1
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Fogarty MJ. Dendritic morphology of motor neurons and interneurons within the compact, semicompact, and loose formations of the rat nucleus ambiguus. Front Cell Neurosci 2024; 18:1409974. [PMID: 38933178 PMCID: PMC11199410 DOI: 10.3389/fncel.2024.1409974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 05/27/2024] [Indexed: 06/28/2024] Open
Abstract
Introduction Motor neurons (MNs) within the nucleus ambiguus innervate the skeletal muscles of the larynx, pharynx, and oesophagus. These muscles are activated during vocalisation and swallowing and must be coordinated with several respiratory and other behaviours. Despite many studies evaluating the projections and orientation of MNs within the nucleus ambiguus, there is no quantitative information regarding the dendritic arbours of MNs residing in the compact, and semicompact/loose formations of the nucleus ambiguus.. Methods In female and male Fischer 344 rats, we evaluated MN number using Nissl staining, and MN and non-MN dendritic morphology using Golgi-Cox impregnation Brightfield imaging of transverse Nissl sections (15 μm) were taken to stereologically assess the number of nucleus ambiguus MNs within the compact and semicompact/loose formations. Pseudo-confocal imaging of Golgi-impregnated neurons within the nucleus ambiguus (sectioned transversely at 180 μm) was traced in 3D to determine dendritic arbourisation. Results We found a greater abundance of MNs within the compact than the semicompact/loose formations. Dendritic lengths, complexity, and convex hull surface areas were greatest in MNs of the semicompact/loose formation, with compact formation MNs being smaller. MNs from both regions were larger than non-MNs reconstructed within the nucleus ambiguus. Conclusion Adding HBLS to the diet could be a potentially effective strategy to improve horses' health.
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Affiliation(s)
- Matthew J. Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
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2
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Haynes RL, Trachtenberg F, Darnall R, Haas EA, Goldstein RD, Mena OJ, Krous HF, Kinney HC. Altered 5-HT2A/C receptor binding in the medulla oblongata in the sudden infant death syndrome (SIDS): Part I. Tissue-based evidence for serotonin receptor signaling abnormalities in cardiorespiratory- and arousal-related circuits. J Neuropathol Exp Neurol 2023; 82:467-482. [PMID: 37226597 PMCID: PMC10209647 DOI: 10.1093/jnen/nlad030] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
The sudden infant death syndrome (SIDS), the leading cause of postneonatal infant mortality in the United States, is typically associated with a sleep period. Previously, we showed evidence of serotonergic abnormalities in the medulla (e.g. altered serotonin (5-HT)1A receptor binding), in SIDS cases. In rodents, 5-HT2A/C receptor signaling contributes to arousal and autoresuscitation, protecting brain oxygen status during sleep. Nonetheless, the role of 5-HT2A/C receptors in the pathophysiology of SIDS is unclear. We hypothesize that in SIDS, 5-HT2A/C receptor binding is altered in medullary nuclei that are key for arousal and autoresuscitation. Here, we report altered 5-HT2A/C binding in several key medullary nuclei in SIDS cases (n = 58) compared to controls (n = 12). In some nuclei the reduced 5-HT2A/C and 5-HT1A binding overlapped, suggesting abnormal 5-HT receptor interactions. The data presented here (Part 1) suggest that a subset of SIDS is due in part to abnormal 5-HT2A/C and 5-HT1A signaling across multiple medullary nuclei vital for arousal and autoresuscitation. In Part II to follow, we highlight 8 medullary subnetworks with altered 5-HT receptor binding in SIDS. We propose the existence of an integrative brainstem network that fails to facilitate arousal and/or autoresuscitation in SIDS cases.
