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Bush NE, Ramirez JM. Latent neural population dynamics underlying breathing, opioid-induced respiratory depression and gasping. Nat Neurosci 2024; 27:259-271. [PMID: 38182835 PMCID: PMC10849970 DOI: 10.1038/s41593-023-01520-3] [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: 11/30/2022] [Accepted: 11/06/2023] [Indexed: 01/07/2024]
Abstract
Breathing is vital and must be concurrently robust and flexible. This rhythmic behavior is generated and maintained within a rostrocaudally aligned set of medullary nuclei called the ventral respiratory column (VRC). The rhythmic properties of individual VRC nuclei are well known, yet technical challenges have limited the interrogation of the entire VRC population simultaneously. Here we characterize over 15,000 medullary units using high-density electrophysiology, opto-tagging and histological reconstruction. Population dynamics analysis reveals consistent rotational trajectories through a low-dimensional neural manifold. These rotations are robust and maintained even during opioid-induced respiratory depression. During severe hypoxia-induced gasping, the low-dimensional dynamics of the VRC reconfigure from rotational to all-or-none, ballistic efforts. Thus, latent dynamics provide a unifying lens onto the activities of large, heterogeneous populations of neurons involved in the simple, yet vital, behavior of breathing, and well describe how these populations respond to a variety of perturbations.
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Affiliation(s)
- Nicholas Edward Bush
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA.
- Department of Pediatrics, University of Washington, Seattle, WA, USA.
- Department of Neurological Surgery, University of Washington, Seattle, WA, USA.
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2
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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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3
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Kleinfeld D, Deschênes M, Economo MN, Elbaz M, Golomb D, Liao SM, O'Connor DH, Wang F. Low- and high-level coordination of orofacial motor actions. Curr Opin Neurobiol 2023; 83:102784. [PMID: 37757586 PMCID: PMC11034851 DOI: 10.1016/j.conb.2023.102784] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/24/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023]
Abstract
Orofacial motor actions are movements that, in rodents, involve whisking of the vibrissa, deflection of the nose, licking and lapping with the tongue, and consumption through chewing. These actions, along with bobbing and turning of the head, coordinate to subserve exploration while not conflicting with life-supporting actions such as breathing and swallowing. Orofacial and head movements are comprised of two additive components: a rhythm that can be entrained by the breathing oscillator and a broadband component that directs the actuator to the region of interest. We focus on coordinating the rhythmic component of actions into a behavior. We hypothesize that the precise timing of each constituent action is continually adjusted through the merging of low-level oscillator input with sensory-derived, high-level rhythmic feedback. Supporting evidence is discussed.
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Affiliation(s)
- David Kleinfeld
- Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA; Department of Neurobiology, University of California at San Diego, La Jolla, CA 92093, USA.
| | - Martin Deschênes
- Department of Psychiatry and Neuroscience, Laval University, Québec City, G1J 2R3 Canada
| | - Michael N Economo
- Department of Bioengineering, Boston University, Boston, MA 02215, USA
| | - Michaël Elbaz
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - David Golomb
- Department of Physiology and Cell Biology, Ben Gurion University, Be'er-Sheba 8410501, Israel; Department of Physics, Ben Gurion University, Be'er-Sheba 8410501, Israel
| | - Song-Mao Liao
- Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA
| | - Daniel H O'Connor
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Zynval Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Fan Wang
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; McGovern Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Liao SM, Kleinfeld D. A change in behavioral state switches the pattern of motor output that underlies rhythmic head and orofacial movements. Curr Biol 2023; 33:1951-1966.e6. [PMID: 37105167 PMCID: PMC10225163 DOI: 10.1016/j.cub.2023.04.008] [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: 01/12/2023] [Revised: 03/27/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023]
Abstract
The breathing rhythm serves as a reference that paces orofacial motor actions and orchestrates active sensing. Past work has reported that pacing occurs solely at a fixed phase relative to sniffing. We re-evaluated this constraint as a function of exploratory behavior. Allocentric and egocentric rotations of the head and the electromyogenic activity of the motoneurons for head and orofacial movements were recorded in free-ranging rats as they searched for food. We found that a change in state from foraging to rearing is accompanied by a large phase shift in muscular activation relative to sniffing, and a concurrent change in the frequency of sniffing, so that pacing now occurs at one of the two phases. Further, head turning is biased such that an animal gathers a novel sample of its environment upon inhalation. In total, the coordination of active sensing has a previously unrealized computational complexity. This can emerge from hindbrain circuits with fixed architecture and credible synaptic time delays.
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Affiliation(s)
- Song-Mao Liao
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - David Kleinfeld
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA; Department of Neurobiology, University of California San Diego, La Jolla, CA 92093, USA.
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Vafadari B, Tacke C, Harb A, Grützner AA, Hülsmann S. Increase of breathing rate mediated by unilateral optogenetic inactivation of inhibitory neurons in the preBötzinger Complex in vivo. Respir Physiol Neurobiol 2023; 311:104032. [PMID: 36758781 DOI: 10.1016/j.resp.2023.104032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/26/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023]
Abstract
Brainstem neural circuits located in the preBötzinger complex (preBötC) and Bötzinger complex (BötC) play a critical role in the control of breathing. In this study, glycinergic preBötC and BötC neurons were inactivated with optogenetics in vivo using mice with Cre inducible expression of eNpHR3.0-EYFP. Unilateral inhibition of glycinergic neurons in the preBötC, and to a lower extend also in the BötC, led to a higher respiratory rate. It can be concluded that functional inactivation of inhibitory neurons leads to a disinhibition of preBötC excitatory neurons and thus an increase in the respiratory drive of the network.
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Affiliation(s)
- Behnam Vafadari
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany.
| | - Charlotte Tacke
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Ali Harb
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Anja-Annett Grützner
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Swen Hülsmann
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany.
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6
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Krohn F, Novello M, van der Giessen RS, De Zeeuw CI, Pel JJM, Bosman LWJ. The integrated brain network that controls respiration. eLife 2023; 12:83654. [PMID: 36884287 PMCID: PMC9995121 DOI: 10.7554/elife.83654] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/29/2023] [Indexed: 03/09/2023] Open
Abstract
Respiration is a brain function on which our lives essentially depend. Control of respiration ensures that the frequency and depth of breathing adapt continuously to metabolic needs. In addition, the respiratory control network of the brain has to organize muscular synergies that integrate ventilation with posture and body movement. Finally, respiration is coupled to cardiovascular function and emotion. Here, we argue that the brain can handle this all by integrating a brainstem central pattern generator circuit in a larger network that also comprises the cerebellum. Although currently not generally recognized as a respiratory control center, the cerebellum is well known for its coordinating and modulating role in motor behavior, as well as for its role in the autonomic nervous system. In this review, we discuss the role of brain regions involved in the control of respiration, and their anatomical and functional interactions. We discuss how sensory feedback can result in adaptation of respiration, and how these mechanisms can be compromised by various neurological and psychological disorders. Finally, we demonstrate how the respiratory pattern generators are part of a larger and integrated network of respiratory brain regions.
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Affiliation(s)
- Friedrich Krohn
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Manuele Novello
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Johan J M Pel
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
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7
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Casarrubios AM, Pérez-Atencio LF, Martín C, Ibarz JM, Mañas E, Paul DL, Barrio LC. Neural bases for the genesis and CO 2 therapy of periodic Cheyne-Stokes breathing in neonatal male connexin-36 knockout mice. Front Neurosci 2023; 17:1045269. [PMID: 36845442 PMCID: PMC9944137 DOI: 10.3389/fnins.2023.1045269] [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: 09/15/2022] [Accepted: 01/16/2023] [Indexed: 02/11/2023] Open
Abstract
Periodic Cheyne-Stokes breathing (CSB) oscillating between apnea and crescendo-decrescendo hyperpnea is the most common central apnea. Currently, there is no proven therapy for CSB, probably because the fundamental pathophysiological question of how the respiratory center generates this form of breathing instability is still unresolved. Therefore, we aimed to determine the respiratory motor pattern of CSB resulting from the interaction of inspiratory and expiratory oscillators and identify the neural mechanism responsible for breathing regularization induced by the supplemental CO2 administration. Analysis of the inspiratory and expiratory motor pattern in a transgenic mouse model lacking connexin-36 electrical synapses, the neonatal (P14) Cx36 knockout male mouse, with a persistent CSB, revealed that the reconfigurations recurrent between apnea and hyperpnea and vice versa result from cyclical turn on/off of active expiration driven by the expiratory oscillator, which acts as a master pacemaker of respiration and entrains the inspiratory oscillator to restore ventilation. The results also showed that the suppression of CSB by supplemental 12% CO2 in inhaled air is due to the stabilization of coupling between expiratory and inspiratory oscillators, which causes the regularization of respiration. CSB rebooted after washout of CO2 excess when the inspiratory activity depressed again profoundly, indicating that the disability of the inspiratory oscillator to sustain ventilation is the triggering factor of CSB. Under these circumstances, the expiratory oscillator activated by the cyclic increase of CO2 behaves as an "anti-apnea" center generating the crescendo-decrescendo hyperpnea and periodic breathing. The neurogenic mechanism of CSB identified highlights the plasticity of the two-oscillator system in the neural control of respiration and provides a rationale base for CO2 therapy.
