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Mori K, Sakano H. One respiratory cycle as a minimum time unit for making behavioral decisions in the mammalian olfactory system. Front Neurosci 2024; 18:1423694. [PMID: 39315076 PMCID: PMC11417025 DOI: 10.3389/fnins.2024.1423694] [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: 04/26/2024] [Accepted: 08/26/2024] [Indexed: 09/25/2024] Open
Abstract
Voluntary behaviors such as sniffing, moving, and eating require decision-making accompanied by intentional respiration. Based on the study of respiration-coherent activity of rodent olfactory networks, we infer that during the inhalation phase of respiration, olfactory cortical areas process environmental odor information and transmit it to the higher multisensory cognitive areas via feedforward pathways to comprehensively evaluate the surrounding situation. We also infer that during the exhalation phase, the higher multisensory areas generate cognitive-signals and transmit them not only to the behavioral output system but also back to the olfactory cortical areas. We presume that the cortical mechanism couples the intentional respiration with the voluntary behaviors. Thus, in one respiratory cycle, the mammalian brain may transmit and process sensory information to cognize and evaluate the multisensory image of the external world, leading to one behavioral decision and one emotional expression. In this perspective article, we propose that one respiratory cycle provides a minimum time unit for decision making during wakefulness.
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Affiliation(s)
- Kensaku Mori
- RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Hitoshi Sakano
- Department of Brain Function, School of Medical Sciences, University of Fukui, Matsuoka, Japan
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2
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Thomas SJ, Ghosh B, Wang Z, Yang M, Nong J, Severa J, Wright MC, Zhong Y, Lepore AC. Hepatocyte Growth Factor Delivery to Injured Cervical Spinal Cord Using an Engineered Biomaterial Protects Respiratory Neural Circuitry and Preserves Functional Diaphragm Innervation. J Neurotrauma 2024. [PMID: 39078323 DOI: 10.1089/neu.2024.0084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024] Open
Abstract
A major portion of spinal cord injury (SCI) cases occur in the cervical region, where essential components of the respiratory neural circuitry are located. Phrenic motor neurons (PhMNs) housed at cervical spinal cord level C3-C5 directly innervate the diaphragm, and SCI-induced damage to these cells severely impairs respiratory function. In this study, we tested a biomaterial-based approach aimed at preserving this critical phrenic motor circuitry after cervical SCI by locally delivering hepatocyte growth factor (HGF). HGF is a potent mitogen that promotes survival, proliferation, migration, repair, and regeneration of a number of different cell and tissue types in response to injury. We developed a hydrogel-based HGF delivery system that can be injected into the intrathecal space for local delivery of high levels of HGF without damaging the spinal cord. Implantation of HGF hydrogel after unilateral C5 contusion-type SCI in rats preserved diaphragm function, as assessed by in vivo recordings of both compound muscle action potentials and inspiratory electromyography amplitudes. HGF hydrogel also preserved PhMN innervation of the diaphragm, as assessed by both retrograde PhMN tracing and detailed neuromuscular junction morphological analysis. Furthermore, HGF hydrogel significantly decreased lesion size and degeneration of cervical motor neuron cell bodies, as well as reduced levels surrounding the injury site of scar-associated chondroitin sulfate proteoglycan molecules that limit axon growth capacity. Our findings demonstrate that local biomaterial-based delivery of HGF hydrogel to injured cervical spinal cord is an effective strategy for preserving respiratory circuitry and diaphragm function.
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Affiliation(s)
- Samantha J Thomas
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Zhicheng Wang
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Mengxi Yang
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Jia Nong
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Jenna Severa
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, Glenside, Pennsylvania, USA
| | - Yinghui Zhong
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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3
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Khalilpour J, Soltani Zangbar H, Alipour MR, Shahabi P. The hypoxic respiratory response of the pre-Bötzinger complex. Heliyon 2024; 10:e34491. [PMID: 39114066 PMCID: PMC11305331 DOI: 10.1016/j.heliyon.2024.e34491] [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: 04/19/2024] [Revised: 06/18/2024] [Accepted: 07/10/2024] [Indexed: 08/10/2024] Open
Abstract
Since the discovery of the pre-Bötzinger Complex (preBötC) as a crucial region for generating the main respiratory rhythm, our understanding of its cellular and molecular aspects has rapidly increased within the last few decades. It is now apparent that preBötC is a highly flexible neuronal network that reconfigures state-dependently to produce the most appropriate respiratory output in response to various metabolic challenges, such as hypoxia. However, the responses of the preBötC to hypoxic conditions can be varied based on the intensity, pattern, and duration of the hypoxic challenge. This review discusses the preBötC response to hypoxic challenges at the cellular and network level. Particularly, the involvement of preBötC in the classical biphasic response of the respiratory network to acute hypoxia is illuminated. Furthermore, the article discusses the functional and structural changes of preBötC neurons following intermittent and sustained hypoxic challenges. Accumulating evidence shows that the preBötC neural circuits undergo substantial changes following hypoxia and contribute to several types of the respiratory system's hypoxic ventilatory responses.
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Affiliation(s)
- Jamal Khalilpour
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hamid Soltani Zangbar
- Department of Neuroscience, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Parviz Shahabi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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4
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Dereli AS, Oh AYS, McMullan S, Kumar NN. Galaninergic and hypercapnia-activated neuronal projections to the ventral respiratory column. Brain Struct Funct 2024; 229:1121-1142. [PMID: 38578351 PMCID: PMC11147908 DOI: 10.1007/s00429-024-02782-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 02/26/2024] [Indexed: 04/06/2024]
Abstract
In mammals, the ventral respiratory column (VRC) plays a pivotal role in integrating neurochemically diverse inputs from brainstem and forebrain regions to generate respiratory motor patterns. VRC microinjection of the neuropeptide galanin has been reported to dampen carbon dioxide (CO2)-mediated chemoreflex responses. Additionally, we previously demonstrated that galaninergic neurons in the retrotrapezoid nucleus (RTN) are implicated in the adaptive response to hypercapnic stimuli, suggesting a link between RTN neuroplasticity and increased neuronal drive to the VRC. VRC neurons express galanin receptor 1, suggesting potential regulatory action by galanin, however, the precise galaninergic chemoreceptor-VRC circuitry remains to be determined. This study aimed to identify sources of galaninergic input to the VRC that contribute to central respiratory chemoreception. We employed a combination of retrograde neuronal tracing, in situ hybridisation and immunohistochemistry to investigate VRC-projecting neurons that synthesise galanin mRNA. In an additional series of experiments, we used acute hypercapnia exposure (10% CO2, 1 h) and c-Fos immunohistochemistry to ascertain which galaninergic nuclei projecting to the VRC are activated. Our findings reveal that a total of 30 brain nuclei and 51 subnuclei project to the VRC, with 12 of these containing galaninergic neurons, including the RTN. Among these galaninergic populations, only a subset of the RTN neurons (approximately 55%) exhibited activation in response to acute hypercapnia. Our findings highlight that the RTN is the likely source of galaninergic transmission to the VRC in response to hypercapnic stimuli.
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Affiliation(s)
- Ayse S Dereli
- Department of Pharmacology, School of Biomedical Sciences, University of New South Wales, Sydney, Australia
| | - Alice Y S Oh
- Department of Pharmacology, School of Biomedical Sciences, University of New South Wales, Sydney, Australia
| | - Simon McMullan
- Macquarie Medical School, Macquarie University, Sydney, Australia
| | - Natasha N Kumar
- Department of Pharmacology, School of Biomedical Sciences, University of New South Wales, Sydney, Australia.
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5
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Maylott SE, Zeng G, Leung TS, Montenegro CS, Barrios A, Malik A, Delgado RE, Delgado CF, Simpson EA. Newborn auditory brainstem response and sudden infant death syndrome. J Neurosci Res 2024; 102:e25362. [PMID: 38895852 DOI: 10.1002/jnr.25362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 05/28/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024]
Abstract
Sudden infant death syndrome (SIDS)-the sudden and unexplained death of a seemingly healthy infant, <1 year old-may be associated with abnormalities in the brain regions that underlie breathing and arousal during sleep. While post-mortem studies suggest abnormalities in SIDS infants' brainstems, there are no studies of these infants' brainstem function before death. One way to assess the function of the brainstem is with auditory brainstem response (ABR), a routine hearing-screening method that noninvasively measures the brainstem's response to sound. We hypothesize that anomalies in newborns' ABR measures may predict SIDS. Indeed, previous studies identified abnormalities in ABR characteristics in small samples of near-miss SIDS infants hospitalized for infant apnea syndrome. However, there is a need to examine the ABRs of infants who died of SIDS. Therefore, in the current study, we propose integrating two secondary datasets to examine newborns' ABRs (N = 156,972), including those who later died of SIDS (n = ~42; .27 out of every 1000 infants), using existing archived records of neonatal ABR results from a sample of newborns born in Florida. We hypothesize that infants who die from SIDS are more likely than non-SIDS infants to have abnormal ABRs as newborns. Understanding the association between SIDS and ABR may facilitate more accurate identification of an infant's risk for SIDS at birth, enabling increased monitoring, which may facilitate interventions and improve survivorship.
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Affiliation(s)
- Sarah E Maylott
- Department of Psychiatry, Duke University, Durham, North Carolina, USA
| | - Guangyu Zeng
- Division of Applied Psychology, The Chinese University of Hong Kong, Shenzhen, China
| | - Tiffany S Leung
- Department of Psychology, University of Miami, Coral Gables, Florida, USA
| | | | - Alexia Barrios
- University of Miami Miller School of Medicine, Coral Gables, Florida, USA
| | - Arushi Malik
- Department of Psychology, University of Miami, Coral Gables, Florida, USA
| | - Rafael E Delgado
- Department of Psychology, University of Miami, Coral Gables, Florida, USA
- Biomedical Engineering, University of Miami, Coral Gables, Florida, USA
- Intelligent Hearing Systems Corp., Miami, Florida, USA
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6
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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] [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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Tagliabue G, Ji M, Zuege DJ, Easton PA. Divergent expiratory braking activity of costal and crural diaphragm. Respir Physiol Neurobiol 2024; 321:104205. [PMID: 38135107 DOI: 10.1016/j.resp.2023.104205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/27/2023] [Accepted: 12/18/2023] [Indexed: 12/24/2023]
Abstract
BACKGROUND There is increasing clinical interest in understanding the contribution of the diaphragm in early expiration, especially during mechanical ventilation. However, current experimental evidence is limited, so essential activity of the diaphragm during expiration and diaphragm segmental differences in expiratory activity, are unknown. OBJECTIVES To determine if: 1) the diaphragm is normally active into expiration during spontaneous breathing and hypercapnic ventilation, 2) expiratory diaphragmatic activity is distributed equally among the segments of the diaphragm, costal and crural. METHODS In 30 spontaneously breathing male and female canines, awake without confounding anesthetic, we measured directly both inspiratory and expiratory electrical activity (EMG), and corresponding mechanical shortening, of costal and crural diaphragm, during room air and hypercapnia. RESULTS During eupnea, costal and crural diaphragm are active into expiration, showing significant and distinct expiratory activity, with crural expiratory activity greater than costal, for both magnitude and duration. This diaphragm segmental difference diverged further during progressive hypercapnic ventilation: crural expiratory activity progressively increased, while costal expiratory activity disappeared. CONCLUSION The diaphragm is not passive during expiration. During spontaneous breathing, expiratory activity -"braking"- of the diaphragm is expressed routinely, but is not equally distributed. Crural muscle "braking" is greater than costal muscle in magnitude and duration. With increasing ventilation during hypercapnia, expiratory activity -"braking"- diverges notably. Crural expiratory activity greatly increases, while costal expiratory "braking" decreases in magnitude and duration, and disappears. Thus, diaphragm expiratory "braking" action represents an inherent, physiological function of the diaphragm, distinct for each segment, expressing differing neural activation.
