Sustained hypoxia (SH) activates chemoreceptors to produce cardiovascular and respiratory responses to bring the arterial partial pressure of O2 back to the physiological range. We evaluated the effect of SH (fraction of inspired O2 = 0.10, 24 h) on glutamatergic synaptic transmission and the interaction neuron-astrocyte in neurons of the nucleus tractus solitarii (NTS). Tractus solitarius (TS) fiber stimulation induced glutamatergic currents in neurons and astrocytes. SH increased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate (AMPA/kainate) [-183 ± 122 pA (n = 10) vs. -353 ± 101 pA (n = 10)] and N-methyl-d-aspartate (NMDA) current amplitude [61 ± 10 pA (n = 7) vs. 102 ± 37 pA (n = 10)]. To investigate the effects of SH, we used fluoroacetate (FAC), an astrocytic inhibitor, which revealed an excitatory modulation on AMPA/kainate current and an inhibitory modulation of NMDA current in control rats. SH blunted the astrocytic modulation of AMPA [artificial cerebrospinal fluid (aCSF): -353 ± 101 pA vs. aCSF + FAC: -369 ± 76 pA (n = 10)] and NMDA currents [aCSF: 102 ± 37 pA vs. aCSF + FAC: 108 ± 32 pA (n = 10)]. SH increased AMPA current density [control: -6 ± 3.5 pA/pF (n = 6) vs. SH: -20 ± 12 pA/pF (n = 7)], suggesting changes in density, conductance, or affinity of AMPA receptors. SH produced no effect on astrocytic resting membrane potential, input resistance, and AMPA/kainate current. We conclude that SH decreased the neuron-astrocyte interaction at the NTS level, facilitating the glutamatergic transmission, which may contribute to the enhancement of cardiovascular and respiratory responses to baro- and chemoreflexes activation in SH rats. NEW & NOTEWORTHY Using an electrophysiological approach, we have shown that in nucleus tractus solitarii (NTS) from control rats, astrocytes modulate the AMPA and NMDA currents in NTS neurons, changing their excitability. Sustained hypoxia (SH) increased both glutamatergic currents in NTS neurons due to 1) a reduction in the astrocytic modulation and 2) an increase in the density of AMPA receptors. These new findings show the importance of neuron-astrocyte modulation in the excitatory synaptic transmission in NTS of control and SH rats.
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Affiliation(s)
- Daniela Accorsi-Mendonça
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo , Ribeirão Preto, São Paulo , Brazil
| | - Leni G H Bonagamba
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo , Ribeirão Preto, São Paulo , Brazil
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo , Ribeirão Preto, São Paulo , Brazil
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19
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Bailey DM. Making sense of oxygen; quantum leaps with ‘physics‐iology’. Exp Physiol 2019; 104:453-457. [DOI: 10.1113/ep087546] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 01/03/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Damian Miles Bailey
- Neurovascular Research Laboratory Faculty of Life Sciences and Education University of South Wales Pontypridd UK
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20
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Bailey DM. Oxygen, evolution and redox signalling in the human brain; quantum in the quotidian. J Physiol 2018; 597:15-28. [PMID: 30315729 DOI: 10.1113/jp276814] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 09/27/2018] [Indexed: 12/20/2022] Open
Abstract
Rising atmospheric oxygen (O2 ) levels provided a selective pressure for the evolution of O2 -dependent micro-organisms that began with the autotrophic eukaryotes. Since these primordial times, the respiring mammalian cell has become entirely dependent on the constancy of electron flow, with molecular O2 serving as the terminal electron acceptor in mitochondrial oxidative phosphorylation. Indeed, the ability to 'sense' O2 and maintain homeostasis is considered one of the most important roles of the central nervous system (CNS) and probably represented a major driving force in the evolution of the human brain. Today, modern humans have evolved with an oversized brain committed to a continually active state and, as a consequence, paradoxically vulnerable to failure if the O2 supply is interrupted. However, our pre-occupation with O2 , the elixir of life, obscures the fact that it is a gas with a Janus face, capable of sustaining life in physiologically controlled amounts yet paradoxically deadly to the CNS when in excess. A closer look at its quantum structure reveals precisely why; the triplet ground state diatomic O2 molecule is paramagnetic and exists in air as a free radical, constrained from reacting aggressively with the brain's organic molecules due to its 'spin restriction', a thermodynamic quirk of evolutionary fate. By further exploring O2 's free radical 'quantum quirkiness', including emergent (quantum) physiological phenomena, our understanding of precisely how the human brain senses O2 deprivation (hypoxia) and the elaborate redox-signalling defence mechanisms that defend O2 homeostasis has the potential to offer unique insights into the pathophysiology and treatment of human brain disease.