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Affiliation(s)
- Ana M. Casarrubios
- Units of Experimental Neurology and Sleep Apnea, Hospital “Ramón y Cajal” (IRYCIS), Madrid, Spain,Ph.D. Program in Neuroscience, Autonoma de Madrid University-Cajal Institute, Madrid, Spain
| | - Leonel F. Pérez-Atencio
- Units of Experimental Neurology and Sleep Apnea, Hospital “Ramón y Cajal” (IRYCIS), Madrid, Spain
| | - Cristina Martín
- Units of Experimental Neurology and Sleep Apnea, Hospital “Ramón y Cajal” (IRYCIS), Madrid, Spain
| | - José M. Ibarz
- Units of Experimental Neurology and Sleep Apnea, Hospital “Ramón y Cajal” (IRYCIS), Madrid, Spain
| | - Eva Mañas
- Sleep Apnea Unit, Respiratory Department, Hospital “Ramón y Cajal” (IRYCIS), Madrid, Spain
| | - David L. Paul
- Department of Neurobiology, Medical School, Harvard University, Boston, MA, United States
| | - Luis C. Barrio
- Units of Experimental Neurology and Sleep Apnea, Hospital “Ramón y Cajal” (IRYCIS), Madrid, Spain,Center for Biomedical Technology, Universidad Politécnica de Madrid, Madrid, Spain,*Correspondence: Luis C. Barrio, ; orcid.org/0000-0002-9016-3510
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Roberts R, Wall MJ, Braren I, Dhillon K, Evans A, Dunne J, Nyakupinda S, Huckstepp RTR. An Improved Model of Moderate Sleep Apnoea for Investigating Its Effect as a Comorbidity on Neurodegenerative Disease. Front Aging Neurosci 2022; 14:861344. [PMID: 35847678 PMCID: PMC9278434 DOI: 10.3389/fnagi.2022.861344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/19/2022] [Indexed: 11/25/2022] Open
Abstract
Sleep apnoea is a highly prevalent disease that often goes undetected and is associated with poor clinical prognosis, especially as it exacerbates many different disease states. However, most animal models of sleep apnoea (e.g., intermittent hypoxia) have recently been dispelled as physiologically unrealistic and are often unduly severe. Owing to a lack of appropriate models, little is known about the causative link between sleep apnoea and its comorbidities. To overcome these problems, we have created a more realistic animal model of moderate sleep apnoea by reducing the excitability of the respiratory network. This has been achieved through controlled genetically mediated lesions of the preBötzinger complex (preBötC), the inspiratory oscillator. This novel model shows increases in sleep disordered breathing with alterations in breathing during wakefulness (decreased frequency and increased tidal volume) as observed clinically. The increase in dyspnoeic episodes leads to reduction in REM sleep, with all lost active sleep being spent in the awake state. The increase in hypoxic and hypercapnic insults induces both systemic and neural inflammation. Alterations in neurophysiology, an inhibition of hippocampal long-term potentiation (LTP), is reflected in deficits in both long- and short-term spatial memory. This improved model of moderate sleep apnoea may be the key to understanding why this disorder has such far-reaching and often fatal effects on end-organ function.
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Affiliation(s)
- Reno Roberts
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Mark J. Wall
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Ingke Braren
- University Medical Center Eppendorf, Vector Facility, Institute for Experimental Pharmacology and Toxikology, Hamburg, Germany
| | - Karendeep Dhillon
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Amy Evans
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Jack Dunne
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | | | - Robert T. R. Huckstepp
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- *Correspondence: Robert T. R. Huckstepp
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Mechanisms of opioid-induced respiratory depression. Arch Toxicol 2022; 96:2247-2260. [PMID: 35471232 DOI: 10.1007/s00204-022-03300-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/06/2022] [Indexed: 11/02/2022]
Abstract
Opioid-induced respiratory depression (OIRD), the primary cause of opioid-induced death, is the neural depression of respiratory drive which, together with a decreased level of consciousness and obstructive sleep apnea, cause ventilatory insufficiency. Variability of responses to opioids and individual differences in physiological and neurological states (e.g., anesthesia, sleep-disordered breathing, concurrent drug administration) add to the risk. Multiple sites can independently exert a depressive effect on breathing, making it unclear which sites are necessary for the induction of OIRD. The generator of inspiratory rhythm is the preBötzinger complex (preBötC) in the ventrolateral medulla. Other important brainstem respiratory centres include the pontine Kölliker-Fuse and adjacent parabrachial nuclei (KF/PBN) in the dorsal lateral pons, and the dorsal respiratory group in the medulla. Deletion of μ opioid receptors from neurons showed that the preBötC and KF/PBN contribute to OIRD with the KF as a respiratory modulator and the preBötC as inspiratory rhythm generator. Glutamatergic neurons expressing NK-1R and somatostatin involved in the autonomic function of breathing, and modulatory signal pathways involving GIRK and KCNQ potassium channels, remain poorly understood. Reversal of OIRD has relied heavily on naloxone which also reverses analgesia but mismatches between the half-lives of naloxone and opioids can make it difficult to clinically safely avoid OIRD. Maternal opioid use, which is rising, increases apneas and destabilizes neonatal breathing but opioid effects on maternal and neonatal respiratory circuits in neonatal abstinence syndrome (NAS) are not well understood. Methadone, administered to alleviate symptoms of NAS in humans, desensitizes rats to RD.
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Divergent brainstem opioidergic pathways that coordinate breathing with pain and emotions. Neuron 2022; 110:857-873.e9. [PMID: 34921781 PMCID: PMC8897232 DOI: 10.1016/j.neuron.2021.11.029] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 09/08/2021] [Accepted: 11/20/2021] [Indexed: 12/29/2022]
Abstract
Breathing can be heavily influenced by pain or internal emotional states, but the neural circuitry underlying this tight coordination is unknown. Here we report that Oprm1 (μ-opioid receptor)-expressing neurons in the lateral parabrachial nucleus (PBL) are crucial for coordinating breathing with affective pain in mice. Individual PBLOprm1 neuronal activity synchronizes with breathing rhythm and responds to noxious stimuli. Manipulating PBLOprm1 activity directly changes breathing rate, affective pain perception, and anxiety. Furthermore, PBLOprm1 neurons constitute two distinct subpopulations in a "core-shell" configuration that divergently projects to the forebrain and hindbrain. Through non-overlapping projections to the central amygdala and pre-Bötzinger complex, these two subpopulations differentially regulate breathing, affective pain, and negative emotions. Moreover, these subsets form recurrent excitatory networks through reciprocal glutamatergic projections. Together, our data define the divergent parabrachial opioidergic circuits as a common neural substrate that coordinates breathing with various sensations and behaviors such as pain and emotional processing.
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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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12
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de Sousa Abreu RP, Bondarenko E, Feldman JL. Phase- and state-dependent modulation of breathing pattern by preBötzinger complex somatostatin expressing neurons. J Physiol 2022; 600:143-165. [PMID: 34783033 PMCID: PMC9261878 DOI: 10.1113/jp282002] [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: 06/11/2021] [Accepted: 11/12/2021] [Indexed: 01/03/2023] Open
Abstract
As neuronal subtypes are increasingly categorized, delineating their functional role is paramount. The preBötzinger complex (preBötC) subpopulation expressing the neuropeptide somatostatin (SST) is classified as mostly excitatory, inspiratory-modulated and not rhythmogenic. We further characterized their phenotypic identity: 87% were glutamatergic and the balance were glycinergic and/or GABAergic. We then used optogenetics to investigate their modulatory role in both anaesthetized and freely moving mice. In anaesthetized mice, short photostimulation (100 ms) of preBötC SST+ neurons modulated breathing-related variables in a combinatory phase- and state-dependent manner; changes in inspiratory duration, inspiratory peak amplitude (Amp), and phase were different at higher (≥2.5 Hz) vs. lower (<2.5 Hz) breathing frequency (f). Moreover, we observed a biphasic effect of photostimulation during expiration that is probabilistic, that is photostimulation given at the same phase in consecutive cycles can evoke opposite responses (lengthening vs. shortening of the phase). These unexpected probabilistic state- and phase-dependent responses to photostimulation exposed properties of the preBötC that were not predicted and cannot be readily accounted for in current models of preBötC pattern generation. In freely moving mice, prolonged photostimulation decreased f in normoxia, hypoxia or hypercapnia, and increased Amp and produced a phase advance, which was similar to the results in anaesthetized mice when f ≥ 2.5 Hz. We conclude that preBötC SST+ neurons are a key mediator of the extraordinary and essential lability of breathing pattern. KEY POINTS: PreBötzinger complex (preBötC) SST+ neurons, which modulate respiratory pattern but are not rhythmogenic, were transfected with channelrhodopsin to investigate phase- and state-dependent modulation of breathing pattern in anaesthetized and freely behaving mice in normoxia, hypoxia and hypercapnia. In anaesthetized mice, photostimulation during inspiration increased inspiratory duration and amplitude regardless of baseline f, yet the effects were more robust at higher f. In anaesthetized mice with low f (<2.5 Hz), photostimulation during expiration evoked either phase advance or phase delay, whereas in anaesthetized mice with high f (≥2.5 Hz) and in freely behaving mice in normoxia, hypoxia or hypercapnia, photostimulation always evoked phase advance. Phase- and state-dependency is a function of overall breathing network excitability. The f-dependent probabilistic modulation of breathing pattern by preBötC SST+ neurons was unexpected, requiring reconsideration of current models of preBötC function, which neither predict nor can readily account for such responses.
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Oliveira LM, Takakura AC, Moreira TS. Forebrain and Hindbrain Projecting-neurons Target the Post-inspiratory Complex Cholinergic Neurons. Neuroscience 2021; 476:102-115. [PMID: 34582982 DOI: 10.1016/j.neuroscience.2021.09.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/19/2021] [Accepted: 09/20/2021] [Indexed: 02/06/2023]
Abstract
The postinspiratory complex (PiCo) is a region located in the ventromedial medulla involved with the post-inspiratory activity. PiCo neurons are excitatory (VGlut2+) and express the enzyme choline acetyl transferase (ChAT+). Evidence also suggests that PiCo is coupled to two additional groups of neurons involved in breathing process, i.e. the pre-Bötzinger complex (preBötC, inspiration) and the retrotrapezoid nucleus (RTN, active expiration), composing all together, the hypothesized triple respiratory oscillator. Here, our main objective is to demonstrate the afferent connections to PiCo region. We mapped projecting-neurons to PiCo by injecting Fluorogold (FG) retrograde tracer into the PiCo of adult Long-Evans Chat-cre male rats. We reported extensive projections from periaqueductal grey matter and Kölliker-Fuse regions and mild projections from the nucleus of the solitary tract, ventrolateral medulla and hypothalamus. We also injected a cre-dependent vector expressing channelrhodopsin 2 (AAV5-ChR2) fused with enhanced mCherry into the PiCo of ChAT-cre rats to optogenetic activate those neurons and investigate the role of PiCo for inspiratory/postinspiratory activity. Both in urethane-anesthetized and unrestrained conscious rats the response of ChR2-transduced neurons to light induced an increase in postinspiratory activity. Our data confirmed that PiCo seems to be dedicated to postinspiratory activity and represent a site of integration for autonomic and motor components of respiratory and non-respiratory pathways.
