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Flor KC, Maia OAC, Takakura AC, Moreira TS. The pontine Kölliker-Fuse nucleus is important for reduced postinspiratory airflow elicited by stimulation of the ventral respiratory parafacial region. Am J Physiol Lung Cell Mol Physiol 2024; 327:L452-L463. [PMID: 39104318 DOI: 10.1152/ajplung.00155.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 07/22/2024] [Accepted: 07/28/2024] [Indexed: 08/07/2024] Open
Abstract
Considering that the retrotrapezoid nucleus/respiratory parafacial region (RTN/pFRG) would be an important center in the central nervous system involved in the maintenance and modulation of respiratory activity, we hypothesized that neurons in this nucleus would also be involved in the postinspiratory (post-I) phase of the respiratory cycle through a connection with the pontine Kölliker-Fuse (KF) region. Here, we performed pharmacogenetic manipulation (AAV-hM3D(Gq)-mCherry or AAV-hM4D(Gi)-mCherry) in VGlut2-cre, Ai6 conscious mice to evaluate breathing parameters through whole body plethysmography under baseline conditions (normoxia: [Formula: see text] = 0.21) or under hypercapnia or hypoxia challenges ([Formula: see text] = 0.07 or [Formula: see text] = 0.08). Under normoxia, selective stimulation of RTN/pFRG resulted in a smaller increase in V̇e (1,272 ± 102.5, vs. RTN/pFRG stimulation: 1,878 ± 122.1 mL/kg/min), due to a smaller increase in VT (5.4 ± 0.35, vs. RTN/pFRG stimulation: 7.77 ± 0.21 mL/kg) without changing fR in a condition of KF inhibition. However, inhibition of the VGlut2 neurons in the KF did affect the TE1 produced by selective activation of RTN/pFRG (119.9 ± 2.53, vs. RTN/pFRG stimulation: 104 ± 2.46 ms). Both the hypercapnia and hypoxia ventilatory response were reduced after inhibition of VGlut2-expressing KF neurons. Therefore, consistent with anatomical projections RTN/pFRG neurons regulate lung ventilation by controlling all aspects of breathing, i.e., breathing frequency, inspiration, postinspiration, and active expiration. All the modulation seems to be dependent on the integrity of the glutamatergic neurons in the KF region.NEW & NOTEWORTHY Our research reveals specific roles and interactions between the retrotrapezoid nucleus/respiratory parafacial region (RTN/pFRG) and the pontine Kölliker-Fuse (KF) region in controlling respiratory phases. RTN/pFRG neurons are key in regulating all aspects of breathing, including frequency, inspiration, postinspiration, and active expiration. This regulation depends on the functional integrity of glutamatergic neurons in the KF region, aligning with anatomical projections.
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Affiliation(s)
- Karine C Flor
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Octavio A C Maia
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
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2
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Astrocytic contribution to glutamate-related central respiratory chemoreception in vertebrates. Respir Physiol Neurobiol 2021; 294:103744. [PMID: 34302992 DOI: 10.1016/j.resp.2021.103744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/01/2021] [Accepted: 07/18/2021] [Indexed: 12/24/2022]
Abstract
Central respiratory chemoreceptors play a key role in the respiratory homeostasis by sensing CO2 and H+ in brain and activating the respiratory neural network. This ability of specific brain regions to respond to acidosis and hypercapnia is based on neuronal and glial mechanisms. Several decades ago, glutamatergic transmission was proposed to be involved as a main mechanism in central chemoreception. However, a complete identification of mechanism has been elusive. At the rostral medulla, chemosensitive neurons of the retrotrapezoid nucleus (RTN) are glutamatergic and they are stimulated by ATP released by RTN astrocytes in response to hypercapnia. In addition, recent findings show that caudal medullary astrocytes in brainstem can also contribute as CO2 and H+ sensors that release D-serine and glutamate, both gliotransmitters able to activate the respiratory neural network. In this review, we describe the mammalian astrocytic glutamatergic contribution to the central respiratory chemoreception trying to trace in vertebrates the emergence of several components involved in this process.