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Affiliation(s)
- Damian Miles Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Wales, UK
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21
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Brown AG, Thapa M, Hooker JW, Ostrowski TD. Impaired chemoreflex correlates with decreased c-Fos in respiratory brainstem centers of the streptozotocin-induced Alzheimer's disease rat model. Exp Neurol 2018; 311:285-292. [PMID: 30359566 DOI: 10.1016/j.expneurol.2018.10.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/17/2018] [Accepted: 10/20/2018] [Indexed: 12/29/2022]
Abstract
Besides impairment in cognition and memory, patients with Alzheimer's disease (AD) often exhibit marked dysfunction in respiratory control. Sleep-disordered breathing (SDB) is commonly found in cases of AD, resulting in periods of hypoxia during sleep. Early structural changes in brainstem areas controlling respiratory function may account for SDB in the course of AD. However, to date the underlying mechanisms for these complications are not known. The streptozotocin (STZ)-induced rat model of AD exhibits abnormal responses to hypoxia and increased astrogliosis in a key region for respiratory control. In this study we further defined the pathophysiological respiratory response of STZ-AD rats to 10% O2. In addition, we analyzed hypoxia-induced neuronal activation in respiratory and cardiovascular nuclei of the dorsal and ventral brainstem. Two hours of hypoxia induced a transient increase in tidal volume that was followed by a prolonged increase in respiratory rate. Only respiratory rate was significantly blunted in the STZ-AD model, which continued over the entire duration of the hypoxic episode. Analysis of c-Fos expression as a marker for neuronal activation showed abundant labeling throughout the nTS, nuclei of the ventral respiratory column, and A1/C1 cells of cardiovascular centers in the ventral brainstem. STZ-AD rats showed a significant decrease of c-Fos labeling in the caudal/medial nTS, rostral ventral respiratory group, and Bötzinger complex. c-Fos in other respiratory centers and A1/C1 cells was unaltered when compared to control. The results of this study document a region-specific impact of STZ-induced AD in respiratory brainstem nuclei. This decrease in c-Fos expression correlates with the observed blunting of respiration to hypoxia in the STZ-AD rat model.
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Affiliation(s)
- Andrea G Brown
- Department of Physiology, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences, Kirksville, MO, USA
| | - Mahima Thapa
- Department of Biology, Truman State University, Kirksville, MO, USA
| | - John W Hooker
- Department of Biology, Truman State University, Kirksville, MO, USA
| | - Tim D Ostrowski
- Department of Physiology, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences, Kirksville, MO, USA.