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Affiliation(s)
- Luiz M Oliveira
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, 05508-000 Sao Paulo, SP, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, 05508-000 Sao Paulo, SP, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, 05508-000 Sao Paulo, SP, Brazil.
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14
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [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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15
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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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16
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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: 36] [Impact Index Per Article: 12.0] [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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17
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Pitts T, Huff A, Reed M, Iceman K, Mellen N. Evidence of intermediate reticular formation involvement in swallow pattern generation, recorded optically in the neonate rat sagittally sectioned hindbrain. J Neurophysiol 2021; 125:993-1005. [PMID: 33566745 DOI: 10.1152/jn.00623.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Swallow is a primitive behavior regulated by medullary networks, responsible for movement of food/liquid from the oral cavity to the esophagus. To investigate how functionally heterogeneous networks along the medullary intermediate reticular formation (IRt) and ventral respiratory column (VRC) control swallow, we electrically stimulated the nucleus tractus solitarius to induce fictive swallow between inspiratory bursts, with concurrent optical recordings using a synthetic Ca2+ indicator in the neonatal sagittally sectioned rat hindbrain (SSRH) preparation. Simultaneous recordings from hypoglossal nerve rootlet (XIIn) and ventral cervical spinal root C1-C2 enabled identification of the system-level correlates of 1) swallow (identified as activation of the XIIn but not the cervical root) and 2) Breuer-Hering expiratory reflex (BHE; lengthened expiration in response to stimuli during expiration). Optical recording revealed reconfiguration of respiration-modulated networks in the ventrolateral medulla during swallow and the BHE reflex. Recordings identified novel spatially compact networks in the IRt near the facial nucleus (VIIn) that were active during fictive swallow, suggesting that the swallow network is not restricted to the caudal medulla. These findings also establish the utility of using this in vitro preparation to investigate how functionally heterogeneous medullary networks interact and reconfigure to enable a repertoire of orofacial behaviors.NEW & NOTEWORTHY For the first time, medullary networks that control breathing and swallow are recorded optically. Episodic swallows are induced via electrical stimulation along the dorsal medulla, in and near the NTS, during spontaneously occurring fictive respiration. These findings establish that networks regulating both orofacial behaviors and breathing are accessible for optical recording at the surface of the sagittally sectioned rodent hindbrain preparation.
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Affiliation(s)
- Teresa Pitts
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
| | - Alyssa Huff
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Mitchell Reed
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
| | - Kimberly Iceman
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
| | - Nicholas Mellen
- Department of Neurology, University of Louisville, Louisville, Kentucky
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18
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Trevizan-Baú P, Dhingra RR, Furuya WI, Stanić D, Mazzone SB, Dutschmann M. Forebrain projection neurons target functionally diverse respiratory control areas in the midbrain, pons, and medulla oblongata. J Comp Neurol 2020; 529:2243-2264. [PMID: 33340092 DOI: 10.1002/cne.25091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/25/2020] [Accepted: 11/29/2020] [Indexed: 12/12/2022]
Abstract
Eupnea is generated by neural circuits located in the ponto-medullary brainstem, but can be modulated by higher brain inputs which contribute to volitional control of breathing and the expression of orofacial behaviors, such as vocalization, sniffing, coughing, and swallowing. Surprisingly, the anatomical organization of descending inputs that connect the forebrain with the brainstem respiratory network remains poorly defined. We hypothesized that descending forebrain projections target multiple distributed respiratory control nuclei across the neuroaxis. To test our hypothesis, we made discrete unilateral microinjections of the retrograde tracer cholera toxin subunit B in the midbrain periaqueductal gray (PAG), the pontine Kölliker-Fuse nucleus (KFn), the medullary Bötzinger complex (BötC), pre-BötC, or caudal midline raphé nuclei. We quantified the regional distribution of retrogradely labeled neurons in the forebrain 12-14 days postinjection. Overall, our data reveal that descending inputs from cortical areas predominantly target the PAG and KFn. Differential forebrain regions innervating the PAG (prefrontal, cingulate cortices, and lateral septum) and KFn (rhinal, piriform, and somatosensory cortices) imply that volitional motor commands for vocalization are specifically relayed via the PAG, while the KFn may receive commands to coordinate breathing with other orofacial behaviors (e.g., sniffing, swallowing). Additionally, we observed that the limbic or autonomic (interoceptive) systems are connected to broadly distributed downstream bulbar respiratory networks. Collectively, these data provide a neural substrate to explain how volitional, state-dependent, and emotional modulation of breathing is regulated by the forebrain.
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Affiliation(s)
- Pedro Trevizan-Baú
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Rishi R Dhingra
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Werner I Furuya
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Davor Stanić
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
| | - Stuart B Mazzone
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Mathias Dutschmann
- The Florey Institute of Neuroscience and Mental Health, Discovery Neuroscience Theme, The University of Melbourne, Parkville, Victoria, Australia
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19
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Moreira TS, Sobrinho CR, Falquetto B, Oliveira LM, Lima JD, Mulkey DK, Takakura AC. The retrotrapezoid nucleus and the neuromodulation of breathing. J Neurophysiol 2020; 125:699-719. [PMID: 33427575 DOI: 10.1152/jn.00497.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Breathing is regulated by a host of arousal and sleep-wake state-dependent neuromodulators to maintain respiratory homeostasis. Modulators such as acetylcholine, norepinephrine, histamine, serotonin (5-HT), adenosine triphosphate (ATP), substance P, somatostatin, bombesin, orexin, and leptin can serve complementary or off-setting functions depending on the target cell type and signaling mechanisms engaged. Abnormalities in any of these modulatory mechanisms can destabilize breathing, suggesting that modulatory mechanisms are not overly redundant but rather work in concert to maintain stable respiratory output. The present review focuses on the modulation of a specific cluster of neurons located in the ventral medullary surface, named retrotrapezoid nucleus, that are activated by changes in tissue CO2/H+ and regulate several aspects of breathing, including inspiration and active expiration.
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Affiliation(s)
- Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Cleyton R Sobrinho
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Barbara Falquetto
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Luiz M Oliveira
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Janayna D Lima
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
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20
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Quaresma PGF, Dos Santos WO, Wasinski F, Metzger M, Donato J. Neurochemical phenotype of growth hormone-responsive cells in the mouse paraventricular nucleus of the hypothalamus. J Comp Neurol 2020; 529:1228-1239. [PMID: 32844436 DOI: 10.1002/cne.25017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 12/11/2022]
Abstract
Multiple neuroendocrine, autonomic and behavioral responses are regulated by the paraventricular nucleus of the hypothalamus (PVH). Previous studies have shown that PVH neurons express the growth hormone (GH) receptor (GHR), although the role of GH signaling on PVH neurons is still unknown. Given the great heterogeneity of cell types located in the PVH, we performed a detailed analysis of the neurochemical identity of GH-responsive cells to understand the possible physiological importance of GH action on PVH neurons. GH-responsive cells were detected via the phosphorylated form of the signal transducer and activator of transcription-5 (pSTAT5) in adult male mice that received an intraperitoneal GH injection. Approximately 51% of GH-responsive cells in the PVH co-localized with the vesicular glutamate transporter 2. Rare co-localizations between pSTAT5 and vesicular GABA transporter or vasopressin were observed, whereas approximately 20% and 38% of oxytocin and tyrosine hydroxylase (TH) cells, respectively, were responsive to GH in the PVH. Approximately 55%, 35% and 63% of somatostatin, thyrotropin-releasing hormone (TRH) and corticotropin-releasing hormone (CRH) neurons expressed GH-induced pSTAT5, respectively. Additionally, 8%, 49% and 75% of neuroendocrine TH, TRH and CRH neurons, and 67%, 32% and 74% of nonneuroendocrine TH, TRH and CRH neurons were responsive to GH in the PVH of Fluoro-Gold-injected mice. Our findings suggest that GH action on PVH neurons is involved in the regulation of the thyroid, somatotropic and adrenal endocrine axes, possibly influencing homeostatic and stress responses.
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Affiliation(s)
- Paula G F Quaresma
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
| | - Willian O Dos Santos
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
| | - Frederick Wasinski
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
| | - Martin Metzger
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
| | - Jose Donato
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
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21
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Yang CF, Kim EJ, Callaway EM, Feldman JL. Monosynaptic Projections to Excitatory and Inhibitory preBötzinger Complex Neurons. Front Neuroanat 2020; 14:58. [PMID: 33013329 PMCID: PMC7507425 DOI: 10.3389/fnana.2020.00058] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 08/04/2020] [Indexed: 01/01/2023] Open
Abstract
The key driver of breathing rhythm is the preBötzinger Complex (preBötC) whose activity is modulated by various functional inputs, e.g., volitional, physiological, and emotional. While the preBötC is highly interconnected with other regions of the breathing central pattern generator (bCPG) in the brainstem, there is no data about the direct projections to either excitatory and inhibitory preBötC subpopulations from other elements of the bCPG or from suprapontine regions. Using modified rabies tracing, we identified neurons throughout the brain that send monosynaptic projections to identified excitatory and inhibitory preBötC neurons in mice. Within the brainstem, neurons from sites in the bCPG, including the contralateral preBötC, Bötzinger Complex, the nucleus of the solitary tract (NTS), parafacial region (pF L /pF V ), and parabrachial nuclei (PB), send direct projections to both excitatory and inhibitory preBötC neurons. Suprapontine inputs to the excitatory and inhibitory preBötC neurons include the superior colliculus, red nucleus, amygdala, hypothalamus, and cortex; these projections represent potential direct pathways for volitional, emotional, and physiological control of breathing.
