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Oke Y, Miwakeichi F, Oku Y, Hirrlinger J, Hülsmann S. Cell types and synchronous-activity patterns of inspiratory neurons in the preBötzinger complex of mouse medullary slices during early postnatal development. Sci Rep 2023; 13:586. [PMID: 36631589 PMCID: PMC9834223 DOI: 10.1038/s41598-023-27893-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
To examine whether and how the inspiratory neuronal network in the preBötzinger complex (preBötC) develops during the early postnatal period, we quantified the composition of the population of inspiratory neurons between postnatal day 1 (p1) and p10 by applying calcium imaging to medullary transverse slices in double-transgenic mice expressing fluorescent marker proteins. We found that putative excitatory and glycinergic neurons formed a majority of the population of inspiratory neurons, and the composition rates of these two inspiratory neurons inverted at p5-6. We also found that the activity patterns of these two types of inspiratory neurons became significantly well-synchronized with the inspiratory rhythmic bursting pattern in the preBötC within the first postnatal week. GABAergic and GABA-glycine cotransmitting inspiratory neurons formed only a small population just after birth, which almost disappeared until p10. In conclusion, the inspiratory neuronal network in the preBötC matures at the level of both neuronal population and neuronal activities during early postnatal development.
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Affiliation(s)
- Yoshihiko Oke
- Division of Physiome, Department of Physiology, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya, 663-8501, Japan.
| | - Fumikazu Miwakeichi
- grid.507381.80000 0001 1945 4756Department of Statistical Modeling, The Institute of Statistical Mathematics, 10-3, Midori-cho, Tachikawa, 190-0014 Japan ,grid.275033.00000 0004 1763 208XDepartment of Statistical Science, School of Multidisciplinary Sciences, The Graduate University for Advanced Studies, Shounan-Kokusai-Mura, Hayama-cho, Miura, 240-0193 Japan
| | - Yoshitaka Oku
- grid.272264.70000 0000 9142 153XDivision of Physiome, Department of Physiology, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya, 663-8501 Japan
| | - Johannes Hirrlinger
- grid.9647.c0000 0004 7669 9786Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Liebigstraße 27, 04103 Leipzig, Germany ,grid.516369.eDepartment of Neurogenetics, Max Planck Institute for Multidisciplinary Science, Hermann-Rein-Straße 3, 37075 Göttingen, Germany
| | - Swen Hülsmann
- grid.411984.10000 0001 0482 5331Department of Anesthesiology, University Medical Center, Humboldtallee 23, 37073 Göttingen, Germany
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2
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da Silva Junior CA, Patrone LGA, Biancardi V, Vilela-Costa HH, Marques DA, Cristina-Silva C, da Costa Silva KS, Bícego KC, Szawka RE, Gargaglioni LH. Sexually dimorphic effects of prenatal diazepam exposure on respiratory control and the monoaminergic system of neonate and young rats. Pflugers Arch 2022; 474:1185-1200. [DOI: 10.1007/s00424-022-02730-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/05/2022] [Accepted: 07/08/2022] [Indexed: 11/30/2022]
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Chronic, Episodic Nicotine Alters Hypoglossal Motor Neuron Function at a Critical Developmental Time Point in Neonatal Rats. eNeuro 2021; 8:ENEURO.0203-21.2021. [PMID: 34193508 PMCID: PMC8366915 DOI: 10.1523/eneuro.0203-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/03/2021] [Accepted: 06/09/2021] [Indexed: 02/07/2023] Open
Abstract
Developmental nicotine exposure (DNE), alters brainstem neurons that control breathing, including hypoglossal motor neurons (XIIMNs), which innervate the tongue. Here, we tested the hypothesis that chronic, episodic DNE (eDNE), which mimics nicotine replacement therapies such as e-cigarettes or nicotine gum, alters the function of nicotinic acetylcholine receptors (nAChRs), XIIMN intrinsic properties, and tongue muscle function in vivo similar to what we have observed with a chronic, sustained exposure model. We delivered nicotine to pregnant Sprague Dawley rats through drinking water and studied pups of either sex in two age groups: postnatal day (P)1–P5 and P10–P12, which encompasses a critical period in brain development. At P1–P5, eDNE was associated with delayed recovery of nAChRs from desensitization; however, there were no changes in the magnitude of desensitization, XIIMN intrinsic properties, or tongue muscle function in vivo. By P10–P12, eDNE XIIMNs had lower peak firing frequencies in response to depolarizing current injection, larger delayed rectifier potassium currents, and continued to exhibit delayed nAChR recovery. Moreover, this age group exhibited a blunted and delayed tongue muscle response to nasal occlusion in vivo, indicating that changes to XIIMN intrinsic properties is an important mechanism behind this effect, as it is not produced by altered nAChR function alone. Together, these results show that eDNE alters XIIMNs and tongue muscle function during a critical period in brain development and that the specific effects of chronic nicotine exposure may be pattern dependent.
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Thyroid hormones during the perinatal period are necessary to respiratory network development of newborn rats. Exp Neurol 2021; 345:113813. [PMID: 34284029 DOI: 10.1016/j.expneurol.2021.113813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/09/2021] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
Thyroid hormones (THs) are essential for foetal brain development. Because the gestating mother is the main source of THs to the foetus, maternal hypothyroidism and/or premature birth compromise neurological outcomes in the offspring. Respiratory instability and recurrent apneas due to immaturity of the respiratory control network are major causes of morbidity in infants. Inadequate TH supply may be sufficient to delay perinatal maturation of the respiratory control system; however, this hypothesis remains untested. To address this issue, maternal hypothyroidism was induced by adding methimazole (MMI; 0.02% w/v) to the drinking water of pregnant dams from conception to postpartum day 4 (P4). The effect of TH supplementation on respiratory function was tested by injecting levothyroxine (L-T4) in newborns at P1. Respiratory function was assessed by plethysmography (in vivo) and recording of phrenic output from medullary preparations (in vitro). By comparison with controls, TH deficiency increased the frequency of apneas and decreased basal ventilation in vivo and prevented the age-dependent increase in phrenic burst frequency normally observed in vitro. The effects of TH deficiency on GABAergic modulation of respiratory activity were measured by bath application of muscimol (GABAA agonist) or bicuculline (GABAA antagonist). The phrenic burst frequency responses to GABAergic agents were consistently greater in preparations from TH deficient pups. L-T4 supplementation reversed part of the respiratory anomalies related to MMI treatment in vitro. We conclude that TH deficiency during the perinatal period is sufficient to delay maturation of the respiratory control network development. Excessive GABAergic inhibition may contribute to this effect.
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5
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Polese D, Fagioli M, Virgili F, Fiori Nastro P. Something must happen before first breath. BMC Med Ethics 2021; 22:57. [PMID: 33980199 PMCID: PMC8114486 DOI: 10.1186/s12910-021-00624-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/04/2021] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Definition and concept of the 'beginning of human life' are weakened by co-existing contrasting hypotheses based on humanistic or religious beliefs rather than scientific foundations. This plethora of conceptually distant views have important common concerns in different fields of science and shape, in turn, several societal aspects including laws related, for instance, to inheritance eligibility or abortion, end-of-life care and euthanasia, and reproductive technology. Also, they are fundamental to evaluate opportunity for resuscitation vs. palliative care in extremely preterm infants. In this article, we address one of the most common tenets in medicine: the acceptance that human life starts with first breath, even though several events are well-documented to take place before its occurrence. MAIN TEXT Several studies show how pivotal physiological events take place before first breath. Evidence of a number of neurological events occurring before first breath opens the way to the primacy of the Central Nervous System, given its immediate extra-uterine activation at birth. This activation eventually sets specific physiological conditions that allow the complex sequence of events determining the muscle activity associated with the influx of air in the lung and the settling of a continuous and successful extra-uterine respiration. We would like to invite the scientific community to endorse a clear-cut position against the paradigm of 'first breath' as the beginning of life. Herein, we also assume how, a still undefined, yet possibly specific quid in the external environment triggers further physiological response in newborns. Better understanding of the critical events that occur at the beginning of human life is likely to cause great concern and expectations in scientists, researchers and physicians working in the domain of brain, and its physiology, and mental health. CONCLUSIONS The comparison between beliefs and evidence-based observations generates confusion, misperceptions and false expectations in society, hence, in the scientific and medical community. Different and more solid alternatives about the carachterization of the 'beginning of human life' are indeed available and require to be explored and defined.