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Affiliation(s)
- Robin L Haynes
- CJ Murphy Laboratory for SIDS Research, Department of Pathology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Robert’s Program on Sudden Unexpected Death in Pediatrics, Division of General Pediatrics, Department of Pediatrics, Boston Children’s Hospital, Boston, Massachusetts, USA
| | | | - Ryan Darnall
- CJ Murphy Laboratory for SIDS Research, Department of Pathology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Elisabeth A Haas
- Department of Research, Rady Children’s Hospital, San Diego, California, USA
| | - Richard D Goldstein
- Robert’s Program on Sudden Unexpected Death in Pediatrics, Division of General Pediatrics, Department of Pediatrics, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Othon J Mena
- San Diego County Medical Examiner Office, San Diego, California, USA
| | - Henry F Krous
- University of California, San Diego, San Diego, California, USA
- Rady Children’s Hospital, San Diego, California, USA
| | - Hannah C Kinney
- CJ Murphy Laboratory for SIDS Research, Department of Pathology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Robert’s Program on Sudden Unexpected Death in Pediatrics, Division of General Pediatrics, Department of Pediatrics, Boston Children’s Hospital, Boston, Massachusetts, USA
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3
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Betka S, Adler D, Similowski T, Blanke O. Breathing control, brain, and bodily self-consciousness: Toward immersive digiceuticals to alleviate respiratory suffering. Biol Psychol 2022; 171:108329. [PMID: 35452780 DOI: 10.1016/j.biopsycho.2022.108329] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 01/19/2023]
Abstract
Breathing is peculiar among autonomic functions through several characteristics. It generates a very rich afferent traffic from an array of structures belonging to the respiratory system to various areas of the brain. It is intimately associated with bodily movements. It bears particular relationships with consciousness as its efferent motor control can be automatic or voluntary. In this review within the scope of "respiratory neurophysiology" or "respiratory neuroscience", we describe the physiological organisation of breathing control. We then review findings linking breathing and bodily self-consciousness through respiratory manipulations using virtual reality (VR). After discussing the currently admitted neurophysiological model for dyspnea, as well as a new Bayesian model applied to breathing control, we propose that visuo-respiratory paradigms -as developed in cognitive neuroscience- will foster insights into some of the basic mechanisms of the human respiratory system and will also lead to the development of immersive VR-based digital health tools (i.e. digiceuticals).
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Affiliation(s)
- Sophie Betka
- Laboratory of Cognitive Neuroscience, Brain Mind Institute and Center for Neuroprosthetics, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, (EPFL), Geneva 1202, Switzerland.
| | - Dan Adler
- Division of Lung Diseases, University Hospital and Geneva Medical School, University of Geneva, Switzerland
| | - Thomas Similowski
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005 Paris, France; AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, site Pitié-Salpêtrière, Département R3S (Respiration, Réanimation, Réhabilitation respiratoire, Sommeil), F-75013 Paris, France
| | - Olaf Blanke
- Laboratory of Cognitive Neuroscience, Brain Mind Institute and Center for Neuroprosthetics, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, (EPFL), Geneva 1202, Switzerland; Department of Clinical Neurosciences, University Hospital and Geneva Medical School, University of Geneva, Switzerland
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4
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A New Therapeutic Approach for Dystussia and Atussia in Neurogenic Dysphagia: Effect of Aerosolized Capsaicin on Peak Cough Flow. Dysphagia 2022; 37:1814-1821. [PMID: 35430718 PMCID: PMC9643184 DOI: 10.1007/s00455-022-10439-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 03/28/2022] [Indexed: 12/16/2022]
Abstract
Swallowing and cough are crucial components of airway protection. In patients with neurogenic dysphagia (ND), there is a high prevalence of dystussia (impaired cough) and atussia (absence of cough). As a result, the ability to detect and remove aspirated material from the airway decreases, exacerbating the sequelae associated with ND, including aspiration pneumonia, a leading cause of mortality in ND. This controlled intervention study aimed to quantify the cough response to aerosolized capsaicin (AC) in patients with ND and assess the potential of AC as a therapeutic tool in treating ND-related dystussia and atussia. Furthermore, we propose a novel application method that enables AC treatment to be performed at home. Spirometry was used to measure peak cough flow (PCF) of voluntary cough (cough on command) and reflexive cough (cough secondary to pharyngeal exposure to AC) in 30 subjects with and 30 without ND. The capsaicin aerosol was generated by adding 1-10 drops of liquid cayenne extract (1.5-2% capsaicin) to 100 mL carbonated water (0.00075-0.001% to 0.0075-0.01% capsaicin). Voluntary PCF in the ND group was significantly lower than in the control group (p < 0.001), while there was no significant difference in reflexive PCF (p = 0.225). Within the ND group, reflexive PCF was significantly higher than voluntary PCF (p = 0.001), while in healthy controls, reflexive PCF was significantly lower (p < 0.001). The data show that AC increased the tracheobronchial clearance efficacy in ND patients with dystussia and atussia, as it enabled subjects to access their individual cough potential, which is present, but inaccessible, due to neurological disorder.
