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Tacke C, Bischoff AM, Harb A, Vafadari B, Hülsmann S. Fiber optical imaging of astroglial calcium signaling in the respiratory network in the working heart brainstem preparation. Front Physiol 2023; 14:1237376. [PMID: 37693007 PMCID: PMC10484401 DOI: 10.3389/fphys.2023.1237376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 08/10/2023] [Indexed: 09/12/2023] Open
Abstract
The neuronal activity in the respiratory network strongly depends on a variety of different neuromodulators. Given the essential role of astrocytes in stabilizing respiratory network activity generated by neurons in the preBötzinger complex (preBötC), our aim was to investigate astrocytic calcium signaling in the working heart brainstem preparation using fiber-optical imaging. By using transgenic mice that express GCaMP6s specifically in astrocytes, we successfully recorded astrocytic calcium signals in response to norepinephrine from individual astrocytes.
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Affiliation(s)
| | | | | | | | - Swen Hülsmann
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
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2
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Moreira TS, Sobrinho CR, Falquetto B, Oliveira LM, Lima JD, Mulkey DK, Takakura AC. The retrotrapezoid nucleus and the neuromodulation of breathing. J Neurophysiol 2020; 125:699-719. [PMID: 33427575 DOI: 10.1152/jn.00497.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Breathing is regulated by a host of arousal and sleep-wake state-dependent neuromodulators to maintain respiratory homeostasis. Modulators such as acetylcholine, norepinephrine, histamine, serotonin (5-HT), adenosine triphosphate (ATP), substance P, somatostatin, bombesin, orexin, and leptin can serve complementary or off-setting functions depending on the target cell type and signaling mechanisms engaged. Abnormalities in any of these modulatory mechanisms can destabilize breathing, suggesting that modulatory mechanisms are not overly redundant but rather work in concert to maintain stable respiratory output. The present review focuses on the modulation of a specific cluster of neurons located in the ventral medullary surface, named retrotrapezoid nucleus, that are activated by changes in tissue CO2/H+ and regulate several aspects of breathing, including inspiration and active expiration.
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Affiliation(s)
- Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Cleyton R Sobrinho
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Barbara Falquetto
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Luiz M Oliveira
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Janayna D Lima
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
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Ferrari D, Vuerich M, Casciano F, Longhi MS, Melloni E, Secchiero P, Zech A, Robson SC, Müller T, Idzko M. Eosinophils and Purinergic Signaling in Health and Disease. Front Immunol 2020; 11:1339. [PMID: 32733449 PMCID: PMC7360723 DOI: 10.3389/fimmu.2020.01339] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 05/26/2020] [Indexed: 12/17/2022] Open
Abstract
Eosinophils are major effector cells against parasites, fungi, bacteria, and viruses. However, these cells also take part in local and systemic inflammation, which are central to eczema, atopy, rhinitis, asthma, and autoimmune diseases. A role for eosinophils has been also shown in vascular thrombotic disorders and in cancer. Many, if not all, above-mentioned conditions involve the release of intracellular nucleotides (ATP, ADP, UTP, etc.) and nucleosides (adenosine) in the extracellular environment. Simultaneously, eosinophils further release ATP, which in autocrine and paracrine manners, stimulates P2 receptors. Purinergic signaling in eosinophils mediates a variety of responses including CD11b induction, ROI production, release of granule contents and enzymes, as well as cytokines. Exposure to extracellular ATP also modulates the expression of endothelial adhesion molecules, thereby favoring eosinophil extravasation and accumulation. In addition, eosinophils express the immunosuppressive adenosine P1 receptors, which regulate degranulation and migration. However, pro-inflammatory responses induced by extracellular ATP predominate. Due to their important role in innate immunity and tissue damage, pharmacological targeting of nucleotide- and nucleoside-mediated signaling in eosinophils could represent a novel approach to alleviate eosinophilic acute and chronic inflammatory diseases. These innovative approaches might also have salutary effects, particularly in host defense against parasites and in cancer.