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Affiliation(s)
- Daniela Polese
- Department of Mental Health and Sensory Organs (NESMOS), Sant’Andrea University Hospital, Sapienza University of Rome, Rome, Italy
| | | | - Fabio Virgili
- Department of Sciences, University Tor Vergata, Rome, Italy
| | - Paolo Fiori Nastro
- School of Medicine and Dentistry, Sapienza University of Rome, Rome, Italy
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6
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Fogarty MJ, Enninga EAL, Ibirogba ER, Ruano R, Sieck GC. Impact of congenital diaphragmatic hernia on diaphragm muscle function in neonatal rats. J Appl Physiol (1985) 2021; 130:801-812. [PMID: 33507852 DOI: 10.1152/japplphysiol.00852.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Congenital diaphragmatic hernia (CDH) is characterized by incomplete partitioning of the thoracic and abdominal cavities by the diaphragm muscle (DIAm). The resulting in utero invasion of the abdominal viscera into the thoracic cavity leads to impaired fetal breathing movements, severe pulmonary hypoplasia, and pulmonary hypertension. We hypothesized that in a well-established rodent model of Nitrofen-induced CDH, DIAm isometric force generation, and DIAm fiber cross-sectional areas would be reduced compared with nonlesioned littermate and Control pups. In CDH and nonlesioned pups at embryonic day 21 or birth, DIAm isometric force responses to supramaximal field stimulation (200 mA, 0.5 ms duration pulses in 1-s duration trains at rates ranging from 10 to 100 Hz) was measured ex vivo. Further, DIAm fatigue was determined in response to 120 s of repetitive stimulation at 40 Hz in 330-ms duration trains repeated each second. The DIAm was then stretched to Lo, frozen, and fiber cross-sectional areas were measured in 10 μm transverse sections. In CDH pups, there was a marked reduction in DIAm-specific force and force following 120 s of fatiguing contraction. The cross-sectional area of DIAm fibers was also reduced in CDH pups compared with nonlesioned littermates and Control pups. These results show that CDH is associated with a dramatic weakening of the DIAm, which may contribute to poor survival despite various surgical efforts to repair the hernia and improve lung development.NEW & NOTEWORTHY There are notable respiratory deficits related to congenital diaphragmatic hernia (CDH), yet the contribution, if any, of frank diaphragm muscle weakness to CDH is unexplored. Here, we use the well-established Nitrofen teratogen model to induce CDH in rat pups, followed by diaphragm muscle contractility and morphological assessments. Our results show diaphragm muscle weakness in conjunction with reduced muscle fiber density and size, contributing to CDH morbidity.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota.,School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | | | - Eniola R Ibirogba
- Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, Minnesota
| | - Rodrigo Ruano
- Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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7
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Abstract
In the United States, preterm birth rates have steadily increased since 2014. Despite the recent advances in neonatal-perinatal care, more than 40% of very low-birth-weight infants develop chronic lung disease (CLD) and almost 25% have feeding difficulties resulting in delayed achievement of full oral feeds and longer hospital stay. Establishment of full oral feeds, a major challenge for preterm infants, becomes magnified among those on respiratory support and/or with CLD. The strategies to minimize aerodigestive disorders include supporting nonnutritive sucking, developing infant-directed feeding protocols, sensory oromotor stimulation, and early introduction of oral feeds.
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8
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Erickson JT. Central serotonin and autoresuscitation capability in mammalian neonates. Exp Neurol 2020; 326:113162. [DOI: 10.1016/j.expneurol.2019.113162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/04/2019] [Accepted: 12/23/2019] [Indexed: 01/08/2023]
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9
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Szoták-Ajtay K, Szõke D, Kovács G, Andréka J, Brenner GB, Giricz Z, Penninger J, Kahn ML, Jakus Z. Reduced Prenatal Pulmonary Lymphatic Function Is Observed in Clp1 K/K Embryos With Impaired Motor Functions Including Fetal Breathing Movements in Preparation of the Developing Lung for Inflation at Birth. Front Bioeng Biotechnol 2020; 8:136. [PMID: 32211389 PMCID: PMC7067749 DOI: 10.3389/fbioe.2020.00136] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 02/11/2020] [Indexed: 11/13/2022] Open
Abstract
Embryonic lungs must be inflated immediately after birth to establish respiration. In addition to pulmonary surfactant, recently, we have revealed lymphatic function as a previously unknown regulator of prenatal lung compliance that prepares the embryonic lung for inflation at birth. It is well-documented that the late gestation embryo performs episodic breathing-like movements called as fetal breathing movements (FBMs), but the physiological importance of these events is not clear. Here we aimed to study the physiological role of FBMs in preparation for air inflation at birth. Clp1K/K late gestation embryos develop a progressive loss of spinal motor neurons associated with axonal degeneration and denervation of neuromuscular junctions serving as an ideal genetic model to test the possible role of FBMs. We demonstrated that Clp1K/K newborns show impaired motor function resulting in fatal respiratory failure after birth. Next, we showed that the alveolar septa are thicker, and the alveolar area is reduced in Clp1K/K late gestation embryos, while the expression of molecular markers of lung development are not affected. Importantly, pulmonary lymphatic vessels are dilated and the prenatal pulmonary lymphatic function is reduced in Clp1K/K late gestation embryos. Our results have revealed that Clp1K/K mice show impaired motor functions including FBMs, and late gestation Clp1K/K embryos display reduced prenatal lymphatic function and impaired lung expansion represented as thickened alveolar septa and reduced alveolar area in preparation of the developing lung for inflation at birth. These findings suggest a possible mechanism that FBMs, similarly to breathing movements after birth, stimulate prenatal lymphatic function in pulmonary collecting lymphatics lacking smooth muscle coverage to prepare the developing lung for inflation and gas exchange at birth. Moreover, these results raise the possibility that stimulating FBMs during late gestation might be an effective way to reduce the risk of the development of neonatal respiratory failure.
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Affiliation(s)
- Kitti Szoták-Ajtay
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary.,MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - Dániel Szõke
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary.,MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - Gábor Kovács
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary.,MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - Judit Andréka
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary.,MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - Gábor B Brenner
- Department of Pharmacology and Pharmacotherapy, Semmelweis University School of Medicine, Budapest, Hungary
| | - Zoltán Giricz
- Department of Pharmacology and Pharmacotherapy, Semmelweis University School of Medicine, Budapest, Hungary
| | - Josef Penninger
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria.,Department of Medical Genetics, Life Science Institute, University of British Columbia, Vancouver, BC, Canada
| | - Mark L Kahn
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Zoltán Jakus
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary.,MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
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10
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Rousseau JP, Noda M, Kinkead R. Facilitation of microglial motility by thyroid hormones requires the presence of neurons in cell culture: A distinctive feature of the brainstem versus the cortex. Brain Res Bull 2020; 157:37-40. [PMID: 31954812 DOI: 10.1016/j.brainresbull.2020.01.010] [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: 11/21/2019] [Revised: 01/09/2020] [Accepted: 01/13/2020] [Indexed: 10/25/2022]
Abstract
Microglia are critical for the refinement of neural networks that takes place during the perinatal period. Their phenotype and actions are guided by the signals produced by neighbouring cells and hormones present in their surrounding milieu. Cell populations and the signals they produce differ between regions. The fact that thyroid hormones (THs) promote the growth and morphological differentiation of microglia within the cortex contributes to the TH's powerful actions on the developing brain. The brainstem is especially active during early life owing to its role in generation of the rhythmic respiratory motor command. Despite evidences indicating that THs are necessary to proper development of the neural networks regulating this vital homeostatic function, their actions on microglia originating from the brainstem remain unknown. Using primary cultured microglia from newborn mice (C57BL/6J), we first report that regulation of microglial motility by THs is different between cortex and brainstem. Microglial motility (μm traveled over 3 h) was monitored with or without triiodothyronine (T3, 1μM). Exposure to T3 did not stimulate microglial motility from brainstem, but significantly stimulated (316 %) when they were co-cultured with neurons. Motility of cortex microglia was stimulated to the similar extent either with or without neurons. These data suggest that the microglial function in different regions of the brain is determined by the surrounding environment.
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Affiliation(s)
- Jean-Philippe Rousseau
- Department of Pediatrics, Centre de recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, G1V 4G5, Canada.
| | - Mami Noda
- Laboratory of Pathophysiology, Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
| | - Richard Kinkead
- Department of Pediatrics, Centre de recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, G1V 4G5, Canada
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11
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Ikeda K, Onimaru H, Matsuura T, Kawakami K. Different impacts on brain function depending on the mode of delivery. Brain Res 2019; 1720:146289. [DOI: 10.1016/j.brainres.2019.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 06/09/2019] [Indexed: 12/17/2022]
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12
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Niblock MM, Perez A, Broitman S, Jacoby B, Aviv E, Gilkey S. In utero development of fetal breathing movements in C57BL6 mice. Respir Physiol Neurobiol 2019; 271:103288. [PMID: 31505274 DOI: 10.1016/j.resp.2019.103288] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/06/2019] [Accepted: 09/05/2019] [Indexed: 11/18/2022]
Abstract
Fetuses of many species, including humans, breathe during development. This fetal breathing aids in lung development, strengthens respiratory muscles, and is posited to fine-tune the neural circuitry that drives breathing. Previous studies suggested that fetal breathing could begin as early as the fifteenth day of gestation in the mouse, but fetal breathing movements (FBMs) had not been observed in mice in utero. We aimed to determine if and when FBMs commence in mice and if they change over time. We examined unanesthetised pregnant C57BL6 mice with ultrasound beginning on the seventh day of gestation. We first reliably observed episodic FBMs in mice on embryonic day 16. FBMs were sporadic, clustered, or rhythmic, and their frequency increased with age. Ultrasound examination of FBMs in mice has great potential utility in the study of transgenic mouse models to help us understand the prenatal characteristics of breathing related human developmental disorders, including Congenital Central Hypoventilation Syndrome (CCHS) and apnea of prematurity.