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5
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Sander L, Horvath A, Pezold S, Andermatt S, Amann M, Sinnecker T, Wendebourg MJ, Kesenheimer E, Yaldizli Ö, Kappos L, Granziera C, Wuerfel J, Cattin P, Schlaeger R. Improving Accuracy of Brainstem MRI Volumetry: Effects of Age and Sex, and Normalization Strategies. Front Neurosci 2021; 14:609422. [PMID: 33424541 PMCID: PMC7785816 DOI: 10.3389/fnins.2020.609422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/30/2020] [Indexed: 12/04/2022] Open
Abstract
Background: Brainstem-mediated functions are impaired in neurodegenerative diseases and aging. Atrophy can be visualized by MRI. This study investigates extrinsic sources of brainstem volume variability, intrinsic sources of anatomical variability, and the influence of age and sex on the brainstem volumes in healthy subjects. We aimed to develop efficient normalization strategies to reduce the effects of intrinsic anatomic variability on brainstem volumetry. Methods: Brainstem segmentation was performed from MPRAGE data using our deep-learning-based brainstem segmentation algorithm MD-GRU. The extrinsic variability of brainstem volume assessments across scanners and protocols was investigated in two groups comprising 11 (median age 33.3 years, 7 women) and 22 healthy subjects (median age 27.6 years, 50% women) scanned twice and compared using Dice scores. Intrinsic anatomical inter-individual variability and age and sex effects on brainstem volumes were assessed in segmentations of 110 healthy subjects (median age 30.9 years, range 18–72 years, 53.6% women) acquired on 1.5T (45%) and 3T (55%) scanners. The association between brainstem volumes and predefined anatomical covariates was studied using Pearson correlations. Anatomical variables with associations of |r| > 0.30 as well as the variables age and sex were used to construct normalization models using backward selection. The effect of the resulting normalization models was assessed by % relative standard deviation reduction and by comparing the inter-individual variability of the normalized brainstem volumes to the non-normalized values using paired t- tests with Bonferroni correction. Results: The extrinsic variability of brainstem volumetry across different field strengths and imaging protocols was low (Dice scores > 0.94). Mean inter-individual variability/SD of total brainstem volumes was 9.8%/7.36. A normalization based on either total intracranial volume (TICV), TICV and age, or v-scale significantly reduced the inter-individual variability of total brainstem volumes compared to non-normalized volumes and similarly reduced the relative standard deviation by about 35%. Conclusion: The extrinsic variability of the novel brainstem segmentation method MD-GRU across different scanners and imaging protocols is very low. Anatomic inter-individual variability of brainstem volumes is substantial. This study presents efficient normalization models for variability reduction in brainstem volumetry in healthy subjects.
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Affiliation(s)
- Laura Sander
- Neurologic Clinic and Policlinic, Departments of Medicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Translational Imaging in Neurology (ThINK) Basel, Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Antal Horvath
- Department of Biomedical Engineering, Center for Medical Image Analysis & Navigation (CIAN), University of Basel, Allschwil, Switzerland
| | - Simon Pezold
- Department of Biomedical Engineering, Center for Medical Image Analysis & Navigation (CIAN), University of Basel, Allschwil, Switzerland
| | - Simon Andermatt
- Department of Biomedical Engineering, Center for Medical Image Analysis & Navigation (CIAN), University of Basel, Allschwil, Switzerland
| | - Michael Amann
- Department of Biomedical Engineering, Medical Image Analysis Center (MIAC AG) and qbig, University of Basel, Basel, Switzerland
| | - Tim Sinnecker
- Neurologic Clinic and Policlinic, Departments of Medicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Translational Imaging in Neurology (ThINK) Basel, Department of Biomedical Engineering, University of Basel, Basel, Switzerland.,Department of Biomedical Engineering, Medical Image Analysis Center (MIAC AG) and qbig, University of Basel, Basel, Switzerland
| | - Maria J Wendebourg
- Neurologic Clinic and Policlinic, Departments of Medicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Translational Imaging in Neurology (ThINK) Basel, Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Eva Kesenheimer
- Neurologic Clinic and Policlinic, Departments of Medicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Translational Imaging in Neurology (ThINK) Basel, Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Özgür Yaldizli
- Neurologic Clinic and Policlinic, Departments of Medicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Translational Imaging in Neurology (ThINK) Basel, Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Ludwig Kappos