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Affiliation(s)
- Davide Ferrari
- Section of Microbiology and Applied Pathology, Department of Life Science and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Marta Vuerich
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Fabio Casciano
- Department of Morphology, Surgery and Experimental Medicine and LTTA Centre, University of Ferrara, Ferrara, Italy
| | - Maria Serena Longhi
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Elisabetta Melloni
- Department of Morphology, Surgery and Experimental Medicine and LTTA Centre, University of Ferrara, Ferrara, Italy
| | - Paola Secchiero
- Department of Morphology, Surgery and Experimental Medicine and LTTA Centre, University of Ferrara, Ferrara, Italy
| | - Andreas Zech
- Department of Pulmonology, Medical University of Vienna, Vienna, Austria
| | - Simon C Robson
- Department of Anesthesia, Critical Care & Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Tobias Müller
- Division of Pneumology, University Hospital RWTH Aachen, Aachen, Germany
| | - Marco Idzko
- Department of Pulmonology, Medical University of Vienna, Vienna, Austria
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Reklow RJ, Alvares TS, Zhang Y, Miranda Tapia AP, Biancardi V, Katzell AK, Frangos SM, Hansen MA, Toohey AW, Cass CE, Young JD, Pagliardini S, Boison D, Funk GD. The Purinome and the preBötzinger Complex - A Ménage of Unexplored Mechanisms That May Modulate/Shape the Hypoxic Ventilatory Response. Front Cell Neurosci 2019; 13:365. [PMID: 31496935 PMCID: PMC6712068 DOI: 10.3389/fncel.2019.00365] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/29/2019] [Indexed: 12/20/2022] Open
Abstract
Exploration of purinergic signaling in brainstem homeostatic control processes is challenging the traditional view that the biphasic hypoxic ventilatory response, which comprises a rapid initial increase in breathing followed by a slower secondary depression, reflects the interaction between peripheral chemoreceptor-mediated excitation and central inhibition. While controversial, accumulating evidence supports that in addition to peripheral excitation, interactions between central excitatory and inhibitory purinergic mechanisms shape this key homeostatic reflex. The objective of this review is to present our working model of how purinergic signaling modulates the glutamatergic inspiratory synapse in the preBötzinger Complex (key site of inspiratory rhythm generation) to shape the hypoxic ventilatory response. It is based on the perspective that has emerged from decades of analysis of glutamatergic synapses in the hippocampus, where the actions of extracellular ATP are determined by a complex signaling system, the purinome. The purinome involves not only the actions of ATP and adenosine at P2 and P1 receptors, respectively, but diverse families of enzymes and transporters that collectively determine the rate of ATP degradation, adenosine accumulation and adenosine clearance. We summarize current knowledge of the roles played by these different purinergic elements in the hypoxic ventilatory response, often drawing on examples from other brain regions, and look ahead to many unanswered questions and remaining challenges.
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Affiliation(s)
- Robert J. Reklow
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Tucaaue S. Alvares
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Yong Zhang
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ana P. Miranda Tapia
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Vivian Biancardi
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Alexis K. Katzell
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Sara M. Frangos
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Megan A. Hansen
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Alexander W. Toohey
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Carol E. Cass
- Professor Emerita, Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - James D. Young
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Silvia Pagliardini
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson Medical School and New Jersey Medical School, Rutgers University, New Brunswick, NJ, United States
| | - Gregory D. Funk
- Department of Physiology, Women and Children’s Health Research Institute, Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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Rajani V, Zhang Y, Jalubula V, Rancic V, SheikhBahaei S, Zwicker JD, Pagliardini S, Dickson CT, Ballanyi K, Kasparov S, Gourine AV, Funk GD. Release of ATP by pre-Bötzinger complex astrocytes contributes to the hypoxic ventilatory response via a Ca 2+ -dependent P2Y 1 receptor mechanism. J Physiol 2018; 596:3245-3269. [PMID: 28678385 PMCID: PMC6068109 DOI: 10.1113/jp274727] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 06/27/2017] [Indexed: 01/03/2023] Open
Abstract