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Affiliation(s)
- Cindy F. Yang
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Euiseok J. Kim
- Systems Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Edward M. Callaway
- Systems Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Jack L. Feldman
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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22
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Cinelli E, Bongianni F, Pantaleo T, Mutolo D. Activation of μ-opioid receptors differentially affects the preBötzinger Complex and neighbouring regions of the respiratory network in the adult rabbit. Respir Physiol Neurobiol 2020; 280:103482. [DOI: 10.1016/j.resp.2020.103482] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/05/2020] [Accepted: 06/12/2020] [Indexed: 11/25/2022]
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23
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Biancardi V, Saini J, Pageni A, Prashaad M. H, Funk GD, Pagliardini S. Mapping of the excitatory, inhibitory, and modulatory afferent projections to the anatomically defined active expiratory oscillator in adult male rats. J Comp Neurol 2020; 529:853-884. [DOI: 10.1002/cne.24984] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/29/2020] [Accepted: 07/05/2020] [Indexed: 01/21/2023]
Affiliation(s)
- Vivian Biancardi
- Department of Physiology University of Alberta Edmonton Canada
- Women and Children's Health Research Institute, Faculty of Medicine and Dentistry University of Alberta Edmonton Canada
| | - Jashan Saini
- Department of Physiology University of Alberta Edmonton Canada
| | - Anileen Pageni
- Department of Physiology University of Alberta Edmonton Canada
| | | | - Gregory D. Funk
- Department of Physiology University of Alberta Edmonton Canada
- Women and Children's Health Research Institute, Faculty of Medicine and Dentistry University of Alberta Edmonton Canada
- Neuroscience and Mental Health Institute University of Alberta Edmonton Canada
| | - Silvia Pagliardini
- Department of Physiology University of Alberta Edmonton Canada
- Women and Children's Health Research Institute, Faculty of Medicine and Dentistry University of Alberta Edmonton Canada
- Neuroscience and Mental Health Institute University of Alberta Edmonton Canada
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24
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Ashhad S, Feldman JL. Emergent Elements of Inspiratory Rhythmogenesis: Network Synchronization and Synchrony Propagation. Neuron 2020; 106:482-497.e4. [PMID: 32130872 PMCID: PMC11221628 DOI: 10.1016/j.neuron.2020.02.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/15/2020] [Accepted: 02/07/2020] [Indexed: 12/22/2022]
Abstract
We assessed the mechanism of mammalian breathing rhythmogenesis in the preBötzinger complex (preBötC) in vitro, where experimental tests remain inconsistent with hypotheses of canonical rhythmogenic cellular or synaptic mechanisms, i.e., pacemaker neurons or inhibition. Under rhythmic conditions, in each cycle, an inspiratory burst emerges as (presumptive) preBötC rhythmogenic neurons transition from aperiodic uncorrelated population spike activity to become increasingly synchronized during preinspiration (for ∼50-500 ms), which can trigger inspiratory bursts that propagate to motoneurons. In nonrhythmic conditions, antagonizing GABAA receptors can initiate this synchronization while inducing a higher conductance state in nonrhythmogenic preBötC output neurons. Our analyses uncover salient features of preBötC network dynamics where inspiratory bursts arise when and only when the preBötC rhythmogenic subpopulation strongly synchronizes to drive output neurons. Furthermore, downstream propagation of preBötC network activity, ultimately to motoneurons, is dependent on the strength of input synchrony onto preBötC output neurons exemplifying synchronous propagation of network activity.
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Affiliation(s)
- Sufyan Ashhad
- Department of Neurobiology, University of California, Los Angeles, Box 951763, Los Angeles, CA 90095-1763, USA
| | - Jack L Feldman
- Department of Neurobiology, University of California, Los Angeles, Box 951763, Los Angeles, CA 90095-1763, USA.
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25
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Varga AG, Reid BT, Kieffer BL, Levitt ES. Differential impact of two critical respiratory centres in opioid-induced respiratory depression in awake mice. J Physiol 2020; 598:189-205. [PMID: 31589332 PMCID: PMC6938533 DOI: 10.1113/jp278612] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/03/2019] [Indexed: 12/29/2022] Open
Abstract
KEY POINTS The main cause of death from opioid overdose is respiratory depression due to the activation of µ-opioid receptors (MORs). We conditionally deleted MORs from neurons in two key areas of the brainstem respiratory circuitry (the Kölliker-Fuse nucleus (KF) and pre-Bötzinger complex (preBötC)) to determine their role in opioid-induced respiratory disturbances in adult, awake mice. Deletion of MORs from KF neurons attenuated respiratory rate depression at all doses of morphine. Deletion of MORs from preBötC neurons attenuated rate depression at the low dose, but had no effect on rate following high doses of morphine. Instead, high doses of morphine increased the occurrence of apnoeas. The results indicate that opioids affect distributed key areas of the respiratory network in a dose-dependent manner and countering the respiratory effects of high dose opioids via the KF may be an effective approach to combat overdose. ABSTRACT The primary cause of death from opioid overdose is respiratory failure. High doses of opioids cause severe rate depression and increased risk of fatal apnoea, which correlate with increasing irregularities in breathing pattern. µ-Opioid receptors (MORs) are widely distributed throughout the brainstem respiratory network, but the mechanisms underlying respiratory depression are poorly understood. The medullary pre-Bötzinger complex (preBötC) and the pontine Kölliker-Fuse nucleus (KF) are considered critical for inducing opioid-related respiratory disturbances. We used a conditional knockout approach to investigate the roles and relative contribution of MORs in KF and preBötC neurons in opioid-induced respiratory depression in awake adult mice. The results revealed dose-dependent and region-specific opioid effects on the control of both respiratory rate and pattern. Respiratory depression induced by an anti-nociceptive dose of morphine was significantly attenuated following deletion of MORs from either the KF or the preBötC, suggesting cumulative network effects on respiratory rate control at low opioid doses. Deletion of MORs from KF neurons also relieved rate depression at near-maximal respiratory depressant doses of morphine. Meanwhile, deletion of MORs from the preBötC had no effect on rate following administration of high doses of morphine. Instead, a severe ataxic breathing pattern emerged with many apnoeas. We conclude that opioids affect distributed areas of the respiratory network and opioid-induced respiratory depression cannot be attributed to only one area in isolation. However, countering the effects of near maximal respiratory depressant doses of opioids in the KF may be a powerful approach to combat opioid overdose.
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Affiliation(s)
- Adrienn G. Varga
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy, University of Florida, Gainesville, FL 32610
| | - Brandon T. Reid
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610
| | | | - Erica S. Levitt
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610
- Center for Respiratory Research and Rehabilitation, Department of Physical Therapy, University of Florida, Gainesville, FL 32610
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Sun X, Thörn Pérez C, Halemani D N, Shao XM, Greenwood M, Heath S, Feldman JL, Kam K. Opioids modulate an emergent rhythmogenic process to depress breathing. eLife 2019; 8:e50613. [PMID: 31841107 PMCID: PMC6938398 DOI: 10.7554/elife.50613] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022] Open
Abstract
How mammalian neural circuits generate rhythmic activity in motor behaviors, such as breathing, walking, and chewing, remains elusive. For breathing, rhythm generation is localized to a brainstem nucleus, the preBötzinger Complex (preBötC). Rhythmic preBötC population activity consists of strong inspiratory bursts, which drive motoneuronal activity, and weaker burstlets, which we hypothesize reflect an emergent rhythmogenic process. If burstlets underlie inspiratory rhythmogenesis, respiratory depressants, such as opioids, should reduce burstlet frequency. Indeed, in medullary slices from neonatal mice, the μ-opioid receptor (μOR) agonist DAMGO slowed burstlet generation. Genetic deletion of μORs in a glutamatergic preBötC subpopulation abolished opioid-mediated depression, and the neuropeptide Substance P, but not blockade of inhibitory synaptic transmission, reduced opioidergic effects. We conclude that inspiratory rhythmogenesis is an emergent process, modulated by opioids, that does not rely on strong bursts of activity associated with motor output. These findings also point to strategies for ameliorating opioid-induced depression of breathing.
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Affiliation(s)
- Xiaolu Sun
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Carolina Thörn Pérez
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Nagaraj Halemani D
- Department of Cell Biology and AnatomyChicago Medical School, Rosalind Franklin University of Medicine and ScienceNorth ChicagoUnited States
| | - Xuesi M Shao
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Morgan Greenwood
- RFUMS/DePaul Research Internship ProgramRosalind Franklin University of Medicine and ScienceNorth ChicagoUnited States
| | - Sarah Heath
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Jack L Feldman
- Department of NeurobiologyDavid Geffen School of Medicine at UCLALos AngelesUnited States
| | - Kaiwen Kam
- Department of Cell Biology and AnatomyChicago Medical School, Rosalind Franklin University of Medicine and ScienceNorth ChicagoUnited States
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Souza GMPR, Kanbar R, Stornetta DS, Abbott SBG, Stornetta RL, Guyenet PG. Breathing regulation and blood gas homeostasis after near complete lesions of the retrotrapezoid nucleus in adult rats. J Physiol 2019; 596:2521-2545. [PMID: 29667182 DOI: 10.1113/jp275866] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/04/2018] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS The retrotrapezoid nucleus (RTN) drives breathing proportionally to brain PCO2 but its role during various states of vigilance needs clarification. Under normoxia, RTN lesions increased the arterial PCO2 set-point, lowered the PO2 set-point and reduced alveolar ventilation relative to CO2 production. Tidal volume was reduced and breathing frequency increased to a comparable degree during wake, slow-wave sleep and REM sleep. RTN lesions did not produce apnoeas or disordered breathing during sleep. RTN lesions in rats virtually eliminated the central respiratory chemoreflex (CRC) while preserving the cardiorespiratory responses to hypoxia; the relationship between CRC and number of surviving RTN Nmb neurons was an inverse exponential. The CRC does not function without the RTN. In the quasi-complete absence of the RTN and CRC, alveolar ventilation is reduced despite an increased drive to breathe from the carotid bodies. ABSTRACT The retrotrapezoid nucleus (RTN) is one of several CNS nuclei that contribute, in various capacities (e.g. CO2 detection, neuronal modulation) to the central respiratory chemoreflex (CRC). Here we test how important the RTN is to PCO2 homeostasis and breathing during sleep or wake. RTN Nmb-positive neurons were killed with targeted microinjections of substance P-saporin conjugate in adult rats. Under normoxia, rats with large RTN lesions (92 ± 4% cell loss) had normal blood pressure and arterial pH but were hypoxic (-8 mmHg PaO2 ) and hypercapnic (+10 mmHg ). In resting conditions, minute volume (VE ) was normal but breathing frequency (fR ) was elevated and tidal volume (VT ) reduced. Resting O2 consumption and CO2 production were normal. The hypercapnic ventilatory reflex in 65% FiO2 had an inverse exponential relationship with the number of surviving RTN neurons and was decreased by up to 92%. The hypoxic ventilatory reflex (HVR; FiO2 21-10%) persisted after RTN lesions, hypoxia-induced sighing was normal and hypoxia-induced hypotension was reduced. In rats with RTN lesions, breathing was lowest during slow-wave sleep, especially under hyperoxia, but apnoeas and sleep-disordered breathing were not observed. In conclusion, near complete RTN destruction in rats virtually eliminates the CRC but the HVR persists and sighing and the state dependence of breathing are unchanged. Under normoxia, RTN lesions cause no change in VE but alveolar ventilation is reduced by at least 21%, probably because of increased physiological dead volume. RTN lesions do not cause sleep apnoea during slow-wave sleep, even under hyperoxia.