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Affiliation(s)
- Mary M Niblock
- Department of Biology, Dickinson College, Carlisle, PA, United States; Neuroscience Program, Dickinson College, Carlisle, PA, United States.
| | - Alanis Perez
- Department of Biology, Dickinson College, Carlisle, PA, United States
| | - Shahar Broitman
- Neuroscience Program, Dickinson College, Carlisle, PA, United States
| | - Brigitte Jacoby
- Neuroscience Program, Dickinson College, Carlisle, PA, United States; Biochemistry and Molecular Biology Program, Dickinson College, Carlisle, PA, United States
| | - Elana Aviv
- Department of Biology, Dickinson College, Carlisle, PA, United States
| | - Sydney Gilkey
- Neuroscience Program, Dickinson College, Carlisle, PA, United States; Biochemistry and Molecular Biology Program, Dickinson College, Carlisle, PA, United States
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13
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Sex differences in breathing. Comp Biochem Physiol A Mol Integr Physiol 2019; 238:110543. [PMID: 31445081 DOI: 10.1016/j.cbpa.2019.110543] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 01/15/2023]
Abstract
Breathing is a vital behavior that ensures both the adequate supply of oxygen and the elimination of CO2, and it is influenced by many factors. Despite that most of the studies in respiratory physiology rely heavily on male subjects, there is much evidence to suggest that sex is an important factor in the respiratory control system, including the susceptibility for some diseases. These different respiratory responses in males and females may be related to the actions of sex hormones, especially in adulthood. These hormones affect neuromodulatory systems that influence the central medullary rhythm/pontine pattern generator and integrator, sensory inputs to the integrator and motor output to the respiratory muscles. In this article, we will first review the sex dependence on the prevalence of some respiratory-related diseases. Then, we will discuss the role of sex and gonadal hormones in respiratory control under resting conditions and during respiratory challenges, such as hypoxia and hypercapnia, and whether hormonal fluctuations during the estrous/menstrual cycle affect breathing control. We will then discuss the role of the locus coeruleus, a sexually dimorphic CO2/pH-chemosensitive nucleus, on breathing regulation in males and females. Next, we will highlight the studies that exist regarding sex differences in respiratory control during development. Finally, the few existing studies regarding the influence of sex on breathing control in non-mammalian vertebrates will be discussed.
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14
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Fogarty MJ, Sieck GC. Evolution and Functional Differentiation of the Diaphragm Muscle of Mammals. Compr Physiol 2019; 9:715-766. [PMID: 30873594 PMCID: PMC7082849 DOI: 10.1002/cphy.c180012] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Symmorphosis is a concept of economy of biological design, whereby structural properties are matched to functional demands. According to symmorphosis, biological structures are never over designed to exceed functional demands. Based on this concept, the evolution of the diaphragm muscle (DIAm) in mammals is a tale of two structures, a membrane that separates and partitions the primitive coelomic cavity into separate abdominal and thoracic cavities and a muscle that serves as a pump to generate intra-abdominal (Pab ) and intrathoracic (Pth ) pressures. The DIAm partition evolved in reptiles from folds of the pleural and peritoneal membranes that was driven by the biological advantage of separating organs in the larger coelomic cavity into separate thoracic and abdominal cavities, especially with the evolution of aspiration breathing. The DIAm pump evolved from the advantage afforded by more effective generation of both a negative Pth for ventilation of the lungs and a positive Pab for venous return of blood to the heart and expulsive behaviors such as airway clearance, defecation, micturition, and child birth. © 2019 American Physiological Society. Compr Physiol 9:715-766, 2019.
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Affiliation(s)
- Matthew J Fogarty
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
| | - Gary C Sieck
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
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15
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Lumb KJ, Schneider JM, Ibrahim T, Rigaux A, Hasan SU. Afferent neural feedback overrides the modulating effects of arousal, hypercapnia and hypoxaemia on neonatal cardiorespiratory control. J Physiol 2018; 596:6009-6019. [PMID: 29676798 PMCID: PMC6265552 DOI: 10.1113/jp275682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/13/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Evidence obtained at whole animal, organ-system, and cellular and molecular levels suggests that afferent volume feedback is critical for the establishment of adequate ventilation at birth. As a result of the irreversible nature of the vagal ablation studies performed to date, it was difficult to quantify the roles of afferent volume input, arousal and changes in blood gas tensions on neonatal respiratory control. During reversible perineural vagal block, profound apnoeas and hypoxaemia and hypercarbia were observed, necessitating the termination of perineural blockade. Respiratory depression and apnoeas were independent of sleep state. We demonstrate that profound apnoeas and life-threatening respiratory failure in vagally denervated animals do not result from a lack of arousal or hypoxaemia. A change in sleep state and concomitant respiratory depression result from a lack of afferent volume feedback, which appears to be critical for the maintenance of normal breathing patterns and adequate gas exchange during the early postnatal period. ABSTRACT Afferent volume feedback plays a vital role in neonatal respiratory control. Mechanisms for the profound respiratory depression and life-threatening apnoeas observed in vagally denervated neonatal animals remain unclear. We investigated the roles of sleep states, hypoxic-hypercapnia and afferent volume feedback on respiratory depression using reversible perineural vagal block during the early postnatal period. Seven lambs were instrumented during the first 48 h of life to record/analyse sleep states, diaphragmatic electromyograph, arterial blood gas tensions, systemic arterial blood pressure and rectal temperature. Perineural cuffs were placed around the vagi to attain reversible blockade. Postoperatively, during the awake state, both vagi were blocked using 2% xylocaine for up to 30 min. Compared to baseline values, pHa , P a o 2 and S a o 2 decreased and P ac o 2 increased during perineural blockade (P < 0.05). Four of seven animals exhibited apnoeas of ≥20 s requiring the immediate termination of perineural blockade. Breathing rates decreased from the baseline value of 53 ± 12 to 24 ± 20 breaths min-1 during blockade despite an increased P ac o 2 (P < 0.001). Following blockade, breathing patterns returned to baseline values despite marked hypocapnia ( P ac o 2 33 ± 3 torr; P = 0.03). Respiratory depression and apnoeas were independent of sleep states. The present study provides the much needed physiological evidence indicating that profound apnoeas and life-threatening respiratory failure in vagally denervated animals do not result from a lack of arousal or hypoxaemia. Rather, a change in sleep state and concomitant respiratory depression result from a lack of afferent volume feedback, which appears to be critical for the maintenance of normal breathing patterns and adequate gas exchange during the early postnatal period.
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Affiliation(s)
- Kathleen J. Lumb
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | - Jennifer M. Schneider
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | - Thowfique Ibrahim
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | - Anita Rigaux
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | - Shabih U. Hasan
- Department of PediatricsAlberta Children's Hospital Research Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
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Johnson SM, Randhawa KS, Epstein JJ, Gustafson E, Hocker AD, Huxtable AG, Baker TL, Watters JJ. Gestational intermittent hypoxia increases susceptibility to neuroinflammation and alters respiratory motor control in neonatal rats. Respir Physiol Neurobiol 2018; 256:128-142. [PMID: 29174411 PMCID: PMC5963968 DOI: 10.1016/j.resp.2017.11.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/13/2017] [Accepted: 11/21/2017] [Indexed: 10/18/2022]
Abstract
Sleep disordered breathing (SDB) and obstructive sleep apnea (OSA) during pregnancy are growing health concerns because these conditions are associated with adverse outcomes for newborn infants. SDB/OSA during pregnancy exposes the mother and the fetus to intermittent hypoxia. Direct exposure of adults and neonates to IH causes neuroinflammation and neuronal apoptosis, and exposure to IH during gestation (GIH) causes long-term deficits in offspring respiratory function. However, the role of neuroinflammation in CNS respiratory control centers of GIH offspring has not been investigated. Thus, the goal of this hybrid review/research article is to comprehensively review the available literature both in humans and experimental rodent models of SDB in order to highlight key gaps in knowledge. To begin to address some of these gaps, we also include data demonstrating the consequences of GIH on respiratory rhythm generation and neuroinflammation in CNS respiratory control regions. Pregnant rats were exposed to daily intermittent hypoxia during gestation (G10-G21). Neuroinflammation in brainstem and cervical spinal cord was evaluated in P0-P3 pups that were injected with saline or lipopolysaccharide (LPS; 0.1mg/kg, 3h). In CNS respiratory control centers, we found that GIH attenuated the normal CNS immune response to LPS challenge in a gene-, sex-, and CNS region-specific manner. GIH also altered normal respiratory motor responses to LPS in newborn offspring brainstem-spinal cord preparations. These data underscore the need for further study of the long-term consequences of maternal SDB on the relationship between inflammation and the respiratory control system, in both neonatal and adult offspring.