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Affiliation(s)
- Giovanni Tagliabue
- University of Calgary, Cumming School of Medicine, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Michael Ji
- University of Calgary, Cumming School of Medicine, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Danny J Zuege
- University of Calgary, Cumming School of Medicine, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Paul A Easton
- University of Calgary, Cumming School of Medicine, Department of Critical Care Medicine, Calgary, Alberta, Canada.
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Missaghi K, Le Gal JP, Mercier J, Grover M, Beauséjour PA, Chartré S, Messihad O, Auclair F, Dubuc R. Revisiting the two rhythm generators for respiration in lampreys. Front Neuroanat 2024; 17:1270535. [PMID: 38250023 PMCID: PMC10796688 DOI: 10.3389/fnana.2023.1270535] [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: 07/31/2023] [Accepted: 11/17/2023] [Indexed: 01/23/2024] Open
Abstract
In lampreys, respiration consists of a fast and a slow rhythm. This study was aimed at characterizing both anatomically and physiologically the brainstem regions involved in generating the two rhythms. The fast rhythm generator has been located by us and others in the rostral hindbrain, rostro-lateral to the trigeminal motor nucleus. More recently, this was challenged by researchers reporting that the fast rhythm generator was located more rostrally and dorsomedially, in a region corresponding to the mesencephalic locomotor region. These contradictory observations made us re-examine the location of the fast rhythm generator using anatomical lesions and physiological recordings. We now confirm that the fast respiratory rhythm generator is in the rostro-lateral hindbrain as originally described. The slow rhythm generator has received less attention. Previous studies suggested that it was composed of bilateral, interconnected rhythm generating regions located in the caudal hindbrain, with ascending projections to the fast rhythm generator. We used anatomical and physiological approaches to locate neurons that could be part of this slow rhythm generator. Combinations of unilateral injections of anatomical tracers, one in the fast rhythm generator area and another in the lateral tegmentum of the caudal hindbrain, were performed to label candidate neurons on the non-injected side of the lateral tegmentum. We found a population of neurons extending from the facial to the caudal vagal motor nuclei, with no clear clustering in the cell distribution. We examined the effects of stimulating different portions of the labeled population on the respiratory activity. The rostro-caudal extent of the population was arbitrarily divided in three portions that were each stimulated electrically or chemically. Stimulation of either of the three sites triggered bursts of discharge characteristic of the slow rhythm, whereas inactivating any of them stopped the slow rhythm. Substance P injected locally in the lateral tegmentum accelerated the slow respiratory rhythm in a caudal hindbrain preparation. Our results show that the fast respiratory rhythm generator consists mostly of a population of neurons rostro-lateral to the trigeminal motor nucleus, whereas the slow rhythm generator is distributed in the lateral tegmentum of the caudal hindbrain.
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Affiliation(s)
- Kianoush Missaghi
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
| | | | - Julien Mercier
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
- Groupe de Recherche en Activité Physique Adaptée (GRAPA), Département des Sciences de l’Activité Physique, Université du Québec à Montréal, Montréal, QC, Canada
| | - Martin Grover
- Groupe de Recherche en Activité Physique Adaptée (GRAPA), Département des Sciences de l’Activité Physique, Université du Québec à Montréal, Montréal, QC, Canada
| | | | - Shannon Chartré
- Groupe de Recherche en Activité Physique Adaptée (GRAPA), Département des Sciences de l’Activité Physique, Université du Québec à Montréal, Montréal, QC, Canada
| | - Omima Messihad
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - François Auclair
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Réjean Dubuc
- Département de Neurosciences, Université de Montréal, Montréal, QC, Canada
- Groupe de Recherche en Activité Physique Adaptée (GRAPA), Département des Sciences de l’Activité Physique, Université du Québec à Montréal, Montréal, QC, Canada
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Turk AZ, Millwater M, SheikhBahaei S. Whole-brain analysis of CO 2 chemosensitive regions and identification of the retrotrapezoid and medullary raphé nuclei in the common marmoset ( Callithrix jacchus). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.26.558361. [PMID: 37986845 PMCID: PMC10659419 DOI: 10.1101/2023.09.26.558361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Respiratory chemosensitivity is an important mechanism by which the brain senses changes in blood partial pressure of CO2 (PCO2). It is proposed that special neurons (and astrocytes) in various brainstem regions play key roles as CO2 central respiratory chemosensors in rodents. Although common marmosets (Callithrix jacchus), New-World non-human primates, show similar respiratory responses to elevated inspired CO2 as rodents, the chemosensitive regions in marmoset brain have not been defined yet. Here, we used c-fos immunostainings to identify brain-wide CO2-activated brain regions in common marmosets. In addition, we mapped the location of the retrotrapezoid nucleus (RTN) and raphé nuclei in the marmoset brainstem based on colocalization of CO2-induced c-fos immunoreactivity with Phox2b, and TPH immunostaining, respectively. Our data also indicated that, similar to rodents, marmoset RTN astrocytes express Phox2b and have complex processes that create a meshwork structure at the ventral surface of medulla. Our data highlight some cellular and structural regional similarities in brainstem of the common marmosets and rodents.
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Affiliation(s)
- Ariana Z. Turk
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, 20892 MD, USA
| | - Marissa Millwater
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, 20892 MD, USA
| | - Shahriar SheikhBahaei
- Neuron-Glia Signaling and Circuits Unit, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, 20892 MD, USA
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10
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Joffe AR. Consent for the Apnea Test: Asking the Wrong Question. Pediatr Crit Care Med 2023; 24:427-429. [PMID: 37140335 DOI: 10.1097/pcc.0000000000003223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- Ari R Joffe
- Division of Critical Care Medicine, Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
- John Dossetor Health Ethics Center, University of Alberta, Edmonton, AB, Canada
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11
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Xie Z, Zhang X, Zhao M, Huo L, Huang M, Li D, Zhang S, Cheng X, Gu H, Zhang C, Zhan C, Wang F, Shang C, Cao P. The gut-to-brain axis for toxin-induced defensive responses. Cell 2022; 185:4298-4316.e21. [PMID: 36323317 DOI: 10.1016/j.cell.2022.10.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 08/16/2022] [Accepted: 09/30/2022] [Indexed: 11/11/2022]
Abstract
After ingestion of toxin-contaminated food, the brain initiates a series of defensive responses (e.g., nausea, retching, and vomiting). How the brain detects ingested toxin and coordinates diverse defensive responses remains poorly understood. Here, we developed a mouse-based paradigm to study defensive responses induced by bacterial toxins. Using this paradigm, we identified a set of molecularly defined gut-to-brain and brain circuits that jointly mediate toxin-induced defensive responses. The gut-to-brain circuit consists of a subset of Htr3a+ vagal sensory neurons that transmit toxin-related signals from intestinal enterochromaffin cells to Tac1+ neurons in the dorsal vagal complex (DVC). Tac1+ DVC neurons drive retching-like behavior and conditioned flavor avoidance via divergent projections to the rostral ventral respiratory group and lateral parabrachial nucleus, respectively. Manipulating these circuits also interferes with defensive responses induced by the chemotherapeutic drug doxorubicin. These results suggest that food poisoning and chemotherapy recruit similar circuit modules to initiate defensive responses.
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Affiliation(s)
- Zhiyong Xie
- National Institute of Biological Sciences, Beijing, China; Department of Psychological Medicine, Zhongshan Hospital, State Key Laboratory of Medical Neurobiology, Institute for Translational Brain Research, MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China.
| | - Xianying Zhang
- National Institute of Biological Sciences, Beijing, China; College of Life Sciences, Beijing Normal University, Beijing, China
| | - Miao Zhao
- National Institute of Biological Sciences, Beijing, China
| | - Lifang Huo
- Innovation Center for Advanced Interdisciplinary Medicine, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Laboratory, Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Meizhu Huang
- National Institute of Biological Sciences, Beijing, China; Innovation Center for Advanced Interdisciplinary Medicine, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Laboratory, Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Dapeng Li
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | | | - Xinyu Cheng
- National Institute of Biological Sciences, Beijing, China
| | - Huating Gu
- National Institute of Biological Sciences, Beijing, China
| | - Chen Zhang
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Cheng Zhan
- School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Fengchao Wang
- National Institute of Biological Sciences, Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
| | - Congping Shang
- Innovation Center for Advanced Interdisciplinary Medicine, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou Laboratory, Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.
| | - Peng Cao
- National Institute of Biological Sciences, Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
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12
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Ciumas C, Rheims S, Ryvlin P. fMRI studies evaluating central respiratory control in humans. Front Neural Circuits 2022; 16:982963. [PMID: 36213203 PMCID: PMC9537466 DOI: 10.3389/fncir.2022.982963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/01/2022] [Indexed: 11/13/2022] Open
Abstract
A plethora of neural centers in the central nervous system control the fundamental respiratory pattern. This control is ensured by neurons that act as pacemakers, modulating activity through chemical control driven by changes in the O2/CO2 balance. Most of the respiratory neural centers are located in the brainstem, but difficult to localize on magnetic resonance imaging (MRI) due to their small size, lack of visually-detectable borders with neighboring areas, and significant physiological noise hampering detection of its activity with functional MRI (fMRI). Yet, several approaches make it possible to study the normal response to different abnormal stimuli or conditions such as CO2 inhalation, induced hypercapnia, volitional apnea, induced hypoxia etc. This review provides a comprehensive overview of the majority of available studies on central respiratory control in humans.
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Affiliation(s)
- Carolina Ciumas
- Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- Lyon Neuroscience Research Center, Institut National de la Santé et de la Recherche Médicale U1028/CNRS UMR 5292 Lyon 1 University, Bron, France
- IDEE Epilepsy Institute, Lyon, France
| | - Sylvain Rheims
- Lyon Neuroscience Research Center, Institut National de la Santé et de la Recherche Médicale U1028/CNRS UMR 5292 Lyon 1 University, Bron, France
- IDEE Epilepsy Institute, Lyon, France
- Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Lyon, France
| | - Philippe Ryvlin
- Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
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13
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Niakani S, Liu H, Liu WY, Horner RL. Differential pharmacological and sex-specific effects of antimuscarinic agents at the hypoglossal motor nucleus in vivo in rats. Sci Rep 2022; 12:14896. [PMID: 36050440 PMCID: PMC9437041 DOI: 10.1038/s41598-022-19233-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/25/2022] [Indexed: 12/01/2022] Open
Abstract
Successful cholinergic-noradrenergic pharmacotherapy for obstructive sleep apnea (OSA) is thought to be due to effects at the hypoglossal motor nucleus (HMN). Clinical efficacy varies with muscarinic-receptor (MR) subtype affinities. We hypothesized that oxybutynin (cholinergic agent in successful OSA pharmacotherapy) is an effective MR antagonist at the HMN and characterized its efficacy with other antagonists. We recorded tongue muscle activity of isoflurane anesthetized rats (121 males and 60 females, 7-13 per group across 13 protocols) in response to HMN microperfusion with MR antagonists with and without: (i) eserine-induced increased endogenous acetylcholine at the HMN and (ii) muscarine. Eserine-induced increased acetylcholine decreased tongue motor activity (p < 0.001) with lesser cholinergic suppression in females versus males (p = 0.017). Motor suppression was significantly attenuated by the MR antagonists atropine, oxybutynin, and omadacycline (MR2 antagonist), each p < 0.001, with similar residual activity between agents (p ≥ 0.089) suggesting similar efficacy at the HMN. Sex differences remained with atropine and oxybutynin (p < 0.001 to 0.05) but not omadacycline (p = 0.722). Muscarine at the HMN also decreased motor activity (p < 0.001) but this was not sex-specific (p = 0.849). These findings have translational relevance to antimuscarinic agents in OSA pharmacotherapy and understanding potential sex differences in HMN suppression with increased endogenous acetylcholine related to sparing nicotinic excitation.