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Affiliation(s)
- George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Roy Kanbar
- Department of Pharmaceutical Sciences, Lebanese American University, Beyrouth, Lebanon
| | - Daniel S Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
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The pre-Bötzinger complex: Generation and modulation of respiratory rhythm. NEUROLOGÍA (ENGLISH EDITION) 2019. [DOI: 10.1016/j.nrleng.2018.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Abstract
Breathing is a well-described, vital and surprisingly complex behaviour, with behavioural and physiological outputs that are easy to directly measure. Key neural elements for generating breathing pattern are distinct, compact and form a network amenable to detailed interrogation, promising the imminent discovery of molecular, cellular, synaptic and network mechanisms that give rise to the behaviour. Coupled oscillatory microcircuits make up the rhythmic core of the breathing network. Primary among these is the preBötzinger Complex (preBötC), which is composed of excitatory rhythmogenic interneurons and excitatory and inhibitory pattern-forming interneurons that together produce the essential periodic drive for inspiration. The preBötC coordinates all phases of the breathing cycle, coordinates breathing with orofacial behaviours and strongly influences, and is influenced by, emotion and cognition. Here, we review progress towards cracking the inner workings of this vital core.
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Muscarinic Inhibition of Hypoglossal Motoneurons: Possible Implications for Upper Airway Muscle Hypotonia during REM Sleep. J Neurosci 2019; 39:7910-7919. [PMID: 31420456 DOI: 10.1523/jneurosci.0461-19.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 07/08/2019] [Accepted: 08/13/2019] [Indexed: 01/02/2023] Open
Abstract
Proper function of pharyngeal dilator muscles, including the genioglossus muscle of the tongue, is required to maintain upper airway patency. During sleep, the activity of these muscles is suppressed, and as a result individuals with obstructive sleep apnea experience repeated episodes of upper airway closure when they are asleep, in particular during rapid-eye-movement (REM) sleep. Blocking cholinergic transmission in the hypoglossal motor nucleus (MoXII) restores REM sleep genioglossus activity, highlighting the importance of cholinergic transmission in the inhibition of hypoglossal motor neurons (HMNs) during REM sleep. Glutamatergic afferent input from neurons in the parahypoglossal (PH) region to the HMNs is critical for MoXII respiratory motor output. We hypothesized that state-dependent cholinergic regulation may be mediated by this pathway. Here we studied the effects of cholinergic transmission in HMNs in adult male and female mice using patch-clamp recordings in brain slices. Using channelrhodopsin-2-assisted circuit mapping, we first demonstrated that PH glutamatergic neurons directly and robustly activate HMNs (PHGlut → HMNs). We then show that carbachol consistently depresses this input and that this effect is presynaptic. Additionally, carbachol directly affects HMNs by a variable combination of muscarinic-mediated excitatory and inhibitory responses. Altogether, our results suggest that cholinergic signaling impairs upper airway dilator muscle activity by suppressing glutamatergic input from PH premotoneurons to HMNs and by directly inhibiting HMNs. Our findings highlight the complexity of cholinergic control of HMNs at both the presynaptic and postsynaptic levels and provide a possible mechanism for REM sleep suppression of upper airway muscle activity.SIGNIFICANCE STATEMENT Individuals with obstructive sleep apnea can breathe adequately when awake but experience repeated episodes of upper airway closure when asleep, in particular during REM sleep. Similar to skeletal postural muscles, pharyngeal dilator muscles responsible for maintaining an open upper airway become hypotonic during REM sleep. Unlike spinal motoneurons controlling postural muscles that are inhibited by glycinergic transmission during REM sleep, hypoglossal motoneurons that control the upper airway muscles are inhibited in REM sleep by the combination of monoaminergic disfacilitation and cholinergic inhibition. In this study, we demonstrated how cholinergic signaling inhibits hypoglossal motoneurons through presynaptic and postsynaptic muscarinic receptors. Our results provide a potential mechanism for upper airway hypotonia during REM sleep.
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Sarnat HB, Flores-Sarnat L, Boltshauser E. Area Postrema: Fetal Maturation, Tumors, Vomiting Center, Growth, Role in Neuromyelitis Optica. Pediatr Neurol 2019; 94:21-31. [PMID: 30797593 DOI: 10.1016/j.pediatrneurol.2018.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 12/12/2018] [Accepted: 12/17/2018] [Indexed: 01/17/2023]
Abstract
INTRODUCTION The area postrema in the caudal fourth ventricular floor is highly vascular without blood-brain or blood-cerebrospinal fluid barrier. In addition to its function as vomiting center, several others are part of the circumventricular organs for vasomotor/angiotensin II regulation, role in neuromyelitis optica related to aquaporin-4, and somatic growth and appetite regulation. Functions are immature at birth. The purpose was to demonstrate neuronal, synaptic, glial, or ependymal maturation in the area postrema of normal fetuses. We describe three area postrema tumors. METHODS Sections of caudal fourth ventricle of 12 normal human fetal brains at autopsy aged six to 40 weeks and three infants aged three to 18 months were examined. Immunocytochemical neuronal and glial markers were applied to paraffin sections. Two infants with area postrema tumors and another with neurocutaneous melanocytosis and pernicious vomiting also studied. RESULTS Area postrema neurons exhibited cytologic maturity and synaptic circuitry by 14 weeks'. Astrocytes coexpressed vimentin, glial fibrillary acidic protein, and S-100β protein. The ependyma is thin over area postrema, with fetal ependymocytic basal processes. A glial layer separates area postrema from medullary tegmentum. Melanocytes infiltrated area postrema in the toddler with pernicious vomiting; two children had primary area postrema pilocytic astrocytomas. CONCLUSIONS Although area postrema is cytologically mature by 14 weeks, growth increases and functions mature during postnatal months. We recommend neuroimaging for patients with unexplained vomiting and that area postrema neuropathology includes synaptophysin and microtubule-associated protein-2 in patients with suspected dysfunction.
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Affiliation(s)
- Harvey B Sarnat
- Departments of Paediatrics, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada; Pathology (Neuropathology), University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada; Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada.
| | - Laura Flores-Sarnat
- Departments of Paediatrics, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada; Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Eugen Boltshauser
- Department of Paediatric Neurology, Children's University Hospital, Zürich, Switzerland
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Kurnikova A, Deschênes M, Kleinfeld D. Functional brain stem circuits for control of nose motion. J Neurophysiol 2019; 121:205-217. [PMID: 30461370 PMCID: PMC6383659 DOI: 10.1152/jn.00608.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 11/22/2022] Open
Abstract
Rodents shift their nose from side to side when they actively explore and lateralize odors in the space. This motor action is driven by a pair of muscles, the deflector nasi. We studied the premotor control of this motion. We used replication-competent rabies virus to transsynaptically label inputs to the deflector nasi muscle and find putative premotor labeling throughout the parvocellular, intermediate, and gigantocellular reticular formations, as well as the trigeminal nuclei, pontine reticular formation, midbrain reticular formation, red nucleus, and superior colliculus. Two areas with extensive labeling were analyzed for their impact on nose movement. One area is in the reticular formation caudal to the facial motor nucleus and is denoted the nose retrofacial area. The second is in the caudal part of the intermediate reticular region near the oscillator for whisking (the nose IRt). Functionally, we find that optogenetic activation of glutamatergic cells in both areas drives deflection of the nose. Ablation of cells in the nose retrofacial area, but not the nose IRt, impairs movement of the nose in response to the presentation of odorants but otherwise leaves movement unaffected. These data suggest that the nose retrofacial area is a conduit for a sensory-driven orofacial motor action. Furthermore, we find labeling of neurons that are immediately upstream of premotor neurons in the preBötzinger complex that presumably synchronizes a small, rhythmic component of nose motion to breathing. NEW & NOTEWORTHY We identify two previously undescribed premotor areas in the medulla that control deflection of the nose. This includes a pathway for directed motion of the nose in response to an odorant.
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Affiliation(s)
- Anastasia Kurnikova
- Neurosciences Graduate Program, University of California San Diego , La Jolla, California
| | - Martin Deschênes
- Centre de Recherche Université Laval Robert-Giffard , Quebec City, Quebec , Canada
| | - David Kleinfeld
- Department of Physics, University of California, San Diego, La Jolla, California
- Section of Neurobiology, University of California, San Diego, La Jolla, California
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Orexinergic neurons are involved in the chemosensory control of breathing during the dark phase in a Parkinson's disease model. Exp Neurol 2018; 309:107-118. [PMID: 30110606 DOI: 10.1016/j.expneurol.2018.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/02/2018] [Accepted: 08/11/2018] [Indexed: 02/07/2023]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons in the substantia nigra compacta (SNpc) and the only risk factor is aging. We showed that in 6-hydroxydopamine (6-OHDA)-model of PD there is a reduction in the neuronal profile within the brainstem ventral respiratory column with a decrease in the hypercapnic ventilatory response. Here we tested the involvement of orexin cells from the lateral hypothalamus/perifornical area (LH/PeF) on breathing in a 6-OHDA PD model. In this model of PD, there is a reduction in the total number of orexinergic neurons and in the number of orexinergic neurons that project to the RTN, without changing the number of CO2-activated orexinergic neurons during the dark phase. The ventilation at rest and in response to hypercapnia (7% CO2) was assessed in animals that received 6-OHDA or vehicle injections into the striatum and saporin anti-Orexin-B or IgG saporin into the LH/PeF during the sleep and awake states. The experiments showed a reduction of respiratory frequency (fR) at rest during the light phase in PD animals only during sleep. During the dark phase, there was an impaired fR response to hypercapnia in PD animals with depletion of orexinergic neurons in awake and sleeping rats. In conclusion, the degeneration of orexinergic neurons in this model of PD can be related to impaired chemoreceptor function in the dark phase.