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Affiliation(s)
- Stephen M Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States.
| | - Karanbir S Randhawa
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Jenna J Epstein
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Ellen Gustafson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Austin D Hocker
- Department of Human Physiology, University of Oregon, Eugene, OR 97401, United States
| | - Adrianne G Huxtable
- Department of Human Physiology, University of Oregon, Eugene, OR 97401, United States
| | - Tracy L Baker
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Jyoti J Watters
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
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17
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Patrone LGA, Biancardi V, Marques DA, Bícego KC, Gargaglioni LH. Brainstem catecholaminergic neurones and breathing control during postnatal development in male and female rats. J Physiol 2018; 596:3299-3325. [PMID: 29479699 DOI: 10.1113/jp275731] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 02/21/2018] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS The brainstem catecholaminergic (CA) modulation on ventilation changes with development. We determined the role of the brainstem CA system in ventilatory control under normocapnic and hypercapnic conditions during different phases of development [postnatal day (P)7-8, P14-15 and P20-21] in male and female Wistar rats. Brainstem CA neurones produce a tonic inhibitory drive that affects breathing frequency in P7-8 rats and provide an inhibitory drive during hypercapnic conditions in both males and females at P7-8 and P14-15. In pre-pubertal rats, brainstem CA neurones become excitatory for the CO2 ventilatory response in males but remain inhibitory in females. Diseases such as sudden infant death syndrome, congenital central hypoventilation syndrome and Rett syndrome have been associated with abnormalities in the functioning of CA neurones; therefore, the results of the present study contribute to a better understanding of this system. ABSTRACT The respiratory network undergoes significant development during the postnatal phase, including the maturation of the catecholaminergic (CA) system. However, postnatal development of this network and its effect on the control of pulmonary ventilation ( V̇E ) is not fully understood. We investigated the involvement of brainstem CA neurones in respiratory control during postnatal development [postnatal day (P)7-8, P14-15 and P20-21], in male and female rats, through chemical injury with conjugated saporin anti-dopamine β-hydroxylase (DβH-SAP). Thus, DβH-SAP (420 ng μL-1 ), saporin (SAP) or phosphate buffered solution (PBS) was injected into the fourth ventricle of neonatal Wistar rats of both sexes. V̇E and oxygen consumption were recorded 1 week after the injections in unanaesthetized neonatal and juvenile rats during room air and hypercapnia. The resting ventilation was higher in both male and female P7-8 lesioned rats by 33%, with a decrease in respiratory variability being observed in males. The hypercapnic ventilatory response (HCVR) was altered in male and female lesioned rats at all postnatal ages. At P7-8, the HCVR for males and females was increased by 37% and 30%, respectively. For both sexes at P14-15 rats, the increase in V̇E during hypercapnia was 37% higher for lesioned rats. A sex-specific difference in HCRV was observed at P20-21, with lesioned males showing a 33% decrease, and lesioned females showing an increase of 33%. We conclude that brainstem CA neurones exert a tonic inhibitory effect on V̇E in the early postnatal days of the life of a rat, increase variability in P7-8 males and modulate HCRV during the postnatal phase.
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Affiliation(s)
- Luis Gustavo A Patrone
- Department of Animal Morphology and Physiology, Sao Paulo State University - UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Vivian Biancardi
- Department of Animal Morphology and Physiology, Sao Paulo State University - UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Danuzia A Marques
- Department of Animal Morphology and Physiology, Sao Paulo State University - UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, Sao Paulo State University - UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University - UNESP/FCAV at Jaboticabal, SP, Brazil
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18
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Stojanovska V, Miller SL, Hooper SB, Polglase GR. The Consequences of Preterm Birth and Chorioamnionitis on Brainstem Respiratory Centers: Implications for Neurochemical Development and Altered Functions by Inflammation and Prostaglandins. Front Cell Neurosci 2018; 12:26. [PMID: 29449803 PMCID: PMC5799271 DOI: 10.3389/fncel.2018.00026] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 01/17/2018] [Indexed: 11/16/2022] Open
Abstract
Preterm birth is a major cause for neonatal morbidity and mortality, and is frequently associated with adverse neurological outcomes. The transition from intrauterine to extrauterine life at birth is particularly challenging for preterm infants. The main physiological driver for extrauterine transition is the establishment of spontaneous breathing. However, preterm infants have difficulty clearing lung liquid, have insufficient surfactant levels, and underdeveloped lungs. Further, preterm infants have an underdeveloped brainstem, resulting in reduced respiratory drive. These factors facilitate the increased requirement for respiratory support. A principal cause of preterm birth is intrauterine infection/inflammation (chorioamnionitis), and infants with chorioamnionitis have an increased risk and severity of neurological damage, but also demonstrate impaired autoresuscitation capacity and prevalent apnoeic episodes. The brainstem contains vital respiratory centers which provide the neural drive for breathing, but the impact of preterm birth and/or chorioamnionitis on this brain region is not well understood. The aim of this review is to provide an overview of the role and function of the brainstem respiratory centers, and to highlight the proposed mechanisms of how preterm birth and chorioamnionitis may affect central respiratory functions.
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Affiliation(s)
- Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University and Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University and Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University and Hudson Institute of Medical Research, Melbourne, VIC, Australia
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González-Castillo C, Muñoz-Ortiz E, Guzmán-Brambila C, Rojas-Mayorquín AE, Beltran-Parrazal L, Ortuño-Sahagún D, Morgado-Valle C. Differential Expression of Ion Channels in Adult and Neonatal Rat Ventral Respiratory Column. J Mol Neurosci 2017; 64:51-61. [DOI: 10.1007/s12031-017-1001-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/10/2017] [Indexed: 12/14/2022]
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20
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Rousseau JP, Tenorio-Lopes L, Baldy C, Janes TA, Fournier S, Kinkead R. On the origins of sex-based differences in respiratory disorders: Lessons and hypotheses from stress neuroendocrinology in developing rats. Respir Physiol Neurobiol 2017; 245:105-121. [DOI: 10.1016/j.resp.2017.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/28/2017] [Accepted: 03/31/2017] [Indexed: 12/31/2022]
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21
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Abstract
Breathing in mammals relies on permanent rhythmic and bilaterally synchronized contractions of inspiratory pump muscles. These motor drives emerge from interactions between critical sets of brainstem neurons whose origins and synaptic ordered organization remain obscure. Here, we show, using a virus-based transsynaptic tracing strategy from the diaphragm muscle in the mouse, that the principal inspiratory premotor neurons share V0 identity with, and are connected by, neurons of the preBötzinger complex that paces inspiration. Deleting the commissural projections of V0s results in left-right desynchronized inspiratory motor commands in reduced brain preparations and breathing at birth. This work reveals the existence of a core inspiratory circuit in which V0 to V0 synapses enabling function of the rhythm generator also direct its output to secure bilaterally coordinated contractions of inspiratory effector muscles required for efficient breathing. The developmental origin and functional organization of the brainstem breathing circuits are poorly understood. Here using virus-based circuit-mapping approaches in mice, the authors reveal the lineage, neurotransmitter phenotype, and connectivity patterns of phrenic premotor neurons, which are a crucial component of the inspiratory circuit.
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22
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Momose-Sato Y, Sato K. Development of Spontaneous Activity in the Avian Hindbrain. Front Neural Circuits 2016; 10:63. [PMID: 27570506 PMCID: PMC4981603 DOI: 10.3389/fncir.2016.00063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 07/29/2016] [Indexed: 11/13/2022] Open
Abstract
Spontaneous activity in the developing central nervous system occurs before the brain responds to external sensory inputs, and appears in the hindbrain and spinal cord as rhythmic electrical discharges of cranial and spinal nerves. This spontaneous activity recruits a large population of neurons and propagates like a wave over a wide region of the central nervous system. Here, we review spontaneous activity in the chick hindbrain by focusing on this large-scale synchronized activity. Asynchronous activity that is expressed earlier than the above mentioned synchronized activity and activity originating in midline serotonergic neurons are also briefly mentioned.
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Affiliation(s)
- Yoko Momose-Sato
- Department of Nutrition and Dietetics, College of Nutrition, Kanto Gakuin University Yokohama, Japan
| | - Katsushige Sato
- Department of Health and Nutrition Sciences, Faculty of Human Health, Komazawa Women's University Tokyo, Japan
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23
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Abstract
AbstractMore than 35 years ago, Meltzoff and Moore (1977) published their famous article, “Imitation of facial and manual gestures by human neonates.” Their central conclusion, that neonates can imitate, was and continues to be controversial. Here, we focus on an often-neglected aspect of this debate, namely, neonatal spontaneous behaviors themselves. We present a case study of a paradigmatic orofacial “gesture,” namely tongue protrusion and retraction (TP/R). Against the background of new research on mammalian aerodigestive development, we ask: How does the human aerodigestive system develop, and what role does TP/R play in the neonate's emerging system of aerodigestion? We show that mammalian aerodigestion develops in two phases: (1) from the onset of isolated orofacial movementsin uteroto the postnatal mastery of suckling at 4 months after birth; and (2) thereafter, from preparation to the mastery of mastication and deglutition of solid foods. Like other orofacial stereotypies, TP/R emerges in the first phase and vanishes prior to the second. Based upon recent advances in activity-driven early neural development, we suggest a sequence of three developmental events in which TP/R might participate: the acquisition of tongue control, the integration of the central pattern generator (CPG) for TP/R with other aerodigestive CPGs, and the formation of connections within the cortical maps of S1 and M1. If correct, orofacial stereotypies are crucial to the maturation of aerodigestion in the neonatal period but also unlikely to co-occur with imitative behavior.