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Affiliation(s)
- Sepehr Niakani
- Department of Physiology, University of Toronto, Toronto, Canada
| | - Hattie Liu
- Department of Physiology, University of Toronto, Toronto, Canada
| | - Wen-Ying Liu
- Department of Physiology, University of Toronto, Toronto, Canada
| | - Richard L Horner
- Department of Physiology, University of Toronto, Toronto, Canada.
- Department of Medicine, University of Toronto, 3206 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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14
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Tagliabue G, Ji M, Suneby Jagers JV, Zuege DJ, Kieser TM, Easton PA. Expiratory and Inspiratory Action of Transversus Abdominis During Eupnea and Hypercapnic Ventilation. Respir Physiol Neurobiol 2022; 306:103951. [PMID: 35914691 DOI: 10.1016/j.resp.2022.103951] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/20/2022] [Accepted: 07/24/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Recently, there is interest in the clinical importance of monitoring abdominal muscles during respiratory failure. The clinical interpretation relies on the assumption that expiration is a passive physiologic process and, since diaphragm and abdomen are arranged in series, any inward motion of the abdominal wall represents a sign of diaphragm dysfunction. However, previous studies suggest Transversus Abdominis might be active even during eupnea and is preferentially recruited over the other abdominal muscles. OBJECTIVE 1) Is Transversus Abdominis normally recruited during eupnea? 2) What is the degree of activation of Transversus Abdominis during hypercapnia? 3) Does the end-inspiratory length of Transversus Abdominis change during hypercapnia, while diaphragm function is normal? METHODS In 30 spontaneously breathing canines, awake without confounding anesthetic, we measured directly both electrical activity and corresponding mechanical length and shortening of Transversus Abdominis during eupnea and hypercapnia. RESULTS Transversus Abdominis is consistently recruited during eupnea. During hypercapnia, Transversus Abdominis recruitment is progressive and significant. Throughout hypercapnia, Transversus Abdominis baseline end-inspiratory length is not constant: baseline length decreases progressively throughout hypercapnia. After expiration, into early inspiration, Transversus Abdominis shows a consistent neural mechanical post -expiratory expiratory activity (PEEA) at rest, which progressively increases during hypercapnia. CONCLUSION Transversus Abdominis is an obligatory expiratory muscle, reinforcing the fundamental principle expiration is not a passive process. Beyond expiration, during hypercapnic ventilation, Transversus Abdominis contributes as an "accessory inspiratory muscle" into the early phase of inspiration. Clinical monitoring of abdominal wall motion during respiratory failure may be confounded by action of Transversus Abdominis.
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Affiliation(s)
- Giovanni Tagliabue
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Michael Ji
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Jenny V Suneby Jagers
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Dan J Zuege
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Teresa M Kieser
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Paul A Easton
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada.
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15
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Heart rate variability comparison between young males after 4-6 weeks from the end of SARS-CoV-2 infection and controls. Sci Rep 2022; 12:8832. [PMID: 35614330 PMCID: PMC9130989 DOI: 10.1038/s41598-022-12844-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 05/11/2022] [Indexed: 11/11/2022] Open
Abstract
Due to the prolonged inflammatory process induced by infection of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), indices of autonomic nervous system dysfunction may persist long after viral shedding. Previous studies showed significant changes in HRV parameters in severe (including fatal) infection of SARS-CoV-2. However, few studies have comprehensively examined HRV in individuals who previously presented as asymptomatic or mildly symptomatic cases of COVID-19. In this study, we examined HRV in asymptomatic or mildly symptomatic individuals 5–7 weeks following positive confirmation of SARS-CoV-2 infection. Sixty-five ECG Holter recordings from young (mean age 22.6 ± 3.4 years), physically fit male subjects 4–6 weeks after the second negative test (considered to be the start of recovery) and twenty-six control male subjects (mean age 23.2 ± 2.9 years) were considered in the study. Night-time RR time series were extracted from ECG signals. Selected linear as well as nonlinear HRV parameters were calculated. We found significant differences in Porta’s symbolic analysis parameters V0 and V2 (p < 0.001), α2 (p < 0.001), very low-frequency component (VLF; p = 0.022) and respiratory peak (from the PRSA method; p = 0.012). These differences may be caused by the changes of activity of the parasympathetic autonomic nervous system as well as by the coupling of respiratory rhythm with heart rate due to an increase in pulmonary arterial vascular resistance. The results suggest that the differences with the control group in the HRV parameters, that reflect the functional state of the autonomic nervous system, are measurable after a few weeks from the beginning of the recovery even in the post-COVID group—a young and physically active population. We indicate HRV sensitive markers which may be used in long-term monitoring of patients after recovery.
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16
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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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17
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Zaccaro A, Piarulli A, Melosini L, Menicucci D, Gemignani A. Neural Correlates of Non-ordinary States of Consciousness in Pranayama Practitioners: The Role of Slow Nasal Breathing. Front Syst Neurosci 2022; 16:803904. [PMID: 35387390 PMCID: PMC8977447 DOI: 10.3389/fnsys.2022.803904] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/17/2022] [Indexed: 12/24/2022] Open
Abstract
The modulatory effect of nasal respiration on integrative brain functions and hence consciousness has recently been unambiguously demonstrated. This effect is sustained by the olfactory epithelium mechanical sensitivity complemented by the existence of massive projections between the olfactory bulb and the prefrontal cortex. However, studies on slow nasal breathing (SNB) in the context of contemplative practices have sustained the fundamental role of respiratory vagal stimulation, with little attention to the contribution of the olfactory epithelium mechanical stimulation. This study aims at disentangling the effects of olfactory epithelium stimulation (proper of nasal breathing) from those related to respiratory vagal stimulation (common to slow nasal and mouth breathing). We investigated the psychophysiological (cardio-respiratory and electroencephalographic parameters) and phenomenological (perceived state of consciousness) aftereffects of SNB (epithelium mechanical – 2.5 breaths/min) in 12 experienced meditators. We compared the nasal breathing aftereffects with those observed after a session of mouth breathing at the same respiratory rate and with those related to a resting state condition. SNB induced (1) slowing of electroencephalography (EEG) activities (delta-theta bands) in prefrontal regions, (2) a widespread increase of theta and high-beta connectivity complemented by an increase of phase-amplitude coupling between the two bands in prefrontal and posterior regions belonging to the Default Mode Network, (3) an increase of high-beta networks small-worldness. (4) a higher perception of being in a non-ordinary state of consciousness. The emerging scenario strongly suggests that the effects of SNB, beyond the relative contribution of vagal stimulation, are mainly ascribable to olfactory epithelium stimulation. In conclusion, slow Pranayama breathing modulates brain activity and hence subjective experience up to the point of inducing a non-ordinary state of consciousness.
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Affiliation(s)
- Andrea Zaccaro
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy
- Department of Neuroscience, Imaging and Clinical Sciences, “G. d’Annunzio” University of Chieti-Pescara, Chieti, Italy
| | - Andrea Piarulli
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy
- Giga Consciousness, Coma Science Group, University of Liège, Liège, Belgium
- *Correspondence: Andrea Piarulli,
| | - Lorenza Melosini
- Pneumology Branch, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
| | - Danilo Menicucci
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy
| | - Angelo Gemignani
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy
- Clinical Psychology Branch, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
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18
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Stojanovska V, Atta J, Kelly SB, Zahra VA, Matthews-Staindl E, Nitsos I, Moxham A, Pham Y, Hooper SB, Herlenius E, Galinsky R, Polglase GR. Increased Prostaglandin E2 in Brainstem Respiratory Centers Is Associated With Inhibition of Breathing Movements in Fetal Sheep Exposed to Progressive Systemic Inflammation. Front Physiol 2022; 13:841229. [PMID: 35309054 PMCID: PMC8928579 DOI: 10.3389/fphys.2022.841229] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/08/2022] [Indexed: 12/11/2022] Open
Abstract
Background Preterm newborns commonly experience apnoeas after birth and require respiratory stimulants and support. Antenatal inflammation is a common antecedent of preterm birth and inflammatory mediators, particularly prostaglandin E2 (PGE2), are associated with inhibition of vital brainstem respiratory centers. In this study, we tested the hypothesis that exposure to antenatal inflammation inhibits fetal breathing movements (FBMs) and increases inflammation and PGE2 levels in brainstem respiratory centers, cerebrospinal fluid (CSF) and blood plasma. Methods Chronically instrumented late preterm fetal sheep at 0.85 of gestation were randomly assigned to receive repeated intravenous saline (n = 8) or lipopolysaccharide (LPS) infusions (experimental day 1 = 300 ng, day 2 = 600 ng, day 3 = 1200 ng, n = 8). Fetal breathing movements were recorded throughout the experimental period. Sheep were euthanized 4 days after starting infusions for assessment of brainstem respiratory center histology. Results LPS infusions increased circulating and cerebrospinal fluid PGE2 levels, decreased arterial oxygen saturation, increased the partial pressure of carbon dioxide and lactate concentration, and decreased pH (p < 0.05 for all) compared to controls. LPS infusions caused transient reductions in the % of time fetuses spent breathing and the proportion of vigorous fetal breathing movements (P < 0.05 vs. control). LPS-exposure increased PGE2 expression in the RTN/pFRG (P < 0.05 vs. control) but not the pBÖTC (P < 0.07 vs. control) of the brainstem. No significant changes in gene expression were observed for PGE2 enzymes or caspase 3. LPS-exposure reduced the numbers of GFAP-immunoreactive astrocytes in the RTN/pFRG, NTS and XII of the brainstem (P < 0.05 vs. control for all) and increased microglial activation in the RTN/pFRG, preBÖTC, NTS, and XII brainstem respiratory centers (P < 0.05 vs. control for all). Conclusion Chronic LPS-exposure in late preterm fetal sheep increased PGE2 levels within the brainstem, CSF and plasma, and was associated with inhibition of FBMs, astrocyte loss and microglial activation within the brainstem respiratory centers. Further studies are needed to determine whether the inflammation-induced increase in PGE2 levels plays a key role in depressing respiratory drive in the perinatal period.