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Revill AL, Katzell A, Del Negro CA, Milsom WK, Funk GD. KCNQ Current Contributes to Inspiratory Burst Termination in the Pre-Bötzinger Complex of Neonatal Rats in vitro. Front Physiol 2021; 12:626470. [PMID: 33927636 PMCID: PMC8078421 DOI: 10.3389/fphys.2021.626470] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 02/23/2021] [Indexed: 12/23/2022] Open
Abstract
The pre-Bötzinger complex (preBötC) of the ventral medulla generates the mammalian inspiratory breathing rhythm. When isolated in explants and deprived of synaptic inhibition, the preBötC continues to generate inspiratory-related rhythm. Mechanisms underlying burst generation have been investigated for decades, but cellular and synaptic mechanisms responsible for burst termination have received less attention. KCNQ-mediated K+ currents contribute to burst termination in other systems, and their transcripts are expressed in preBötC neurons. Therefore, we tested the hypothesis that KCNQ channels also contribute to burst termination in the preBötC. We recorded KCNQ-like currents in preBötC inspiratory neurons in neonatal rat slices that retain respiratory rhythmicity. Blocking KCNQ channels with XE991 or linopirdine (applied via superfusion or locally) increased inspiratory burst duration by 2- to 3-fold. By contrast, activation of KCNQ with retigabine decreased inspiratory burst duration by ~35%. These data from reduced preparations suggest that the KCNQ current in preBötC neurons contributes to inspiratory burst termination.
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Affiliation(s)
- Ann L. Revill
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
- Women and Children’s Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Alexis Katzell
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
- Women and Children’s Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | | | - William K. Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Gregory D. Funk
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
- Women and Children’s Health Research Institute, University of Alberta, Edmonton, AB, Canada
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王 贝, 阚 清, 邹 芸, 程 锐, 周 晓. [Sudden unexpected postnatal collapse in a neonate]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2021; 23:283-287. [PMID: 33691923 PMCID: PMC7969186 DOI: 10.7499/j.issn.1008-8830.2012020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
A healthy full-term female neonate, aged 3 days and born by vaginal delivery (with a 1-minute Apgar score of 10 and a 5-minute Apgar score of 10), had unexpected cardiac and respiratory arrests in the early morning on day 3 after birth and recovered to spontaneous breathing and heartbeat after a 10-minute resuscitation. The child had poor response and convulsion after resuscitation. Blood gas analysis showed metabolic acidosis, and amplitude-integrated EEG showed a burst-suppression pattern. She was diagnosed with sudden unexpected postnatal collapse but improved after hypothermia and symptomatic/supportive treatment. This article reports the first case of sudden unexpected postnatal collapse in China and summarizes related risk factors, pathophysiological mechanisms, and preventive and treatment measures of this disorder.
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Affiliation(s)
- 贝贝 王
- />南京医科大学附属儿童医院新生儿医疗中心, 江苏南京 210008Department of Neonatology, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - 清 阚
- />南京医科大学附属儿童医院新生儿医疗中心, 江苏南京 210008Department of Neonatology, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - 芸苏 邹
- />南京医科大学附属儿童医院新生儿医疗中心, 江苏南京 210008Department of Neonatology, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - 锐 程
- />南京医科大学附属儿童医院新生儿医疗中心, 江苏南京 210008Department of Neonatology, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - 晓光 周
- />南京医科大学附属儿童医院新生儿医疗中心, 江苏南京 210008Department of Neonatology, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
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5
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Dutschmann M, Bautista TG, Trevizan-Baú P, Dhingra RR, Furuya WI. The pontine Kölliker-Fuse nucleus gates facial, hypoglossal, and vagal upper airway related motor activity. Respir Physiol Neurobiol 2020; 284:103563. [PMID: 33053424 DOI: 10.1016/j.resp.2020.103563] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/04/2020] [Accepted: 10/06/2020] [Indexed: 01/31/2023]
Abstract
The pontine Kölliker-Fuse nucleus (KFn) is a core nucleus of respiratory network that mediates the inspiratory-expiratory phase transition and gates eupneic motor discharges in the vagal and hypoglossal nerves. In the present study, we investigated whether the same KFn circuit may also gate motor activities that control the resistance of the nasal airway, which is of particular importance in rodents. To do so, we simultaneously recorded phrenic, facial, vagal and hypoglossal cranial nerve activity in an in situ perfused brainstem preparation before and after bilateral injection of the GABA-receptor agonist isoguvacine (50-70 nl, 10 mM) into the KFn (n = 11). Our results show that bilateral inhibition of the KFn triggers apneusis (prolonged inspiration) and abolished pre-inspiratory discharge of facial, vagal and hypoglossal nerves as well as post-inspiratory discharge in the vagus. We conclude that the KFn plays a critical role for the eupneic regulation of naso-pharyngeal airway patency and the potential functions of the KFn in regulating airway patency and orofacial behavior is discussed.