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22
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Bailey DM. RETRACTED ARTICLE: The quantum physiology of oxygen; from electrons to the evolution of redox signaling in the human brain. Bioelectron Med 2018; 4:13. [PMID: 32232089 PMCID: PMC7098224 DOI: 10.1186/s42234-018-0014-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 09/19/2018] [Indexed: 12/11/2022] Open
Abstract
Rising atmospheric oxygen (O2) levels provided a selective pressure for the evolution of O2-dependent micro-organisms that began with the autotrophic eukaryotes. Since these primordial times, the respiring mammalian cell has become entirely dependent on the constancy of electron flow with molecular O2 serving as the terminal electron acceptor in mitochondrial oxidative phosphorylation. Indeed, the ability to “sense” O2 and maintain homeostasis is considered one of the most important roles of the central nervous system (CNS) and likely represented a major driving force in the evolution of the human brain. Today, modern humans have evolved with an oversized brain committed to a continually active state and as a consequence, paradoxically vulnerable to failure if the O2 supply is interrupted. However, our pre-occupation with O2, the elixir of life, obscures the fact that it is a gas with a Janus Face, capable of sustaining life in physiologically controlled amounts yet paradoxically deadly to the CNS when in excess. A closer look at its quantum structure reveals precisely why; the triplet ground state diatomic O2 molecule is paramagnetic and exists in air as a free radical, constrained from reacting aggressively with the brain’s organic molecules due to its “spin restriction”, a thermodynamic quirk of evolutionary fate. By further exploring O2’s free radical “quantum quirkiness” including emergent quantum physiological phenomena, our understanding of precisely how the human brain senses O2 deprivation (hypoxia) and the elaborate redox-signaling defense mechanisms that defend O2 homeostasis has the potential to offer unique insights into the pathophysiology and treatment of human brain disease.
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Affiliation(s)
- Damian Miles Bailey
- Neurovascular Research Laboratory, Alfred Russel Wallace Building, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, CF37 4AT UK
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23
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Bilateral carotid sinus nerve transection exacerbates morphine-induced respiratory depression. Eur J Pharmacol 2018; 834:17-29. [PMID: 30012498 DOI: 10.1016/j.ejphar.2018.07.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 07/06/2018] [Accepted: 07/12/2018] [Indexed: 01/04/2023]
Abstract
Opioid-induced respiratory depression (OIRD) involves decreased sensitivity of ventilatory control systems to decreased blood levels of oxygen (hypoxia) and elevated levels of carbon dioxide (hypercapnia). Understanding the sites and mechanisms by which opioids elicit respiratory depression is pivotal for finding novel therapeutics to prevent and/or reverse OIRD. To examine the contribution of carotid body chemoreceptors OIRD, we used whole-body plethysmography to evaluate hypoxic (HVR) and hypercapnic (HCVR) ventilatory responses including changes in frequency of breathing, tidal volume, minute ventilation and inspiratory drive, after intravenous injection of morphine (10 mg/kg) in sham-operated (SHAM) and in bilateral carotid sinus nerve transected (CSNX) Sprague-Dawley rats. In SHAM rats, morphine produced sustained respiratory depression (e.g., decreases in tidal volume, minute ventilation and inspiratory drive) and reduced the HVR and HCVR responses. Unexpectedly, morphine-induced suppression of HVR and HCVR were substantially greater in CSNX rats than in SHAM rats. This suggests that morphine did not compromise the function of the carotid body-chemoafferent complex and indeed, that the carotid body acts to defend against morphine-induced respiratory depression. These data are the first in vivo evidence that carotid body chemoreceptor afferents defend against rather than participate in OIRD in conscious rats. As such, drugs that stimulate ventilation by targeting primary glomus cells and/or chemoafferent terminals in the carotid bodies may help to alleviate OIRD.