- Neurologic Clinic and Policlinic, Departments of Medicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Translational Imaging in Neurology (ThINK) Basel, Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Cristina Granziera
- Neurologic Clinic and Policlinic, Departments of Medicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Translational Imaging in Neurology (ThINK) Basel, Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Jens Wuerfel
- Department of Biomedical Engineering, Medical Image Analysis Center (MIAC AG) and qbig, University of Basel, Basel, Switzerland
| | - Philippe Cattin
- Department of Biomedical Engineering, Center for Medical Image Analysis & Navigation (CIAN), University of Basel, Allschwil, Switzerland
| | - Regina Schlaeger
- Neurologic Clinic and Policlinic, Departments of Medicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Translational Imaging in Neurology (ThINK) Basel, Department of Biomedical Engineering, University of Basel, Basel, Switzerland
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6
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Webster LR, Karan S. The Physiology and Maintenance of Respiration: A Narrative Review. Pain Ther 2020; 9:467-486. [PMID: 33021707 PMCID: PMC7648809 DOI: 10.1007/s40122-020-00203-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 09/26/2020] [Indexed: 01/12/2023] Open
Abstract
Chronic pain is one of the most common reasons adults seek medical care and is often managed with opioid analgesics; however, opioids may cause respiratory depression by suppressing various components of respiration. Respiration is the physiological process that facilitates gas exchange and is mediated through the proper function of and communication among central neural control (respiratory drive), sensory input systems, the lungs, and the muscles involved in respiration. Normal respiratory function can be dampened with the use of central nervous system (CNS) depressants and/or underlying health conditions. Patients with chronic pain are often exposed to CNS depressants other than opioids, including benzodiazepines, barbiturates, nonbenzodiazepine sedative-hypnotics, and ethanol, which can function synergistically with opioids to increase the risk of respiratory depression. Some patients may also have underlying health issues, such as obstructive sleep apnea, that can be exacerbated with the use of opioids and other CNS depressants and further contribute to respiratory depression. Clinicians should have a thorough understanding of respiration, recognize how various CNS depressants suppress it, and take necessary steps to mitigate the risk of opioid-induced respiratory depression by collaborating with a multidisciplinary team (i.e., sleep and pain specialists), choosing appropriate medications, and educating patients on the proper use and storage of opioids.
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Affiliation(s)
| | - Suzanne Karan
- University of Rochester Medical Center, Rochester, NY, USA
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7
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Biancardi V, Saini J, Pageni A, Prashaad M. H, Funk GD, Pagliardini S. Mapping of the excitatory, inhibitory, and modulatory afferent projections to the anatomically defined active expiratory oscillator in adult male rats. J Comp Neurol 2020; 529:853-884. [DOI: 10.1002/cne.24984] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/29/2020] [Accepted: 07/05/2020] [Indexed: 01/21/2023]
Affiliation(s)
- Vivian Biancardi
- Department of Physiology University of Alberta Edmonton Canada
- Women and Children's Health Research Institute, Faculty of Medicine and Dentistry University of Alberta Edmonton Canada
| | - Jashan Saini
- Department of Physiology University of Alberta Edmonton Canada
| | - Anileen Pageni
- Department of Physiology University of Alberta Edmonton Canada
| | | | - Gregory D. Funk
- Department of Physiology University of Alberta Edmonton Canada
- Women and Children's Health Research Institute, Faculty of Medicine and Dentistry University of Alberta Edmonton Canada
- Neuroscience and Mental Health Institute University of Alberta Edmonton Canada
| | - Silvia Pagliardini
- Department of Physiology University of Alberta Edmonton Canada
- Women and Children's Health Research Institute, Faculty of Medicine and Dentistry University of Alberta Edmonton Canada
- Neuroscience and Mental Health Institute University of Alberta Edmonton Canada
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8
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Chen SD, Ju YT, Wei YJ, Hsieh ML, Liu CC, Wu JM, Wang JN. Timing of Endotracheal Intubation in Patients with Fulminant Enterovirus 71 Infection. MEDICINA-LITHUANIA 2020; 56:medicina56040203. [PMID: 32344662 PMCID: PMC7230837 DOI: 10.3390/medicina56040203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/17/2020] [Accepted: 04/21/2020] [Indexed: 11/16/2022]