KEY POINTS The ventilatory response to reduced oxygen (hypoxia) is biphasic, comprising an initial increase in ventilation followed by a secondary depression. Our findings indicate that, during hypoxia, astrocytes in the pre-Bötzinger complex (preBötC), a critical site of inspiratory rhythm generation, release a gliotransmitter that acts via P2Y1 receptors to stimulate ventilation and reduce the secondary depression. In vitro analyses reveal that ATP excitation of the preBötC involves P2Y1 receptor-mediated release of Ca2+ from intracellular stores. By identifying a role for gliotransmission and the sites, P2 receptor subtype, and signalling mechanisms via which ATP modulates breathing during hypoxia, these data advance our understanding of the mechanisms underlying the hypoxic ventilatory response and highlight the significance of purinergic signalling and gliotransmission in homeostatic control. Clinically, these findings are relevant to conditions in which hypoxia and respiratory depression are implicated, including apnoea of prematurity, sleep disordered breathing and congestive heart failure. ABSTRACT The hypoxic ventilatory response (HVR) is biphasic, consisting of a phase I increase in ventilation followed by a secondary depression (to a steady-state phase II) that can be life-threatening in premature infants who suffer from frequent apnoeas and respiratory depression. ATP released in the ventrolateral medulla oblongata during hypoxia attenuates the secondary depression. We explored a working hypothesis that vesicular release of ATP by astrocytes in the pre-Bötzinger Complex (preBötC) inspiratory rhythm-generating network acts via P2Y1 receptors to mediate this effect. Blockade of vesicular exocytosis in preBötC astrocytes bilaterally (using an adenoviral vector to specifically express tetanus toxin light chain in astrocytes) reduced the HVR in anaesthetized rats, indicating that exocytotic release of a gliotransmitter within the preBötC contributes to the hypoxia-induced increases in ventilation. Unilateral blockade of P2Y1 receptors in the preBötC via local antagonist injection enhanced the secondary respiratory depression, suggesting that a significant component of the phase II increase in ventilation is mediated by ATP acting at P2Y1 receptors. In vitro responses of the preBötC inspiratory network, preBötC inspiratory neurons and cultured preBötC glia to purinergic agents demonstrated that the P2Y1 receptor-mediated increase in fictive inspiratory frequency involves Ca2+ recruitment from intracellular stores leading to increases in intracellular Ca2+ ([Ca2+ ]i ) in inspiratory neurons and glia. These data suggest that ATP is released by preBötC astrocytes during hypoxia and acts via P2Y1 receptors on inspiratory neurons (and/or glia) to evoke Ca2+ release from intracellular stores and an increase in ventilation that counteracts the hypoxic respiratory depression.
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Affiliation(s)
- Vishaal Rajani
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
- Present address: Neurosciences & Mental Health, Peter Gilgan Centre for Research and Learning (PGCRL)The Hospital for Sick ChildrenTorontoOntarioCanada
| | - Yong Zhang
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Venkatesh Jalubula
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Vladimir Rancic
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Shahriar SheikhBahaei
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke (NINDS)National Institutes of Health (NIH)BethesdaMDUSA
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonUK
| | - Jennifer D. Zwicker
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Silvia Pagliardini
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Clayton T. Dickson
- Department of Psychology, Neuroscience and Mental Health Institute (NMHI)Faculty of ScienceEdmontonAlbertaCanada
| | - Klaus Ballanyi
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
| | - Sergey Kasparov
- Department of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | - Alexander V. Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology & PharmacologyUniversity College LondonLondonUK
| | - Gregory D. Funk
- Department of Physiology, Neuroscience and Mental Health Institute (NMHI), Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
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Inhibition of the hypercapnic ventilatory response by adenosine in the retrotrapezoid nucleus in awake rats. Neuropharmacology 2018; 138:47-56. [PMID: 29857188 DOI: 10.1016/j.neuropharm.2018.05.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 05/14/2018] [Accepted: 05/22/2018] [Indexed: 01/13/2023]
Abstract
The brain regulates breathing in response to changes in tissue CO2/H+ via a process called central chemoreception. Neurons and astrocytes in the retrotrapezoid nucleus (RTN) function as respiratory chemoreceptors. The role of astrocytes in this process appears to involve CO2/H+-dependent release of ATP to enhance activity of chemosensitive RTN neurons. Considering that in most brain regions extracellular ATP is rapidly broken down to adenosine by ectonucleotidase activity and since adenosine is a potent neuromodulator, we wondered whether adenosine signaling contributes to RTN chemoreceptor function. To explore this possibility, we pharmacologically manipulated activity of adenosine receptors in the RTN under control conditions and during inhalation of 7-10% CO2 (hypercapnia). In urethane-anesthetized or unrestrained conscious rats, bilateral injections of adenosine into the RTN blunted the hypercapnia ventilatory response. The inhibitory effect of adenosine on breathing was blunted by prior RTN injection of a broad spectrum adenosine receptor blocker (8-PT) or a selective A1-receptor blocker (DPCPX). Although RTN injections of 8PT, DPCPX or the ectonucleotidase inhibitor ARL67156 did not affected baseline breathing in either anesthetized or awake rats. We did find that RTN application of DPCPX or ARL67156 potentiated the respiratory frequency response to CO2, suggesting a portion of ATP released in the RTN during high CO2/H+ is converted to adenosine and serves to limit chemoreceptor function. These results identify adenosine as a novel purinergic regulator of RTN chemoreceptor function during hypercapnia.