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Affiliation(s)
- Vanesa Stojanovska
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - John Atta
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Sharmony B. Kelly
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Valerie A. Zahra
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Eva Matthews-Staindl
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Ilias Nitsos
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Alison Moxham
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Yen Pham
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Stuart B. Hooper
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Eric Herlenius
- Department of Women’s and Children’s Health, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
- Astrid Lindgren Childrens Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Robert Galinsky
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
- *Correspondence: Robert Galinsky,
| | - Graeme R. Polglase
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
- Graeme R. Polglase,
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19
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Hirsch D, Kohl A, Wang Y, Sela-Donenfeld D. Axonal Projection Patterns of the Dorsal Interneuron Populations in the Embryonic Hindbrain. Front Neuroanat 2022; 15:793161. [PMID: 35002640 PMCID: PMC8738170 DOI: 10.3389/fnana.2021.793161] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022] Open
Abstract
Unraveling the inner workings of neural circuits entails understanding the cellular origin and axonal pathfinding of various neuronal groups during development. In the embryonic hindbrain, different subtypes of dorsal interneurons (dINs) evolve along the dorsal-ventral (DV) axis of rhombomeres and are imperative for the assembly of central brainstem circuits. dINs are divided into two classes, class A and class B, each containing four neuronal subgroups (dA1-4 and dB1-4) that are born in well-defined DV positions. While all interneurons belonging to class A express the transcription factor Olig3 and become excitatory, all class B interneurons express the transcription factor Lbx1 but are diverse in their excitatory or inhibitory fate. Moreover, within every class, each interneuron subtype displays its own specification genes and axonal projection patterns which are required to govern the stage-by-stage assembly of their connectivity toward their target sites. Remarkably, despite the similar genetic landmark of each dINs subgroup along the anterior-posterior (AP) axis of the hindbrain, genetic fate maps of some dA/dB neuronal subtypes uncovered their contribution to different nuclei centers in relation to their rhombomeric origin. Thus, DV and AP positional information has to be orchestrated in each dA/dB subpopulation to form distinct neuronal circuits in the hindbrain. Over the span of several decades, different axonal routes have been well-documented to dynamically emerge and grow throughout the hindbrain DV and AP positions. Yet, the genetic link between these distinct axonal bundles and their neuronal origin is not fully clear. In this study, we reviewed the available data regarding the association between the specification of early-born dorsal interneuron subpopulations in the hindbrain and their axonal circuitry development and fate, as well as the present existing knowledge on molecular effectors underlying the process of axonal growth.
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Affiliation(s)
- Dana Hirsch
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.,Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Ayelet Kohl
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yuan Wang
- Department of Biomedical Sciences, Program in Neuroscience, College of Medicine, Florida State University, Tallahassee, FL, United States
| | - Dalit Sela-Donenfeld
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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20
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Smith JC. Respiratory rhythm and pattern generation: Brainstem cellular and circuit mechanisms. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:1-35. [PMID: 35965022 DOI: 10.1016/b978-0-323-91534-2.00004-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Breathing movements in mammals are driven by rhythmic neural activity automatically generated within spatially and functionally organized brainstem neural circuits comprising the respiratory central pattern generator (CPG). This chapter reviews up-to-date experimental information and theoretical studies of the cellular and circuit mechanisms of respiratory rhythm and pattern generation operating within critical components of this CPG in the lower brainstem. Over the past several decades, there have been substantial advances in delineating the spatial architecture of essential medullary regions and their regional cellular and circuit properties required to understand rhythm and pattern generation mechanisms. A fundamental concept is that the circuits in these regions have rhythm-generating capabilities at multiple cellular and circuit organization levels. The regional cellular properties, circuit organization, and control mechanisms allow flexible expression of neural activity patterns for a repertoire of respiratory behaviors under various physiologic conditions that are dictated by requirements for homeostatic regulation and behavioral integration. Many mechanistic insights have been provided by computational modeling studies driven by experimental results and have advanced understanding in the field. These conceptual and theoretical developments are discussed.
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Affiliation(s)
- Jeffrey C Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
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21
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Aquino YC, Cabral LM, Miranda NC, Naccarato MC, Falquetto B, Moreira TS, Takakura AC. Respiratory disorders of Parkinson's disease. J Neurophysiol 2022; 127:1-15. [PMID: 34817281 DOI: 10.1152/jn.00363.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra, mainly affecting people over 60 yr of age. Patients develop both classic symptoms (tremors, muscle rigidity, bradykinesia, and postural instability) and nonclassical symptoms (orthostatic hypotension, neuropsychiatric deficiency, sleep disturbances, and respiratory disorders). Thus, patients with PD can have a significantly impaired quality of life, especially when they do not have multimodality therapeutic follow-up. The respiratory alterations associated with this syndrome are the main cause of mortality in PD. They can be classified as peripheral when caused by disorders of the upper airways or muscles involved in breathing and as central when triggered by functional deficits of important neurons located in the brainstem involved in respiratory control. Currently, there is little research describing these disorders, and therefore, there is no well-established knowledge about the subject, making the treatment of patients with respiratory symptoms difficult. In this review, the history of the pathology and data about the respiratory changes in PD obtained thus far will be addressed.
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Affiliation(s)
- Yasmin C Aquino
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, São Paulo, Brazil
| | - Laís M Cabral
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, São Paulo, Brazil
| | - Nicole C Miranda
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, São Paulo, Brazil
| | - Monique C Naccarato
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, São Paulo, Brazil
| | - Bárbara Falquetto
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, São Paulo, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, São Paulo, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, São Paulo, Brazil
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22
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Wu Y, Cui N, Xing H, Zhong W, Arrowood C, Johnson CM, Jiang C. In vivo evidence for the cellular basis of central hypoventilation of Rett syndrome and pharmacological correction in the rat model. J Cell Physiol 2021; 236:8082-8098. [PMID: 34077559 DOI: 10.1002/jcp.30462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 04/13/2021] [Accepted: 05/08/2021] [Indexed: 12/29/2022]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused mostly by mutations in the MECP2 gene. RTT patients show periodical hypoventilation attacks. The breathing disorder contributing to the high incidence of sudden death is thought to be due to depressed central inspiratory (I) activity via unknown cellular processes. Demonstration of such processes may lead to targets for pharmacological control of the RTT-type hypoventilation. We performed in vivo recordings from medullary respiratory neurons on the RTT rat model. To our surprise, both I and expiratory (E) neurons in the ventral respiratory column (VRC) increased their firing activity in Mecp2-null rats with severe hypoventilation. These I neurons including E-I phase-spanning and other I neurons remained active during apneas. Consistent with enhanced central I drive, ectopic phrenic discharges during expiration as well as apnea were observed in the Mecp2-null rats. Considering the increased I neuronal firing and ectopic phrenic activity, the RTT-type hypoventilation does not seem to be caused by depression in central I activity, neither reduced medullary I premotor output. This as well as excessive E neuronal firing as shown in our previous studies suggests inadequate synaptic inhibition for phase transition. We found that the abnormal respiratory neuronal firing, ectopic phrenic discharge as well as RTT-type hypoventilation all can be corrected by enhancing GABAergic inhibition. More strikingly, Mecp2-null rats reaching humane endpoints with severe hypoventilation can be rescued by GABAergic augmentation. Thus, defective GABAergic inhibition among respiratory neurons is likely to play a role in the RTT-type hypoventilation, which can be effectively controlled with pharmacological agents.
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Affiliation(s)
- Yang Wu
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Ningren Cui
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Hao Xing
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Weiwei Zhong
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Colin Arrowood
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | | | - Chun Jiang
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
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23
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Joffe AR, Khaira G, de Caen AR. The intractable problems with brain death and possible solutions. Philos Ethics Humanit Med 2021; 16:11. [PMID: 34625089 PMCID: PMC8500820 DOI: 10.1186/s13010-021-00107-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 09/14/2021] [Indexed: 05/21/2023] Open
Abstract
Brain death has been accepted worldwide medically and legally as the biological state of death of the organism. Nevertheless, the literature has described persistent problems with this acceptance ever since brain death was described. Many of these problems are not widely known or properly understood by much of the medical community. Here we aim to clarify these issues, based on the two intractable problems in the brain death debates. First, the metaphysical problem: there is no reason that withstands critical scrutiny to believe that BD is the state of biological death of the human organism. Second, the epistemic problem: there is no way currently to diagnose the state of BD, the irreversible loss of all brain functions, using clinical tests and ancillary tests, given potential confounders to testing. We discuss these problems and their main objections and conclude that these problems are intractable in that there has been no acceptable solution offered other than bare assertions of an 'operational definition' of death. We present possible ways to move forward that accept both the metaphysical problem - that BD is not biological death of the human organism - and the epistemic problem - that as currently diagnosed, BD is a devastating neurological state where recovery of sentience is very unlikely, but not a confirmed state of irreversible loss of all [critical] brain functions. We argue that the best solution is to abandon the dead donor rule, thus allowing vital organ donation from patients currently diagnosed as BD, assuming appropriate changes are made to the consent process and to laws about killing.
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Affiliation(s)
- Ari R Joffe
- University of Alberta and Stollery Children's Hospital, Division of Pediatric Critical Care, Edmonton, Alberta, Canada.
- University of Alberta, John Dossetor Health Ethics Center, 4-546 Edmonton Clinic Health Academy, 11405 112 Street, Edmonton, Alberta, T6G 1C9, Canada.
| | - Gurpreet Khaira
- University of Alberta and Stollery Children's Hospital, Division of Pediatric Critical Care, Edmonton, Alberta, Canada
| | - Allan R de Caen
- University of Alberta and Stollery Children's Hospital, Division of Pediatric Critical Care, Edmonton, Alberta, Canada
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GABAergic Inhibition of Presynaptic Ca 2+ Transients in Respiratory PreBötzinger Neurons in Organotypic Slice Cultures. eNeuro 2021; 8:ENEURO.0154-21.2021. [PMID: 34380658 PMCID: PMC8387147 DOI: 10.1523/eneuro.0154-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/02/2021] [Accepted: 08/08/2021] [Indexed: 11/21/2022] Open
Abstract
GABAergic somatodendritic inhibition in the preBötzinger complex (preBötC), a medullary site for the generation of inspiratory rhythm, is involved in respiratory rhythmogenesis and patterning. Nevertheless, whether GABA acts distally on presynaptic terminals, evoking presynaptic inhibition is unknown. Here, we begin to address this problem by measuring presynaptic Ca2+ transients in preBötC neurons, under rhythmic and non-rhythmic conditions, with two variants of genetically encoded Ca2+ indicators (GECIs). Organotypic slice cultures from newborn mice, containing the preBötC, were drop-transduced with jGCaMP7s, or injected with jGCaMP7f-labeling commissural preBötC neurons. Then, Ca2+ imaging combined with whole-cell patch-clamp or field stimulation was obtained from inspiratory preBötC neurons. We found that rhythmically active neurons expressed synchronized Ca2+ transients in soma, proximal and distal dendritic regions, and punctate synapse-like structures. Expansion microscopy revealed morphologic characteristics of bona fide synaptic boutons of the en passant and terminal type. Under non-rhythmic conditions, we found that bath application of the GABAA receptor agonist muscimol, and local microiontophoresis of GABA, reduced action potential (AP)-evoked and field stimulus-evoked Ca2+ transients in presynaptic terminals in inspiratory neurons and commissural neurons projecting to the contralateral preBötC. In addition, under rhythmic conditions, network rhythmic activity was suppressed by muscimol, while the GABAA receptor antagonist bicuculline completely re-activated spontaneous activity. These observations demonstrate that the preBötC includes neurons that show GABAergic inhibition of presynaptic Ca2+ transients, and presynaptic inhibition may play a role in the network activity that underlies breathing.