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Yang CF, Feldman JL. Efferent projections of excitatory and inhibitory preBötzinger Complex neurons. J Comp Neurol 2018; 526:1389-1402. [PMID: 29473167 DOI: 10.1002/cne.24415] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 02/04/2018] [Accepted: 02/09/2018] [Indexed: 02/01/2023]
Abstract
The preBötzinger Complex (preBötC), a compact medullary region essential for generating normal breathing rhythm and pattern, is the kernel of the breathing central pattern generator (CPG). Excitatory preBötC neurons in rats project to major breathing-related brainstem regions. Here, we provide a brainstem connectivity map in mice for both excitatory and inhibitory preBötC neurons. Using a genetic strategy to label preBötC neurons, we confirmed extensive projections of preBötC excitatory neurons within the brainstem breathing CPG including the contralateral preBötC, Bötzinger Complex (BötC), ventral respiratory group, nucleus of the solitary tract, parahypoglossal nucleus, parafacial region (RTN/pFRG or alternatively, pFL /pFV ), parabrachial and Kölliker-Füse nuclei, as well as major projections to the midbrain periaqueductal gray. Interestingly, preBötC inhibitory projections paralleled the excitatory projections. Moreover, we examined overlapping projections in the pons in detail and found that they targeted the same neurons. We further explored the direct anatomical link between the preBötC and suprapontine brain regions that may govern emotion and other complex behaviors that can affect or be affected by breathing. Forebrain efferent projections were sparse and restricted to specific nuclei within the thalamus and hypothalamus, with processes rarely observed in cortex, basal ganglia, or other limbic regions, e.g., amygdala or hippocampus. We conclude that the preBötC sends direct, presumably inspiratory-modulated, excitatory and inhibitory projections in parallel to distinct targets throughout the brain that generate and modulate breathing pattern and/or coordinate breathing with other behaviors, physiology, cognition, or emotional state.
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Affiliation(s)
- Cindy F Yang
- Department of Neurobiology, David Geffen School of Medicine, UCLA, Los Angeles, California, 90095-1763
| | - Jack L Feldman
- Department of Neurobiology, David Geffen School of Medicine, UCLA, Los Angeles, California, 90095-1763
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McElvain LE, Friedman B, Karten HJ, Svoboda K, Wang F, Deschênes M, Kleinfeld D. Circuits in the rodent brainstem that control whisking in concert with other orofacial motor actions. Neuroscience 2018; 368:152-170. [PMID: 28843993 PMCID: PMC5849401 DOI: 10.1016/j.neuroscience.2017.08.034] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/12/2017] [Accepted: 08/15/2017] [Indexed: 12/25/2022]
Abstract
The world view of rodents is largely determined by sensation on two length scales. One is within the animal's peri-personal space; sensorimotor control on this scale involves active movements of the nose, tongue, head, and vibrissa, along with sniffing to determine olfactory clues. The second scale involves the detection of more distant space through vision and audition; these detection processes also impact repositioning of the head, eyes, and ears. Here we focus on orofacial motor actions, primarily vibrissa-based touch but including nose twitching, head bobbing, and licking, that control sensation at short, peri-personal distances. The orofacial nuclei for control of the motor plants, as well as primary and secondary sensory nuclei associated with these motor actions, lie within the hindbrain. The current data support three themes: First, the position of the sensors is determined by the summation of two drive signals, i.e., a fast rhythmic component and an evolving orienting component. Second, the rhythmic component is coordinated across all orofacial motor actions and is phase-locked to sniffing as the animal explores. Reverse engineering reveals that the preBötzinger inspiratory complex provides the reset to the relevant premotor oscillators. Third, direct feedback from somatosensory trigeminal nuclei can rapidly alter motion of the sensors. This feedback is disynaptic and can be tuned by high-level inputs. A holistic model for the coordination of orofacial motor actions into behaviors will encompass feedback pathways through the midbrain and forebrain, as well as hindbrain areas.
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Affiliation(s)
- Lauren E McElvain
- Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA
| | - Beth Friedman
- Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA
| | - Harvey J Karten
- Department of Neurosciences, University of California at San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Karel Svoboda
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
| | - Fan Wang
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Martin Deschênes
- Department of Psychiatry and Neuroscience, Laval University, Québec City, G1J 2G3, Canada
| | - David Kleinfeld
- Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA; Section of Neurobiology, University of California at San Diego, La Jolla, CA 92093, USA; Department of Electrical and Computer Engineering, University of California at San Diego, La Jolla, CA 92093, USA.
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Verin E, Morelot-Panzini C, Gonzalez-Bermejo J, Veber B, Perrouin Verbe B, Soudrie B, Leroi AM, Marie JP, Similowski T. Reinnervation of the diaphragm by the inferior laryngeal nerve to the phrenic nerve in ventilator-dependent tetraplegic patients with C3-5 damage. ERJ Open Res 2017; 3:00052-2017. [PMID: 29181382 PMCID: PMC5699880 DOI: 10.1183/23120541.00052-2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 08/11/2017] [Indexed: 11/05/2022] Open
Abstract
The aim of this study was to evaluate the feasibility of unilateral diaphragmatic reinnervation in humans by the inferior laryngeal nerve. This pilot study included chronically ventilated tetraplegic patients with destruction of phrenic nerve motoneurons. Five patients were included. They all had a high level of tetraplegia, with phrenic nerve motor neuron destruction. They were highly dependent on ventilation, without any possibility of weaning. They did not have other chronic pathologies, especially laryngeal disease. They all had diaphragmatic explorations to diagnose the destruction of the motoneurons of the phrenic nerves and nasoendoscopy to be sure that they did not have laryngeal or pharyngeal disease. Then, surgical anastomosis of the right phrenic nerve was performed with the inferior laryngeal nerve, by a cervical approach. A laryngeal reinnervation was performed at the same time, using the ansa hypoglossi. One patient was excluded because of a functional phrenic nerve and one patient died 6 months after the surgery of a cardiac arrest. The remaining three patients were evaluated after the anastomosis every 6 months. They did not present any swallowing or vocal alterations. In these three patients, the diaphragmatic explorations showed that there was a recovery of the diaphragmatic electromyogram of the right and left hemidiaphragms after 1 year. Two patients had surgical diaphragmatic explorations for diaphragmatic pacing 18-24 months after the reinnervation with excellent results. At 36 months, none of the patients could restore their automatic ventilation. In conclusion, this study demonstrated that diaphragmatic reinnervation by the inferior laryngeal nerve is effective, without any vocal or swallowing complications.
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Affiliation(s)
- Eric Verin
- EA 3830, Normandy University, Groupe de recherche sur le handicap ventilatoire (GRHV), Université de Rouen, Rouen, France.,Service de physiologie, CHU de Rouen, Rouen, France.,CRMPR les herbiers, Bois Guillaume, France
| | - Capucine Morelot-Panzini
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie et Réanimation Médicale (Département "R3S"), Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMRS1158 Neurophysiologie respiratoire expérimentale et clinique, Paris, France
| | - Jesus Gonzalez-Bermejo
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie et Réanimation Médicale (Département "R3S"), Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMRS1158 Neurophysiologie respiratoire expérimentale et clinique, Paris, France
| | - Benoit Veber
- Service de réanimation chirurgicale, CHU de Rouen, Rouen, France
| | | | | | | | - Jean Paul Marie
- EA 3830, Normandy University, Groupe de recherche sur le handicap ventilatoire (GRHV), Université de Rouen, Rouen, France.,Service d'ORL et Chirurgie Cervicofaciale CHU de Rouen, Rouen, France
| | - Thomas Similowski
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie et Réanimation Médicale (Département "R3S"), Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMRS1158 Neurophysiologie respiratoire expérimentale et clinique, Paris, France
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Harris KD, Dashevskiy T, Mendoza J, Garcia AJ, Ramirez JM, Shea-Brown E. Different roles for inhibition in the rhythm-generating respiratory network. J Neurophysiol 2017; 118:2070-2088. [PMID: 28615332 PMCID: PMC5626906 DOI: 10.1152/jn.00174.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/25/2017] [Accepted: 06/12/2017] [Indexed: 12/20/2022] Open
Abstract
Unraveling the interplay of excitation and inhibition within rhythm-generating networks remains a fundamental issue in neuroscience. We use a biophysical model to investigate the different roles of local and long-range inhibition in the respiratory network, a key component of which is the pre-Bötzinger complex inspiratory microcircuit. Increasing inhibition within the microcircuit results in a limited number of out-of-phase neurons before rhythmicity and synchrony degenerate. Thus unstructured local inhibition is destabilizing and cannot support the generation of more than one rhythm. A two-phase rhythm requires restructuring the network into two microcircuits coupled by long-range inhibition in the manner of a half-center. In this context, inhibition leads to greater stability of the two out-of-phase rhythms. We support our computational results with in vitro recordings from mouse pre-Bötzinger complex. Partial excitation block leads to increased rhythmic variability, but this recovers after blockade of inhibition. Our results support the idea that local inhibition in the pre-Bötzinger complex is present to allow for descending control of synchrony or robustness to adverse conditions like hypoxia. We conclude that the balance of inhibition and excitation determines the stability of rhythmogenesis, but with opposite roles within and between areas. These different inhibitory roles may apply to a variety of rhythmic behaviors that emerge in widespread pattern-generating circuits of the nervous system.NEW & NOTEWORTHY The roles of inhibition within the pre-Bötzinger complex (preBötC) are a matter of debate. Using a combination of modeling and experiment, we demonstrate that inhibition affects synchrony, period variability, and overall frequency of the preBötC and coupled rhythmogenic networks. This work expands our understanding of ubiquitous motor and cognitive oscillatory networks.
