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Trevizan-Baú P, Stanić D, Furuya WI, Dhingra RR, Dutschmann M. Neuroanatomical frameworks for volitional control of breathing and orofacial behaviors. Respir Physiol Neurobiol 2024; 323:104227. [PMID: 38295924 DOI: 10.1016/j.resp.2024.104227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/22/2024] [Accepted: 01/25/2024] [Indexed: 02/16/2024]
Abstract
Breathing is the only vital function that can be volitionally controlled. However, a detailed understanding how volitional (cortical) motor commands can transform vital breathing activity into adaptive breathing patterns that accommodate orofacial behaviors such as swallowing, vocalization or sniffing remains to be developed. Recent neuroanatomical tract tracing studies have identified patterns and origins of descending forebrain projections that target brain nuclei involved in laryngeal adductor function which is critically involved in orofacial behavior. These nuclei include the midbrain periaqueductal gray and nuclei of the respiratory rhythm and pattern generating network in the brainstem, specifically including the pontine Kölliker-Fuse nucleus and the pre-Bötzinger complex in the medulla oblongata. This review discusses the functional implications of the forebrain-brainstem anatomical connectivity that could underlie the volitional control and coordination of orofacial behaviors with breathing.
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Affiliation(s)
- Pedro Trevizan-Baú
- The Florey Institute, University of Melbourne, Victoria, Australia; Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Davor Stanić
- The Florey Institute, University of Melbourne, Victoria, Australia
| | - Werner I Furuya
- The Florey Institute, University of Melbourne, Victoria, Australia
| | - Rishi R Dhingra
- The Florey Institute, University of Melbourne, Victoria, Australia; Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Mathias Dutschmann
- The Florey Institute, University of Melbourne, Victoria, Australia; Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, OH, USA.
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Kola G, Clifford CW, Campanaro CK, Dhingra RR, Dutschmann M, Jacono FJ, Dick TE. Peritoneal sepsis caused by Escherichia coli triggers brainstem inflammation and alters the function of sympatho-respiratory control circuits. J Neuroinflammation 2024; 21:45. [PMID: 38331902 PMCID: PMC10854125 DOI: 10.1186/s12974-024-03025-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/19/2024] [Indexed: 02/10/2024] Open
Abstract
BACKGROUND Sepsis has a high mortality rate due to multiple organ failure. However, the influence of peripheral inflammation on brainstem autonomic and respiratory circuits in sepsis is poorly understood. Our working hypothesis is that peripheral inflammation affects central autonomic circuits and consequently contributes to multiorgan failure in sepsis. METHODS In an Escherichia coli (E. coli)-fibrin clot model of peritonitis, we first recorded ventilatory patterns using plethysmography before and 24 h after fibrin clot implantation. To assess whether peritonitis was associated with brainstem neuro-inflammation, we measured cytokine and chemokine levels in Luminex assays. To determine the effect of E. coli peritonitis on brainstem function, we assessed sympatho-respiratory nerve activities at baseline and during brief (20 s) hypoxemic ischemia challenges using in situ-perfused brainstem preparations (PBPs) from sham or infected rats. PBPs lack peripheral organs and blood, but generate vascular tone and in vivo rhythmic activities in thoracic sympathetic (tSNA), phrenic and vagal nerves. RESULTS Respiratory frequency was greater (p < 0.001) at 24 h post-infection with E. coli than in the sham control. However, breath-by-breath variability and total protein in the BALF did not differ. IL-1β (p < 0.05), IL-6 (p < 0.05) and IL-17 (p < 0.04) concentrations were greater in the brainstem of infected rats. In the PBP, integrated tSNA (p < 0.05) and perfusion pressure were greater (p < 0.001), indicating a neural-mediated pathophysiological high sympathetic drive. Moreover, respiratory frequency was greater (p < 0.001) in PBPs from infected rats than from sham rats. Normalized phase durations of inspiration and expiration were greater (p < 0.009, p < 0.015, respectively), but the post-inspiratory phase (p < 0.007) and the breath-by-breath variability (p < 0.001) were less compared to sham PBPs. Hypoxemic ischemia triggered a biphasic response, respiratory augmentation followed by depression. PBPs from infected rats had weaker respiratory augmentation (p < 0.001) and depression (p < 0.001) than PBPs from sham rats. In contrast, tSNA in E. coli-treated PBPs was enhanced throughout the entire response to hypoxemic ischemia (p < 0.01), consistent with sympathetic hyperactivity. CONCLUSION We show that peripheral sepsis caused brainstem inflammation and impaired sympatho-respiratory motor control in a single day after infection. We conclude that central sympathetic hyperactivity may impact vital organ systems in sepsis.
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Affiliation(s)
- Gjinovefa Kola
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Caitlyn W Clifford
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Cara K Campanaro
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Rishi R Dhingra
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Mathias Dutschmann
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, 44106, USA
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, BRB 319, Cleveland, OH, 44106-1714, USA.
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
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Dhingra RR, Furuya WI, Yoong YK, Dutschmann M. The pre-Bötzinger complex is necessary for the expression of inspiratory and post-inspiratory motor discharge of the vagus. Respir Physiol Neurobiol 2024; 320:104202. [PMID: 38049044 DOI: 10.1016/j.resp.2023.104202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 12/06/2023]
Abstract
The mammalian three-phase respiratory motor pattern of inspiration, post-inspiration and expiration is expressed in spinal and cranial motor nerve discharge and is generated by a distributed ponto-medullary respiratory pattern generating network. Respiratory motor pattern generation depends on a rhythmogenic kernel located within the pre-Bötzinger complex (pre-BötC). In the present study, we tested the effect of unilateral and bilateral inactivation of the pre-BötC after local microinjection of the GABAA receptor agonist isoguvacine (10 mM, 50 nl) on phrenic (PNA), hypoglossal (HNA) and vagal nerve (VNA) respiratory motor activities in an in situ perfused brainstem preparation of rats. Bilateral inactivation of the pre-BötC triggered cessation of phrenic (PNA), hypoglossal (HNA) and vagal (VNA) nerve activities for 15-20 min. Ipsilateral isoguvacine injections into the pre-BötC triggered transient (6-8 min) cessation of inspiratory and post-inspiratory VNA (p < 0.001) and suppressed inspiratory HNA by - 70 ± 15% (p < 0.01), while inspiratory PNA burst frequency increased by 46 ± 30% (p < 0.01). Taken together, these observations confirm the role of the pre-BötC as the rhythmogenic kernel of the mammalian respiratory network in situ and highlight a significant role for the pre-BötC in the transmission of vagal inspiratory and post-inspiratory pre-motor drive to the nucleus ambiguus.
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Affiliation(s)
- Rishi R Dhingra
- The Florey Department of Neuroscience & Mental Health, University of Melbourne, Parkville, Australia; Division of Pulmonary, Critical Care & Sleep, Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Werner I Furuya
- The Florey Department of Neuroscience & Mental Health, University of Melbourne, Parkville, Australia
| | - Yi Kee Yoong
- The Florey Department of Neuroscience & Mental Health, University of Melbourne, Parkville, Australia
| | - Mathias Dutschmann
- The Florey Department of Neuroscience & Mental Health, University of Melbourne, Parkville, Australia; Division of Pulmonary, Critical Care & Sleep, Department of Medicine, Case Western Reserve University, Cleveland, OH, USA.