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Hernández VS, Zetter MA, Guerra EC, Hernández-Araiza I, Karuzin N, Hernández-Pérez OR, Eiden LE, Zhang L. ACE2 expression in rat brain: Implications for COVID-19 associated neurological manifestations. Exp Neurol 2021; 345:113837. [PMID: 34400158 PMCID: PMC8361001 DOI: 10.1016/j.expneurol.2021.113837] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 07/12/2021] [Accepted: 08/06/2021] [Indexed: 02/07/2023]
Abstract
We examined cell type-specific expression and distribution of rat brain angiotensin-converting enzyme 2 (ACE2), the receptor for SARS-CoV-2, in the rodent brain. ACE2 is ubiquitously present in brain vasculature, with the highest density of ACE2 expressing capillaries found in the olfactory bulb, the hypothalamic paraventricular, supraoptic, and mammillary nuclei, the midbrain substantia nigra and ventral tegmental area, and the hindbrain pontine nucleus, the pre-Bötzinger complex, and nucleus of tractus solitarius. ACE2 was expressed in astrocytes and astrocytic foot processes, pericytes and endothelial cells, key components of the blood-brain barrier. We found discrete neuronal groups immunopositive for ACE2 in brainstem respiratory rhythm generating centers, including the pontine nucleus, the parafascicular/retrotrapezoid nucleus, the parabrachial nucleus, the Bötzinger, and pre-Bötzinger complexes and the nucleus of tractus solitarius; in the arousal-related pontine reticular nucleus and gigantocellular reticular nuclei; in brainstem aminergic nuclei, including substantia nigra, ventral tegmental area, dorsal raphe, and locus coeruleus; in the epithalamic habenula, hypothalamic paraventricular and supramammillary nuclei; and in the hippocampus. Identification of ACE2-expressing neurons in rat brain within well-established functional circuits facilitates prediction of possible neurological manifestations of brain ACE2 dysregulation during and after COVID-19 infection.
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Affiliation(s)
- Vito S Hernández
- Dept. Physiology, Laboratory of Systems Neuroscience, School of Medicine, National Autonomous University of Mexico (UNAM, Mexico City, Mexico)
| | - Mario A Zetter
- Dept. Physiology, Laboratory of Systems Neuroscience, School of Medicine, National Autonomous University of Mexico (UNAM, Mexico City, Mexico)
| | - Enrique C Guerra
- Dept. Physiology, Laboratory of Systems Neuroscience, School of Medicine, National Autonomous University of Mexico (UNAM, Mexico City, Mexico)
| | - Ileana Hernández-Araiza
- Dept. Physiology, Laboratory of Systems Neuroscience, School of Medicine, National Autonomous University of Mexico (UNAM, Mexico City, Mexico); School of Medicine University of Maryland, Baltimore, MD, USA
| | - Nikita Karuzin
- Dept. Physiology, Laboratory of Systems Neuroscience, School of Medicine, National Autonomous University of Mexico (UNAM, Mexico City, Mexico); School of Medicine, Pan-American University, Mexico City, Mexico
| | - Oscar R Hernández-Pérez
- Dept. Physiology, Laboratory of Systems Neuroscience, School of Medicine, National Autonomous University of Mexico (UNAM, Mexico City, Mexico)
| | - Lee E Eiden
- Section on Molecular Neuroscience, NIMH-IRP, NIH, Bethesda, MD, USA
| | - Limei Zhang
- Dept. Physiology, Laboratory of Systems Neuroscience, School of Medicine, National Autonomous University of Mexico (UNAM, Mexico City, Mexico).
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26
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Cinelli E, Mutolo D, Pantaleo T, Bongianni F. Neural mechanisms underlying respiratory regulation within the preBötzinger complex of the rabbit. Respir Physiol Neurobiol 2021; 293:103736. [PMID: 34224867 DOI: 10.1016/j.resp.2021.103736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/01/2021] [Accepted: 07/01/2021] [Indexed: 11/29/2022]
Abstract
The preBötzinger complex (preBötC) is a medullary area essential for normal breathing and widely recognized as necessary and sufficient to generate the inspiratory phase of respiration. It has been studied mainly in rodents. Here we report the main results of our studies revealing the characteristics of the rabbit preBötC identified by means of neuronal recordings, D,L-homocysteic acid microinjections and histological controls. A crucial role in the respiratory rhythmogenesis within this neural substrate is played by excitatory amino acids, but also GABA and glycine display important contributions. Increases in respiratory frequency are induced by microinjections of neurokinins, somatostatin as well by serotonin (5-HT) through an action on 5-HT1A and 5-HT3 receptors or the disinhibition of a GABAergic circuit. Respiratory depression is observed in response to microinjections of the μ-opioid receptor agonist DAMGO. Our results show similarities and differences with the rodent preBötC and emphasize the importance of comparative studies on the mechanisms underlying respiratory rhythmogenesis in different animal species.
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Affiliation(s)
- Elenia Cinelli
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università Degli Studi di Firenze, Viale G.B. Morgagni 63, Firenze, 50134, Italy
| | - Donatella Mutolo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università Degli Studi di Firenze, Viale G.B. Morgagni 63, Firenze, 50134, Italy
| | - Tito Pantaleo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università Degli Studi di Firenze, Viale G.B. Morgagni 63, Firenze, 50134, Italy
| | - Fulvia Bongianni
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università Degli Studi di Firenze, Viale G.B. Morgagni 63, Firenze, 50134, Italy.
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27
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Yu H, Shi L, Chen J, Jun S, Hao Y, Wang S, Fu C, Zhang X, Lu H, Wang S, Yuan F. A Neural Circuit Mechanism Controlling Breathing by Leptin in the Nucleus Tractus Solitarii. Neurosci Bull 2021; 38:149-165. [PMID: 34212297 PMCID: PMC8821766 DOI: 10.1007/s12264-021-00742-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/07/2021] [Indexed: 02/03/2023] Open
Abstract
Leptin, an adipocyte-derived peptide hormone, has been shown to facilitate breathing. However, the central sites and circuit mechanisms underlying the respiratory effects of leptin remain incompletely understood. The present study aimed to address whether neurons expressing leptin receptor b (LepRb) in the nucleus tractus solitarii (NTS) contribute to respiratory control. Both chemogenetic and optogenetic stimulation of LepRb-expressing NTS (NTSLepRb) neurons notably activated breathing. Moreover, stimulation of NTSLepRb neurons projecting to the lateral parabrachial nucleus (LPBN) not only remarkably increased basal ventilation to a level similar to that of the stimulation of all NTSLepRb neurons, but also activated LPBN neurons projecting to the preBötzinger complex (preBötC). By contrast, ablation of NTSLepRb neurons projecting to the LPBN notably eliminated the enhanced respiratory effect induced by NTSLepRb neuron stimulation. In brainstem slices, bath application of leptin rapidly depolarized the membrane potential, increased the spontaneous firing rate, and accelerated the Ca2+ transients in most NTSLepRb neurons. Therefore, leptin potentiates breathing in the NTS most likely via an NTS-LPBN-preBötC circuit.
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Affiliation(s)
- Hongxiao Yu
- grid.256883.20000 0004 1760 8442Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 Hebei China
| | - Luo Shi
- grid.256883.20000 0004 1760 8442Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 Hebei China
| | - Jinting Chen
- grid.256883.20000 0004 1760 8442Core Facilities and Centers, Institute of Medicine and Health, Hebei Medical University, Shijiazhuang, 050017 Hebei China
| | - Shirui Jun
- grid.256883.20000 0004 1760 8442Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 Hebei China
| | - Yinchao Hao
- grid.256883.20000 0004 1760 8442Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 Hebei China
| | - Shuang Wang
- grid.256883.20000 0004 1760 8442Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 Hebei China
| | - Congrui Fu
- grid.256883.20000 0004 1760 8442School of Nursing, Hebei Medical University, Shijiazhuang, 050000 Hebei China
| | - Xiang Zhang
- grid.256883.20000 0004 1760 8442Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 Hebei China
| | - Haiyan Lu
- grid.256883.20000 0004 1760 8442Department of Orthodontics, College of Stomatology, Hebei Medical University, Shijiazhuang, 050017 Hebei China
| | - Sheng Wang
- grid.256883.20000 0004 1760 8442Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 Hebei China ,Hebei Key Laboratory of Neurophysiology, Shijiazhuang, 050017 Hebei China
| | - Fang Yuan
- grid.256883.20000 0004 1760 8442Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 Hebei China ,Hebei Key Laboratory of Neurophysiology, Shijiazhuang, 050017 Hebei China
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28
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Lee E, Vera K, Asirvatham-Jeyaraj N, Chantigian D, Larson M, Keller-Ross M. Menstrual phase does not influence ventilatory responses to group III/IV afferent signaling in eumenorrheic young females. Respir Physiol Neurobiol 2021; 292:103712. [PMID: 34118436 DOI: 10.1016/j.resp.2021.103712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/02/2021] [Accepted: 06/02/2021] [Indexed: 11/28/2022]
Abstract
Estrogen can reduce sympathetic activity, but its effects on minute ventilation (VE) with group III/IV afferent activation remain unclear. This study examined the influence of estrogen on VE during lower-extremity exercise with group III/IV activation. Females completed two identical visits in follicular and ovulatory menstrual phases. Nine participants (age 25 ± 4 years) performed three minutes of baseline steady-state cycle ergometry and then group III/IV afferents were further activated with proximal thigh cuffs inflated to 20, 60, and 100 mmHg (randomized) for two minutes and five minutes of cycling between each occlusion. Metaboreflex was isolated by post-exercise circulatory occlusion. Ventilation was measured continuously and rating of perceived exertion (RPE) was recorded for each stage. During rest and exercise, VE (p < 0.001) and tidal volume (VT) (p = 0.033) were higher in the follicular than ovulatory phase. Minute ventilation, VT, and respiratory rate (RR) with ergoreflex and metaboreflex activation were similar across phases. With cuff occlusion of 100 mmHg, VE increased from baseline by 26.3 ± 7.0 L/min in the follicular phase (p < 0.001) and by 25.3±7.7 L/min in the ovulatory phase (p < 0.001), with no difference between phases (p> 0.05); RR and VT increased similarly with occlusion, also with no phase differences. In eumenorrheic females, menstrual phase influences ventilation but not ventilatory responses to group III/IV isolation.