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Affiliation(s)
- M Dutschmann
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia.
| | - T G Bautista
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia
| | - P Trevizan-Baú
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia
| | - R R Dhingra
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia
| | - W I Furuya
- Florey Department of Neuroscience and Mental Health, Melbourne University, Gate 11 Royal Parade, University of Melbourne, VIC 3010, Australia
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6
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Barnett WH, Jenkin SEM, Milsom WK, Paton JFR, Abdala AP, Molkov YI, Zoccal DB. The Kölliker-Fuse nucleus orchestrates the timing of expiratory abdominal nerve bursting. J Neurophysiol 2017; 119:401-412. [PMID: 29070631 DOI: 10.1152/jn.00499.2017] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Coordination of respiratory pump and valve muscle activity is essential for normal breathing. A hallmark respiratory response to hypercapnia and hypoxia is the emergence of active exhalation, characterized by abdominal muscle pumping during the late one-third of expiration (late-E phase). Late-E abdominal activity during hypercapnia has been attributed to the activation of expiratory neurons located within the parafacial respiratory group (pFRG). However, the mechanisms that control emergence of active exhalation, and its silencing in restful breathing, are not completely understood. We hypothesized that inputs from the Kölliker-Fuse nucleus (KF) control the emergence of late-E activity during hypercapnia. Previously, we reported that reversible inhibition of the KF reduced postinspiratory (post-I) motor output to laryngeal adductor muscles and brought forward the onset of hypercapnia-induced late-E abdominal activity. Here we explored the contribution of the KF for late-E abdominal recruitment during hypercapnia by pharmacologically disinhibiting the KF in in situ decerebrate arterially perfused rat preparations. These data were combined with previous results and incorporated into a computational model of the respiratory central pattern generator. Disinhibition of the KF through local parenchymal microinjections of gabazine (GABAA receptor antagonist) prolonged vagal post-I activity and inhibited late-E abdominal output during hypercapnia. In silico, we reproduced this behavior and predicted a mechanism in which the KF provides excitatory drive to post-I inhibitory neurons, which in turn inhibit late-E neurons of the pFRG. Although the exact mechanism proposed by the model requires testing, our data confirm that the KF modulates the formation of late-E abdominal activity during hypercapnia. NEW & NOTEWORTHY The pons is essential for the formation of the three-phase respiratory pattern, controlling the inspiratory-expiratory phase transition. We provide functional evidence of a novel role for the Kölliker-Fuse nucleus (KF) controlling the emergence of abdominal expiratory bursts during active expiration. A computational model of the respiratory central pattern generator predicts a possible mechanism by which the KF interacts indirectly with the parafacial respiratory group and exerts an inhibitory effect on the expiratory conditional oscillator.
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Affiliation(s)
- William H Barnett
- Department of Mathematics and Statistics, Georgia State University , Atlanta, Georgia
| | - Sarah E M Jenkin
- Department of Zoology, University of British Columbia , Vancouver, British Columbia , Canada
| | - William K Milsom
- Department of Zoology, University of British Columbia , Vancouver, British Columbia , Canada
| | - Julian F R Paton
- School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol , Bristol , United Kingdom.,Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland , Auckland , New Zealand
| | - Ana P Abdala
- School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol , Bristol , United Kingdom
| | - Yaroslav I Molkov
- Department of Mathematics and Statistics, Georgia State University , Atlanta, Georgia.,Neuroscience Institute, Georgia State University , Atlanta, Georgia
| | - Daniel B Zoccal
- Department of Physiology and Pathology, São Paulo State University , Araraquara , Brazil
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7
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Bai Z, Voituron N, Wuren T, Jeton F, Jin G, Marchant D, Richalet JP, Ge RL, Pichon AP. Role of glutamate and serotonin on the hypoxic ventilatory response in high-altitude-adapted plateau Pika. Respir Physiol Neurobiol 2015; 212-214:39-45. [PMID: 25890014 DOI: 10.1016/j.resp.2015.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 03/17/2015] [Accepted: 03/19/2015] [Indexed: 10/23/2022]
Abstract