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Bathgate RAD, Praveen P, Sethi A, Furuya WI, Dhingra RR, Kocan M, Ou Q, Valkovic AL, Gil-Miravet I, Navarro-Sánchez M, Olucha-Bordonau FE, Gundlach AL, Rosengren KJ, Gooley PR, Dutschmann M, Hossain MA. Noncovalent Peptide Stapling Using Alpha-Methyl-l-Phenylalanine for α-Helical Peptidomimetics. J Am Chem Soc 2023; 145:20242-20247. [PMID: 37439676 DOI: 10.1021/jacs.3c02743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Peptides and peptidomimetics are attractive drug candidates because of their high target specificity and low-toxicity profiles. Developing peptidomimetics using hydrocarbon (HC)-stapling or other stapling strategies has gained momentum because of their high stability and resistance to proteases; however, they have limitations. Here, we take advantage of the α-methyl group and an aromatic phenyl ring in a unique unnatural amino acid, α-methyl-l-phenylalanine (αF), and propose a novel, noncovalent stapling strategy to stabilize peptides. We utilized this strategy to create an α-helical B-chain mimetic of a complex insulin-like peptide, human relaxin-3 (H3 relaxin). Our comprehensive data set (in vitro, ex vivo, and in vivo) confirmed that the new high-yielding B-chain mimetic, H3B10-27(13/17αF), is remarkably stable in serum and fully mimics the biological function of H3 relaxin. H3B10-27(13/17αF) is an excellent scaffold for further development as a drug lead and an important tool to decipher the physiological functions of the neuropeptide G protein-coupled receptor, RXFP3.
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Affiliation(s)
- Ross A D Bathgate
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Praveen Praveen
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Ashish Sethi
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3052, Australia
- Australian Nuclear Science Technology Organisation, The Australian Synchrotron, Clayton, VIC 3168, Australia
| | - Werner I Furuya
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Rishi R Dhingra
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Martina Kocan
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Qinghao Ou
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Adam L Valkovic
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Isis Gil-Miravet
- Predepartmental Unit of Medicine, Faculty of Health Sciences, Universitat Jaume I, Avenida de Vicent Sos Baynat, s/n, 12071 Castelló de La Plana, Spain
| | - Mónica Navarro-Sánchez
- Predepartmental Unit of Medicine, Faculty of Health Sciences, Universitat Jaume I, Avenida de Vicent Sos Baynat, s/n, 12071 Castelló de La Plana, Spain
| | - Francisco E Olucha-Bordonau
- Predepartmental Unit of Medicine, Faculty of Health Sciences, Universitat Jaume I, Avenida de Vicent Sos Baynat, s/n, 12071 Castelló de La Plana, Spain
| | - Andrew L Gundlach
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3052, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - K Johan Rosengren
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Paul R Gooley
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3052, Australia
- Bio21 Molecular Science and Biotechnology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Mathias Dutschmann
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Mohammed Akhter Hossain
- The Florey, The University of Melbourne, Parkville, VIC 3052, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3052, Australia
- School of Chemistry, The University of Melbourne, Parkville, VIC 3052, Australia
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Paton JFR, Machado BH, Moraes DJA, Zoccal DB, Abdala AP, Smith JC, Antunes VR, Murphy D, Dutschmann M, Dhingra RR, McAllen R, Pickering AE, Wilson RJA, Day TA, Barioni NO, Allen AM, Menuet C, Donnelly J, Felippe I, St-John WM. Advancing respiratory-cardiovascular physiology with the working heart-brainstem preparation over 25 years. J Physiol 2022; 600:2049-2075. [PMID: 35294064 PMCID: PMC9322470 DOI: 10.1113/jp281953] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 03/04/2022] [Indexed: 11/24/2022] Open
Abstract
Twenty‐five years ago, a new physiological preparation called the working heart–brainstem preparation (WHBP) was introduced with the claim it would provide a new platform allowing studies not possible before in cardiovascular, neuroendocrine, autonomic and respiratory research. Herein, we review some of the progress made with the WHBP, some advantages and disadvantages along with potential future applications, and provide photographs and technical drawings of all the customised equipment used for the preparation. Using mice or rats, the WHBP is an in situ experimental model that is perfused via an extracorporeal circuit benefitting from unprecedented surgical access, mechanical stability of the brain for whole cell recording and an uncompromised use of pharmacological agents akin to in vitro approaches. The preparation has revealed novel mechanistic insights into, for example, the generation of distinct respiratory rhythms, the neurogenesis of sympathetic activity, coupling between respiration and the heart and circulation, hypothalamic and spinal control mechanisms, and peripheral and central chemoreceptor mechanisms. Insights have been gleaned into diseases such as hypertension, heart failure and sleep apnoea. Findings from the in situ preparation have been ratified in conscious in vivo animals and when tested have translated to humans. We conclude by discussing potential future applications of the WHBP including two‐photon imaging of peripheral and central nervous systems and adoption of pharmacogenetic tools that will improve our understanding of physiological mechanisms and reveal novel mechanisms that may guide new treatment strategies for cardiorespiratory diseases.