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7
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Niu X, Li S, Zheng S, Xiong H, Lv J, Zhang H, Liu H. Hypoxia-induced brain cell damage in male albino wistar rat. Saudi J Biol Sci 2017; 25:1473-1477. [PMID: 30505197 PMCID: PMC6252012 DOI: 10.1016/j.sjbs.2017.03.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/24/2017] [Accepted: 03/28/2017] [Indexed: 12/26/2022] Open
Abstract
The biochemical markers of rat under low oxygen concentration, including brain water level, lactic acid, necrosis and Na+-K+-ATPase, was detected to analyze the hypoxia-induced brain damage, and to analyze the mechanism of brain injury. Histopathological alteration in brain tissue induced by hypoxia were investigated through hematoxylin and eosin stain (HE). Hypoxia induced factor-1a (HIF-1a) expression level in the brain was carried out using immunohistochemistry. Lactic acid level was positively correlated with the level of hypoxia, while concentration-dependent decrease in total Na+-K+-ATPase activity was noted. Hypoxia induced rathad a significant difference on brain water content compared to controls. The level of necrosis and lactic acid level was increased, and the decrease of Na+-K+-ATPase activity was observed. Histopathological examination of brain confirmed that there was neuronal cell death in hippocampal region. HIF-1a expression increased the hypoxia adaptation capability of the rat through the expressions of genes. Lactic acid, Na+-K+-ATPase and HIF-1a plays an important role in brain injury.
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Affiliation(s)
- Xiaoli Niu
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Siyuan Li
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Simin Zheng
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Hongfei Xiong
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Junlin Lv
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Huijuan Zhang
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Hongtao Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
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8
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Norepinephrine-induced calcium signaling in astrocytes in the respiratory network of the ventrolateral medulla. Respir Physiol Neurobiol 2015; 226:18-23. [PMID: 26514085 DOI: 10.1016/j.resp.2015.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 10/14/2015] [Accepted: 10/15/2015] [Indexed: 11/22/2022]
Abstract
The neuronal activity in the respiratory network of the ventrolateral medulla strongly depends on a variety of different neuromodulators. Since the respiratory activity generated by neurons in the pre-Bötzinger complex (preBötC) is stabilized by astrocytes, we investigated potential effects of the neuromodulator norepinephrine (NE) on the astrocytic calcium signaling in the ventral respiratory group. In acutely isolated brainstem slices from wild type mice (postnatal day 1-10) we performed calcium imaging experiments using Oregon Green 488 BAPTA-1 AM as a calcium indicator dye. Astrocytes in the preBötC, which were identified by their unique intracellular calcium rise after the reduction of the extracellular K(+) concentration, showed calcium rises in response to norepinephrine. These calcium signals persisted after blockade of neuronal activity by tetrodotoxin (TTX) indicating that they were independent of neuronal activity. Furthermore, application of the endoplasmic reticulum calcium pump blocker cyclopiazonic acid (CPA) diminished norepinephrine-induced calcium signals. This results could be confirmed using transgenic mice with astrocyte specific expression of GCaMP3. Thus, norepinephrine might, apart from acting directly on neurons, influence and modulate respiratory network activity via the modulation of astroglial calcium signaling.