The highland "plateau Pika" is considered to be adapted to chronic hypoxia. We hypothesized that glutamate N-methyl-D-aspartate (NMDA) and non-NMDA receptors, nitric oxide (NO) synthase, and serotonin are involved in hypoxic ventilatory response (HVR) in Pikas. We tested the effects of NMDA (memantine) and non-NMDA receptors (DNQX) antagonists, NO synthase inhibitor (L-NAME), and selective serotonin reuptake inhibitors (fluoxetine) on ventilation and HVR in Pikas. Ventilatory parameters were measured before and after drug (or vehicle) injections in conscious Pikas at their natural living altitude (PIO2 86 mmHg) and after a hypoxic challenge (PIO2 57 mmHg, 3 min) to assess the influence of peripheral chemoreceptor on HVR. Minute ventilation (VI) and tidal volume (Vt) increased during hypoxic challenge after vehicle injection, whereas the Ti/Ttot ratio remained unchanged. The increase in VI and Vt observed with vehicle at PIO2-57, when compared with PIO2-86, was inhibited after memantine and fluoxetine injection, whereas the DNQX injection increased HVR. At PIO2-57, L-NAME induced an increase in the Ti/Ttot ratio when compared with vehicle. Therefore, the glutamate through NMDA-R/AMPA receptor bindings and serotonin pathway are implicated at the peripheral chemoreceptor level in HVR in Pikas. However, NO influences the ventilatory pattern of Pikas at their habitual living altitude.
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Affiliation(s)
- Zhenzhong Bai
- Research Centre for High Altitude Medicine, Qinghai University Medical College, Xining, Qinghai, PR China
| | - Nicolas Voituron
- Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie & Poumon" EA2363, Bobigny, France; Laboratory of Excellence GR-Ex, PRES Sorbonne Paris Cité, Paris, France
| | - Tana Wuren
- Research Centre for High Altitude Medicine, Qinghai University Medical College, Xining, Qinghai, PR China
| | - Florine Jeton
- Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie & Poumon" EA2363, Bobigny, France; Laboratory of Excellence GR-Ex, PRES Sorbonne Paris Cité, Paris, France
| | - Guoen Jin
- Research Centre for High Altitude Medicine, Qinghai University Medical College, Xining, Qinghai, PR China
| | - Dominique Marchant
- Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie & Poumon" EA2363, Bobigny, France
| | - Jean-Paul Richalet
- Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie & Poumon" EA2363, Bobigny, France; Laboratory of Excellence GR-Ex, PRES Sorbonne Paris Cité, Paris, France
| | - Ri-Li Ge
- Research Centre for High Altitude Medicine, Qinghai University Medical College, Xining, Qinghai, PR China.
| | - Aurélien P Pichon
- Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie & Poumon" EA2363, Bobigny, France; Laboratory of Excellence GR-Ex, PRES Sorbonne Paris Cité, Paris, France.
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8
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Poon CS, Song G. Bidirectional plasticity of pontine pneumotaxic postinspiratory drive: implication for a pontomedullary respiratory central pattern generator. PROGRESS IN BRAIN RESEARCH 2014; 209:235-54. [PMID: 24746051 DOI: 10.1016/b978-0-444-63274-6.00012-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The "pneumotaxic center" in the rostral dorsolateral pons as delineated by Lumsden nine decades ago is known to play an important role in promoting the inspiratory off-switch (IOS) for inspiratory-expiratory phase transition as a fail-safe mechanism for preventing apneusis in the absence of vagal input. Traditionally, the pontine pneumotaxic mechanism has been thought to contribute a tonic descending input that lowers the IOS threshold in medullary respiratory central pattern generator (rCPG) circuits, but otherwise does not constitute part of the rCPG. Recent evidence indicates that descending input from the Kölliker-Fuse nucleus (KFN) within the pneumotaxic center is essential for gating the postinspiratory phase of the three-phase respiratory rhythm to control the IOS in vagotomized animals. A critical question arising is whether such a descending pneumotaxic input from KFN that drives postinspiratory activity is tonic (null hypothesis) or rhythmic with postinspiratory phase modulation (alternative hypothesis). Here, we show that multifarious evidence reported in the literature collectively indicates that the descending pneumotaxic input may exhibit NMDA receptor-dependent short-term plasticity in the form of a biphasic neural differentiator that bidirectionally and phase-selectively modulates postinspiratory phase duration in response to vagal and peripheral chemoreceptor inputs independent of the responses in inspiratory and late-expiratory activities. The phase-selectivity property of the descending pneumotaxic input implicates a population of pontine early-expiratory (postinspiratory/expiratory-decrementing) neurons as the most likely neural correlate of the pneumotaxic mechanism that drives post-I activity, suggesting that the pontine pneumotaxic mechanism may be an integral part of a pontomedullary rCPG that underlies the three-phase respiratory rhythm.