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24
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DeHaan KL, Seton C, Fitzgerald DA, Waters KA, MacLean JE. Polysomnography for the diagnosis of sleep disordered breathing in children under 2 years of age. Pediatr Pulmonol 2015; 50:1346-53. [PMID: 25777054 PMCID: PMC6680200 DOI: 10.1002/ppul.23169] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 01/03/2015] [Accepted: 01/21/2015] [Indexed: 11/09/2022]
Abstract
OBJECTIVES To describe clinical polysomnography (PSG) results, sleep physicians' diagnosis, and treatment of sleep disorder breathing in children less than 2 years of age. STUDY DESIGN Retrospective clinical chart review at a pediatric tertiary care center, pediatric sleep laboratory. SUBJECT SELECTION Children less than 2 years of age who underwent clinical PSG over a 3-year period. METHODOLOGY PSG results and physician interpretations were identified for inclusions. Children were excluded if either PSG results or physician interpretations were unavailable for review. Infants were classified in three age groups for comparison: <6 months, 6-12 months, and >12 months. RESULTS Matched records were available for 233 PSGs undertaken at a mean age 11.1 ± 7.0 months; 31% were <6 months, 23% were 6-12 months, and 46% were 12-24 months of age. Infants <6 months showed significant differences on sleep parameters and respiratory indicators compared to other groups. Compared to physician sleep disordered breathing (SDB) classification, current pediatric apnea-hypopnea index (AHI)-based SDB severity classification overestimated SDB severity. Age and obstructive-mixed AHI (OMAHI) were most closely associated with physician identification of SDB. CONCLUSION Children <6 months of age appear to represent a distinct group with respect to PSG. Experienced sleep physicians appear to incorporate age and respiratory event frequently when determining the presence of SDB. Further information about clinical significance of apnea in infancy is required, assisted by identification of factors that sleep physicians use to identify SDB in children <6 months of age.
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Affiliation(s)
- Kristie L DeHaan
- Department of Paediatrics, Division of Respiratory Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Chris Seton
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Dominic A Fitzgerald
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, New South Wales, Australia.,Discipline of Paediatrics and Child Health, University of Sydney, Sydney, New South Wales, Australia
| | - Karen A Waters
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, New South Wales, Australia.,Discipline of Paediatrics and Child Health, University of Sydney, Sydney, New South Wales, Australia.,Department of Physiology, University of Sydney, Sydney, New South Wales, Australia
| | - Joanna E MacLean
- Department of Paediatrics, Division of Respiratory Medicine, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
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25
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MacLean JE, Fitzgerald DA, Waters KA. Developmental changes in sleep and breathing across infancy and childhood. Paediatr Respir Rev 2015; 16:276-84. [PMID: 26364005 DOI: 10.1016/j.prrv.2015.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 08/06/2015] [Indexed: 11/24/2022]
Abstract
Sleep and breathing are physiological processes that begin in utero and undergo progressive change. While the major period of change for both sleep and breathing occurs during the months after birth, considered a period of vulnerability, more subtle changes continue to occur throughout childhood. The systems that control sleep and breathing develop separately, but sleep represents an activity state during which breathing and breathing control is significantly altered. Infants and young children may spend up to 12 hours a day sleeping; therefore, the effects of sleep on breathing are fundamental to understanding both processes in childhood. This review summarizes the current literature relevant to understanding the normal development of sleep and breathing across infancy and childhood.
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Affiliation(s)
- Joanna E MacLean
- Division of Respiratory Medicine, Department of Pediatrics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada; Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Australia; Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, NSW, Australia.
| | - Dominic A Fitzgerald
- Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Australia; Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - Karen A Waters
- Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Australia; Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, NSW, Australia
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26
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Ren J, Ding X, Greer JJ. Ampakines Enhance Weak Endogenous Respiratory Drive and Alleviate Apnea in Perinatal Rats. Am J Respir Crit Care Med 2015; 191:704-10. [DOI: 10.1164/rccm.201410-1898oc] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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27
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Dzal YA, Jenkin SEM, Lague SL, Reichert MN, York JM, Pamenter ME. Oxygen in demand: How oxygen has shaped vertebrate physiology. Comp Biochem Physiol A Mol Integr Physiol 2015; 186:4-26. [PMID: 25698654 DOI: 10.1016/j.cbpa.2014.10.029] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 10/07/2014] [Accepted: 10/10/2014] [Indexed: 10/24/2022]
Abstract
In response to varying environmental and physiological challenges, vertebrates have evolved complex and often overlapping systems. These systems detect changes in environmental oxygen availability and respond by increasing oxygen supply to the tissues and/or by decreasing oxygen demand at the cellular level. This suite of responses is termed the oxygen transport cascade and is comprised of several components. These components include 1) chemosensory detectors that sense changes in oxygen, carbon dioxide, and pH in the blood, and initiate changes in 2) ventilation and 3) cardiac work, thereby altering the rate of oxygen delivery to, and carbon dioxide clearance from, the tissues. In addition, changes in 4) cellular and systemic metabolism alters tissue-level metabolic demand. Thus the need for oxygen can be managed locally when increasing oxygen supply is not sufficient or possible. Together, these mechanisms provide a spectrum of responses that facilitate the maintenance of systemic oxygen homeostasis in the face of environmental hypoxia or physiological oxygen depletion (i.e. due to exercise or disease). Bill Milsom has dedicated his career to the study of these responses across phylogenies, repeatedly demonstrating the power of applying the comparative approach to physiological questions. The focus of this review is to discuss the anatomy, signalling pathways, and mechanics of each step of the oxygen transport cascade from the perspective of a Milsomite. That is, by taking into account the developmental, physiological, and evolutionary components of questions related to oxygen transport. We also highlight examples of some of the remarkable species that have captured Bill's attention through their unique adaptations in multiple components of the oxygen transport cascade, which allow them to achieve astounding physiological feats. Bill's research examining the oxygen transport cascade has provided important insight and leadership to the study of the diverse suite of adaptations that maintain cellular oxygen content across vertebrate taxa, which underscores the value of the comparative approach to the study of physiological systems.
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Affiliation(s)
- Yvonne A Dzal
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Sarah E M Jenkin
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Sabine L Lague
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Michelle N Reichert
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Julia M York
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Matthew E Pamenter
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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28
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Connexin hemichannels contribute to spontaneous electrical activity in the human fetal cortex. Proc Natl Acad Sci U S A 2014; 111:E3919-28. [PMID: 25197082 DOI: 10.1073/pnas.1405253111] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Before the human cortex is able to process sensory information, young postmitotic neurons must maintain occasional bursts of action-potential firing to attract and keep synaptic contacts, to drive gene expression, and to transition to mature membrane properties. Before birth, human subplate (SP) neurons are spontaneously active, displaying bursts of electrical activity (plateau depolarizations with action potentials). Using whole-cell recordings in acute cortical slices, we investigated the source of this early activity. The spontaneous depolarizations in human SP neurons at midgestation (17-23 gestational weeks) were not completely eliminated by tetrodotoxin--a drug that blocks action potential firing and network activity--or by antagonists of glutamatergic, GABAergic, or glycinergic synaptic transmission. We then turned our focus away from standard chemical synapses to connexin-based gap junctions and hemichannels. PCR and immunohistochemical analysis identified the presence of connexins (Cx26/Cx32/Cx36) in the human fetal cortex. However, the connexin-positive cells were not found in clusters but, rather, were dispersed in the SP zone. Also, gap junction-permeable dyes did not diffuse to neighboring cells, suggesting that SP neurons were not strongly coupled to other cells at this age. Application of the gap junction and hemichannel inhibitors octanol, flufenamic acid, and carbenoxolone significantly blocked spontaneous activity. The putative hemichannel antagonist lanthanum alone was a potent inhibitor of the spontaneous activity. Together, these data suggest that connexin hemichannels contribute to spontaneous depolarizations in the human fetal cortex during the second trimester of gestation.
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29
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Zwicker JD, Zhang Y, Ren J, Hutchinson MR, Rice KC, Watkins LR, Greer JJ, Funk GD. Glial TLR4 signaling does not contribute to opioid-induced depression of respiration. J Appl Physiol (1985) 2014; 117:857-68. [PMID: 25103966 DOI: 10.1152/japplphysiol.00534.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Opioids activate glia in the central nervous system in part by activating the toll-like receptor 4 (TLR4)/myeloid differentiation 2 (MD2) complex. TLR4/MD2-mediated activation of glia by opioids compromises their analgesic actions. Glial activation is also hypothesized as pivotal in opioid-mediated reward and tolerance and as a contributor to opioid-mediated respiratory depression. We tested the contribution of TLR4 to opioid-induced respiratory depression using rhythmically active medullary slices that contain the pre-Bötzinger Complex (preBötC, an important site of respiratory rhythm generation) and adult rats in vivo. Injection with DAMGO (μ-opioid receptor agonist; 50 μM) or bath application of DAMGO (500 nM) or fentanyl (1 μM) slowed frequency recorded from XII nerves to 40%, 40%, or 50% of control, respectively. This DAMGO-mediated frequency inhibition was unaffected by preapplication of lipopolysaccharides from Rhodobacter sphaeroides (a TLR4 antagonist, 2,000 ng/ml) or (+)naloxone (1-10 μM, a TLR4-antagonist). Bath application of (-)naloxone (500 nM; a TLR4 and μ-opioid antagonist), however, rapidly reversed the opioid-mediated frequency decrease. We also compared the opioid-induced respiratory depression in slices in vitro in the absence and presence of bath-applied minocycline (an inhibitor of microglial activation) and in slices prepared from mice injected (ip) 18 h earlier with minocycline or saline. Minocycline had no effect on respiratory depression in vitro. Finally, the respiratory depression evoked in anesthetized rats by tail vein infusion of fentanyl was unaffected by subsequent injection of (+)naloxone, but completely reversed by (-)naloxone. These data indicate that neither activation of microglia in preBötC nor TLR4/MD2-activation contribute to opioid-induced respiratory depression.