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9
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Muere C, Neumueller S, Olesiak S, Miller J, Langer T, Hodges MR, Pan L, Forster HV. Combined unilateral blockade of cholinergic, peptidergic, and serotonergic receptors in the ventral respiratory column does not affect breathing in awake or sleeping goats. J Appl Physiol (1985) 2015; 119:308-20. [PMID: 26023224 DOI: 10.1152/japplphysiol.00145.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 05/23/2015] [Indexed: 12/21/2022] Open
Abstract
Previous work in intact awake and sleeping goats has found that unilateral blockade of excitatory inputs in the ventral respiratory column (VRC) elicits changes in the concentrations of multiple neurochemicals, including serotonin (5-HT), substance P, glycine, and GABA, while increasing or having no effect on breathing. These findings are consistent with the concept of interdependence between neuromodulators, whereby attenuation of one modulator elicits compensatory changes in other modulators to maintain breathing. Because there is a large degree of redundancy and multiplicity of excitatory inputs to the VRC, we herein tested the hypothesis that combined unilateral blockade of muscarinic acetylcholine (mACh), neurokinin-1 (NK1, the receptor for substance P), and 5-HT2A receptors would elicit changes in multiple neurochemicals, but would not change breathing. We unilaterally reverse-dialyzed a cocktail of antagonists targeting these receptors into the VRC of intact adult goats. Breathing was continuously monitored while effluent fluid from dialysis was collected for quantification of neurochemicals. We found that neither double blockade of mACh and NK1 receptors, nor triple blockade of mACh, NK1, and 5-HT2A receptors significantly affected breathing (P ≥ 0.05) in goats that were awake or in non-rapid eye movement (NREM) sleep. However, both double and triple blockade increased the effluent concentration of substance P (P < 0.001) and decreased GABA concentrations. These findings support our hypothesis and, together with past data, suggest that both in wakefulness and NREM sleep, multiple neuromodulator systems collaborate to stabilize breathing when a deficit in one or multiple excitatory neuromodulators exists.
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Affiliation(s)
- Clarissa Muere
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Suzanne Neumueller
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Samantha Olesiak
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Justin Miller
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin; Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Thomas Langer
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Lawrence Pan
- Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin; and
| | - Hubert V Forster
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin; Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
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10
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Muere C, Neumueller S, Olesiak S, Miller J, Hodges MR, Pan L, Forster HV. Blockade of neurokinin-1 receptors in the ventral respiratory column does not affect breathing but alters neurochemical release. J Appl Physiol (1985) 2015; 118:732-41. [PMID: 25635003 DOI: 10.1152/japplphysiol.00884.2014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Substance P (SP) and its receptor, neurokinin-1 (NK1R), have been shown to be excitatory modulators of respiratory frequency and to stabilize breathing regularity. Studies in anesthetized mice suggest that tonic activation of NK1Rs is particularly important when other excitatory inputs to the pre-Bötzinger complex in the ventral respiratory column (VRC) are attenuated. Consistent with these findings, muscarinic receptor blockade in the VRC of intact goats elicits an increase in breathing frequency associated with increases in SP and serotonin concentrations, suggesting an involvement of these substances in neuromodulator compensation. To gain insight on the contribution to breathing of endogenous SP and NK1R activation, and how NK1R modulates the release of other neurochemicals, we individually dialyzed antagonists to NK1R (133, 267, 500 μM Spantide; 3 mM RP67580) throughout the VRC of awake and sleeping goats. We found that NK1R blockade with either Spantide at any dose or RP67580 had no effect on breathing or regularity. Both antagonists significantly (P < 0.001) increased SP, while RP67580 also increased serotonin and glycine and decreased thyrotropin-releasing hormone concentrations in the dialysate. Taken together, these data support the concept of neuromodulator interdependence, and we believe that the loss of excitatory input from NK1Rs was locally compensated by changes in other neurochemicals.
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Affiliation(s)
- Clarissa Muere
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Suzanne Neumueller
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Samantha Olesiak
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Justin Miller
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin; Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Lawrence Pan
- Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin; and
| | - Hubert V Forster
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin; Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
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11
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Funk GD, Rajani V, Alvares TS, Revill AL, Zhang Y, Chu NY, Biancardi V, Linhares-Taxini C, Katzell A, Reklow R. Neuroglia and their roles in central respiratory control; an overview. Comp Biochem Physiol A Mol Integr Physiol 2015; 186:83-95. [PMID: 25634606 DOI: 10.1016/j.cbpa.2015.01.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 01/15/2015] [Accepted: 01/16/2015] [Indexed: 01/12/2023]
Abstract
While once viewed as mere housekeepers, providing structural and metabolic support for neurons, it is now clear that neuroglia do much more. Phylogenetically, they have undergone enormous proliferation and diversification as central nervous systems grew in their complexity. In addition, they: i) are morphologically and functionally diverse; ii) play numerous, vital roles in maintaining CNS homeostasis; iii) are key players in brain development and responses to injury; and, iv) via gliotransmission, are likely participants in information processing. In this review, we discuss the diverse roles of neuroglia in maintaining homeostasis in the CNS, their evolutionary origins, the different types of neuroglia and their functional significance for respiratory control, and finally consider evidence that they contribute to the processing of chemosensory information in the respiratory network and the homeostatic control of blood gases.