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Affiliation(s)
- Chi-Sang Poon
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Gang Song
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
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9
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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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10
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Molkov YI, Bacak BJ, Dick TE, Rybak IA. Control of breathing by interacting pontine and pulmonary feedback loops. Front Neural Circuits 2013; 7:16. [PMID: 23408512 PMCID: PMC3570896 DOI: 10.3389/fncir.2013.00016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 01/24/2013] [Indexed: 12/20/2022] Open
Abstract
The medullary respiratory network generates respiratory rhythm via sequential phase switching, which in turn is controlled by multiple feedbacks including those from the pons and nucleus tractus solitarii; the latter mediates pulmonary afferent feedback to the medullary circuits. It is hypothesized that both pontine and pulmonary feedback pathways operate via activation of medullary respiratory neurons that are critically involved in phase switching. Moreover, the pontine and pulmonary control loops interact, so that pulmonary afferents control the gain of pontine influence of the respiratory pattern. We used an established computational model of the respiratory network (Smith et al., 2007) and extended it by incorporating pontine circuits and pulmonary feedback. In the extended model, the pontine neurons receive phasic excitatory activation from, and provide feedback to, medullary respiratory neurons responsible for the onset and termination of inspiration. The model was used to study the effects of: (1) "vagotomy" (removal of pulmonary feedback), (2) suppression of pontine activity attenuating pontine feedback, and (3) these perturbations applied together on the respiratory pattern and durations of inspiration (T(I)) and expiration (T(E)). In our model: (a) the simulated vagotomy resulted in increases of both T(I) and T(E), (b) the suppression of pontine-medullary interactions led to the prolongation of T(I) at relatively constant, but variable T(E), and (c) these perturbations applied together resulted in "apneusis," characterized by a significantly prolonged T(I). The results of modeling were compared with, and provided a reasonable explanation for, multiple experimental data. The characteristic changes in T(I) and T(E) demonstrated with the model may represent characteristic changes in the balance between the pontine and pulmonary feedback control mechanisms that may reflect specific cardio-respiratory disorders and diseases.
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Affiliation(s)
- Yaroslav I Molkov
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA ; Department of Mathematical Sciences, Indiana University - Purdue University Indianapolis, IN, USA
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Menuet C, Borghgraef P, Voituron N, Gestreau C, Gielis L, Devijver H, Dutschmann M, Van Leuven F, Hilaire G. Isoflurane anesthesia precipitates tauopathy and upper airways dysfunction in pre-symptomatic Tau.P301L mice: Possible implication for neurodegenerative diseases. Neurobiol Dis 2012; 46:234-43. [DOI: 10.1016/j.nbd.2012.01.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/14/2011] [Accepted: 01/23/2012] [Indexed: 11/26/2022] Open
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12
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Dhingra RR, Jacono FJ, Fishman M, Loparo KA, Rybak IA, Dick TE. Vagal-dependent nonlinear variability in the respiratory pattern of anesthetized, spontaneously breathing rats. J Appl Physiol (1985) 2011; 111:272-84. [PMID: 21527661 DOI: 10.1152/japplphysiol.91196.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Physiological rhythms, including respiration, exhibit endogenous variability associated with health, and deviations from this are associated with disease. Specific changes in the linear and nonlinear sources of breathing variability have not been investigated. In this study, we used information theory-based techniques, combined with surrogate data testing, to quantify and characterize the vagal-dependent nonlinear pattern variability in urethane-anesthetized, spontaneously breathing adult rats. Surrogate data sets preserved the amplitude distribution and linear correlations of the original data set, but nonlinear correlation structure in the data was removed. Differences in mutual information and sample entropy between original and surrogate data sets indicated the presence of deterministic nonlinear or stochastic non-Gaussian variability. With vagi intact (n = 11), the respiratory cycle exhibited significant nonlinear behavior in templates of points separated by time delays ranging from one sample to one cycle length. After vagotomy (n = 6), even though nonlinear variability was reduced significantly, nonlinear properties were still evident at various time delays. Nonlinear deterministic variability did not change further after subsequent bilateral microinjection of MK-801, an N-methyl-D-aspartate receptor antagonist, in the Kölliker-Fuse nuclei. Reversing the sequence (n = 5), blocking N-methyl-D-aspartate receptors bilaterally in the dorsolateral pons significantly decreased nonlinear variability in the respiratory pattern, even with the vagi intact, and subsequent vagotomy did not change nonlinear variability. Thus both vagal and dorsolateral pontine influences contribute to nonlinear respiratory pattern variability. Furthermore, breathing dynamics of the intact system are mutually dependent on vagal and pontine sources of nonlinear complexity. Understanding the structure and modulation of variability provides insight into disease effects on respiratory patterning.