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Fernandes IA, Rocha MP, Campos MO, Mattos JD, Mansur DE, Rocha HNM, Terra PAC, Garcia VP, Rocha NG, Secher NH, Nóbrega ACL. Reduced arterial vasodilatation in response to hypoxia impairs cerebral and peripheral oxygen delivery in hypertensive men. J Physiol 2018; 596:1167-1179. [PMID: 29462837 DOI: 10.1113/jp275545] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 01/16/2018] [Indexed: 01/31/2023] Open
Abstract
KEY POINTS Hypoxaemia evokes a repertoire of homeostatic adjustments that maintain oxygen supply to organs and tissues including the brain and skeletal muscles. Because hypertensive patients have impaired endothelial-dependent vasodilatation and an increased sympathetic response to arterial oxygen desaturation, we investigated whether hypertension impairs isocapnic hypoxia-induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. In middle-aged hypertensive men, vertebral and femoral artery blood flow do not increase in response to isocapnic hypoxia, limiting brain and peripheral hyperaemia and oxygen supply. Increased chemoreflex-induced sympathetic activation impairs skeletal muscle perfusion and oxygen supply, whereas an attenuation of local vasodilatory signalling in the posterior cerebrovasculature reduced brain hyperperfusion of hypertensive middle-aged men in response to isocapnic hypoxia. ABSTRACT The present study investigated whether hypertension impairs isocapnic hypoxia (IH)-induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. Oxygen saturation (oxymetry), mean arterial pressure (photoplethysmography) and muscle sympathetic nerve activity (MSNA; microneugraphy), as well as femoral artery (FA), internal carotid artery and vertebral artery (VA) blood flow (BF; Doppler ultrasound), were quantified in nine normotensive (NT) (aged 40 ± 11 years, systolic pressure 119 ± 7 mmHg and diastolic pressure 73 ± 6 mmHg) and nine hypertensive men (HT) (aged 44 ± 12 years, systolic pressure 152 ± 11 mmHg and diastolic pressure 90 ± 9 mmHg) during 5 min of normoxia (21% O2 ) and IH (10% O2 ). Total cerebral blood flow (tCBF), brain (CDO2 ) and leg (LDO2 ) oxygen delivery were estimated. IH provoked similar oxygen desaturation without changing mean arterial pressure. Internal carotid artery perfusion increased in both groups during IH. However, VA and FA BF only increased in NT. Thus, IH-induced increase in tCBF was smaller in HT. CDO2 only increased in NT and LDO2 decreased in HT. Furthermore, IH evoked a greater increase in HT MSNA. Changes in MSNA were inversely related to FA BF, LDO2 and end-tidal oxygen tension. In conclusion, hypertension disturbs regional and total cerebrovascular and peripheral responses to IH and consequently limits oxygen supply to the brain and skeletal muscle. Although increased chemoreflex-induced sympathetic activation may explain impaired peripheral perfusion, attenuated vasodilatory signalling in the posterior cerebrovasculature appears to be responsible for the small increase in tCBF when HT were exposed to IH.
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Affiliation(s)
- Igor A Fernandes
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Marcos P Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Helena N M Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Paulo A C Terra
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Vinícius P Garcia
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Natália G Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
| | - Niels H Secher
- Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, RJ, Brazil
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Amorim MR, de Deus JL. Purinergic signalling and TRPV1 receptors are associated with the carotid body plasticity induced by an apnoea-like stimulus. J Physiol 2018; 596:2961-2962. [PMID: 29478282 DOI: 10.1113/jp275889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Mateus Ramos Amorim
- Department of Morphology, Physiology, and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Júnia Lara de Deus
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
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26
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Agnati LF, Guidolin D, Maura G, Marcoli M. Functional roles of three cues that provide nonsynaptic modes of communication in the brain: electromagnetic field, oxygen, and carbon dioxide. J Neurophysiol 2017; 119:356-368. [PMID: 29070628 DOI: 10.1152/jn.00413.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The integrative actions of the brain depend on the exchange of information among its computational elements. Hence, this phenomenon plays the key role in driving the complex dynamics of the central nervous system, in which true computations interact with noncomputational dynamical processes to generate brain representations of the body and of the body in the external world, and hence the finalistic behavior of the organism. In this context, it should be pointed out that, besides the intercellular interactions mediated by classical electrochemical signals, other types of interactions, namely, "cues" and "coercions," also appear to be exploited by the system to achieve its function. The present review focuses mainly on cues present in the environment and on those produced by cells of the body, which "pervade" the brain and contribute to its dynamics. These cues can also be metabolic substrates, and, in most cases, they are of fundamental importance to brain function and the survival of the entire organism. Three of these highly pervasive cues will be analyzed in greater detail, namely, oxygen, carbon dioxide, and electromagnetic fields (EMF). Special emphasis will be placed on EMF, since several authors have suggested that these highly pervasive energy fluctuations may play an important role in the global integrative actions of the brain; hence, EMF signaling may transcend classical connectionist models of brain function. Thus the new concept of "broadcasted neuroconnectomics" has been introduced, which transcends the current connectomics view of the brain.