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Affiliation(s)
- Jennifer D Zwicker
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Yong Zhang
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jun Ren
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Mark R Hutchinson
- Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Kenner C Rice
- Chemical Biology Research Branch, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, Rockville, Maryland; and
| | - Linda R Watkins
- Department of Psychology and The Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado
| | - John J Greer
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Gregory D Funk
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada;
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30
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Tupal S, Huang WH, Picardo MCD, Ling GY, Del Negro CA, Zoghbi HY, Gray PA. Atoh1-dependent rhombic lip neurons are required for temporal delay between independent respiratory oscillators in embryonic mice. eLife 2014; 3:e02265. [PMID: 24842997 PMCID: PMC4060005 DOI: 10.7554/elife.02265] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
All motor behaviors require precise temporal coordination of different muscle groups. Breathing, for example, involves the sequential activation of numerous muscles hypothesized to be driven by a primary respiratory oscillator, the preBötzinger Complex, and at least one other as-yet unidentified rhythmogenic population. We tested the roles of Atoh1-, Phox2b-, and Dbx1-derived neurons (three groups that have known roles in respiration) in the generation and coordination of respiratory output. We found that Dbx1-derived neurons are necessary for all respiratory behaviors, whereas independent but coupled respiratory rhythms persist from at least three different motor pools after eliminating or silencing Phox2b- or Atoh1-expressing hindbrain neurons. Without Atoh1 neurons, however, the motor pools become temporally disorganized and coupling between independent respiratory oscillators decreases. We propose Atoh1 neurons tune the sequential activation of independent oscillators essential for the fine control of different muscles during breathing.DOI: http://dx.doi.org/10.7554/eLife.02265.001.
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Affiliation(s)
- Srinivasan Tupal
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, United States
| | - Wei-Hsiang Huang
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Baylor College of Medicine, Houston, United States
| | | | - Guang-Yi Ling
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, United States
| | | | - Huda Y Zoghbi
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Baylor College of Medicine, Houston, United States Department of Molecular and Human Genetics, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Paul A Gray
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, United States
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Warren PM, Alilain WJ. The challenges of respiratory motor system recovery following cervical spinal cord injury. PROGRESS IN BRAIN RESEARCH 2014; 212:173-220. [DOI: 10.1016/b978-0-444-63488-7.00010-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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32
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Abstract
Breathing movements have been demonstrated in the fetuses of every mammalian species investigated and are a critical component of normal fetal development. The classic sheep preparations instrumented for chronic fetal monitoring determined that fetal breathing movements (FBMs) occur in aggregates interspersed with long periods of quiescence that are strongly associated with neurophysiological state. The fetal sheep model also provided data regarding the neurochemical modulation of behavioral state and FBMs under a variety of in utero conditions. Subsequently, in vitro rodent models have been developed to advance our understanding of cellular, synaptic, network, and more detailed neuropharmacological aspects of perinatal respiratory neural control. This includes the ontogeny of the inspiratory rhythm generating center, the preBötzinger complex (preBötC), and the anatomical and functional development of phrenic motoneurons (PMNs) and diaphragm during the perinatal period. A variety of newborn animal models and studies of human infants have provided insights into age-dependent changes in state-dependent respiratory control, responses to hypoxia/hypercapnia and respiratory pathologies.
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Affiliation(s)
- John J Greer
- Department of Physiology, Centre for Neuroscience, Women and Children Health Research Institute, University of Alberta, Edmonton, Alberta, Canada.
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33
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Abstract
Pontine respiratory nuclei provide synaptic input to medullary rhythmogenic circuits to shape and adapt the breathing pattern. An understanding of this statement depends on appreciating breathing as a behavior, rather than a stereotypic rhythm. In this review, we focus on the pontine-mediated inspiratory off-switch (IOS) associated with postinspiratory glottal constriction. Further, IOS is examined in the context of pontine regulation of glottal resistance in response to multimodal sensory inputs and higher commands, which in turn rules timing, duration, and patterning of respiratory airflow. In addition, network plasticity in respiratory control emerges during the development of the pons. Synaptic plasticity is required for dynamic and efficient modulation of the expiratory breathing pattern to cope with rapid changes from eupneic to adaptive breathing linked to exploratory (foraging and sniffing) and expulsive (vocalizing, coughing, sneezing, and retching) behaviors, as well as conveyance of basic emotions. The speed and complexity of changes in the breathing pattern of behaving animals implies that "learning to breathe" is necessary to adjust to changing internal and external states to maintain homeostasis and survival.
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Affiliation(s)
- Mathias Dutschmann
- Florey Neurosciences Institutes, University of Melbourne, Victoria, Australia.
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34
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Abstract
The main functions of the respiratory neural network are to produce a coordinated, efficient, rhythmic motor behavior and maintain homeostatic control over blood oxygen and CO2/pH levels. Purinergic (ATP) signaling features prominently in these homeostatic reflexes. The signaling actions of ATP are produced through its binding to a diversity of ionotropic P2X and metabotropic P2Y receptors. However, its net effect on neuronal and network excitability is determined by the interaction between the three limbs of a complex system comprising the signaling actions of ATP at P2Rs, the distribution of multiple ectonucleotidases that differentially metabolize ATP into ADP, AMP, and adenosine (ADO), and the signaling actions of ATP metabolites, especially ADP at P2YRs and ADO at P1Rs. Understanding the significance of purinergic signaling is further complicated by the fact that neurons, glia, and the vasculature differentially express P2 and P1Rs, and that both neurons and glia release ATP. This article reviews at cellular, synaptic, and network levels, current understanding and emerging concepts about the diverse roles played by this three-part signaling system in: mediating the chemosensitivity of respiratory networks to hypoxia and CO2/pH; modulating the activity of rhythm generating networks and inspiratory motoneurons, and; controlling blood flow through the cerebral vasculature.
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Affiliation(s)
- Gregory D Funk
- Department of Physiology, Centre for Neuroscience, Women & Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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Abstract
Hibernation in endotherms and ectotherms is characterized by an energy-conserving metabolic depression due to low body temperatures and poorly understood temperature-independent mechanisms. Rates of gas exchange are correspondly reduced. In hibernating mammals, ventilation falls even more than metabolic rate leading to a relative respiratory acidosis that may contribute to metabolic depression. Breathing in some mammals becomes episodic and in some small mammals significant apneic gas exchange may occur by passive diffusion via airways or skin. In ectothermic vertebrates, extrapulmonary gas exchange predominates and in reptiles and amphibians hibernating underwater accounts for all gas exchange. In aerated water diffusive exchange permits amphibians and many species of turtles to remain fully aerobic, but hypoxic conditions can challenge many of these animals. Oxygen uptake into blood in both endotherms and ectotherms is enhanced by increased affinity of hemoglobin for O₂ at low temperature. Regulation of gas exchange in hibernating mammals is predominately linked to CO₂/pH, and in episodic breathers, control is principally directed at the duration of the apneic period. Control in submerged hibernating ectotherms is poorly understood, although skin-diffusing capacity may increase under hypoxic conditions. In aerated water blood pH of frogs and turtles either adheres to alphastat regulation (pH ∼8.0) or may even exhibit respiratory alkalosis. Arousal in hibernating mammals leads to restoration of euthermic temperature, metabolic rate, and gas exchange and occurs periodically even as ambient temperatures remain low, whereas body temperature, metabolic rate, and gas exchange of hibernating ectotherms are tightly linked to ambient temperature.
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Affiliation(s)
- William K Milsom
- Department of Zoology, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia, Canada
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Momose-Sato Y, Sato K. Large-scale synchronized activity in the embryonic brainstem and spinal cord. Front Cell Neurosci 2013; 7:36. [PMID: 23596392 PMCID: PMC3625830 DOI: 10.3389/fncel.2013.00036] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 03/20/2013] [Indexed: 01/09/2023] Open
Abstract
In the developing central nervous system, spontaneous activity appears well before the brain responds to external sensory inputs. One of the earliest activities is observed in the hindbrain and spinal cord, which is detected as rhythmic electrical discharges of cranial and spinal motoneurons or oscillations of Ca(2+)- and voltage-related optical signals. Shortly after the initial expression, the spontaneous activity appearing in the hindbrain and spinal cord exhibits a large-scale correlated wave that propagates over a wide region of the central nervous system, maximally extending to the lumbosacral cord and to the forebrain. In this review, we describe several aspects of this synchronized activity by focusing on the basic properties, development, origin, propagation pattern, pharmacological characteristics, and possible mechanisms underlying the generation of the activity. These profiles differ from those of the respiratory and locomotion pattern generators observed in the mature brainstem and spinal cord, suggesting that the wave is primordial activity that appears during a specific period of embryonic development and plays some important roles in the development of the central nervous system.