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Affiliation(s)
- Julian F R Paton
- Manaaki Manawa - The Centre for Heart Research, Faculty of Medical & Health Science, University of Auckland, Park Road, Grafton, Auckland, 1142, New Zealand
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Davi J A Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University, Araraquara, São Paulo, Brazil
| | - Ana P Abdala
- School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol, England, BS8 1TD, UK
| | - Jeffrey C Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Vagner R Antunes
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Mathias Dutschmann
- Florey institute of Neuroscience and Mental Health, University of Melbourne, 30, Royal Parade, Parkville, Victoria, 3052, Australia
| | - Rishi R Dhingra
- Florey institute of Neuroscience and Mental Health, University of Melbourne, 30, Royal Parade, Parkville, Victoria, 3052, Australia
| | - Robin McAllen
- Florey institute of Neuroscience and Mental Health, University of Melbourne, 30, Royal Parade, Parkville, Victoria, 3052, Australia
| | - Anthony E Pickering
- School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol, England, BS8 1TD, UK
| | - Richard J A Wilson
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Trevor A Day
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Nicole O Barioni
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrew M Allen
- Department of Anatomy & Physiology, The University of Melbourne, Victoria, 3010, Australia
| | - Clément Menuet
- Institut de Neurobiologie de la Méditerranée, INMED UMR1249, INSERM, Aix-Marseille Université, Marseille, France
| | - Joseph Donnelly
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
| | - Igor Felippe
- Manaaki Manawa - The Centre for Heart Research, Faculty of Medical & Health Science, University of Auckland, Park Road, Grafton, Auckland, 1142, New Zealand
| | - Walter M St-John
- Emeritus Professor, Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Dartmouth, New Hampshire, USA
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Trevizan-Baú P, Furuya WI, Mazzone SB, Stanić D, Dhingra RR, Dutschmann M. Reciprocal connectivity of the periaqueductal gray with the ponto-medullary respiratory network in rat. Brain Res 2021; 1757:147255. [PMID: 33515533 DOI: 10.1016/j.brainres.2020.147255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/14/2020] [Accepted: 12/17/2020] [Indexed: 01/08/2023]
Abstract
Synaptic activities of the periaqueductal gray (PAG) can modulate or appropriate the respiratory motor activities in the context of behavior and emotion via descending projections to nucleus retroambiguus. However, alternative anatomical pathways for the mediation of PAG-evoked respiratory modulation via core nuclei of the brainstem respiratory network remains only partially described. We injected the retrograde tracer Cholera toxin subunit B (CT-B) in the pontine Kölliker-Fuse nucleus (KFn, n = 5), medullary Bötzinger (BötC, n = 3) and pre-Bötzinger complexes (pre-BötC; n = 3), and the caudal raphé nuclei (n = 3), and quantified the descending connectivity of the PAG targeting these brainstem respiratory regions. CT-B injections in the KFn, pre-BötC, and caudal raphé, but not in the BötC, resulted in CT-B-labeled neurons that were predominantly located in the lateral and ventrolateral PAG columns. In turn, CT-B injections in the lateral and ventrolateral PAG columns (n = 4) produced the highest numbers of CT-B-labeled neurons in the KFn and far fewer numbers of labeled neurons in the pre-BötC, BötC, and caudal raphé. Analysis of the relative projection strength revealed that the KFn shares the densest reciprocal connectivity with the PAG (ventrolateral and lateral columns, in particular). Overall, our data imply that the PAG may engage a distributed respiratory rhythm and pattern generating network beyond the nucleus retroambiguus to mediate downstream modulation of breathing. However, the reciprocal connectivity of the KFn and PAG suggests specific roles for synaptic interaction between these two nuclei that are most likely related to the regulation of upper airway patency during vocalization or other volitional orofacial behaviors.
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Affiliation(s)
- Pedro Trevizan-Baú
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Werner I Furuya
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Stuart B Mazzone
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Davor Stanić
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Rishi R Dhingra
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, VIC 3010, Australia.
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Furuya WI, Dhingra RR, Trevizan-Baú P, McAllen RM, Dutschmann M. The role of glycinergic inhibition in respiratory pattern formation and cardio-respiratory coupling in rats. Curr Res Physiol 2021; 4:80-93. [PMID: 34746829 PMCID: PMC8562146 DOI: 10.1016/j.crphys.2021.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 02/11/2021] [Accepted: 03/12/2021] [Indexed: 01/08/2023] Open
Abstract
Cardio-respiratory coupling is reflected as respiratory sinus arrhythmia (RSA) and inspiratory-related bursting of sympathetic nerve activity. Inspiratory-related inhibitory and/or postinspiratory-related excitatory drive of cardiac vagal motoneurons (CVMs) can generate RSA. Since respiratory oscillations may depend on synaptic inhibition, we investigated the effects of blocking glycinergic neurotransmission (systemic and local application of the glycine receptor (GlyR) antagonist, strychnine) on the expression of the respiratory motor pattern, RSA and sympatho-respiratory coupling. We recorded heart-rate, phrenic, recurrent laryngeal and thoracic sympathetic nerve activities (PNA, RLNA, t-SNA) in a working-heart-brainstem preparation of rats, and show that systemic strychnine (50–200 nM) abolished RSA and triggered a shift of postinspiratory RLNA into inspiration, while t-SNA remained unchanged. Bilateral strychnine microinjection into the ventrolateral medullary area containing CVMs and laryngeal motoneurons (LMNs) of the nucleus ambiguus (NA/CVLM), the nucleus tractus solitarii, pre-Bötzinger Complex, Bötzinger Complex or Kölliker-Fuse nuclei revealed that only NA/CVLM strychnine microinjections mimicked the effects of systemic application. In all other target nuclei, except the Bötzinger Complex, GlyR-blockade attenuated the inspiratory-tachycardia of the RSA to a similar degree while evoking only a modest change in respiratory motor patterning, without changing the timing of postinspiratory-RLNA, or t-SNA. Thus, glycinergic inhibition at the motoneuronal level is involved in the generation of RSA and the separation of inspiratory and postinspiratory bursting of LMNs. Within the distributed ponto-medullary respiratory pre-motor network, local glycinergic inhibition contribute to the modulation of RSA tachycardia, respiratory frequency and phase duration but, surprisingly it had no major role in the mediation of respiratory-sympathetic coupling. Glycinergic inhibition controls inspiratory tachycardia via inhibition of cardiac vagal motoneurons. Glycinergic inhibition controls the discharge pattern of expiratory laryngeal motoneurons. Glycinergic neurotransmission has no major role in pattern formation at the pre-motor level. Glycinergic inhibition has no role in sympatho-respiratory coupling.
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Trevizan-Baú P, Dhingra RR, Furuya WI, Stanić D, Mazzone SB, Dutschmann M. Forebrain projection neurons target functionally diverse respiratory control areas in the midbrain, pons, and medulla oblongata. J Comp Neurol 2020; 529:2243-2264. [PMID: 33340092 DOI: 10.1002/cne.25091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/25/2020] [Accepted: 11/29/2020] [Indexed: 12/12/2022]
Abstract
Eupnea is generated by neural circuits located in the ponto-medullary brainstem, but can be modulated by higher brain inputs which contribute to volitional control of breathing and the expression of orofacial behaviors, such as vocalization, sniffing, coughing, and swallowing. Surprisingly, the anatomical organization of descending inputs that connect the forebrain with the brainstem respiratory network remains poorly defined. We hypothesized that descending forebrain projections target multiple distributed respiratory control nuclei across the neuroaxis. To test our hypothesis, we made discrete unilateral microinjections of the retrograde tracer cholera toxin subunit B in the midbrain periaqueductal gray (PAG), the pontine Kölliker-Fuse nucleus (KFn), the medullary Bötzinger complex (BötC), pre-BötC, or caudal midline raphé nuclei. We quantified the regional distribution of retrogradely labeled neurons in the forebrain 12-14 days postinjection. Overall, our data reveal that descending inputs from cortical areas predominantly target the PAG and KFn. Differential forebrain regions innervating the PAG (prefrontal, cingulate cortices, and lateral septum) and KFn (rhinal, piriform, and somatosensory cortices) imply that volitional motor commands for vocalization are specifically relayed via the PAG, while the KFn may receive commands to coordinate breathing with other orofacial behaviors (e.g., sniffing, swallowing). Additionally, we observed that the limbic or autonomic (interoceptive) systems are connected to broadly distributed downstream bulbar respiratory networks. Collectively, these data provide a neural substrate to explain how volitional, state-dependent, and emotional modulation of breathing is regulated by the forebrain.