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Affiliation(s)
| | - Tatiana Dashevskiy
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Joshua Mendoza
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
| | - Alfredo J Garcia
- Institute for Integrative Physiology and Section of Emergency Medicine, University of Chicago, Chicago, Illinois; and
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington
| | - Eric Shea-Brown
- Department of Applied Mathematics, University of Washington, Seattle, Washington
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Affiliation(s)
- Shahriar Sheikhbahaei
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.,Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Jeffrey C Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Affiliation(s)
- Shahriar Sheikhbahaei
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Jeffrey C Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Abstract
Breathing is vital for survival but also interesting from the perspective of rhythm generation. This rhythmic behavior is generated within the brainstem and is thought to emerge through the interaction between independent oscillatory neuronal networks. In mammals, breathing is composed of three phases - inspiration, post-inspiration, and active expiration - and this article discusses the concept that each phase is generated by anatomically distinct rhythm-generating networks: the preBötzinger complex (preBötC), the post-inspiratory complex (PiCo), and the lateral parafacial nucleus (pF L), respectively. The preBötC was first discovered 25 years ago and was shown to be both necessary and sufficient for the generation of inspiration. More recently, networks have been described that are responsible for post-inspiration and active expiration. Here, we attempt to collate the current knowledge and hypotheses regarding how respiratory rhythms are generated, the role that inhibition plays, and the interactions between the medullary networks. Our considerations may have implications for rhythm generation in general.
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Affiliation(s)
- Tatiana M. Anderson
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Graduate Program for Neuroscience, University of Washington School of Medicine, Seattle, WA, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Neurological Surgery and Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
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Villiere SM, Nakase K, Kollmar R, Silverman J, Sundaram K, Stewart M. Seizure-associated central apnea in a rat model: Evidence for resetting the respiratory rhythm and activation of the diving reflex. Neurobiol Dis 2017; 101:8-15. [PMID: 28153424 DOI: 10.1016/j.nbd.2017.01.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 01/02/2017] [Accepted: 01/25/2017] [Indexed: 12/18/2022] Open
Abstract
Respiratory derangements, including irregular, tachypnic breathing and central or obstructive apnea can be consequences of seizure activity in epilepsy patients and animal models. Periods of seizure-associated central apnea, defined as periods >1s with rapid onset and offset of no airflow during plethysmography, suggest that seizures spread to brainstem respiratory regions to disrupt breathing. We sought to characterize seizure-associated central apneic episodes as an indicator of seizure impact on the respiratory rhythm in rats anesthetized with urethane and given parenteral kainic acid to induce recurring seizures. We measured central apneic period onsets and offsets to determine if onset-offset relations were a consequence of 1) a reset of the respiratory rhythm, 2) a transient pausing of the respiratory rhythm, resuming from the pause point at the end of the apneic period, 3) a transient suppression of respiratory behavior with apnea offset predicted by a continuation of the breathing pattern preceding apnea, or 4) a random re-entry into the respiratory cycle. Animals were monitored with continuous ECG, EEG, and plethysmography. One hundred ninety central apnea episodes (1.04 to 36.18s, mean: 3.2±3.7s) were recorded during seizure activity from 7 rats with multiple apneic episodes. The majority of apneic period onsets occurred during expiration (125/161 apneic episodes, 78%). In either expiration or inspiration, apneic onsets tended to occur late in the cycle, i.e. between the time of the peak and end of expiration (82/125, 66%) or inspiration (34/36, 94%). Apneic period offsets were more uniformly distributed between early and late expiration (27%, 34%) and inspiration (16%, 23%). Differences between the respiratory phase at the onset of apnea and the corresponding offset phase varied widely, even within individual animals. Each central apneic episode was associated with a high frequency event in EEG or ECG records at onset. High frequency events that were not associated with flatline plethysmographs revealed a constant plethysmograph pattern within each animal, suggesting a clear reset of the respiratory rhythm. The respiratory rhythm became highly variable after about 1s, however, accounting for the unpredictability of the offset phase. The dissociation of respiratory rhythm reset from the cessation of airflow also suggested that central apneic periods involved activation of brainstem regions serving the diving reflex to eliminate the expression of respiratory movements. This conclusion was supported by the decreased heart rate as a function of apnea duration. We conclude that seizure-associated central apnea episodes are associated with 1) a reset of the respiratory rhythm, and 2) activation of brainstem regions serving the diving reflex to suppress respiratory behavior. The significance of these conclusions is that these details of seizure impact on brainstem circuitry represent metrics for assessing seizure spread and potentially subclassifying seizure patterns.
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Affiliation(s)
- S M Villiere
- Department of Physiology & Pharmacology, State University of New York Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, United States; Research Initiative for Scientific Enhancement (RISE) Program, City University of New York Medgar Evers College, 1638 Bedford Avenue, Brooklyn, NY 11225, United States
| | - K Nakase
- Department of Physiology & Pharmacology, State University of New York Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, United States
| | - R Kollmar
- Department of Cell Biology, State University of New York Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, United States; Department of Otolaryngology, State University of New York Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, United States
| | - J Silverman
- Department of Otolaryngology, State University of New York Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, United States
| | - K Sundaram
- Department of Otolaryngology, State University of New York Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, United States
| | - M Stewart
- Department of Physiology & Pharmacology, State University of New York Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, United States; Department of Neurology, State University of New York Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, United States.
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Llona I, Farías P, Troc-Gajardo JL. Early Postnatal Development of Somastostatinergic Systems in Brainstem Respiratory Network. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1015:131-144. [DOI: 10.1007/978-3-319-62817-2_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Distinct Cortical Signatures Associated with Sedation and Respiratory Rate Depression by Morphine in a Pediatric Population. Anesthesiology 2016; 125:889-903. [DOI: 10.1097/aln.0000000000001303] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Abstract
Background
Opioid analgesia is an essential component of perioperative care, but effective analgesia can be limited by excessive sedation and respiratory depression. The cortical signatures associated with sedation by opioids and the relationship between changes in cortical activity and respiratory function are not well understood. The objectives of this study were to identify the electroencephalogram signatures of sedation and respiratory changes induced by morphine in a pediatric population after elective surgery.
Methods
After otologic surgery, patients (14.8 ± 2.8 yr, n = 10) stayed overnight for pain relief with morphine (3 to 10 mg), hydration, and clinical observation. Electroencephalogram activity and polysomnography were performed before and after morphine, and electroencephalogram spectral properties and cardiorespiratory activities were analyzed.
Results
Compared to wakefulness and non–rapid eye movement sleep, morphine reduced high-frequency β1 (13.5 to 20 Hz) and β2 (20 to 30Hz) electroencephalogram powers (n = 10) and decreased coherence between frontal and occipital β2 electroencephalogram activities (n = 9), therefore indicating that morphine induced a deep sedative state. Morphine also reduced respiratory rate by 8.3% (n = 10). Interestingly, there was a significant correlation between the reduction in β1 electroencephalogram activity and the depression in respiratory rate induced by morphine (R = 0.715, n = 10). With significant reduction in β1 power, respiratory rate was decreased by more than 25%, suggesting that reduction in cortical arousal is associated with the severity of respiratory rate depression.
Conclusions
Analgesic doses of morphine are associated with reduction in respiratory rate when accompanied by reduction in β1 electroencephalogram power, indicating a powerful effect of cortical arousal state per se in respiratory rate depression by morphine.
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Schlenker EH. Sexual dimorphism of cardiopulmonary regulation in the arcuate nucleus of the hypothalamus. Respir Physiol Neurobiol 2016; 245:37-44. [PMID: 27756648 DOI: 10.1016/j.resp.2016.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/11/2016] [Accepted: 10/12/2016] [Indexed: 11/19/2022]
Abstract
The arcuate nucleus of the hypothalamus (ANH) interacts with other hypothalamic nuclei, forebrain regions, and downstream brain sites to affect autonomic nervous system outflow, energy balance, temperature regulation, sleep, arousal, neuroendocrine function, reproduction, and cardiopulmonary regulation. Compared to studies of other ANH functions, how the ANH regulates cardiopulmonary function is less understood. Importantly, the ANH exhibits structural and functional sexually dimorphic characteristics and contains numerous neuroactive substances and receptors including leptin, neuropeptide Y, glutamate, acetylcholine, endorphins, orexin, kisspeptin, insulin, Agouti-related protein, cocaine and amphetamine-regulated transcript, dopamine, somatostatin, components of renin-angiotensin system and gamma amino butyric acid that modulate physiological functions. Moreover, several clinically relevant disorders are associated with ANH ventilatory control dysfunction. This review highlights how ANH neurotransmitter systems and receptors modulate breathing differently in male and female rodents. Results highlight the significance of the ANH in cardiopulmonary regulation. The paucity of studies in this area that will hopefully spark investigations of sexually dimorphic ANH-modulation of breathing.
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Affiliation(s)
- Evelyn H Schlenker
- Division of Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, 414 East Clark St., Vermillion, SD, 57069, United States.
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Shuai H, Xu Y, Yu Q, Gylfe E, Tengholm A. Fluorescent protein vectors for pancreatic islet cell identification in live-cell imaging. Pflugers Arch 2016; 468:1765-77. [PMID: 27539300 PMCID: PMC5026721 DOI: 10.1007/s00424-016-1864-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 08/02/2016] [Accepted: 08/04/2016] [Indexed: 11/25/2022]
Abstract
The islets of Langerhans contain different types of endocrine cells, which are crucial for glucose homeostasis. β- and α-cells that release insulin and glucagon, respectively, are most abundant, whereas somatostatin-producing δ-cells and particularly pancreatic polypeptide-releasing PP-cells are more scarce. Studies of islet cell function are hampered by difficulties to identify the different cell types, especially in live-cell imaging experiments when immunostaining is unsuitable. The aim of the present study was to create a set of vectors for fluorescent protein expression with cell-type-specific promoters and evaluate their applicability in functional islet imaging. We constructed six adenoviral vectors for expression of red and green fluorescent proteins controlled by the insulin, preproglucagon, somatostatin, or pancreatic polypeptide promoters. After transduction of mouse and human islets or dispersed islet cells, a majority of the fluorescent cells also immunostained for the appropriate hormone. Recordings of the sub-plasma membrane Ca(2+) and cAMP concentrations with a fluorescent indicator and a protein biosensor, respectively, showed that labeled cells respond to glucose and other modulators of secretion and revealed a striking variability in Ca(2+) signaling among α-cells. The measurements allowed comparison of the phase relationship of Ca(2+) oscillations between different types of cells within intact islets. We conclude that the fluorescent protein vectors allow easy identification of specific islet cell types and can be used in live-cell imaging together with organic dyes and genetically encoded biosensors. This approach will facilitate studies of normal islet physiology and help to clarify molecular defects and disturbed cell interactions in diabetic islets.