Abstract
Background and objective: Enterovirus 71 (EV 71) infections may result in the rapid progression of cardiopulmonary failure. Early endotracheal intubation is considered to be of primary importance. However, the appropriate timing for this is still not known. The aim of this study is to investigate the timing of intubation of children with fulminant EV71 infection. Material and Methods: From March 1998 to May 2012, patients with severe EV71 infection who were admitted to the pediatric intensive care unit of the National Cheng Kung University Hospital were enrolled in this study. Medical records were retrospectively reviewed. The patients were classified into three groups in accordance with the outcome of intubation. We used rhombencephalitis grading to describe the neurological presentation of these patients. The study was approved by the institutional review board. Results: There were a total of 105 patients enrolled. Of these, 77 patients were in Grade I, and only three of them needed intubation, who were, however, soon extubated within 24 h. There were 10 patients in Grade II; nine of them needed intubation. In total, 18 patients belonged to Grade III, and all of them need to be intubated. We then compared the outcome of intubation of grades II and III. There was only one patient out of the nine patients in grade II who experienced failed extubation due to the progression of the disease. Among grade III patients, only four patients were successfully extubated. We also listed clinical parameters to determine which one could be a sign that indicated intubation. Comparing the favorable outcomes, cranial nerve involvement was a good indicator for the timing of intubation. Conclusions: This study showed that early intubation in Grade II provides favorable outcomes and improves morbidity and mortality. We also found that if cranial nerve involvement was present, then early intubation is indicated.
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Affiliation(s)
- Shen-Dar Chen
- Department of Pediatrics, Dalin Tzu Chi hospital, Buddhist Tzu Chi Medical Foundation, Chia-Yi 62247, Taiwan;
| | - Ying-Tzu Ju
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70421, Taiwan; (Y.-T.J.); (Y.-J.W.); (M.-L.H.); (C.-C.L.); (J.-M.W.)
| | - Yu-Jen Wei
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70421, Taiwan; (Y.-T.J.); (Y.-J.W.); (M.-L.H.); (C.-C.L.); (J.-M.W.)
| | - Min-Ling Hsieh
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70421, Taiwan; (Y.-T.J.); (Y.-J.W.); (M.-L.H.); (C.-C.L.); (J.-M.W.)
| | - Ching-Chuan Liu
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70421, Taiwan; (Y.-T.J.); (Y.-J.W.); (M.-L.H.); (C.-C.L.); (J.-M.W.)
| | - Jing-Ming Wu
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70421, Taiwan; (Y.-T.J.); (Y.-J.W.); (M.-L.H.); (C.-C.L.); (J.-M.W.)
| | - Jieh-Neng Wang
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70421, Taiwan; (Y.-T.J.); (Y.-J.W.); (M.-L.H.); (C.-C.L.); (J.-M.W.)
- Correspondence: ; Tel.: +886-6-2353535 (ext. 4189)
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9
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Thoracic sympathetic chain stimulation modulates and entrains the respiratory pattern. Auton Neurosci 2019; 218:16-24. [DOI: 10.1016/j.autneu.2019.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 11/21/2022]
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10
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Fogarty MJ, Sieck GC. Evolution and Functional Differentiation of the Diaphragm Muscle of Mammals. Compr Physiol 2019; 9:715-766. [PMID: 30873594 PMCID: PMC7082849 DOI: 10.1002/cphy.c180012] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Symmorphosis is a concept of economy of biological design, whereby structural properties are matched to functional demands. According to symmorphosis, biological structures are never over designed to exceed functional demands. Based on this concept, the evolution of the diaphragm muscle (DIAm) in mammals is a tale of two structures, a membrane that separates and partitions the primitive coelomic cavity into separate abdominal and thoracic cavities and a muscle that serves as a pump to generate intra-abdominal (Pab ) and intrathoracic (Pth ) pressures. The DIAm partition evolved in reptiles from folds of the pleural and peritoneal membranes that was driven by the biological advantage of separating organs in the larger coelomic cavity into separate thoracic and abdominal cavities, especially with the evolution of aspiration breathing. The DIAm pump evolved from the advantage afforded by more effective generation of both a negative Pth for ventilation of the lungs and a positive Pab for venous return of blood to the heart and expulsive behaviors such as airway clearance, defecation, micturition, and child birth. © 2019 American Physiological Society. Compr Physiol 9:715-766, 2019.