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Affiliation(s)
- Emma Lee
- Division of Physical Therapy, University of Minnesota, 420 Delaware St. SE, Minneapolis, MN, 55455, United States.
| | - Kathryn Vera
- Division of Rehabilitation Science, University of Minnesota, 420 Delaware St. SE, Minneapolis, MN, 55455, United States; Department of Health and Human Performance, University of Wisconsin - River Falls, 1110 S. Main St., River Falls, WI, 54022, United States
| | | | - Daniel Chantigian
- Division of Physical Therapy, University of Minnesota, 420 Delaware St. SE, Minneapolis, MN, 55455, United States
| | - Mia Larson
- Lillehei Clinical Research Unit, University of Minnesota, Cancer & Cardiovascular Research Center, 2231 6th St. E, Minneapolis, MN, 55455, United States
| | - Manda Keller-Ross
- Division of Physical Therapy, University of Minnesota, 420 Delaware St. SE, Minneapolis, MN, 55455, United States; Division of Rehabilitation Science, University of Minnesota, 420 Delaware St. SE, Minneapolis, MN, 55455, United States
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29
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Tagliabue G, Ji MS, Suneby Jagers JV, Zuege DJ, Kortbeek JB, Easton PA. Parasternal intercostal, costal, and crural diaphragm neural activation during hypercapnia. J Appl Physiol (1985) 2021; 131:672-680. [PMID: 34080922 DOI: 10.1152/japplphysiol.00261.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The parasternal intercostal is an obligatory inspiratory muscle working in coordination with the diaphragm, apparently sharing a common pathway of neural response. This similarity has attracted clinical interest, promoting the parasternal as a noninvasive alternative to the diaphragm, to monitor central neural respiratory output. However, this role may be confounded by the distinct and different functions of the costal and crural diaphragm. Given the anatomic location, parasternal activation may significantly impact the chest wall via both mechanical shortening or as a "fixator" for the chest wall. Either mechanical function of the parasternal may also impact differential function of the costal and crural. The objectives of the present study were, during eupnea and hypercapnia, 1) to compare the intensity of neural activation of the parasternal with the costal and crural diaphragm and 2) to examine parasternal recruitment and changes in mechanical action during progressive hypercapnia, including muscle baseline length and shortening. In 30 spontaneously breathing canines, awake without confounding anesthetic, we directly measured the electrical activity of the parasternal, costal, and crural diaphragm, and the corresponding mechanical shortening of the parasternal, during eupnea and hypercapnia. During eupnea and hypercapnia, the parasternal and costal diaphragm share a similar intensity of neural activation, whereas both differ significantly from crural diaphragm activity. The shortening of the parasternal increases significantly with hypercapnia, without a change in baseline end-expiratory length. In conclusion, the parasternal shares an equivalent intensity of neural activation with the costal, but not crural, diaphragm. The parasternal maintains and increases its active inspiratory shortening during augmented ventilation, despite high levels of diaphragm recruitment. Throughout hypercapnic ventilation, the parasternal contributes mechanically; it is not relegated to chest wall fixation.NEW & NOTEWORTHY This investigation directly compares neural activation of the parasternal intercostal muscle with the two distinct segments of the diaphragm, costal and crural, during room air and hypercapnic ventilation. During eupnea and hypercapnia, the parasternal intercostal muscle and costal diaphragm share a similar neural activation, whereas they both differ significantly from the crural diaphragm. The parasternal intercostal muscle maintains and increases active inspiratory mechanical action with shortening during ventilation, even with high levels of diaphragm recruitment.
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Affiliation(s)
- Giovanni Tagliabue
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Michael Sukjoon Ji
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jenny V Suneby Jagers
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Danny J Zuege
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - John B Kortbeek
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Paul A Easton
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
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30
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Dhaibar HA, Hamilton KA, Glasscock E. Kv1.1 subunits localize to cardiorespiratory brain networks in mice where their absence induces astrogliosis and microgliosis. Mol Cell Neurosci 2021; 113:103615. [PMID: 33901631 DOI: 10.1016/j.mcn.2021.103615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 12/27/2022] Open
Abstract
Cardiorespiratory collapse following a seizure is a suspected cause of sudden unexpected death in epilepsy (SUDEP), the leading cause of epilepsy-related mortality. In the commonly used Kcna1 gene knockout (Kcna1-/-) mouse model of SUDEP, cardiorespiratory profiling reveals an array of aberrant breathing patterns that could contribute to risk of seizure-related mortality. However, the brain structures mediating these respiratory abnormalities remain unknown. We hypothesize that Kv1.1 deficiency in respiratory control centers of the brain contribute to respiratory dysfunction in Kcna1-/- mice leading to increased SUDEP risk. Thus, in this study, we first used immunohistochemistry to map expression of Kv1.1 protein in cardiorespiratory brain regions of wild-type Kcna1+/+ (WT) mice. Next, GFAP and Iba1 immunostaining was used to test for the presence of astrogliosis and microgliosis, respectively, in the cardiorespiratory centers of Kcna1-/- mice, which could be indicative of seizure-related brain injury that could impair breathing. In WT mice, we detected Kv1.1 protein in all cardiorespiratory centers examined, including the basolateral amygdala, dorsal respiratory group, dorsal motor nucleus of vagus, nucleus ambiguus, ventral respiratory column, and pontine respiratory group, as well as chemosensory centers including the retrotrapezoid and median raphae nuclei. Extensive gliosis was observed in the same areas in Kcna1-/- mice suggesting that seizure-associated brain injury could contribute to respiratory abnormalities.
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Affiliation(s)
- Hemangini A Dhaibar
- Department of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center, Shreveport, LA, USA.
| | - Kathryn A Hamilton
- Department of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center, Shreveport, LA, USA.
| | - Edward Glasscock
- Department of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center, Shreveport, LA, USA; Department of Biological Sciences, Southern Methodist University, Dallas, TX, USA.
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31
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Broadhead MJ, Miles GB. A common role for astrocytes in rhythmic behaviours? Prog Neurobiol 2021; 202:102052. [PMID: 33894330 DOI: 10.1016/j.pneurobio.2021.102052] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/03/2021] [Accepted: 04/13/2021] [Indexed: 01/16/2023]
Abstract
Astrocytes are a functionally diverse form of glial cell involved in various aspects of nervous system infrastructure, from the metabolic and structural support of neurons to direct neuromodulation of synaptic activity. Investigating how astrocytes behave in functionally related circuits may help us understand whether there is any conserved logic to the role of astrocytes within neuronal networks. Astrocytes are implicated as key neuromodulatory cells within neural circuits that control a number of rhythmic behaviours such as breathing, locomotion and circadian sleep-wake cycles. In this review, we examine the evidence that astrocytes are directly involved in the regulation of the neural circuits underlying six different rhythmic behaviours: locomotion, breathing, chewing, gastrointestinal motility, circadian sleep-wake cycles and oscillatory feeding behaviour. We discuss how astrocytes are integrated into the neuronal networks that regulate these behaviours, and identify the potential gliotransmission signalling mechanisms involved. From reviewing the evidence of astrocytic involvement in a range of rhythmic behaviours, we reveal a heterogenous array of gliotransmission mechanisms, which help to regulate neuronal networks. However, we also observe an intriguing thread of commonality, in the form of purinergic gliotransmission, which is frequently utilised to facilitate feedback inhibition within rhythmic networks to constrain a given behaviour within its operational range.
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Affiliation(s)
- Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK.
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
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32
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Ramirez JM, Burgraff NJ, Wei AD, Baertsch NA, Varga AG, Baghdoyan HA, Lydic R, Morris KF, Bolser DC, Levitt ES. Neuronal mechanisms underlying opioid-induced respiratory depression: our current understanding. J Neurophysiol 2021; 125:1899-1919. [PMID: 33826874 DOI: 10.1152/jn.00017.2021] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Opioid-induced respiratory depression (OIRD) represents the primary cause of death associated with therapeutic and recreational opioid use. Within the United States, the rate of death from opioid abuse since the early 1990s has grown disproportionally, prompting the classification as a nationwide "epidemic." Since this time, we have begun to unravel many fundamental cellular and systems-level mechanisms associated with opioid-related death. However, factors such as individual vulnerability, neuromodulatory compensation, and redundancy of opioid effects across central and peripheral nervous systems have created a barrier to a concise, integrative view of OIRD. Within this review, we bring together multiple perspectives in the field of OIRD to create an overarching viewpoint of what we know, and where we view this essential topic of research going forward into the future.
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Affiliation(s)
- Jan-Marino Ramirez
- Department of Neurological Surgery, University of Washington, Seattle, Washington.,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Nicholas J Burgraff
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Aguan D Wei
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Nathan A Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Adrienn G Varga
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida.,Center for Respiratory Research and Rehabilitation, Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Helen A Baghdoyan
- Department of Psychology, University of Tennessee, Knoxville, Tennessee.,Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Ralph Lydic
- Department of Psychology, University of Tennessee, Knoxville, Tennessee.,Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Kendall F Morris
- 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
| | - Erica S Levitt
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida.,Center for Respiratory Research and Rehabilitation, Department of Physical Therapy, University of Florida, Gainesville, Florida
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33
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Inspiratory Off-Switch Mediated by Optogenetic Activation of Inhibitory Neurons in the preBötzinger Complex In Vivo. Int J Mol Sci 2021; 22:ijms22042019. [PMID: 33670653 PMCID: PMC7922779 DOI: 10.3390/ijms22042019] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/14/2021] [Accepted: 02/16/2021] [Indexed: 01/02/2023] Open
Abstract
The role of inhibitory neurons in the respiratory network is a matter of ongoing debate. Conflicting and contradicting results are manifold and the question whether inhibitory neurons are essential for the generation of the respiratory rhythm as such is controversial. Inhibitory neurons are required in pulmonary reflexes for adapting the activity of the central respiratory network to the status of the lung and it is hypothesized that glycinergic neurons mediate the inspiratory off-switch. Over the years, optogenetic tools have been developed that allow for cell-specific activation of subsets of neurons in vitro and in vivo. In this study, we aimed to identify the effect of activation of inhibitory neurons in vivo. Here, we used a conditional transgenic mouse line that expresses Channelrhodopsin 2 in inhibitory neurons. A 200 µm multimode optical fiber ferrule was implanted in adult mice using stereotaxic surgery, allowing us to stimulate inhibitory, respiratory neurons within the core excitatory network in the preBötzinger complex of the ventrolateral medulla. We show that, in anesthetized mice, activation of inhibitory neurons by blue light (470 nm) continuously or with stimulation frequencies above 10 Hz results in a significant reduction of the respiratory rate, in some cases leading to complete cessation of breathing. However, a lower stimulation frequency (4–5 Hz) could induce a significant increase in the respiratory rate. This phenomenon can be explained by the resetting of the respiratory cycle, since stimulation during inspiration shortened the associated breath and thereby increased the respiratory rate, while stimulation during the expiratory interval reduced the respiratory rate. Taken together, these results support the concept that activation of inhibitory neurons mediates phase-switching by inhibiting excitatory rhythmogenic neurons in the preBötzinger complex.
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34
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Ahn JH, Lee TK, Tae HJ, Kim B, Sim H, Lee JC, Kim DW, Kim YS, Shin MC, Park Y, Cho JH, Park JH, Lee CH, Choi SY, Won MH. Neuronal Death in the CNS Autonomic Control Center Comes Very Early after Cardiac Arrest and Is Not Significantly Attenuated by Prompt Hypothermic Treatment in Rats. Cells 2021; 10:E60. [PMID: 33401719 PMCID: PMC7824613 DOI: 10.3390/cells10010060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/28/2020] [Accepted: 12/29/2020] [Indexed: 12/19/2022] Open
Abstract
Autonomic dysfunction in the central nervous system (CNS) can cause death after recovery from a cardiac arrest (CA). However, few studies on histopathological changes in animal models of CA have been reported. In this study, we investigated the prevalence of neuronal death and damage in various brain regions and the spinal cord at early times after asphyxial CA and we studied the relationship between the mortality rate and neuronal damage following hypothermic treatment after CA. Rats were subjected to 7-8 min of asphyxial CA, followed by resuscitation and prompt hypothermic treatment. Eight regions related to autonomic control (the cingulate cortex, hippocampus, thalamus, hypothalamus, myelencephalon, and spinal cord) were examined using cresyl violet (a marker for Nissl substance) and Fluoro-Jade B (a marker for neuronal death). The survival rate was 44.5% 1 day post-CA, 18.2% 2 days post-CA and 0% 5 days post-CA. Neuronal death started 12 h post-CA in the gigantocellular reticular nucleus and caudoventrolateral reticular nucleus in the myelencephalon and lamina VII in the cervical, thoracic, lumbar, and sacral spinal cord, of which neurons are related to autonomic lower motor neurons. In these regions, Iba-1 immunoreactivity indicating microglial activation (microgliosis) was gradually increased with time after CA. Prompt hypothermic treatment increased the survival rate at 5 days after CA with an attenuation of neuronal damages and death in the damaged regions. However, the survival rate was 0% at 12 days after CA. Taken together, our study suggests that the early damage and death of neurons related to autonomic lower motor neurons was significantly related to the high mortality rate after CA and that prompt hypothermic therapy could increase the survival rate temporarily after CA, but could not ultimately save the animal.