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Affiliation(s)
- R R Dhingra
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA
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Geambasu A, Krukoff TL. Adrenomedullin acts in the lateral parabrachial nucleus to increase arterial blood pressure through mechanisms mediated by glutamate and nitric oxide. Am J Physiol Regul Integr Comp Physiol 2008; 295:R38-44. [PMID: 18495835 DOI: 10.1152/ajpregu.00172.2008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adrenomedullin (ADM) acts in a site-specific manner within autonomic centers of the brain to modulate mean arterial pressure (MAP). To determine the role of ADM in the pontine autonomic center, the lateral parabrachial nucleus (LPBN), we used urethane-anesthetized adult Sprague-Dawley male rats to test the hypothesis that ADM increases MAP at this site through glutamate- and nitric oxide (NO)-dependent mechanisms. ADM microinjected into the LPBN increased MAP in a dose-dependent manner. The pressor effect of ADM (0.01 pmol) had a peak value of 11.9 +/- 1.9 mmHg at 2 min and lasted for 7 min. We demonstrated that ADM's effect is receptor mediated by blocking the effect with the ADM receptor antagonist, ADM22-52. We showed that glutamate mediates ADM's pressor response, as this response was blocked using coinjections of ADM with dizolcipine hydrogen maleate or 6-cyano-7-nitroquinoxaline-2,3-dione, N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptor antagonists, respectively. We tested the roles of NO with coinjections of ADM with either N5-(1-iminoethyl)-L-ornithine or 7-nitroindazole monosodium salt, nonspecific and neuronal NO synthase (NOS) inhibitors, respectively; both inhibitors blocked ADM's pressor effect. Finally, we studied the role of calcium influx in ADM's pressor effect, as intracellular calcium is important in both glutamate and NO neurotransmission. ADM's effect was blocked when nifedipine, an L-type calcium channel blocker, was coinjected with ADM into the LPBN. This study is the first to show that ADM acts in the LPBN to increase MAP through mechanisms dependent on activation of ionotropic glutamate receptors, neuronal and endothelial NOS-mediated NO synthesis, and L-type calcium channel activation.
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Affiliation(s)
- Adrian Geambasu
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Waters KA, Machaalani R. Role of NMDA receptors in development of respiratory control. Respir Physiol Neurobiol 2005; 149:123-30. [PMID: 15908286 DOI: 10.1016/j.resp.2005.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 03/15/2005] [Accepted: 03/15/2005] [Indexed: 10/25/2022]
Abstract
The N-methyl-D-aspartate (NMDA) receptor has many functions throughout the central nervous system (CNS) including its role within the centers controlling respiration. Although NMDA receptors are important for normal breathing, they are specifically active under conditions of stress, such as hypoxia. Consistent with its role in other neurological functions, the NMDA receptor is also important to the prenatal development of normal neurological pathways for the control of ventilation. The importance of NMDA receptors to both normal breathing and stress responses is demonstrated by recent observations of antenatal effects of disturbances to the NMDA receptor which disrupts normal breathing as well as causing reduced ventilatory responses during stress in newborns. These characteristics fit with the known NMDA influences on neuronal development and plasticity. The methods used to evaluate these functions have mainly included pharmacological agents for activation (agonists) or depression (antagonists) of NMDA receptors. NMDA receptor expression has also been measured histologically, and more recently knockout animal models have been used to provide additional functional information.
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Affiliation(s)
- Karen A Waters
- Department of Medicine, Room 206, Blackburn Building, DO6, University of Sydney, NSW 2006, Australia.