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Affiliation(s)
- Yoko Momose-Sato
- Department of Health and Nutrition, College of Human Environmental Studies, Kanto Gakuin UniversityYokohama, Japan
| | - Katsushige Sato
- Department of Health and Nutrition Sciences, Faculty of Human Health, Komazawa Women's UniversityTokyo, Japan
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Gestational stress promotes pathological apneas and sex-specific disruption of respiratory control development in newborn rat. J Neurosci 2013; 33:563-73. [PMID: 23303936 DOI: 10.1523/jneurosci.1214-12.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Recurrent apneas are important causes of hospitalization and morbidity in newborns. Gestational stress (GS) compromises fetal brain development. Maternal stress and anxiety during gestation are linked to respiratory disorders in newborns; however, the mechanisms remain unknown. Here, we tested the hypothesis that repeated activation of the neuroendocrine response to stress during gestation is sufficient to disrupt the development of respiratory control and augment the occurrence of apneas in newborn rats. Pregnant dams were displaced and exposed to predator odor from days 9 to 19 of gestation. Control dams were undisturbed. Experiments were performed on male and female rats aged between 0 and 4 d old. Apnea frequency decreased with age but was consistently higher in stressed pups than controls. At day 4, GS augmented the proportion of apneas with O(2) desaturations by 12%. During acute hypoxia (12% O(2)), the reflexive increase in breathing augmented with age; however, this response was lower in stressed pups. Instability of respiratory rhythm recorded from medullary preparations decreased with age but was higher in stressed pups than controls. GS reduced medullary serotonin (5-HT) levels in newborn pups by 32%. Bath application of 5-HT and injection of 8-OH-DPAT [(±)-8-hydroxy-2-di-(n-propylamino) tetralin hydrobromide; 5-HT(1A) agonist; in vivo] reduced respiratory instability and apneas; these effects were greater in stressed pups than controls. Sex-specific effects were observed. We conclude that activation of the stress response during gestation is sufficient to disrupt respiratory control development and promote pathological apneas in newborn rats. A deficit in medullary 5-HT contributes to these effects.
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Wang CC, Billett E, Borchert A, Kuhn H, Ufer C. Monoamine oxidases in development. Cell Mol Life Sci 2013; 70:599-630. [PMID: 22782111 PMCID: PMC11113580 DOI: 10.1007/s00018-012-1065-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 06/13/2012] [Accepted: 06/19/2012] [Indexed: 12/29/2022]
Abstract
Monoamine oxidases (MAOs) are flavoproteins of the outer mitochondrial membrane that catalyze the oxidative deamination of biogenic and xenobiotic amines. In mammals there are two isoforms (MAO-A and MAO-B) that can be distinguished on the basis of their substrate specificity and their sensitivity towards specific inhibitors. Both isoforms are expressed in most tissues, but their expression in the central nervous system and their ability to metabolize monoaminergic neurotransmitters have focused MAO research on the functionality of the mature brain. MAO activities have been related to neurodegenerative diseases as well as to neurological and psychiatric disorders. More recently evidence has been accumulating indicating that MAO isoforms are expressed not only in adult mammals, but also before birth, and that defective MAO expression induces developmental abnormalities in particular of the brain. This review is aimed at summarizing and critically evaluating the new findings on the developmental functions of MAO isoforms during embryogenesis.
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Affiliation(s)
- Chi Chiu Wang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, Shatin, Hong Kong
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ellen Billett
- School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS UK
| | - Astrid Borchert
- Institute of Biochemistry, University Medicine Berlin-Charité, Oudenarder Str. 16, 13347 Berlin, Germany
| | - Hartmut Kuhn
- Institute of Biochemistry, University Medicine Berlin-Charité, Oudenarder Str. 16, 13347 Berlin, Germany
| | - Christoph Ufer
- Institute of Biochemistry, University Medicine Berlin-Charité, Oudenarder Str. 16, 13347 Berlin, Germany
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Momose-Sato Y, Nakamori T, Sato K. Pharmacological mechanisms underlying switching from the large-scale depolarization wave to segregated activity in the mouse central nervous system. Eur J Neurosci 2012; 35:1242-52. [PMID: 22512255 DOI: 10.1111/j.1460-9568.2012.08040.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
During the early development of the nervous system, synchronized activity is observed in a variety of structures, and is considered to play a fundamental role in neural development. One of the most striking examples of such activity is the depolarization wave reported in chick and rat embryos. In the accompanying paper (Momose-Sato et al., 2012), we have demonstrated that a depolarization wave is also present in the mouse embryo by showing large-scale optical waves, which spread remarkably over the central nervous system, including the spinal cord, hindbrain, cerebellum, midbrain, and forebrain. In the present study, we examined the pharmacological nature of the mouse depolarization wave and its developmental changes. We show here that two types of switching in pharmacological characteristics occur during development. One is that the depolarization wave is strongly dependent on nicotinic acetylcholine receptors during the early developmental stage [embryonic day (E)11-12], but is dominated by glutamate at the later stage (E13 onwards). The second is that γ-aminobutyric acid (GABA), which acts as an excitatory mediator of the depolarization wave during the early phase, becomes an inhibitory modulator by E14. These changes seemed to occur earlier in the hindbrain than in the spinal cord. Furthermore, we show that the second switch causes the loss of synchronization over the network, resulting in the disappearance of the depolarization wave and segregation of the activity into discrete regions of the medulla and spinal cord. We suggest that pharmacological switching is a possible mechanism underlying replacement of the primordial correlated network by a mature neuronal circuit.
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Affiliation(s)
- Yoko Momose-Sato
- Department of Health and Nutrition, College of Human Environmental Studies, Kanto Gakuin University, 1-50-1 Mutsuura-Higashi, Kanazawa-ku, Yokohama, 236-8503, Japan.
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40
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Cifra A, Mazzone GL, Nani F, Nistri A, Mladinic M. Postnatal developmental profile of neurons and glia in motor nuclei of the brainstem and spinal cord, and its comparison with organotypic slice cultures. Dev Neurobiol 2012; 72:1140-60. [PMID: 22021114 DOI: 10.1002/dneu.20991] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 10/18/2011] [Indexed: 01/31/2023]
Abstract
In vitro preparations of the neonatal rat spinal cord or brainstem are useful to investigate the organization of motor networks and their dysfunction in neurological disease models. Long-term spinal cord organotypic cultures can extend our understanding of such pathophysiological processes over longer times. It is, however, surprising that detailed descriptions of the type (and number) of neurons and glia in such preparations are currently unavailable to evaluate cell-selectivity of experimental damage. The focus of the present immunohistochemical study is the novel characterization of the cell population in the lumbar locomotor region of the rat spinal cord and in the brainstem motor nucleus hypoglossus at 0-4 postnatal days, and its comparison with spinal organotypic cultures at 2-22 days in vitro. In the nucleus hypoglossus, neurons were 40% of all cells and 80% of these were motoneurons. Astrocytes (35% of total cells) were the main glial cells, while microglia was <10%. In the spinal gray matter, the highest neuronal density was in the dorsal horn (>80%) and the lowest in the ventral horn (≤57%) with inverse astroglia numbers and few microglia. The number of neurons (including motoneurons) and astrocytes was stable after birth. Like in the spinal cord, motoneurons in organotypic spinal culture were <10% of ventral horn cells, with neurons <40%, and the rest made up by glia. The present report indicates a comparable degree of neuronal and glial maturation in brainstem and spinal motor nuclei, and that this condition is also observed in 3-week-old organotypic cultures.