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Affiliation(s)
- Matthew J Fogarty
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
| | - Gary C Sieck
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
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11
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Khurram OU, Fogarty MJ, Rana S, Vang P, Sieck GC, Mantilla CB. Diaphragm muscle function following midcervical contusion injury in rats. J Appl Physiol (1985) 2018; 126:221-230. [PMID: 30236045 DOI: 10.1152/japplphysiol.00481.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Midcervical spinal cord contusion injury results in tissue damage, disruption of spinal pathways, and motor neuron loss. Unilateral C4 contusion results in loss of 40%-50% of phrenic motor neurons ipsilateral to the injury (~25% of the total phrenic motor neuron pool). Over time after unilateral C4 contusion injury, diaphragm muscle (DIAm) electromyogram activity increases both contralateral and ipsilateral to the side of injury in rats, suggesting compensation because of increased activation of the surviving motor neurons. However, the impact of contusion injury on DIAm force generation is less clear. Transdiaphragmatic pressure (Pdi) was measured across motor behaviors over time after unilateral C4 contusion injury in adult male Sprague-Dawley rats. Maximum Pdi (Pdimax) was elicited by bilateral phrenic nerve stimulation at 7 days postinjury. We hypothesized that Pdimax is reduced following unilateral C4 contusion injury, whereas ventilatory behaviors of the DIAm are unimpaired. In support of our hypothesis, Pdimax was reduced by ~25% after unilateral C4 contusion, consistent with the extent of phrenic motor neuron loss following contusion injury. One day after contusion injury, the Pdi amplitude during airway occlusion was reduced from ~30 to ~20 cmH2O, but this reduction was completely reversed by 7 days postinjury. Ventilatory behaviors (~10 cmH2O), DIAm-specific force, and muscle fiber cross-sectional area did not differ between the laminectomy and contusion groups. These results indicate that the large reserve capacity for DIAm force generation allows for higher-force motor behaviors to be accomplished despite motor neuron loss, likely reflecting changes in motor unit recruitment. NEW & NOTEWORTHY Respiratory muscles such as the diaphragm generate the pressures necessary to accomplish a variety of motor behaviors ranging from ventilation to near-maximal expulsive behaviors. However, the impact of contusion injury on diaphragm pressure generation across behaviors is not clear. The present study shows that contusion injury impairs maximal pressure generation while preserving the ability of the diaphragm to accomplish lower-force motor behaviors, likely reflecting changes in diaphragm motor unit recruitment.
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Affiliation(s)
- Obaid U Khurram
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,School of Biomedical Sciences, The University of Queensland , St. Lucia, QLD , Australia
| | - Sabhya Rana
- Department of Neurobiology of Disease, Mayo Clinic , Rochester, Minnesota
| | - Pangdra Vang
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
| | - Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
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12
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Horton KK, Segers LS, Nuding SC, O'Connor R, Alencar PA, Davenport PW, Bolser DC, Pitts T, Lindsey BG, Morris KF, Gestreau C. Central Respiration and Mechanical Ventilation in the Gating of Swallow With Breathing. Front Physiol 2018; 9:785. [PMID: 30013484 PMCID: PMC6036260 DOI: 10.3389/fphys.2018.00785] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/05/2018] [Indexed: 11/13/2022] Open
Abstract
Swallow-breathing coordination safeguards the lower airways from tracheal aspiration of bolus material as it moves through the pharynx into the esophagus. Impaired movements of the shared muscles or structures of the aerodigestive tract, or disruptions in the interaction of brainstem swallow and respiratory central pattern generators (CPGs) result in dysphagia. To maximize lower airway protection these CPGs integrate respiratory rhythm generation signals and vagal afferent feedback to synchronize swallow with breathing. Despite extensive study, the roles of central respiratory activity and vagal feedback from the lungs as key elements for effective swallow-breathing coordination remain unclear. The effect of altered timing of bronchopulmonary vagal afferent input on swallows triggered during electrical stimulation of the superior laryngeal nerves or by injection of water into the pharyngeal cavity was studied in decerebrate, paralyzed, and artificially ventilated cats. We observed two types of single swallows that produced distinct effects on central respiratory-rhythm across all conditions: post-inspiratory type swallows disrupted central-inspiratory activity without affecting expiration, whereas expiratory type swallows prolonged expiration without affecting central-inspiratory activity. Repetitive swallows observed during apnea reset the E2 phase of central respiration and produced facilitation of swallow motor output nerve burst durations. Moreover, swallow initiation was negatively modulated by vagal feedback and was reset by lung inflation. Collectively, these findings support a novel model of reciprocal inhibition between the swallow CPG and inspiratory or expiratory cells of the respiratory CPG where lung distension and phases of central respiratory activity represent a dual peripheral and central gating mechanism of swallow-breathing coordination.