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Affiliation(s)
- Pedro Trevizan-Baú
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Rishi R Dhingra
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Werner I Furuya
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Davor Stanić
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Stuart B Mazzone
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
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Dhingra RR, Furuya WI, Dick TE, Dutschmann M. Response to: The post-inspiratory complex (PiCo), what is the evidence? J Physiol 2020; 599:361-362. [PMID: 33197048 DOI: 10.1113/jp280958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 11/09/2020] [Indexed: 12/14/2022] Open
Affiliation(s)
- Rishi R Dhingra
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, 30 Royal Parade, Parkville, Victoria, Australia
| | - Werner I Furuya
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, 30 Royal Parade, Parkville, Victoria, Australia
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep, Department of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, USA
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, 30 Royal Parade, Parkville, Victoria, Australia
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10
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Dutschmann M, Bautista TG, Trevizan-Baú P, Dhingra RR, Furuya WI. The pontine Kölliker-Fuse nucleus gates facial, hypoglossal, and vagal upper airway related motor activity. Respir Physiol Neurobiol 2020; 284:103563. [PMID: 33053424 DOI: 10.1016/j.resp.2020.103563] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/04/2020] [Accepted: 10/06/2020] [Indexed: 01/31/2023]
Abstract
The pontine Kölliker-Fuse nucleus (KFn) is a core nucleus of respiratory network that mediates the inspiratory-expiratory phase transition and gates eupneic motor discharges in the vagal and hypoglossal nerves. In the present study, we investigated whether the same KFn circuit may also gate motor activities that control the resistance of the nasal airway, which is of particular importance in rodents. To do so, we simultaneously recorded phrenic, facial, vagal and hypoglossal cranial nerve activity in an in situ perfused brainstem preparation before and after bilateral injection of the GABA-receptor agonist isoguvacine (50-70 nl, 10 mM) into the KFn (n = 11). Our results show that bilateral inhibition of the KFn triggers apneusis (prolonged inspiration) and abolished pre-inspiratory discharge of facial, vagal and hypoglossal nerves as well as post-inspiratory discharge in the vagus. We conclude that the KFn plays a critical role for the eupneic regulation of naso-pharyngeal airway patency and the potential functions of the KFn in regulating airway patency and orofacial behavior is discussed.
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Affiliation(s)
- M Dutschmann
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia.
| | - T G Bautista
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia
| | - P Trevizan-Baú
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia
| | - R R Dhingra
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia
| | - W I Furuya
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia
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11
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Soliz J, Schneider-Gasser EM, Arias-Reyes C, Aliaga-Raduan F, Poma-Machicao L, Zubieta-Calleja G, Furuya WI, Trevizan-Baú P, Dhingra RR, Dutschmann M. Coping with hypoxemia: Could erythropoietin (EPO) be an adjuvant treatment of COVID-19? Respir Physiol Neurobiol 2020; 279:103476. [PMID: 32522574 PMCID: PMC7275159 DOI: 10.1016/j.resp.2020.103476] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 05/29/2020] [Accepted: 05/30/2020] [Indexed: 12/13/2022]
Abstract
A very recent epidemiological study provides preliminary evidence that living in habitats located at 2500 m above sea level (masl) might protect from the development of severe respiratory symptoms following infection with the novel SARS-CoV-2 virus. This epidemiological finding raises the question of whether physiological mechanisms underlying the acclimatization to high altitude identifies therapeutic targets for the effective treatment of severe acute respiratory syndrome pivotal to the reduction of global mortality during the COVID-19 pandemic. This article compares the symptoms of acute mountain sickness (AMS) with those of SARS-CoV-2 infection and explores overlapping patho-physiological mechanisms of the respiratory system including impaired oxygen transport, pulmonary gas exchange and brainstem circuits controlling respiration. In this context, we also discuss the potential impact of SARS-CoV-2 infection on oxygen sensing in the carotid body. Finally, since erythropoietin (EPO) is an effective prophylactic treatment for AMS, this article reviews the potential benefits of implementing FDA-approved erythropoietin-based (EPO) drug therapies to counteract a variety of acute respiratory and non-respiratory (e.g. excessive inflammation of vascular beds) symptoms of SARS-CoV-2 infection.
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Affiliation(s)
- Jorge Soliz
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC, Canada; High Altitude Pulmonary and Pathology Institute IPPA, La Paz, Bolivia.
| | - Edith M Schneider-Gasser
- Institute of Veterinary Physiology, Vetsuisse-Faculty University of Zurich, Winterthurerstrasse 260, Switzerland
| | - Christian Arias-Reyes
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Fernanda Aliaga-Raduan
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Liliana Poma-Machicao
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC, Canada
| | | | - Werner I Furuya
- Florey Institute of Neuroscience and Mental Health, Melbourne Victoria, Australia; The Florey Department of Neuroscience, University of Melbourne, Melbourne Victoria, Australia
| | - Pedro Trevizan-Baú
- Florey Institute of Neuroscience and Mental Health, Melbourne Victoria, Australia; The Florey Department of Neuroscience, University of Melbourne, Melbourne Victoria, Australia
| | - Rishi R Dhingra
- Florey Institute of Neuroscience and Mental Health, Melbourne Victoria, Australia
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, Melbourne Victoria, Australia; The Florey Department of Neuroscience, University of Melbourne, Melbourne Victoria, Australia
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Dhingra RR, Dick TE, Furuya WI, Galán RF, Dutschmann M. Volumetric mapping of the functional neuroanatomy of the respiratory network in the perfused brainstem preparation of rats. J Physiol 2020; 598:2061-2079. [PMID: 32100293 DOI: 10.1113/jp279605] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 02/05/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The functional neuroanatomy of the mammalian respiratory network is far from being understood since experimental tools that measure neural activity across this brainstem-wide circuit are lacking. Here, we use silicon multi-electrode arrays to record respiratory local field potentials (rLFPs) from 196-364 electrode sites within 8-10 mm3 of brainstem tissue in single arterially perfused brainstem preparations with respect to the ongoing respiratory motor pattern of inspiration (I), post-inspiration (PI) and late-expiration (E2). rLFPs peaked specifically at the three respiratory phase transitions, E2-I, I-PI and PI-E2. We show, for the first time, that only the I-PI transition engages a brainstem-wide network, and that rLFPs during the PI-E2 transition identify a hitherto unknown role for the dorsal respiratory group. Volumetric mapping of pontomedullary rLFPs in single preparations could become a reliable tool for assessing the functional neuroanatomy of the respiratory network in health and disease. ABSTRACT While it is widely accepted that inspiratory rhythm generation depends on the pre-Bötzinger complex, the functional neuroanatomy of the neural circuits that generate expiration is debated. We hypothesized that the compartmental organization of the brainstem respiratory network is sufficient to generate macroscopic local field potentials (LFPs), and if so, respiratory (r) LFPs could be used to map the functional neuroanatomy of the respiratory network. We developed an approach using silicon multi-electrode arrays to record spontaneous LFPs from hundreds of electrode sites in a volume of brainstem tissue while monitoring the respiratory motor pattern on phrenic and vagal nerves in the perfused brainstem preparation. Our results revealed the expression of rLFPs across the pontomedullary brainstem. rLFPs occurred specifically at the three transitions between respiratory phases: (1) from late expiration (E2) to inspiration (I), (2) from I to post-inspiration (PI), and (3) from PI to E2. Thus, respiratory network activity was maximal at respiratory phase transitions. Spatially, the E2-I, and PI-E2 transitions were anatomically localized to the ventral and dorsal respiratory groups, respectively. In contrast, our data show, for the first time, that the generation of controlled expiration during the post-inspiratory phase engages a distributed neuronal population within ventral, dorsal and pontine network compartments. A group-wise independent component analysis demonstrated that all preparations exhibited rLFPs with a similar temporal structure and thus share a similar functional neuroanatomy. Thus, volumetric mapping of rLFPs could allow for the physiological assessment of global respiratory network organization in health and disease.