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Affiliation(s)
- Alessandra Cifra
- Neurobiology Sector and IIT Unit, International School for Advanced Studies (SISSA), Trieste, Italy
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41
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Rasoulpour RJ, Ellis-Hutchings RG, Terry C, Millar NS, Zablotny CL, Gibb A, Marshall V, Collins T, Carney EW, Billington R. A Novel Mode-of-Action Mediated by the Fetal Muscle Nicotinic Acetylcholine Receptor Resulting in Developmental Toxicity in Rats. Toxicol Sci 2012; 127:522-34. [DOI: 10.1093/toxsci/kfs118] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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42
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Anatomically “Calibrated” Isolated Respiratory Networks from Newborn Rodents. ISOLATED CENTRAL NERVOUS SYSTEM CIRCUITS 2012. [DOI: 10.1007/978-1-62703-020-5_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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43
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Gulemetova R, Kinkead R. Neonatal stress increases respiratory instability in rat pups. Respir Physiol Neurobiol 2011; 176:103-9. [DOI: 10.1016/j.resp.2011.01.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 01/31/2011] [Accepted: 01/31/2011] [Indexed: 11/25/2022]
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44
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Cifra A, Nani F, Nistri A. Respiratory motoneurons and pathological conditions: lessons from hypoglossal motoneurons challenged by excitotoxic or oxidative stress. Respir Physiol Neurobiol 2011; 179:89-96. [PMID: 21443969 DOI: 10.1016/j.resp.2011.03.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 03/07/2011] [Accepted: 03/19/2011] [Indexed: 11/27/2022]
Abstract
Hypoglossal motoneurons (HMs) are respiration-related brainstem neurons that command rhythmic contraction of the tongue muscles in concert with the respiratory drive. In experimental conditions, HMs can exhibit a range of rhythmic patterns that may subserve different motor outputs and functions. Neurodegenerative diseases like amyotrophic lateral sclerosis (ALS; Lou-Gehrig disease) often damage HMs with distressing symptoms like dysarthria, dysphagia and breathing difficulty related to degeneration of respiratory motoneurons. While the cause of ALS remains unclear, early diagnosis remains an important goal for potential treatment because fully blown clinical symptoms appear with degeneration of about 30% motoneurons. Using a simple in vitro model of the rat brainstem to study the consequences of excitotoxicity or oxidative stress (believed to occur during the onset of ALS) on HMs, it is possible to observe distinct electrophysiological effects associated with HM experimental pathology. In fact, excitotoxicity caused by glutamate uptake block triggers sustained bursting and enhanced synaptic transmission, whereas oxidative stress generates slow depolarization, augmented repeated firing, and decreased synaptic transmission. In either case, only a subpopulation of HMs shows abnormal functional changes. Although these two insults induce separate functional signatures, the consequences on HMs after a few hours are similar and are preceded by activation of the stress transcription factor ATF-3. The deleterious action of excitotoxicity is inhibited by early administration of riluzole, a drug currently employed for the symptomatic treatment of ALS, demonstrating that this in vitro model can be useful for testing potential neuroprotective agents.
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Affiliation(s)
- Alessandra Cifra
- Neurobiology Sector, International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
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45
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Milsom WK. Adaptive trends in respiratory control: a comparative perspective. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1-10. [DOI: 10.1152/ajpregu.00069.2010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In 1941, August Krogh published a monograph entitled The Comparative Physiology of Respiratory Mechanisms (Philadelphia, PA: University of Pennsylvania Press, 1941). Since that time comparative studies have continued to contribute significantly to our understanding of the fundamentals of respiratory physiology and the adaptive trends in these processes that support a broad range of metabolic performance under demanding environmental conditions. This review specifically focuses on recent advances in our understanding of adaptive trends in respiratory control. Respiratory rhythm generators most likely arose from, and must remain integrated with, rhythm generators for chewing, suckling, and swallowing. Within the central nervous system there are multiple “segmental” rhythm generators, and through evolution there is a caudal shift in the predominant respiratory rhythm-generating site. All sites, however, may still be capable of producing or modulating respiratory rhythm under appropriate conditions. Expression of the respiratory rhythm is conditional on (tonic) input. Once the rhythm is expressed, it is often episodic as the basic medullary rhythm is turned on/off subject to a hierarchy of controls. Breathing patterns reflect differences in pulmonary mechanics resulting from differences in body wall and lung architecture and are modulated in different species by various combinations of upper and lower airway mechanoreceptors and arterial chemoreceptors to protect airways, reduce dead space ventilation, enhance gas exchange efficiency, and reduce the cost of breathing.
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Affiliation(s)
- William K. Milsom
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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46
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Darnall RA. The role of CO(2) and central chemoreception in the control of breathing in the fetus and the neonate. Respir Physiol Neurobiol 2010; 173:201-12. [PMID: 20399912 DOI: 10.1016/j.resp.2010.04.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 04/08/2010] [Accepted: 04/09/2010] [Indexed: 10/19/2022]
Abstract
Central chemoreception is active early in development and likely drives fetal breathing movements, which are influenced by a combination of behavioral state and powerful inhibition. In the premature human infant and newborn rat ventilation increases in response to CO(2); in the rat the sensitivity of the response increases steadily after ∼P12. The premature human infant is more vulnerable to instability than the newborn rat and exhibits periodic breathing that is augmented by hypoxia and eliminated by breathing oxygen or CO(2) or the administration of respiratory stimulants. The sites of central chemoreception active in the fetus are not known, but may involve the parafacial respiratory group which may be a precursor to the adult RTN. The fetal and neonatal rat brainstem-spinal-cord preparations promise to provide important information about central chemoreception in the developing rodent and will increase our understanding of important clinical problems, including The Sudden Infant Death Syndrome, Congenital Central Hypoventilation Syndrome, and periodic breathing and apnea of prematurity.
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Affiliation(s)
- Robert A Darnall
- Departments of Physiology and Neurobiology and Pediatrics, Dartmouth Medical School, Borwell Building, Lebanon, NH 03756, USA.
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47
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Lavezzi AM, Corna MF, Mehboob R, Matturri L. Neuropathology of the intermediolateral nucleus of the spinal cord in sudden unexplained perinatal and infant death. Int J Dev Neurosci 2010; 28:133-8. [PMID: 20083189 DOI: 10.1016/j.ijdevneu.2010.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 01/08/2010] [Accepted: 01/11/2010] [Indexed: 10/20/2022] Open
Abstract
Experimental studies have demonstrated that breathing activity in rats is generated early in embryonic stages in rostral spinal cord, precisely in the intermediolateral nucleus, then establishing a spinal cord-brainstem network. In this study we aimed to individuate and to define the developmental steps of the intermediolateral nucleus, still inadequately known in humans, in the thoracic spinal cord of a large series of perinatal and infant death victims, aged from 17 gestational weeks to 10 months of life. Besides we investigated a possible link between alterations of this nucleus and sudden unexplained perinatal and infant death. The normal developmental pattern of the human intermediolateral nucleus consists of a progressive maturation of its neurons, that change from a round to a polygonal shape with long axons and significantly decrease in number. Various degrees of intermediolateral nucleus hypodevelopment (neuronal immaturity in a normal structure/hypoplasia/agenesis) were found almost exclusively in unexplained fetal and infant death victims. Besides, a significant correlation was found between maternal smoking in pregnancy and the neuropathological results. In conclusion this work underlines the negative effects of prenatal nicotine exposure on the development of autonomic nervous centers checking the vital functions, already in early gestational stages, when the integrity of the intermediolateral nucleus is indispensable for the first breathing bursts.
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Affiliation(s)
- Anna M Lavezzi
- Lino Rossi Research Center for The Study and Prevention of Unexpected Perinatal Death and SIDS-Department of Surgical, Reconstructive and Diagnostic Sciences, University of Milan, Via della Commenda, 19, Milan 20122, Italy.
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48
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Tripartite purinergic modulation of central respiratory networks during perinatal development: the influence of ATP, ectonucleotidases, and ATP metabolites. J Neurosci 2010; 29:14713-25. [PMID: 19940166 DOI: 10.1523/jneurosci.2660-09.2009] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
ATP released during hypoxia from the ventrolateral medulla activates purinergic receptors (P2Rs) to attenuate the secondary hypoxic depression of breathing by a mechanism that likely involves a P2Y(1)R-mediated excitation of preBötzinger complex (preBötC) inspiratory rhythm-generating networks. In this study, we used rhythmically active in vitro preparations from embryonic and postnatal rats and ATP microinjection into the rostral ventral respiratory group (rVRG)/preBötC to reveal that these networks are sensitive to ATP when rhythm emerges at embryonic day 17 (E17). The peak frequency elicited by ATP at E19 and postnatally was the same ( approximately 45 bursts/min), but relative sensitivity was threefold greater at E19, reflecting a lower baseline frequency (5.6 +/- 0.9 vs 19.0 +/- 1.3 bursts/min). Combining microinjection techniques with ATP biosensors revealed that ATP concentration in the rVRG/preBötC falls rapidly as a result of active processes and closely correlates with inspiratory frequency. A phosphate assay established that preBötC-containing tissue punches degrade ATP at rates that increase perinatally. Thus, the agonist profile [ATP/ADP/adenosine (ADO)] produced after ATP release in the rVRG/preBötC will change perinatally. Electrophysiology further established that the ATP metabolite ADP is excitatory and that, in fetal but not postnatal animals, ADO at A(1) receptors exerts a tonic depressive action on rhythm, whereas A(1) antagonists extend the excitatory action of ATP on inspiratory rhythm. These data demonstrate that ATP is a potent excitatory modulator of the rVRG/preBötC inspiratory network from the time it becomes active and that ATP actions are determined by a dynamic interaction between the actions of ATP at P2 receptors, ectonucleotidases that degrade ATP, and ATP metabolites on P2Y and P1 receptors.
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50
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Fong AY, Zimmer MB, Milsom WK. The conditional nature of the “Central Rhythm Generator” and the production of episodic breathing. Respir Physiol Neurobiol 2009; 168:179-87. [DOI: 10.1016/j.resp.2009.05.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 05/20/2009] [Accepted: 05/28/2009] [Indexed: 12/01/2022]
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