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Affiliation(s)
- Luigi F Agnati
- Department of Diagnostics, Clinical Medicine and Public Health, University of Modena and Reggio Emilia , Modena , Italy.,Department of Neuroscience, Karolinska Institutet , Stockholm , Sweden
| | - Diego Guidolin
- Department of Neuroscience, University of Padova , Padua , Italy
| | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova , Genoa , Italy
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova , Genoa , Italy
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27
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Sá RWM, Haibara AS, Gomes PM, Aguiar GL, Nascimento RSL, Pedrosa ML, Alzamora AC, de Oliveira LB, Cardoso LM. Changes in cardiovascular responses to chemoreflex activation of rats recovered from protein restriction are not related to AT 1 receptors. Exp Physiol 2017; 102:34-47. [PMID: 27763697 DOI: 10.1113/ep085791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 10/17/2016] [Indexed: 12/18/2022]
Abstract
NEW FINDINGS What is the central question of this study? In this study, we sought to investigate whether cardiovascular responses to peripheral chemoreflex activation of rats recovered from protein restriction are related to activation of AT1 receptors. What is the main finding and its importance? This study highlights the fact that angiotensinergic mechanisms activated by AT1 receptors do not support increased responses to peripheral chemoreflex activation by KCN in rats recovered from protein restriction. Also, we found that protein restriction led to increased resting ventilation in adult rats, even after recovery. The effects of a low-protein diet followed by recovery on cardiorespiratory responses to peripheral chemoreflex activation were tested before and after systemic angiotensin II type 1 (AT1 ) receptor antagonism. Male Fischer rats were divided into control and recovered (R-PR) groups after weaning. The R-PR rats were fed a low-protein (8%) diet for 35 days and recovered with a normal protein (20%) diet for 70 days. Control rats received a normal protein diet for 105 days (CG105 ). After cannulation surgery, mean arterial pressure, heart rate, respiratory frequency, tidal volume and minute ventilation were acquired using a digital recording system in freely moving rats. The role of angintensin II was evaluated by systemic antagonism of AT1 receptors with losartan (20 mg kg-1 i.v.). The peripheral chemoreflex was elicited by increasing doses of KCN (20-160 μg kg min-1 , i.v.). At baseline, R-PR rats presented increased heart rate and minute ventilation (372 ± 34 beats min-1 and 1.274 ± 377 ml kg-1 min-1 ) compared with CG105 animals (332 ± 22 beats min-1 and 856 ± 112 ml kg-1 min-1 ). Mean arterial pressure was not different between the groups. Pressor and bradycardic responses evoked by KCN (60 μg kg-1 ) were increased in R-PR (+45 ± 13 mmHg and -77 ± 47 beats min-1 ) compared with CG105 rats (+25 ± 17 mmHg and -27 ± 28 beats min-1 ), but no difference was found in the tachypnoeic response. These differences were preserved after losartan. The data suggest that angiotensin II acting on AT1 receptors may not be associated with the increased heart rate, increased minute ventilation and acute cardiovascular responses to peripheral chemoreflex activation in rats that underwent postweaning protein restriction followed by recovery.