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Affiliation(s)
- Rishi R Dhingra
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, Melbourne, Australia
| | - Thomas E Dick
- Division of Pulmonary, Critical Care & Sleep, Department of Medicine, Case Western Reserve University, Cleveland, USA
| | - Werner I Furuya
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, Melbourne, Australia
| | - Roberto F Galán
- Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, USA
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience & Mental Health, University of Melbourne, Melbourne, Australia
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13
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Dhingra RR, Dick TE, Furuya WI, Galan RF, Dutschmann M. Volumetric mapping of the functional neuroanatomy of the brainstem respiratory network in the perfused brainstem preparation of rats. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.03710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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14
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Furuya WI, Dhingra RR, Gundlach AL, Hossain MA, Dutschmann M. Relaxin‐3 receptor (RXFP3) mediated modulation of central respiratory activity. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.04788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Bau PT, Dhingra RR, Furuya WI, Mazzone SB, Dutschmann M. Descending forebrain projections targeting respiratory control areas in the midbrain and brainstem of rats. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.03700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Furuya WI, Dhingra RR, Gundlach AL, Hossain MA, Dutschmann M. Relaxin-3 receptor (RXFP3) activation in the nucleus of the solitary tract modulates respiratory rate and the arterial chemoreceptor reflex in rat. Respir Physiol Neurobiol 2019; 271:103310. [PMID: 31568840 DOI: 10.1016/j.resp.2019.103310] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 11/25/2022]
Abstract
The neuropeptide relaxin-3 is expressed by the pontine nucleus incertus. Relaxin-3 and synthetic agonist peptides modulate arousal and cognitive processes via activation of the relaxin-family peptide 3 receptor (RXFP3). Despite the presence of RXFP3 in the nucleus of the solitary tract (NTS), the ability of RXFP3 to modulate NTS-mediated cardiorespiratory functions has not been explored. Therefore, we examined the effects of bilateral microinjections of the selective agonist, RXFP3-A2 (40 μM, 100 nL/side), into the NTS in perfused working-heart-brainstem-preparations from rats (n = 6), while recording phrenic, vagal, and thoracic sympathetic chain activity (PNA, VNA, t-SCA) and heart rate (HR). RXFP3-A2 significantly increased respiratory rate and shortened post-inspiratory VNA. RXFP3-A2 in the NTS also significantly enhanced arterial chemoreceptor reflex (a-CR)-mediated tachypnea. However, RXFP3-A2 had no significant effect on HR and t-SCA at baseline or during the a-CR. These data represent the first evidence that RXFP3 activation in the NTS can selectively modulate respiration at baseline and during reflex behaviour.
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Affiliation(s)
- Werner I Furuya
- The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Rishi R Dhingra
- The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Mohammad Akhter Hossain
- The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience and Mental Health, and Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3010, Australia.
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Trevizan-Baú P, Dhingra RR, Burrows EL, Dutschmann M, Stanić D. Tauopathy in the periaqueductal gray, kölliker-fuse nucleus and nucleus retroambiguus is not predicted by ultrasonic vocalization in tau-P301L mice. Behav Brain Res 2019; 369:111916. [PMID: 31004684 DOI: 10.1016/j.bbr.2019.111916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/15/2019] [Accepted: 04/15/2019] [Indexed: 10/27/2022]
Abstract
Upper airway and vocalization control areas such as the periaqueductal gray (PAG), kölliker-fuse nucleus (KF) and nucleus retroambiguus (NRA) are prone to developing tauopathy in mice expressing the mutant human tau P301L protein. Consequently, impaired ultrasonic vocalization (USV) previously identified in tau-P301L mice at the terminal disease stage of 8-9 months of age, was attributed to the presence of tauopathy in these regions. Our aim was to establish whether the onset of USV disorders manifest prior to the terminal stage, and if USV disorders are predictive of the presence of tauopathy in the PAG, KF and NRA. USVs produced by tau-P301L and wildtype mice aged 3-4, 5-6 or 8-9 months were recorded during male-female interaction. Immunohistochemistry was then performed to assess the presence or degree of tauopathy in the PAG, KF and NRA of mice displaying normal or abnormal USV patterns. Comparing various USV measurements, including the number, duration and frequency of calls, revealed no differences between tau-P301L and wildtype mice across all age groups, and linear discriminant analysis also failed to identify separate USV populations. Finally, the presence of tauopathy in the PAG, KF and NRA in individual tau-P301L mice did not reliably associate with USV disorders. Our findings that tauopathy in designated mammalian vocalization centres, such as the PAG, KF and NRA, did not associate with USV disturbances in tau-P301L mice questions whether USV phenotypes in this transgenic mouse are valid for studying tauopathy-related human voice and speech disorders.
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Affiliation(s)
- Pedro Trevizan-Baú
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, Australia
| | - Rishi R Dhingra
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, Australia
| | - Emma L Burrows
- Mental Health Theme, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, Australia.
| | - Davor Stanić
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, Australia.
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18
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Dhingra RR, Furuya WI, Galán RF, Dutschmann M. Excitation-inhibition balance regulates the patterning of spinal and cranial inspiratory motor outputs in rats in situ. Respir Physiol Neurobiol 2019; 266:95-102. [DOI: 10.1016/j.resp.2019.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/11/2019] [Accepted: 05/02/2019] [Indexed: 11/25/2022]
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19
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Dhingra RR, Furuya WI, Bautista TG, Dick TE, Galán RF, Dutschmann M. Increasing Local Excitability of Brainstem Respiratory Nuclei Reveals a Distributed Network Underlying Respiratory Motor Pattern Formation. Front Physiol 2019; 10:887. [PMID: 31396094 PMCID: PMC6664290 DOI: 10.3389/fphys.2019.00887] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 06/26/2019] [Indexed: 11/18/2022] Open
Abstract
The core circuit of the respiratory central pattern generator (rCPG) is located in the ventrolateral medulla, especially in the pre-Bötzinger complex (pre-BötC) and the neighboring Bötzinger complex (BötC). To test the hypothesis that this core circuit is embedded within an anatomically distributed pattern-generating network, we investigated whether local disinhibition of the nucleus tractus solitarius (NTS), the Kölliker-Fuse nuclei (KFn), or the midbrain periaqueductal gray area (PAG) can similarly affect the respiratory pattern compared to disinhibition of the pre-BötC/BötC core. In arterially-perfused brainstem preparations of rats, we recorded the three-phase respiratory pattern (inspiration, post-inspiration and late-expiration) from phrenic and vagal nerves before and after bilateral microinjections of the GABA(A)R antagonist bicuculline (50 nl, 10 mM). Local disinhibition of either NTS, pre-BötC/BötC, or KFn, but not PAG, triggered qualitatively similar disruptions of the respiratory pattern resulting in a highly significant increase in the variability of the respiratory cycle length, including inspiratory and expiratory phase durations. To quantitatively analyze these motor pattern perturbations, we measured the strength of phase synchronization between phrenic and vagal motor outputs. This analysis showed that local disinhibition of all brainstem target nuclei, but not the midbrain PAG, significantly decreased the strength of phase synchronization. The convergent perturbations of the respiratory pattern suggest that the rCPG expands rostrally and dorsally from the designated core but does not include higher mid-brain structures. Our data also suggest that excitation-inhibition balance of respiratory network synaptic interactions critically determines the network dynamics that underlie vital respiratory rhythm and pattern formation.