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Affiliation(s)
- Ji Hyeon Ahn
- Department of Physical Therapy, College of Health Science, Youngsan University, Yangsan 50510, Korea;
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, Korea; (B.K.); (H.S.); (J.-C.L.)
| | - Tae-Kyeong Lee
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Korea;
| | - Hyun-Jin Tae
- Bio-Safety Research Institute, College of Veterinary Medicine, Chonbuk National University, Iksan 54596, Korea;
| | - Bora Kim
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, Korea; (B.K.); (H.S.); (J.-C.L.)
| | - Hyejin Sim
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, Korea; (B.K.); (H.S.); (J.-C.L.)
| | - Jae-Chul Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, Korea; (B.K.); (H.S.); (J.-C.L.)
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, and Research Institute of Oral Sciences, College of Dentistry, Gangnung-Wonju National University, Gangneung 25457, Korea;
| | - Yoon Sung Kim
- Department of Emergency Medicine, Samcheok Medical Center, Samcheok 25920, Korea;
| | - Myoung Cheol Shin
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea; (M.C.S.); (Y.P.); (J.H.C.)
| | - Yoonsoo Park
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea; (M.C.S.); (Y.P.); (J.H.C.)
| | - Jun Hwi Cho
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea; (M.C.S.); (Y.P.); (J.H.C.)
| | - Joon Ha Park
- Department of Anatomy, College of Korean Medicine, Dongguk University, Gyeongju 38066, Korea;
| | - Choong-Hyun Lee
- Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan 31116, Korea;
| | - Soo Young Choi
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Korea;
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 24341, Korea; (B.K.); (H.S.); (J.-C.L.)
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Smuder AJ, Turner SM, Schuster CM, Morton AB, Hinkley JM, Fuller DD. Hyperbaric Oxygen Treatment Following Mid-Cervical Spinal Cord Injury Preserves Diaphragm Muscle Function. Int J Mol Sci 2020; 21:ijms21197219. [PMID: 33007822 PMCID: PMC7582297 DOI: 10.3390/ijms21197219] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/24/2020] [Accepted: 09/27/2020] [Indexed: 12/17/2022] Open
Abstract
Oxidative damage to the diaphragm as a result of cervical spinal cord injury (SCI) promotes muscle atrophy and weakness. Respiratory insufficiency is the leading cause of morbidity and mortality in cervical spinal cord injury (SCI) patients, emphasizing the need for strategies to maintain diaphragm function. Hyperbaric oxygen (HBO) increases the amount of oxygen dissolved into the blood, elevating the delivery of oxygen to skeletal muscle and reactive oxygen species (ROS) generation. It is proposed that enhanced ROS production due to HBO treatment stimulates adaptations to diaphragm oxidative capacity, resulting in overall reductions in oxidative stress and inflammation. Therefore, we tested the hypothesis that exposure to HBO therapy acutely following SCI would reduce oxidative damage to the diaphragm muscle, preserving muscle fiber size and contractility. Our results demonstrated that lateral contusion injury at C3/4 results in a significant reduction in diaphragm muscle-specific force production and fiber cross-sectional area, which was associated with augmented mitochondrial hydrogen peroxide emission and a reduced mitochondrial respiratory control ratio. In contrast, rats that underwent SCI followed by HBO exposure consisting of 1 h of 100% oxygen at 3 atmospheres absolute (ATA) delivered for 10 consecutive days demonstrated an improvement in diaphragm-specific force production, and an attenuation of fiber atrophy, mitochondrial dysfunction and ROS production. These beneficial adaptations in the diaphragm were related to HBO-induced increases in antioxidant capacity and a reduction in atrogene expression. These findings suggest that HBO therapy may be an effective adjunctive therapy to promote respiratory health following cervical SCI.
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Affiliation(s)
- Ashley J. Smuder
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA; (A.B.M.); (J.M.H.)
- Breathing Research and Therapeutics, University of Florida, Gainesville, FL 32610, USA;
- Correspondence:
| | - Sara M. Turner
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (S.M.T.); (C.M.S.)
| | - Cassandra M. Schuster
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (S.M.T.); (C.M.S.)
| | - Aaron B. Morton
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA; (A.B.M.); (J.M.H.)
| | - J. Matthew Hinkley
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611, USA; (A.B.M.); (J.M.H.)
| | - David D. Fuller
- Breathing Research and Therapeutics, University of Florida, Gainesville, FL 32610, USA;
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA; (S.M.T.); (C.M.S.)
- McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
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36
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Estimation of neuron parameters from imperfect observations. PLoS Comput Biol 2020; 16:e1008053. [PMID: 32673311 PMCID: PMC7386621 DOI: 10.1371/journal.pcbi.1008053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 07/28/2020] [Accepted: 06/15/2020] [Indexed: 12/21/2022] Open
Abstract
The estimation of parameters controlling the electrical properties of biological neurons is essential to determine their complement of ion channels and to understand the function of biological circuits. By synchronizing conductance models to time series observations of the membrane voltage, one may construct models capable of predicting neuronal dynamics. However, identifying the actual set of parameters of biological ion channels remains a formidable theoretical challenge. Here, we present a regularization method that improves convergence towards this optimal solution when data are noisy and the model is unknown. Our method relies on the existence of an offset in parameter space arising from the interplay between model nonlinearity and experimental error. By tuning this offset, we induce saddle-node bifurcations from sub-optimal to optimal solutions. This regularization method increases the probability of finding the optimal set of parameters from 67% to 94.3%. We also reduce parameter correlations by implementing adaptive sampling and stimulation protocols compatible with parameter identifiability requirements. Our results show that the optimal model parameters may be inferred from imperfect observations provided the conditions of observability and identifiability are fulfilled.
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37
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Ghali MGZ. Retracted: Control of hypoglossal pre‐inspiratory discharge. Exp Physiol 2020; 105:1232-1255. [DOI: 10.1113/ep087329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 06/11/2020] [Indexed: 12/22/2022]
Affiliation(s)
- Michael George Zaki Ghali
- Departments of Neurological Surgery, Internal Medicine, General Surgery, and Neuroscience Karolinska Institutet Huddinge Stockholm Sweden
- Departments of Neurological Surgery, Neurophysiology, Neuroscience University of Oslo Oslo Norway
- Departments of Neurological Surgery and Neurochemistry University of Helsinki Helsinki Finland
- Departments of Neurological Surgery, Internal Medicine, Cardiothoracic Surgery, and Neuroscience University of California Francisco San Francisco CA USA
- Departments of Neurological Surgery and Neuroscience Barrow Neurological Institute Phoenix AZ USA
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Joffe AR. The Apnea Test: Requiring Consent for a Test That is a Self-Fulfilling Prophecy, Not Fit for Purpose, and Always Confounded? THE AMERICAN JOURNAL OF BIOETHICS : AJOB 2020; 20:42-44. [PMID: 32618505 DOI: 10.1080/15265161.2020.1754504] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
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Chrobok L, Northeast RC, Myung J, Cunningham PS, Petit C, Piggins HD. Timekeeping in the hindbrain: a multi-oscillatory circadian centre in the mouse dorsal vagal complex. Commun Biol 2020; 3:225. [PMID: 32385329 PMCID: PMC7210107 DOI: 10.1038/s42003-020-0960-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 04/21/2020] [Indexed: 02/06/2023] Open
Abstract
Metabolic and cardiovascular processes controlled by the hindbrain exhibit 24 h rhythms, but the extent to which the hindbrain possesses endogenous circadian timekeeping is unresolved. Here we provide compelling evidence that genetic, neuronal, and vascular activities of the brainstem’s dorsal vagal complex are subject to intrinsic circadian control with a crucial role for the connection between its components in regulating their rhythmic properties. Robust 24 h variation in clock gene expression in vivo and neuronal firing ex vivo were observed in the area postrema (AP) and nucleus of the solitary tract (NTS), together with enhanced nocturnal responsiveness to metabolic cues. Unexpectedly, we also find functional and molecular evidence for increased penetration of blood borne molecules into the NTS at night. Our findings reveal that the hindbrain houses a local network complex of neuronal and non-neuronal autonomous circadian oscillators, with clear implications for understanding local temporal control of physiology in the brainstem. Lukasz Chrobok, Rebecca Northeast et al. show circadian variation in clock gene expression and neuronal firing within the area postrema and the nucleus of the solitary tract in mice. These regions also exhibit variation in metabolic processes and blood-brain barrier permeability across the 24 hour cycle suggesting the presence of circadian oscillators within the dorsal vagal complex.
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Affiliation(s)
- Lukasz Chrobok
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.,Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, 30-387, Krakow, Poland
| | - Rebecca C Northeast
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Jihwan Myung
- Graduate Institute of Mind, Brain, and Consciousness, Taipei Medical University, No.172-1 Sec. 2 Keelung Road, Da'an District, Taipei, 106, Taiwan.,Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, No. 250, Wu-Hsing Street, Taipei, 110, Taiwan.,Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, Ministry of Health and Welfare, No. 291 Zhongzheng Road, Zhonghe District, New Taipei City, 235, Taiwan
| | - Peter S Cunningham
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Cheryl Petit
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Hugh D Piggins
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, UK. .,School of Physiology, Pharmacology, and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, BS8 1TD, UK.
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40
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Wang Y, Rubin JE. Complex bursting dynamics in an embryonic respiratory neuron model. CHAOS (WOODBURY, N.Y.) 2020; 30:043127. [PMID: 32357647 DOI: 10.1063/1.5138993] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 03/23/2020] [Indexed: 06/11/2023]
Abstract
Pre-Bötzinger complex (pre-BötC) network activity within the mammalian brainstem controls the inspiratory phase of the respiratory rhythm. While bursting in pre-BötC neurons during the postnatal period has been extensively studied, less is known regarding inspiratory pacemaker neuron behavior at embryonic stages. Recent data in mouse embryo brainstem slices have revealed the existence of a variety of bursting activity patterns depending on distinct combinations of burst-generating INaP and ICAN conductances. In this work, we consider a model of an isolated embryonic pre-BötC neuron featuring two distinct bursting mechanisms. We use methods of dynamical systems theory, such as phase plane analysis, fast-slow decomposition, and bifurcation analysis, to uncover mechanisms underlying several different types of intrinsic bursting dynamics observed experimentally including several forms of plateau bursts, bursts involving depolarization block, and various combinations of these patterns. Our analysis also yields predictions about how changes in the balance of the two bursting mechanisms contribute to alterations in an inspiratory pacemaker neuron activity during prenatal development.