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Affiliation(s)
- Renato Willian Martins Sá
- Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto - Campus Universitário Morro do Cruzeiro, 35, 400-000, Ouro Preto, MG, Brazil
| | - Andrea Siqueira Haibara
- Department of Physiology and Biophysics, ICB, Federal University of Minas Gerais, 31, 270-910, Belo Horizonte, MG, Brazil
| | - Paula Magalhães Gomes
- Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto - Campus Universitário Morro do Cruzeiro, 35, 400-000, Ouro Preto, MG, Brazil
| | - Giovana Lopes Aguiar
- Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto - Campus Universitário Morro do Cruzeiro, 35, 400-000, Ouro Preto, MG, Brazil
| | - Rafael Souza Leopoldino Nascimento
- Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto - Campus Universitário Morro do Cruzeiro, 35, 400-000, Ouro Preto, MG, Brazil
| | - Maria Lucia Pedrosa
- Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto - Campus Universitário Morro do Cruzeiro, 35, 400-000, Ouro Preto, MG, Brazil
| | - Andréia Carvalho Alzamora
- Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto - Campus Universitário Morro do Cruzeiro, 35, 400-000, Ouro Preto, MG, Brazil
| | - Lisandra Brandino de Oliveira
- Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto - Campus Universitário Morro do Cruzeiro, 35, 400-000, Ouro Preto, MG, Brazil
| | - Leonardo Máximo Cardoso
- Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto - Campus Universitário Morro do Cruzeiro, 35, 400-000, Ouro Preto, MG, Brazil
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28
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Narkiewicz K, Ratcliffe LEK, Hart EC, Briant LJB, Chrostowska M, Wolf J, Szyndler A, Hering D, Abdala AP, Manghat N, Burchell AE, Durant C, Lobo MD, Sobotka PA, Patel NK, Leiter JC, Engelman ZJ, Nightingale AK, Paton JFR. Unilateral Carotid Body Resection in Resistant Hypertension: A Safety and Feasibility Trial. ACTA ACUST UNITED AC 2016; 1:313-324. [PMID: 27766316 PMCID: PMC5063532 DOI: 10.1016/j.jacbts.2016.06.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 06/06/2016] [Accepted: 06/07/2016] [Indexed: 11/17/2022]
Abstract
Animal and human data indicate pathological afferent signaling emanating from the carotid body that drives sympathetically mediated elevations in blood pressure in conditions of hypertension. This first-in-man, proof-of-principle study tested the safety and feasibility of unilateral carotid body resection in 15 patients with drug-resistant hypertension. The procedure proved to be safe and feasible. Overall, no change in blood pressure was found. However, 8 patients showed significant reductions in ambulatory blood pressure coinciding with decreases in sympathetic activity. The carotid body may be a novel target for treating an identifiable subpopulation of humans with hypertension.
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Key Words
- ABP, ambulatory blood pressure
- ASBP, ambulatory systolic blood pressure
- BRS, baroreceptor reflex sensitivity
- CB, carotid body
- HRV, heart rate variability
- HVR, hypoxic ventilatory response
- MSNA, muscle sympathetic nerve activity
- OBP, office blood pressure
- OSBP, office systolic blood pressure
- afferent drive
- baroreceptor reflex
- hypertension
- hypoxia
- peripheral chemoreceptor
- sympathetic nervous system
- uCB, unilateral carotid body
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Affiliation(s)
- Krzysztof Narkiewicz
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Laura E K Ratcliffe
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Emma C Hart
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom; School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Linford J B Briant
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Marzena Chrostowska
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Jacek Wolf
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Anna Szyndler
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Dagmara Hering
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Ana P Abdala
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Nathan Manghat
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Amy E Burchell
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Claire Durant
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Melvin D Lobo
- NIHR Barts Cardiovascular Biomedical Research Unit, William Harvey Research Institute, QMUL, Charterhouse Square, London, United Kingdom
| | - Paul A Sobotka
- Department of Internal Medicine, Division of Cardiovascular Diseases, The Ohio State University, Columbus, Ohio
| | - Nikunj K Patel
- Neurosurgery, North Bristol NHS Trust, Southmead Hospital, Bristol, United Kingdom
| | - James C Leiter
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
| | | | - Angus K Nightingale
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Julian F R Paton