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Affiliation(s)
- Rishi R Dhingra
- Division of Systems Neurophysiology, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Werner I Furuya
- Division of Systems Neurophysiology, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Tara G Bautista
- Division of Systems Neurophysiology, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep, Department of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Roberto F Galán
- Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH, United States
| | - Mathias Dutschmann
- Division of Systems Neurophysiology, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
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20
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Fuse S, Sugiyama Y, Dhingra RR, Hirano S, Dutschmann M, Oku Y. Effects of pharmacological lesion of the nucleus retroambiguus region on the pharyngeal phase of swallowing. Respir Physiol Neurobiol 2019; 268:103244. [PMID: 31226424 DOI: 10.1016/j.resp.2019.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/07/2019] [Accepted: 06/08/2019] [Indexed: 11/16/2022]
Abstract
Pharyngeal swallowing is controlled by synaptic interactions within a swallowing central pattern generator (sw-CPG) that is composed of a dorsal and a ventral swallowing group (VSG). Here, we used electrical stimulation (10 s) of the superior laryngeal nerve (SLN; 20 Hz; pulse width: 100 μs) to explore the role of the VSG in an arterially-perfused brainstem preparation of rats. To investigate the effects of pharmacological lesion (local microinjection of an GABA(A)-R agonist) of the nucleus retroambiguus (NRA), a designated component of the VSG, we recorded phrenic (PNA) and vagal nerve (VNA) activities. Control SLN stimulation with stepwise increasing stimulus intensities (from 20 μA to 160 μA) elicited robust suppression of PNA and evoked sequential swallowing activity in the VNA. Lesioning of the NRA had no effect on the pattern of pharyngeal swallowing, but significantly increased the sensory gating of SLN inputs. We conclude that the NRA is not part of the VSG, but appears to have important roles for the central gating of swallowing.
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Affiliation(s)
- S Fuse
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Y Sugiyama
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - R R Dhingra
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - S Hirano
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - M Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.
| | - Y Oku
- Department of Physiology, Hyogo College of Medicine, Hyogo, Japan
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21
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Affiliation(s)
- Davor Stanic
- Systems NeurophysiologyThe Florey Institute of Neuroscience and Mental HealthParkvilleAustralia
| | - Pedro Trevizan‐Bau
- Systems NeurophysiologyThe Florey Institute of Neuroscience and Mental HealthParkvilleAustralia
| | - Emma Burrows
- Behavioural NeuroscienceThe Florey Institute of Neuroscience and Mental HealthParkvilleAustralia
| | - Rishi R. Dhingra
- Systems NeurophysiologyThe Florey Institute of Neuroscience and Mental HealthParkvilleAustralia
| | - Mathias Dutschmann
- Systems NeurophysiologyThe Florey Institute of Neuroscience and Mental HealthParkvilleAustralia
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22
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Dhingra RR, Dick TE, Lewis SJ, Galan RF, Dutschmann M. Phase synchronization as a flexible definition of the respiratory pattern: Application to pontine‐dependent control of the respiratory pattern. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.915.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Rishi R. Dhingra
- Division of Systems NeurophysiologyThe Florey Institute of Neuroscience and Mental HealthMelbourneAustralia
| | - Thomas E. Dick
- Department of Medicine and NeurosciencesCase Western Reserve UniversityClevelandOH
| | - Stephen J. Lewis
- Department of PediatricsCase Western Reserve UniversityClevelandOH
| | - Roberto F. Galan
- Department of Electrical Engineering and Computer ScienceCase Western Reserve UniversityClevelandOH
| | - Mathias Dutschmann
- Division of Systems NeurophysiologyThe Florey Institute of Neuroscience and Mental HealthMelbourneAustralia
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23
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Dhingra RR, Dutschmann M, Galán RF, Dick TE. Kölliker-Fuse nuclei regulate respiratory rhythm variability via a gain-control mechanism. Am J Physiol Regul Integr Comp Physiol 2016; 312:R172-R188. [PMID: 27974314 DOI: 10.1152/ajpregu.00238.2016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 11/14/2016] [Accepted: 12/11/2016] [Indexed: 11/22/2022]
Abstract
Respiration varies from breath to breath. On the millisecond timescale of spiking, neuronal circuits exhibit variability due to the stochastic properties of ion channels and synapses. Does this fast, microscopic source of variability contribute to the slower, macroscopic variability of the respiratory period? To address this question, we modeled a stochastic oscillator with forcing; then, we tested its predictions experimentally for the respiratory rhythm generated by the in situ perfused preparation during vagal nerve stimulation (VNS). Our simulations identified a relationship among the gain of the input, entrainment strength, and rhythm variability. Specifically, at high gain, the periodic input entrained the oscillator and reduced variability, whereas at low gain, the noise interacted with the input, causing events known as "phase slips", which increased variability on a slow timescale. Experimentally, the in situ preparation behaved like the low-gain model: VNS entrained respiration but exhibited phase slips that increased rhythm variability. Next, we used bilateral muscimol microinjections in discrete respiratory compartments to identify areas involved in VNS gain control. Suppression of activity in the nucleus tractus solitarii occluded both entrainment and amplification of rhythm variability by VNS, confirming that these effects were due to the activation of the Hering-Breuer reflex. Suppressing activity of the Kölliker-Fuse nuclei (KFn) enhanced entrainment and reduced rhythm variability during VNS, consistent with the predictions of the high-gain model. Together, the model and experiments suggest that the KFn regulates respiratory rhythm variability via a gain control mechanism.