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Affiliation(s)
- Yangyang Wang
- Department of Mathematics, The University of Iowa, Iowa City, Iowa 52242, USA
| | - Jonathan E Rubin
- Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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41
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Kölliker-Fuse/Parabrachial complex mu opioid receptors contribute to fentanyl-induced apnea and respiratory rate depression. Respir Physiol Neurobiol 2020; 275:103388. [PMID: 31953234 DOI: 10.1016/j.resp.2020.103388] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 11/05/2019] [Accepted: 01/13/2020] [Indexed: 12/19/2022]
Abstract
Overdoses caused by the opioid agonist fentanyl have increased exponentially in recent years. Identifying mechanisms to counter progression to fatal respiratory apnea during opioid overdose is desirable, but difficult to study in vivo. The pontine Kölliker-Fuse/Parabrachial complex (KF/PB) provides respiratory drive and contains opioid-sensitive neurons. The contribution of the KF/PB complex to fentanyl-induced apnea was investigated using the in situ arterially perfused preparation of rat. Systemic application of fentanyl resulted in concentration-dependent respiratory disturbances. At low concentrations, respiratory rate slowed and subsequently transitioned to an apneustic-like, 2-phase pattern. Higher concentrations caused prolonged apnea, interrupted by occasional apneustic-like bursts. Application of CTAP, a selective mu opioid receptor antagonist, directly into the KF/PB complex reversed and prevented fentanyl-induced apnea by increasing the frequency of apneustic-like bursting. These results demonstrate that countering opioid effects in the KF/PB complex is sufficient to restore phasic respiratory output at a rate similar to pre-fentanyl conditions, which could be beneficial in opioid overdose.
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42
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Dereli AS, Yaseen Z, Carrive P, Kumar NN. Adaptation of Respiratory-Related Brain Regions to Long-Term Hypercapnia: Focus on Neuropeptides in the RTN. Front Neurosci 2019; 13:1343. [PMID: 31920508 PMCID: PMC6923677 DOI: 10.3389/fnins.2019.01343] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/28/2019] [Indexed: 12/21/2022] Open
Abstract
Long-term hypercapnia is associated with respiratory conditions including obstructive sleep apnea, chronic obstructive pulmonary disease and obesity hypoventilation syndrome. Animal studies have demonstrated an initial (within hours) increase in ventilatory drive followed by a decrease in this response over the long-term (days–weeks) in response hypercapnia. Little is known about whether changes in the central respiratory chemoreflex are involved. Here we investigated whether central respiratory chemoreceptor neurons of the retrotrapezoid nucleus (RTN), which project to the respiratory pattern generator within the ventral respiratory column (VRC) have a role in the mechanism of neuroplasticity associated with long-term hypercapnia. Adult male C57BL/6 mice (n = 5/group) were used. Our aims were (1) to determine if galanin, neuromedin B and gastrin-releasing peptide gene expression is altered in the RTN after long-term hypercapnia. This was achieved using qPCR to measure mRNA expression changes of neuropeptides in the RTN after short-term hypercapnia (6 or 8 h, 5 or 8% CO2) or long-term hypercapnia exposure (10 day, 5 or 8% CO2), (2) in the mouse brainstem, to determine the distribution of preprogalanin in chemoreceptors, and the co-occurrence of the galanin receptor 1 (GalR1:Gi-coupled receptor) with inhibitory GlyT2 ventral respiratory column neurons using in situ hybridization (ISH) to better characterize galaninergic RTN-VRC circuitry, (3) to investigate whether long-term hypercapnia causes changes to recruitment (detected by cFos immunohistochemistry) of respiratory related neural populations including the RTN neurons and their galaninergic subset, in vivo. Collectively, we found that hypercapnia decreases neuropeptide expression in the RTN in the short-term and has the opposite effect over the long-term. Following long term hypercapnia, the number of RTN galanin neurons remains unchanged, and their responsiveness to acute chemoreflex is sustained; in contrast, we identified multiple respiratory related sites that exhibit blunted chemoreflex activation. GalR1 was distributed in 11% of preBötC and 30% of BötC glycinergic neurons. Our working hypothesis is that during long-term hypercapnia, galanin co-release from RTN neurons may counterbalance glutamatergic inputs to respiratory centers to downscale energetically wasteful hyperventilation, thereby having a role in neuroplasticity by contributing to a decrease in ventilation, through the inhibitory effects of galanin.
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Affiliation(s)
- Ayse Sumeyra Dereli
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Zarwa Yaseen
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Pascal Carrive
- Department of Anatomy, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Natasha N Kumar
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
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43
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Charsar BA, Brinton MA, Locke K, Chen AY, Ghosh B, Urban MW, Komaravolu S, Krishnamurthy K, Smit R, Pasinelli P, Wright MC, Smith GM, Lepore AC. AAV2-BDNF promotes respiratory axon plasticity and recovery of diaphragm function following spinal cord injury. FASEB J 2019; 33:13775-13793. [PMID: 31577916 DOI: 10.1096/fj.201901730r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
More than half of spinal cord injury (SCI) cases occur in the cervical region, leading to respiratory dysfunction due to damaged neural circuitry that controls critically important muscles such as the diaphragm. The C3-C5 spinal cord is the location of phrenic motor neurons (PhMNs) that are responsible for diaphragm activation; PhMNs receive bulbospinal excitatory drive predominately from supraspinal neurons of the rostral ventral respiratory group (rVRG). Cervical SCI results in rVRG axon damage, PhMN denervation, and consequent partial-to-complete paralysis of hemidiaphragm. In a rat model of C2 hemisection SCI, we expressed the axon guidance molecule, brain-derived neurotrophic factor (BDNF), selectively at the location of PhMNs (ipsilateral to lesion) to promote directed growth of rVRG axons toward PhMN targets by performing intraspinal injections of adeno-associated virus serotype 2 (AAV2)-BDNF vector. AAV2-BDNF promoted significant functional diaphragm recovery, as assessed by in vivo electromyography. Within the PhMN pool ipsilateral to injury, AAV2-BDNF robustly increased sprouting of both spared contralateral-originating rVRG axons and serotonergic fibers. Furthermore, AAV2-BDNF significantly increased numbers of putative monosynaptic connections between PhMNs and these sprouting rVRG and serotonergic axons. These findings show that targeting circuit plasticity mechanisms involving the enhancement of synaptic inputs from spared axon populations is a powerful strategy for restoring respiratory function post-SCI.-Charsar, B. A., Brinton, M. A., Locke, K., Chen, A. Y., Ghosh, B., Urban, M. W., Komaravolu, S., Krishnamurthy, K., Smit, R., Pasinelli, P., Wright, M. C., Smith, G. M., Lepore, A. C. AAV2-BDNF promotes respiratory axon plasticity and recovery of diaphragm function following spinal cord injury.
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Affiliation(s)
- Brittany A Charsar
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael A Brinton
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Katherine Locke
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Anna Y Chen
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Mark W Urban
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Sreeya Komaravolu
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Karthik Krishnamurthy
- Department of Neuroscience, Jefferson Weinberg Amyotrophic Lateral Sclerosis (ALS) Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Rupert Smit
- Department of Anatomy and Cell Biology, Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Piera Pasinelli
- Department of Neuroscience, Jefferson Weinberg Amyotrophic Lateral Sclerosis (ALS) Center, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, Philadelphia, Pennsylvania, USA
| | - George M Smith
- Department of Anatomy and Cell Biology, Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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44
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Steuer I, Guertin PA. Central pattern generators in the brainstem and spinal cord: an overview of basic principles, similarities and differences. Rev Neurosci 2019; 30:107-164. [PMID: 30543520 DOI: 10.1515/revneuro-2017-0102] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/30/2018] [Indexed: 12/11/2022]
Abstract
Central pattern generators (CPGs) are generally defined as networks of neurons capable of enabling the production of central commands, specifically controlling stereotyped, rhythmic motor behaviors. Several CPGs localized in brainstem and spinal cord areas have been shown to underlie the expression of complex behaviors such as deglutition, mastication, respiration, defecation, micturition, ejaculation, and locomotion. Their pivotal roles have clearly been demonstrated although their organization and cellular properties remain incompletely characterized. In recent years, insightful findings about CPGs have been made mainly because (1) several complementary animal models were developed; (2) these models enabled a wide variety of techniques to be used and, hence, a plethora of characteristics to be discovered; and (3) organizations, functions, and cell properties across all models and species studied thus far were generally found to be well-preserved phylogenetically. This article aims at providing an overview for non-experts of the most important findings made on CPGs in in vivo animal models, in vitro preparations from invertebrate and vertebrate species as well as in primates. Data about CPG functions, adaptation, organization, and cellular properties will be summarized with a special attention paid to the network for locomotion given its advanced level of characterization compared with some of the other CPGs. Similarities and differences between these networks will also be highlighted.
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Affiliation(s)
- Inge Steuer
- Neuroscience Unit, Laval University Medical Center (CHUL - CHU de Québec), 2705 Laurier Blvd, Quebec City, Quebec G1V 4G2, Canada
| | - Pierre A Guertin
- Neuroscience Unit, Laval University Medical Center (CHUL - CHU de Québec), 2705 Laurier Blvd, Quebec City, Quebec G1V 4G2, Canada
- Faculty of Medicine, Department of Psychiatry and Neurosciences, Laval University, Quebec City, Quebec G1V 0A6, Canada
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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] [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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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: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [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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Morinaga R, Nakamuta N, Yamamoto Y. Serotonergic projections to the ventral respiratory column from raphe nuclei in rats. Neurosci Res 2019; 143:20-30. [DOI: 10.1016/j.neures.2018.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 12/22/2022]
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48
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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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49
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Abstract
Breathing is a vital rhythmic behavior that originates from neural networks within the brainstem. It is hypothesized that the breathing rhythm is generated by spatially distinct networks localized to discrete kernels or compartments. Here, we provide evidence that the functional boundaries of these compartments expand and contract dynamically based on behavioral or physiological demands. The ability of these rhythmic networks to change in size may allow the breathing rhythm to be very reliable, yet flexible enough to accommodate the large repertoire of mammalian behaviors that must be integrated with breathing. The ability of neuronal networks to reconfigure is a key property underlying behavioral flexibility. Networks with recurrent topology are particularly prone to reconfiguration through changes in synaptic and intrinsic properties. Here, we explore spatial reconfiguration in the reticular networks of the medulla that generate breathing. Combined results from in vitro and in vivo approaches demonstrate that the network architecture underlying generation of the inspiratory phase of breathing is not static but can be spatially redistributed by shifts in the balance of excitatory and inhibitory network influences. These shifts in excitation/inhibition allow the size of the active network to expand and contract along a rostrocaudal medullary column during behavioral or metabolic challenges to breathing, such as changes in sensory feedback, sighing, and gasping. We postulate that the ability of this rhythm-generating network to spatially reconfigure contributes to the remarkable robustness and flexibility of breathing.
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Shevtsova NA, Marchenko V, Bezdudnaya T. Modulation of Respiratory System by Limb Muscle Afferents in Intact and Injured Spinal Cord. Front Neurosci 2019; 13:289. [PMID: 30971888 PMCID: PMC6443963 DOI: 10.3389/fnins.2019.00289] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/11/2019] [Indexed: 12/20/2022] Open
Abstract
Breathing constantly adapts to environmental, metabolic or behavioral changes by responding to different sensory information, including afferent feedback from muscles. Importantly, not just respiratory muscle feedback influences respiratory activity. Afferent sensory information from rhythmically moving limbs has also been shown to play an essential role in the breathing. The present review will discuss the neuronal mechanisms of respiratory modulation by activation of peripheral muscles that usually occurs during locomotion or exercise. An understanding of these mechanisms and finding the most effective approaches to regulate respiratory motor output by stimulation of limb muscles could be extremely beneficial for people with respiratory dysfunctions. Specific attention in the present review is given to the muscle stimulation to treat respiratory deficits following cervical spinal cord injury.
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Affiliation(s)
- Natalia A Shevtsova
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Vitaliy Marchenko
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Tatiana Bezdudnaya
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
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