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Affiliation(s)
- Gregory D Funk
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
| | - Vishaal Rajani
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Tucaauê S Alvares
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Ann L Revill
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), 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 (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Nathan Y Chu
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Vivian Biancardi
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Animal Morphology and Physiology, Fac. de Ciências Agrárias e Veterinárias/UNESP, Via de Acesso Paulo Donato Castellane km 05, Jaboticabal, SP 14884-900, Brazil
| | - Camila Linhares-Taxini
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Animal Morphology and Physiology, Fac. de Ciências Agrárias e Veterinárias/UNESP, Via de Acesso Paulo Donato Castellane km 05, Jaboticabal, SP 14884-900, Brazil
| | - Alexis Katzell
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Robert Reklow
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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12
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Lavezzi AM, Corna MF, Matturri L. Disruption of the brain-derived neurotrophic factor (BDNF) immunoreactivity in the human Kölliker-Fuse nucleus in victims of unexplained fetal and infant death. Front Hum Neurosci 2014; 8:648. [PMID: 25237300 PMCID: PMC4154391 DOI: 10.3389/fnhum.2014.00648] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 08/04/2014] [Indexed: 12/11/2022] Open
Abstract
Experimental studies have demonstrated that the neurotrophin brain-derived neutrophic factor (BDNF) is required for the appropriate development of the central respiratory network, a neuronal complex in the brainstem of vital importance to sustaining life. The pontine Kölliker-Fuse nucleus (KFN) is a fundamental component of this circuitry with strong implications in the pre- and postnatal breathing control. This study provides detailed account for the cytoarchitecture, the physiology and the BDNF behavior of the human KFN in perinatal age. We applied immunohistochemistry in formalin-fixed and paraffin-embedded brainstem samples (from 45 fetuses and newborns died of both known and unknown causes), to analyze BDNF, gliosis and apoptosis patterns of manifestation. The KFN showed clear signs of developmental immaturity, prevalently associated to BDNF altered expression, in high percentages of sudden intrauterine unexplained death syndrome (SIUDS) and sudden infant death syndrome (SIDS) victims. Our results indicate that BDNF pathway dysfunctions can derange the normal KFN development so preventing the breathing control in the sudden perinatal death. The data presented here are also relevant to a better understanding of how the BDNF expression in the KFN can be involved in several human respiratory pathologies such as the Rett's and the congenital central hypoventilation syndromes.