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Affiliation(s)
- Rishi R Dhingra
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio.,Division of Pulmonary, Critical Care & Sleep, Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia; and
| | - Roberto F Galán
- Department of Electrical Engineering and Computer Science, School of Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Thomas E Dick
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; .,Division of Pulmonary, Critical Care & Sleep, Department of Medicine, Case Western Reserve University, Cleveland, Ohio
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24
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Yu H, Dhingra RR, Dick TE, Galán RF. Effects of ion channel noise on neural circuits: an application to the respiratory pattern generator to investigate breathing variability. J Neurophysiol 2016; 117:230-242. [PMID: 27760817 PMCID: PMC5209552 DOI: 10.1152/jn.00416.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 10/18/2016] [Indexed: 01/13/2023] Open
Abstract
Neural activity generally displays irregular firing patterns even in circuits with apparently regular outputs, such as motor pattern generators, in which the output frequency fluctuates randomly around a mean value. This "circuit noise" is inherited from the random firing of single neurons, which emerges from stochastic ion channel gating (channel noise), spontaneous neurotransmitter release, and its diffusion and binding to synaptic receptors. Here we demonstrate how to expand conductance-based network models that are originally deterministic to include realistic, physiological noise, focusing on stochastic ion channel gating. We illustrate this procedure with a well-established conductance-based model of the respiratory pattern generator, which allows us to investigate how channel noise affects neural dynamics at the circuit level and, in particular, to understand the relationship between the respiratory pattern and its breath-to-breath variability. We show that as the channel number increases, the duration of inspiration and expiration varies, and so does the coefficient of variation of the breath-to-breath interval, which attains a minimum when the mean duration of expiration slightly exceeds that of inspiration. For small channel numbers, the variability of the expiratory phase dominates over that of the inspiratory phase, and vice versa for large channel numbers. Among the four different cell types in the respiratory pattern generator, pacemaker cells exhibit the highest sensitivity to channel noise. The model shows that suppressing input from the pons leads to longer inspiratory phases, a reduction in breathing frequency, and larger breath-to-breath variability, whereas enhanced input from the raphe nucleus increases breathing frequency without changing its pattern. NEW & NOTEWORTHY A major source of noise in neuronal circuits is the "flickering" of ion currents passing through the neurons' membranes (channel noise), which cannot be suppressed experimentally. Computational simulations are therefore the best way to investigate the effects of this physiological noise by manipulating its level at will. We investigate the role of noise in the respiratory pattern generator and show that endogenous, breath-to-breath variability is tightly linked to the respiratory pattern.
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Affiliation(s)
- Haitao Yu
- School of Electrical Engineering and Automation, Tianjin University, Tianjin, People's Republic of China.,Department of Electrical Engineering and Computer Science, School of Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Rishi R Dhingra
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and
| | - Thomas E Dick
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, Ohio; and
| | - Roberto F Galán
- Department of Electrical Engineering and Computer Science, School of Engineering, Case Western Reserve University, Cleveland, Ohio
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Dick TE, Hsieh YH, Dhingra RR, Baekey DM, Galán RF, Wehrwein E, Morris KF. Cardiorespiratory coupling: common rhythms in cardiac, sympathetic, and respiratory activities. Prog Brain Res 2014; 209:191-205. [PMID: 24746049 DOI: 10.1016/b978-0-444-63274-6.00010-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Cardiorespiratory coupling is an encompassing term describing more than the well-recognized influences of respiration on heart rate and blood pressure. Our data indicate that cardiorespiratory coupling reflects a reciprocal interaction between autonomic and respiratory control systems, and the cardiovascular system modulates the ventilatory pattern as well. For example, cardioventilatory coupling refers to the influence of heart beats and arterial pulse pressure on respiration and is the tendency for the next inspiration to start at a preferred latency after the last heart beat in expiration. Multiple complementary, well-described mechanisms mediate respiration's influence on cardiovascular function, whereas mechanisms mediating the cardiovascular system's influence on respiration may only be through the baroreceptors but are just being identified. Our review will describe a differential effect of conditioning rats with either chronic intermittent or sustained hypoxia on sympathetic nerve activity but also on ventilatory pattern variability. Both intermittent and sustained hypoxia increase sympathetic nerve activity after 2 weeks but affect sympatho-respiratory coupling differentially. Intermittent hypoxia enhances sympatho-respiratory coupling, which is associated with low variability in the ventilatory pattern. In contrast, after constant hypobaric hypoxia, 1-to-1 coupling between bursts of sympathetic and phrenic nerve activity is replaced by 2-to-3 coupling. This change in coupling pattern is associated with increased variability of the ventilatory pattern. After baro-denervating hypobaric hypoxic-conditioned rats, splanchnic sympathetic nerve activity becomes tonic (distinct bursts are absent) with decreases during phrenic nerve bursts and ventilatory pattern becomes regular. Thus, conditioning rats to either intermittent or sustained hypoxia accentuates the reciprocal nature of cardiorespiratory coupling. Finally, identifying a compelling physiologic purpose for cardiorespiratory coupling is the biggest barrier for recognizing its significance. Cardiorespiratory coupling has only a small effect on the efficiency of gas exchange; rather, we propose that cardiorespiratory control system may act as weakly coupled oscillator to maintain rhythms within a bounded variability.
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Affiliation(s)
- Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA.
| | - Yee-Hsee Hsieh
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Rishi R Dhingra
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - David M Baekey
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Roberto F Galán
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Erica Wehrwein
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
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Dhingra RR, Zhu Y, Jacono FJ, Katz DM, Galán RF, Dick TE. Decreased Hering-Breuer input-output entrainment in a mouse model of Rett syndrome. Front Neural Circuits 2013; 7:42. [PMID: 23565077 PMCID: PMC3615412 DOI: 10.3389/fncir.2013.00042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 03/01/2013] [Indexed: 11/30/2022] Open
Abstract
Rett syndrome, a severe X-linked neurodevelopmental disorder caused by mutations in the gene encoding methyl-CpG-binding protein 2 (Mecp2), is associated with a highly irregular respiratory pattern including severe upper-airway dysfunction. Recent work suggests that hyperexcitability of the Hering-Breuer reflex (HBR) pathway contributes to respiratory dysrhythmia in Mecp2 mutant mice. To assess how enhanced HBR input impacts respiratory entrainment by sensory afferents in closed-loop in vivo-like conditions, we investigated the input (vagal stimulus trains) - output (phrenic bursting) entrainment via the HBR in wild-type and MeCP2-deficient mice. Using the in situ perfused brainstem preparation, which maintains an intact pontomedullary axis capable of generating an in vivo-like respiratory rhythm in the absence of the HBR, we mimicked the HBR feedback input by stimulating the vagus nerve (at threshold current, 0.5 ms pulse duration, 75 Hz pulse frequency, 100 ms train duration) at an inter-burst frequency matching that of the intrinsic oscillation of the inspiratory motor output of each preparation. Using this approach, we observed significant input-output entrainment in wild-type mice as measured by the maximum of the cross-correlation function, the peak of the instantaneous relative phase distribution, and the mutual information of the instantaneous phases. This entrainment was associated with a reduction in inspiratory duration during feedback stimulation. In contrast, the strength of input-output entrainment was significantly weaker in Mecp2 (-/+) mice. However, Mecp2 (-/+) mice also had a reduced inspiratory duration during stimulation, indicating that reflex behavior in the HBR pathway was intact. Together, these observations suggest that the respiratory network compensates for enhanced sensitivity of HBR inputs by reducing HBR input-output entrainment.