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Affiliation(s)
- Kofi-Kermit Horton
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Sarah C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Russell O'Connor
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Pierina A Alencar
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Paul W Davenport
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Teresa Pitts
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States
| | - Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
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13
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Morris KF, Nuding SC, Segers LS, Iceman KE, O'Connor R, Dean JB, Ott MM, Alencar PA, Shuman D, Horton KK, Taylor-Clark TE, Bolser DC, Lindsey BG. Carotid chemoreceptors tune breathing via multipath routing: reticular chain and loop operations supported by parallel spike train correlations. J Neurophysiol 2017; 119:700-722. [PMID: 29046425 DOI: 10.1152/jn.00630.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We tested the hypothesis that carotid chemoreceptors tune breathing through parallel circuit paths that target distinct elements of an inspiratory neuron chain in the ventral respiratory column (VRC). Microelectrode arrays were used to monitor neuronal spike trains simultaneously in the VRC, peri-nucleus tractus solitarius (p-NTS)-medial medulla, the dorsal parafacial region of the lateral tegmental field (FTL-pF), and medullary raphe nuclei together with phrenic nerve activity during selective stimulation of carotid chemoreceptors or transient hypoxia in 19 decerebrate, neuromuscularly blocked, and artificially ventilated cats. Of 994 neurons tested, 56% had a significant change in firing rate. A total of 33,422 cell pairs were evaluated for signs of functional interaction; 63% of chemoresponsive neurons were elements of at least one pair with correlational signatures indicative of paucisynaptic relationships. We detected evidence for postinspiratory neuron inhibition of rostral VRC I-Driver (pre-Bötzinger) neurons, an interaction predicted to modulate breathing frequency, and for reciprocal excitation between chemoresponsive p-NTS neurons and more downstream VRC inspiratory neurons for control of breathing depth. Chemoresponsive pericolumnar tonic expiratory neurons, proposed to amplify inspiratory drive by disinhibition, were correlationally linked to afferent and efferent "chains" of chemoresponsive neurons extending to all monitored regions. The chains included coordinated clusters of chemoresponsive FTL-pF neurons with functional links to widespread medullary sites involved in the control of breathing. The results support long-standing concepts on brain stem network architecture and a circuit model for peripheral chemoreceptor modulation of breathing with multiple circuit loops and chains tuned by tegmental field neurons with quasi-periodic discharge patterns. NEW & NOTEWORTHY We tested the long-standing hypothesis that carotid chemoreceptors tune the frequency and depth of breathing through parallel circuit operations targeting the ventral respiratory column. Responses to stimulation of the chemoreceptors and identified functional connectivity support differential tuning of inspiratory neuron burst duration and firing rate and a model of brain stem network architecture incorporating tonic expiratory "hub" neurons regulated by convergent neuronal chains and loops through rostral lateral tegmental field neurons with quasi-periodic discharge patterns.