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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 Biomedical, Surgical and Dental Sciences, University of Milan Milan, Italy
| | - Melissa F Corna
- "Lino Rossi" Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS Department of Biomedical, Surgical and Dental Sciences, University of Milan Milan, Italy
| | - Luigi Matturri
- "Lino Rossi" Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS Department of Biomedical, Surgical and Dental Sciences, University of Milan Milan, Italy
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13
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Alvares TS, Revill AL, Huxtable AG, Lorenz CD, Funk GD. P2Y1 receptor-mediated potentiation of inspiratory motor output in neonatal rat in vitro. J Physiol 2014; 592:3089-111. [PMID: 24879869 DOI: 10.1113/jphysiol.2013.268136] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PreBötzinger complex inspiratory rhythm-generating networks are excited by metabotropic purinergic receptor subtype 1 (P2Y1R) activation. Despite this, and the fact that inspiratory MNs express P2Y1Rs, the role of P2Y1Rs in modulating motor output is not known for any MN pool. We used rhythmically active brainstem-spinal cord and medullary slice preparations from neonatal rats to investigate the effects of P2Y1R signalling on inspiratory output of phrenic and XII MNs that innervate diaphragm and airway muscles, respectively. MRS2365 (P2Y1R agonist, 0.1 mm) potentiated XII inspiratory burst amplitude by 60 ± 9%; 10-fold higher concentrations potentiated C4 burst amplitude by 25 ± 7%. In whole-cell voltage-clamped XII MNs, MRS2365 evoked small inward currents and potentiated spontaneous EPSCs and inspiratory synaptic currents, but these effects were absent in TTX at resting membrane potential. Voltage ramps revealed a persistent inward current (PIC) that was attenuated by: flufenamic acid (FFA), a blocker of the Ca(2+)-dependent non-selective cation current ICAN; high intracellular concentrations of BAPTA, which buffers Ca(2+) increases necessary for activation of ICAN; and 9-phenanthrol, a selective blocker of TRPM4 channels (candidate for ICAN). Real-time PCR analysis of mRNA extracted from XII punches and laser-microdissected XII MNs revealed the transcript for TRPM4. MRS2365 potentiated the PIC and this potentiation was blocked by FFA, which also blocked the MRS2365 potentiation of glutamate currents. These data suggest that XII MNs are more sensitive to P2Y1R modulation than phrenic MNs and that the P2Y1R potentiation of inspiratory output occurs in part via potentiation of TRPM4-mediated ICAN, which amplifies inspiratory inputs.
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Affiliation(s)
- T S Alvares
- Department of Physiology, Centre for Neuroscience, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - A L Revill
- Department of Physiology, Centre for Neuroscience, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - A G Huxtable
- Department of Physiology, Centre for Neuroscience, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - C D Lorenz
- Department of Physiology, Centre for Neuroscience, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - G D Funk
- Department of Physiology, Centre for Neuroscience, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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14
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Abstract
Apnea of prematurity is a significant problem due to immaturity of the central neural control circuitry responsible for integrating afferent input and central rhythm. In this review, we provide an overview of the pathogenesis of apnea of prematurity--including our current understanding of the role that afferent input to the brain stem plays in synergy with the central pattern generation circuitry in the emergence of apnea of prematurity. We then discuss the interplay of apnea, bradycardia, desaturation, as well as the genesis of central, mixed, and obstructive apnea. Finally, we provide a summary of the physiological basis for current therapeutic approaches to treating apnea of prematurity, and conclude with an overview of proposed long-term consequences of the resultant intermittent hypoxic episodes.
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Affiliation(s)
- Richard J Martin
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA.
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15
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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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16
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Caravagna C, Soliz J, Seaborn T. Brain-derived neurotrophic factor interacts with astrocytes and neurons to control respiration. Eur J Neurosci 2013; 38:3261-9. [PMID: 23930598 DOI: 10.1111/ejn.12320] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 06/24/2013] [Indexed: 01/08/2023]
Abstract
Respiratory rhythm is generated and modulated in the brainstem. Neuronal involvement in respiratory control and rhythmogenesis is now clearly established. However, glial cells have also been shown to modulate the activity of brainstem respiratory groups. Although the potential involvement of other glial cell type(s) cannot be excluded, astrocytes are clearly involved in this modulation. In parallel, brain-derived neurotrophic factor (BDNF) also modulates respiratory rhythm. The currently available data on the respective roles of astrocytes and BDNF in respiratory control and rhythmogenesis lead us to hypothesize that there is BDNF-mediated control of the communication between neurons and astrocytes in the maintenance of a proper neuronal network capable of generating a stable respiratory rhythm. According to this hypothesis, progression of Rett syndrome, an autism spectrum disease with disordered breathing, can be stabilized in mouse models by re-expressing the normal gene pattern in astrocytes or microglia, as well as by stimulating the BDNF signaling pathway. These results illustrate how the signaling mechanisms by which glia exerts its effects in brainstem respiratory groups is of great interest for pathologies associated with neurological respiratory disorders.