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Affiliation(s)
- Rishi R. Dhingra
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve UniversityCleveland, OH, USA
- Department of Neurosciences, Case Western Reserve UniversityCleveland, OH, USA
| | - Yenan Zhu
- Department of Neurosciences, Case Western Reserve UniversityCleveland, OH, USA
- Systems Biology and Bioinformatics Program, Case Western Reserve UniversityCleveland, OH, USA
| | - Frank J. Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve UniversityCleveland, OH, USA
- Louis Stokes Veterans Affairs Medical Center, Case Western Reserve UniversityCleveland, OH, USA
| | - David M. Katz
- Department of Neurosciences, Case Western Reserve UniversityCleveland, OH, USA
| | - Roberto F. Galán
- Department of Neurosciences, Case Western Reserve UniversityCleveland, OH, USA
- Systems Biology and Bioinformatics Program, Case Western Reserve UniversityCleveland, OH, USA
| | - Thomas E. Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve UniversityCleveland, OH, USA
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Zhu Y, Hsieh YH, Dhingra RR, Dick TE, Jacono FJ, Galán RF. Quantifying interactions between real oscillators with information theory and phase models: application to cardiorespiratory coupling. Phys Rev E Stat Nonlin Soft Matter Phys 2013; 87:022709. [PMID: 23496550 PMCID: PMC3767161 DOI: 10.1103/physreve.87.022709] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Indexed: 05/08/2023]
Abstract
Interactions between oscillators can be investigated with standard tools of time series analysis. However, these methods are insensitive to the directionality of the coupling, i.e., the asymmetry of the interactions. An elegant alternative was proposed by Rosenblum and collaborators [M. G. Rosenblum, L. Cimponeriu, A. Bezerianos, A. Patzak, and R. Mrowka, Phys. Rev. E 65, 041909 (2002); M. G. Rosenblum and A. S. Pikovsky, Phys. Rev. E 64, 045202 (2001)] which consists in fitting the empirical phases to a generic model of two weakly coupled phase oscillators. This allows one to obtain the interaction functions defining the coupling and its directionality. A limitation of this approach is that a solution always exists in the least-squares sense, even in the absence of coupling. To preclude spurious results, we propose a three-step protocol: (1) Determine if a statistical dependency exists in the data by evaluating the mutual information of the phases; (2) if so, compute the interaction functions of the oscillators; and (3) validate the empirical oscillator model by comparing the joint probability of the phases obtained from simulating the model with that of the empirical phases. We apply this protocol to a model of two coupled Stuart-Landau oscillators and show that it reliably detects genuine coupling. We also apply this protocol to investigate cardiorespiratory coupling in anesthetized rats. We observe reciprocal coupling between respiration and heartbeat and that the influence of respiration on the heartbeat is generally much stronger than vice versa. In addition, we find that the vagus nerve mediates coupling in both directions.
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Affiliation(s)
- Yenan Zhu
- Department of Neurosciences, School of Medicine, Case Western
Reserve University, Cleveland, Ohio 44106, USA
- Systems Biology and Bioinformatics Program, Case Western Reserve
University, Cleveland, Ohio 44106, USA
| | - Yee-Hsee Hsieh
- Department of Medicine, School of Medicine, Case Western Reserve
University, Cleveland, Ohio 44106, USA
| | - Rishi R. Dhingra
- Department of Neurosciences, School of Medicine, Case Western
Reserve University, Cleveland, Ohio 44106, USA
| | - Thomas E. Dick
- Department of Neurosciences, School of Medicine, Case Western
Reserve University, Cleveland, Ohio 44106, USA
- Department of Medicine, School of Medicine, Case Western Reserve
University, Cleveland, Ohio 44106, USA
| | - Frank J. Jacono
- Department of Medicine, School of Medicine, Case Western Reserve
University, Cleveland, Ohio 44106, USA
- Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio 44106,
USA
- University Hospitals, Cleveland, Ohio 44106, USA
| | - Roberto F. Galán
- Department of Neurosciences, School of Medicine, Case Western
Reserve University, Cleveland, Ohio 44106, USA
- Systems Biology and Bioinformatics Program, Case Western Reserve
University, Cleveland, Ohio 44106, USA
- Corresponding author:
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Dhingra RR, Jacono FJ, Fishman M, Loparo KA, Rybak IA, Dick TE. Vagal-dependent nonlinear variability in the respiratory pattern of anesthetized, spontaneously breathing rats. J Appl Physiol (1985) 2011; 111:272-84. [PMID: 21527661 DOI: 10.1152/japplphysiol.91196.2008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Physiological rhythms, including respiration, exhibit endogenous variability associated with health, and deviations from this are associated with disease. Specific changes in the linear and nonlinear sources of breathing variability have not been investigated. In this study, we used information theory-based techniques, combined with surrogate data testing, to quantify and characterize the vagal-dependent nonlinear pattern variability in urethane-anesthetized, spontaneously breathing adult rats. Surrogate data sets preserved the amplitude distribution and linear correlations of the original data set, but nonlinear correlation structure in the data was removed. Differences in mutual information and sample entropy between original and surrogate data sets indicated the presence of deterministic nonlinear or stochastic non-Gaussian variability. With vagi intact (n = 11), the respiratory cycle exhibited significant nonlinear behavior in templates of points separated by time delays ranging from one sample to one cycle length. After vagotomy (n = 6), even though nonlinear variability was reduced significantly, nonlinear properties were still evident at various time delays. Nonlinear deterministic variability did not change further after subsequent bilateral microinjection of MK-801, an N-methyl-D-aspartate receptor antagonist, in the Kölliker-Fuse nuclei. Reversing the sequence (n = 5), blocking N-methyl-D-aspartate receptors bilaterally in the dorsolateral pons significantly decreased nonlinear variability in the respiratory pattern, even with the vagi intact, and subsequent vagotomy did not change nonlinear variability. Thus both vagal and dorsolateral pontine influences contribute to nonlinear respiratory pattern variability. Furthermore, breathing dynamics of the intact system are mutually dependent on vagal and pontine sources of nonlinear complexity. Understanding the structure and modulation of variability provides insight into disease effects on respiratory patterning.
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Affiliation(s)
- R R Dhingra
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA
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Dhingra RR, Fishman M, Hsieh Y, Loparo KA, Dick TE. GABAergic transmission in the A5 area modulates sympatho‐respiratory response to hypoxia and breathing pattern variability in rats. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.954.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Rishi R Dhingra
- Department of MedicineDivision of PulmonaryCritical Care and Sleep Medicine
| | - Mikkel Fishman
- Department of MedicineDivision of PulmonaryCritical Care and Sleep Medicine
| | - Yee‐Hsee Hsieh
- Department of MedicineDivision of PulmonaryCritical Care and Sleep Medicine
| | - Kenneth A Loparo
- Department of Electrical Engineering and Computer ScienceCase Western Reserve UniversityClevelandOH
| | - Thomas E Dick
- Department of MedicineDivision of PulmonaryCritical Care and Sleep Medicine
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