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Reid SG, Powell FL. Effects of chronic hypoxia on MK-801-induced changes in the acute hypoxic ventilatory response. J Appl Physiol (1985) 2005; 99:2108-14. [PMID: 16109826 DOI: 10.1152/japplphysiol.01205.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic hypoxia increases the sensitivity of the central nervous system to afferent input from carotid body chemoreceptors. We hypothesized that this process involves N-methyl-D-aspartate (NMDA) receptor-mediated mechanisms and predicted that chronic hypoxia would change the effect of the NMDA receptor blocker dizocilpine (MK-801) on the poikilocapnic hypoxic ventilatory response (HVR). Male Sprague-Dawley rats were studied before and after acclimatization to hypoxia (70 Torr inspiratory Po(2) for 9 days). We measured ventilation (VI) and the HVR before and after systemic MK-801 treatment (3 mg/kg ip). MK-801 resulted in a constant respiratory frequency (approximately 175 min(-1)) during acute exposure to 10% and 30% O(2) before and after acclimatization. MK-801 had no effect on tidal volume (VT) before acclimatization, but it significantly decreased Vt when the animals were breathing 10% O(2) after acclimatization. The net effect of MK-801 was to eliminate the O(2) sensitivity of Vi before (via changes in respiratory frequency) and after (via changes in VT) acclimatization. Hence, chronic hypoxia altered the effect of MK-801 on the acute HVR, primarily because of increased effects on Vt. This indicates that changes in NMDA receptor-mediated neurotransmission may be involved in ventilatory acclimatization to hypoxia. However, further experiments are necessary to determine the precise location of such plasticity in the central nervous system.
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Affiliation(s)
- Stephen G Reid
- Dept. of Medicine, Univerity of Califronia, San Diego, La Jolla, CA, USA.
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Song G, Poon CS. Functional and structural models of pontine modulation of mechanoreceptor and chemoreceptor reflexes. Respir Physiol Neurobiol 2005; 143:281-92. [PMID: 15519561 DOI: 10.1016/j.resp.2004.05.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2004] [Indexed: 11/30/2022]
Abstract
The dorsolateral and ventrolateral pons (dl-pons, vl-pons) are critical brainstem structures mediating the plasticity of the Hering-Breuer mechanoreflex (HBR) and carotid chemoreflex (CCR). Review of anatomical evidence indicates that dl-pons and vl-pons are connected reciprocally with one another and with medullary nucleus tractus solitarius (NTS) and ventral respiratory group (VRG). With this structural map, functional models of HBR and CCR are proposed in which the respiratory rhythm is modulated by short-term depression (STD) or potentiation (STP) of corresponding primary NTS-VRG and auxiliary pons-VRG excitatory or inhibitory pathways. Behaviorally, STD and STP of respiratory reflexes are akin to non-associative learning such as habituation, sensitization or desensitization to afferent inputs. Computationally, the STD and STP effects amount to signal differentiation and integration in the time domain, or high-pass and low-pass filtering in the frequency domain, respectively. These functional and structural models of pontomedullary signal processing provide a novel conceptual framework that unifies a wealth of experimental observations regarding mechanoreceptor and chemoreceptor reflex control of breathing.
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Affiliation(s)
- Gang Song
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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Miyamoto K, Iwase M, Kimura H, Homma I. Central histamine contributes to the inspiratory off-switch mechanism via H1 receptors in mice. Respir Physiol Neurobiol 2004; 144:25-33. [PMID: 15522700 DOI: 10.1016/j.resp.2004.07.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2004] [Indexed: 11/21/2022]
Abstract
Central histaminergic neurons are distributed in areas of the medulla and pons concerned with respiratory rhythm generation, but their effects on breathing pattern are unknown. We examined breathing pattern during hypercapnic responses in wild type (WT) and H1 receptor knockout (H1RKO) mice at 9-10 weeks of age before and after vagotomy. Minute ventilation increased with PaCO(2) increase equally in both genotypes; respiratory rate response was lower and tidal volume (V(T)) response higher in H1RKO mice than in WT mice. The V(T)-inspiratory time (T(I)) relation during hypercapnia was hyperbolic in both groups, with the curve in H1RKO mice shifted right-upward. After vagotomy, the V(T)-T(I) relation was a vertical line, which shifted right in H1RKO mice. We conclude that alterations of inspiratory off-switch and respiratory rhythm generation change breathing pattern without affecting central chemosensitivity in H1RKO. Histamine might affect breathing pattern centrally via H1 receptors.
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Affiliation(s)
- Kenichi Miyamoto
- Department of Physiology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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