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Affiliation(s)
- Hongyan Shuai
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23, Uppsala, Sweden
| | - Yunjian Xu
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23, Uppsala, Sweden
| | - Qian Yu
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23, Uppsala, Sweden
| | - Erik Gylfe
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23, Uppsala, Sweden
| | - Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23, Uppsala, Sweden.
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Contribution of the respiratory network to rhythm and motor output revealed by modulation of GIRK channels, somatostatin and neurokinin-1 receptors. Sci Rep 2016; 6:32707. [PMID: 27599866 PMCID: PMC5013327 DOI: 10.1038/srep32707] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 07/28/2016] [Indexed: 01/07/2023] Open
Abstract
Breathing is generated by a respiratory network in the brainstem. At its core, a population of neurons expressing neurokinin-1 receptors (NK1R) and the peptide somatostatin (SST) form the preBötzinger Complex (preBötC), a site essential for the generation of breathing. PreBötC interneurons generate rhythm and follower neurons shape motor outputs by activating upper airway respiratory muscles. Since NK1R-expressing preBötC neurons are preferentially inhibited by μ-opioid receptors via activation of GIRK channels, NK1R stimulation may also involve GIRK channels. Hence, we identify the contribution of GIRK channels to rhythm, motor output and respiratory modulation by NK1Rs and SST. In adult rats, GIRK channels were identified in NK1R-expressing preBötC cells. Their activation decreased breathing rate and genioglossus muscle activity, an important upper airway muscle. NK1R activation increased rhythmic breathing and genioglossus muscle activity in wild-type mice, but not in mice lacking GIRK2 subunits (GIRK2−/−). Conversely, SST decreased rhythmic breathing via SST2 receptors, reduced genioglossus muscle activity likely through SST4 receptors, but did not involve GIRK channels. In summary, NK1R stimulation of rhythm and motor output involved GIRK channels, whereas SST inhibited rhythm and motor output via two SST receptor subtypes, therefore revealing separate circuits mediating rhythm and motor output.
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Ikeda K, Kawakami K, Onimaru H, Okada Y, Yokota S, Koshiya N, Oku Y, Iizuka M, Koizumi H. The respiratory control mechanisms in the brainstem and spinal cord: integrative views of the neuroanatomy and neurophysiology. J Physiol Sci 2016; 67:45-62. [PMID: 27535569 PMCID: PMC5368202 DOI: 10.1007/s12576-016-0475-y] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/22/2016] [Indexed: 12/17/2022]
Abstract
Respiratory activities are produced by medullary respiratory rhythm generators and are modulated from various sites in the lower brainstem, and which are then output as motor activities through premotor efferent networks in the brainstem and spinal cord. Over the past few decades, new knowledge has been accumulated on the anatomical and physiological mechanisms underlying the generation and regulation of respiratory rhythm. In this review, we focus on the recent findings and attempt to elucidate the anatomical and functional mechanisms underlying respiratory control in the lower brainstem and spinal cord.
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Affiliation(s)
- Keiko Ikeda
- Division of Biology, Hyogo College of Medicine, Nishinomiya, Hyogo, 663-8501, Japan.
| | - Kiyoshi Kawakami
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, 329-0498, Japan
| | - Hiroshi Onimaru
- Department of Physiology, Showa University School of Medicine, Shinagawa, Tokyo, 142-8555, Japan.
| | - Yasumasa Okada
- Clinical Research Center, Murayama Medical Center, Musashimurayama, Tokyo, 208-0011, Japan.
| | - Shigefumi Yokota
- Department of Anatomy and Morphological Neuroscience, Shimane University School of Medicine, Izumo, Shimane, 693-8501, Japan
| | - Naohiro Koshiya
- Cellular and Systems Neurobiology Section, NINDS, NIH, Bethesda, MD, 20892, USA.
| | - Yoshitaka Oku
- Department of Physiology, Hyogo College of Medicine, Nishinomiya, Hyogo, 663-8501, Japan.
| | - Makito Iizuka
- Department of Physiology, Showa University School of Medicine, Shinagawa, Tokyo, 142-8555, Japan.
| | - Hidehiko Koizumi
- Cellular and Systems Neurobiology Section, NINDS, NIH, Bethesda, MD, 20892, USA
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Cui Y, Kam K, Sherman D, Janczewski WA, Zheng Y, Feldman JL. Defining preBötzinger Complex Rhythm- and Pattern-Generating Neural Microcircuits In Vivo. Neuron 2016; 91:602-14. [PMID: 27497222 PMCID: PMC4978183 DOI: 10.1016/j.neuron.2016.07.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 04/05/2016] [Accepted: 06/23/2016] [Indexed: 11/16/2022]
Abstract
Normal breathing in rodents requires activity of glutamatergic Dbx1-derived (Dbx1(+)) preBötzinger Complex (preBötC) neurons expressing somatostatin (SST). We combined in vivo optogenetic and pharmacological perturbations to elucidate the functional roles of these neurons in breathing. In transgenic adult mice expressing channelrhodopsin (ChR2) in Dbx1(+) neurons, photoresponsive preBötC neurons had preinspiratory or inspiratory firing patterns associated with excitatory effects on burst timing and pattern. In transgenic adult mice expressing ChR2 in SST(+) neurons, photoresponsive preBötC neurons had inspiratory or postinspiratory firing patterns associated with excitatory responses on pattern or inhibitory responses that were largely eliminated by blocking synaptic inhibition within preBötC or by local viral infection limiting ChR2 expression to preBötC SST(+) neurons. We conclude that: (1) preinspiratory preBötC Dbx1(+) neurons are rhythmogenic, (2) inspiratory preBötC Dbx1(+) and SST(+) neurons primarily act to pattern respiratory motor output, and (3) SST(+)-neuron-mediated pathways and postsynaptic inhibition within preBötC modulate breathing pattern.
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Affiliation(s)
- Yan Cui
- Department of Physiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Kaiwen Kam
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - David Sherman
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Wiktor A Janczewski
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Yu Zheng
- Department of Physiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Jack L Feldman
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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Transporter Protein-Coupled DPCPX Nanoconjugates Induce Diaphragmatic Recovery after SCI by Blocking Adenosine A1 Receptors. J Neurosci 2016; 36:3441-52. [PMID: 27013674 DOI: 10.1523/jneurosci.2577-15.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 01/08/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Respiratory complications in patients with spinal cord injury (SCI) are common and have a negative impact on the quality of patients' lives. Systemic administration of drugs that improve respiratory function often cause deleterious side effects. The present study examines the applicability of a novel nanotechnology-based drug delivery system, which induces recovery of diaphragm function after SCI in the adult rat model. We developed a protein-coupled nanoconjugate to selectively deliver by transsynaptic transport small therapeutic amounts of an A1 adenosine receptor antagonist to the respiratory centers. A single administration of the nanoconjugate restored 75% of the respiratory drive at 0.1% of the systemic therapeutic drug dose. The reduction of the systemic dose may obviate the side effects. The recovery lasted for 4 weeks (the longest period studied). These findings have translational implications for patients with respiratory dysfunction after SCI. SIGNIFICANCE STATEMENT The leading causes of death in humans following SCI are respiratory complications secondary to paralysis of respiratory muscles. Systemic administration of methylxantines improves respiratory function but also leads to the development of deleterious side effects due to actions of the drug on nonrespiratory sites. The importance of the present study lies in the novel drug delivery approach that uses nanotechnology to selectively deliver recovery-inducing drugs to the respiratory centers exclusively. This strategy allows for a reduction in the therapeutic drug dose, which may reduce harmful side effects and markedly improve the quality of life for SCI patients.
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Muñoz-Ortiz J, Muñoz-Ortiz E, López-Meraz ML, Beltran-Parrazal L, Morgado-Valle C. Pre-Bötzinger complex: Generation and modulation of respiratory rhythm. Neurologia 2016; 34:461-468. [PMID: 27443242 DOI: 10.1016/j.nrl.2016.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/14/2016] [Accepted: 05/09/2016] [Indexed: 12/26/2022] Open
Abstract
INTRODUCTION In mammals, the preBötzinger complex (preBötC) is a bilateral and symmetrical neural network located in the brainstem which is essential for the generation and modulation of respiratory rhythm. There are few human studies about the preBötC and, its relationship with neurological diseases has not been described. However, the importance of the preBötC in neural control of breathing and its potential participation in neurological diseases in humans, has been suggested based on pharmacological manipulation and lesion of the preBötC in animal models, both in vivo and in vitro. METHOD In this review, we describe the effects of some drugs on the inspiratory activity in vitro in a transverse slice that contains the preBötC, as well as some in vivo experiments. Drugs were classified according to their effects on the main neurotransmitter systems and their importance as stimulators or inhibitors of preBötC activity and therefore for the generation of the respiratory rhythm. CONCLUSION Clinical neurologists will find this information relevant to understanding how the central nervous system generates the respiratory rhythm and may also relate this information to the findings made in daily practice.
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Affiliation(s)
- J Muñoz-Ortiz
- Doctorado en Investigaciones Cerebrales, Universidad Veracruzana, Xalapa de Enríquez, Veracruz, México
| | - E Muñoz-Ortiz
- Doctorado en Investigaciones Cerebrales, Universidad Veracruzana, Xalapa de Enríquez, Veracruz, México
| | - M L López-Meraz
- Centro de Investigaciones Cerebrales, Dirección General de Investigaciones, Universidad Veracruzana, Xalapa de Enríquez, Veracruz, México
| | - L Beltran-Parrazal
- Centro de Investigaciones Cerebrales, Dirección General de Investigaciones, Universidad Veracruzana, Xalapa de Enríquez, Veracruz, México
| | - C Morgado-Valle
- Centro de Investigaciones Cerebrales, Dirección General de Investigaciones, Universidad Veracruzana, Xalapa de Enríquez, Veracruz, México.
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