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Affiliation(s)
- Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Sarah C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Kimberly E Iceman
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Russell O'Connor
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Jay B Dean
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Mackenzie M Ott
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Pierina A Alencar
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Dale Shuman
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Kofi-Kermit Horton
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Thomas E Taylor-Clark
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida , Gainesville, Florida
| | - Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
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14
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Keller JA, McGovern AE, Mazzone SB. Translating Cough Mechanisms Into Better Cough Suppressants. Chest 2017; 152:833-841. [DOI: 10.1016/j.chest.2017.05.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/14/2017] [Accepted: 05/17/2017] [Indexed: 12/19/2022] Open
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15
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Pathogenesis of Lethal Aspiration Pneumonia in Mecp2-null Mouse Model for Rett Syndrome. Sci Rep 2017; 7:12032. [PMID: 28931890 PMCID: PMC5607245 DOI: 10.1038/s41598-017-12293-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 09/06/2017] [Indexed: 11/09/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder mainly caused by mutations in the gene encoding the transcriptional regulator Methyl-CpG-binding protein 2 (MeCP2), located on the X chromosome. Many RTT patients have breathing abnormalities, such as apnea and breathing irregularity, and respiratory infection is the most common cause of death in these individuals. Previous studies showed that MeCP2 is highly expressed in the lung, but its role in pulmonary function remains unknown. In this study, we found that MeCP2 deficiency affects pulmonary gene expression and structures. We also found that Mecp2-null mice, which also have breathing problems, often exhibit inflammatory lung injury. These injuries occurred in specific sites in the lung lobes. In addition, polarizable foreign materials were identified in the injured lungs of Mecp2-null mice. These results indicated that aspiration might be a cause of inflammatory lung injury in Mecp2-null mice. On the other hand, MeCP2 deficiency affected the expression of several neuromodulator genes in the lower brainstem. Among them, neuropeptide substance P (SP) immunostaining was reduced in Mecp2-null brainstem. These findings suggest that alteration of SP expression in brainstem may be involved in autonomic dysregulation, and may be one of the causes of aspiration in Mecp2-null mice.
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16
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Brainstem mechanisms underlying the cough reflex and its regulation. Respir Physiol Neurobiol 2017; 243:60-76. [DOI: 10.1016/j.resp.2017.05.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 12/12/2022]
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17
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Cinelli E, Iovino L, Bongianni F, Pantaleo T, Mutolo D. GABAA- and glycine-mediated inhibitory modulation of the cough reflex in the caudal nucleus tractus solitarii of the rabbit. Am J Physiol Lung Cell Mol Physiol 2016; 311:L570-80. [PMID: 27402692 DOI: 10.1152/ajplung.00205.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/05/2016] [Indexed: 01/05/2023] Open
Abstract
Cough-related sensory inputs from rapidly adapting receptors (RARs) and C fibers are processed by second-order neurons mainly located in the caudal nucleus tractus solitarii (NTS). Both GABAA and glycine receptors have been proven to be involved in the inhibitory control of second-order cells receiving RAR projections. We investigated the role of these receptors within the caudal NTS in the modulation of the cough reflex induced by either mechanical or chemical stimulation of the tracheobronchial tree in pentobarbital sodium-anesthetized, spontaneously breathing rabbits. Bilateral microinjections (30-50 nl) of the receptor antagonists bicuculline and strychnine as well as of the receptor agonists muscimol and glycine were performed. Bicuculline (0.1 mM) and strychnine (1 mM) caused decreases in peak abdominal activity and marked increases in respiratory frequency due to decreases in both inspiratory time (Ti) and expiratory time (Te), without concomitant changes in arterial blood pressure. Noticeably, these microinjections induced potentiation of the cough reflex consisting of increases in the cough number associated with decreases either in cough-related Ti after bicuculline or in both cough-related Ti and Te after strychnine. The effects caused by muscimol (0.1 mM) and glycine (10 mM) were in the opposite direction to those produced by the corresponding antagonists. The results show that both GABAA and glycine receptors within the caudal NTS mediate a potent inhibitory modulation of the pattern of breathing and cough reflex responses. They strongly suggest that disinhibition is one important mechanism underlying cough regulation and possibly provide new hints for novel effective antitussive strategies.
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Affiliation(s)
- Elenia Cinelli
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Florence, Italy
| | - Ludovica Iovino
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Florence, Italy
| | - Fulvia Bongianni
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Florence, Italy
| | - Tito Pantaleo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Florence, Italy
| | - Donatella Mutolo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Florence, Italy
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