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
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Catecholamine secretion by chemical hypoxia in guinea-pig, but not rat, adrenal medullary cells: differences in mitochondria. Neuroscience 2015; 301:134-43. [PMID: 26047729 DOI: 10.1016/j.neuroscience.2015.05.080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 02/07/2023]
Abstract
The effects of mitochondrial inhibitors (CN(-), a complex IV inhibitor and CCCP, protonophore) on catecholamine (CA) secretion and mitochondrial function were explored functionally and biochemically in rat and guinea-pig adrenal chromaffin cells. Guinea-pig chromaffin cells conspicuously secreted CA in response to CN(-) or CCCP, but rat cells showed a little, if any, secretory response to either of them. The resting metabolic rates in rat adrenal medullae did not differ from those in guinea-pig adrenal medullae. On the other hand, the time course of depolarization of the mitochondrial membrane potential (ΔΨm) in guinea-pig chromaffin cells in response to CN(-) was slower than that in rat chromaffin cells, and this difference was abolished by oligomycin, an F1F0-ATPase inhibitor. The extent of CCCP-induced decrease in cellular ATP in guinea-pig chromaffin cells, which was indirectly measured using a Mg(2+) indicator, was smaller than that in rat chromaffin cells. Relative expression levels of F1F0-ATPase inhibitor factor in guinea-pig adrenal medullae were smaller than in rat adrenal medullae, and the opposite was true for F1F0-ATPase α subunit. The present results indicate that guinea-pig chromaffin cells secrete more CA in response to a mitochondrial inhibitor than rat chromaffin cells and this higher susceptibility in the former is accounted for by a larger extent of reversed operation of F1F0-ATPase with the consequent decrease in ATP under conditions where ΔΨm is depolarized.
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Critchley HD, Nicotra A, Chiesa PA, Nagai Y, Gray MA, Minati L, Bernardi L. Slow breathing and hypoxic challenge: cardiorespiratory consequences and their central neural substrates. PLoS One 2015; 10:e0127082. [PMID: 25973923 PMCID: PMC4431729 DOI: 10.1371/journal.pone.0127082] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 04/11/2015] [Indexed: 11/19/2022] Open
Abstract
Controlled slow breathing (at 6/min, a rate frequently adopted during yoga practice) can benefit cardiovascular function, including responses to hypoxia. We tested the neural substrates of cardiorespiratory control in humans during volitional controlled breathing and hypoxic challenge using functional magnetic resonance imaging (fMRI). Twenty healthy volunteers were scanned during paced (slow and normal rate) breathing and during spontaneous breathing of normoxic and hypoxic (13% inspired O2) air. Cardiovascular and respiratory measures were acquired concurrently, including beat-to-beat blood pressure from a subset of participants (N = 7). Slow breathing was associated with increased tidal ventilatory volume. Induced hypoxia raised heart rate and suppressed heart rate variability. Within the brain, slow breathing activated dorsal pons, periaqueductal grey matter, cerebellum, hypothalamus, thalamus and lateral and anterior insular cortices. Blocks of hypoxia activated mid pons, bilateral amygdalae, anterior insular and occipitotemporal cortices. Interaction between slow breathing and hypoxia was expressed in ventral striatal and frontal polar activity. Across conditions, within brainstem, dorsal medullary and pontine activity correlated with tidal volume and inversely with heart rate. Activity in rostroventral medulla correlated with beat-to-beat blood pressure and heart rate variability. Widespread insula and striatal activity tracked decreases in heart rate, while subregions of insular cortex correlated with momentary increases in tidal volume. Our findings define slow breathing effects on central and cardiovascular responses to hypoxic challenge. They highlight the recruitment of discrete brainstem nuclei to cardiorespiratory control, and the engagement of corticostriatal circuitry in support of physiological responses that accompany breathing regulation during hypoxic challenge.
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Affiliation(s)
- Hugo D. Critchley
- Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
- Sackler Centre for Consciousness Science, University of Sussex, Brighton, United Kingdom
- * E-mail:
| | - Alessia Nicotra
- Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Patrizia A. Chiesa
- Department of Psychology, Sapienza University of Rome, Rome, Italy
- Ghermann Laboratory, University of Queensland, Queensland, Australia
| | - Yoko Nagai
- Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | | | | | - Luciano Bernardi
- Department of Internal Medicine, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
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