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Affiliation(s)
- Céline Caravagna
- Department of Pediatrics, Laval University, Centre de Recherche du Centre Hospitalier Universitaire (CHU) de Québec, Hôpital St-François d'Assise, 10 Rue de l'Espinay, Room D0-742, Québec, QC, Canada
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17
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Läer K, Vennemann M, Rothämel T, Klintschar M. Association between polymorphisms in the P2RY1 and SSTR2 genes and sudden infant death syndrome. Int J Legal Med 2013; 127:1087-91. [PMID: 23828624 DOI: 10.1007/s00414-013-0887-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/20/2013] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Sudden infant death syndrome (SIDS) is a multifactorial syndrome and we believe that an inefficient respiratory response to certain homeostatic stressors, such as hypoxia and hypercapnia, is a key factor in the etiology of SIDS. Hence, we genotyped two single nucleotide polymorphisms (SNPs) in genes of importance for respiratory control: P2RY1 (adenosine diphosphate/adenosine triphosphate receptor) and SSTR2 (somatostatin receptor). METHODS Two SNPs, Rs1466113 (C > G dimorphism in SSTR2) and rs701265 (A > G dimorphism in P2RY1), were typed in 175 SIDS cases and 195 controls and 275 SIDS cases and 338 controls, respectively. Genotyping was performed using TaqMan technology. RESULTS The determined genotype frequencies were SSTR2: CC (14.4 %), CG (49.7 %), GG (35.9 %) in controls and CC (17.1 %), CG (49.1 %), and GG (33.8 %) in SIDS; P2RY1: AA (70.6 %), AG (28.7 %), GG (0.7 %) in SIDS and AA (68.3 %), AG (27.9 %), and GG (3.8 %) in the control group. For rs701265 in P2RY1, homozygous G carriers were significantly more frequent in the control group (p = 0.02). CONCLUSION We think that allele G provides a protective effect in events of ventilatory stress. Moreover, the significant lack of P2Y1 G allele homozygotes in the SIDS group shows that respiratory response plays an important role in the etiology of SIDS. Thus, we believe it is worthwhile to further investigate functional polymorphisms within genes that are involved in respiratory control in the future.
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Affiliation(s)
- Katharina Läer
- Institute of Legal Medicine, Hannover Medical School, Carl-Neuberg-Str.1, 30625, Hannover, Germany
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18
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Abbott SBG, DePuy SD, Nguyen T, Coates MB, Stornetta RL, Guyenet PG. Selective optogenetic activation of rostral ventrolateral medullary catecholaminergic neurons produces cardiorespiratory stimulation in conscious mice. J Neurosci 2013; 33:3164-77. [PMID: 23407970 PMCID: PMC3596815 DOI: 10.1523/jneurosci.1046-12.2013] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 12/18/2012] [Accepted: 01/02/2013] [Indexed: 02/07/2023] Open
Abstract
Activation of rostral ventrolateral medullary catecholaminergic (RVLM-CA) neurons e.g., by hypoxia is thought to increase sympathetic outflow thereby raising blood pressure (BP). Here we test whether these neurons also regulate breathing and cardiovascular variables other than BP. Selective expression of ChR2-mCherry by RVLM-CA neurons was achieved by injecting Cre-dependent vector AAV2-EF1α-DIO-ChR2-mCherry unilaterally into the brainstem of dopamine-β-hydroxylase(Cre/0) mice. Photostimulation of RVLM-CA neurons increased breathing in anesthetized and conscious mice. In conscious mice, photostimulation primarily increased breathing frequency and this effect was fully occluded by hypoxia (10% O(2)). In contrast, the effects of photostimulation were largely unaffected by hypercapnia (3 and 6% CO(2)). The associated cardiovascular effects were complex (slight bradycardia and hypotension) and, using selective autonomic blockers, could be explained by coactivation of the sympathetic and cardiovagal outflows. ChR2-positive RVLM-CA neurons expressed VGLUT2 and their projections were mapped. Their complex cardiorespiratory effects are presumably mediated by their extensive projections to supraspinal sites such as the ventrolateral medulla, the dorsal vagal complex, the dorsolateral pons, and selected hypothalamic nuclei (dorsomedial, lateral, and paraventricular nuclei). In sum, selective optogenetic activation of RVLM-CA neurons in conscious mice revealed two important novel functions of these neurons, namely breathing stimulation and cardiovagal outflow control, effects that are attenuated or absent under anesthesia and are presumably mediated by the numerous supraspinal projections of these neurons. The results also suggest that RVLM-CA neurons may underlie some of the acute respiratory response elicited by carotid body stimulation but contribute little to the central respiratory chemoreflex.
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Affiliation(s)
| | - Seth D. DePuy
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Thanh Nguyen
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Melissa B. Coates
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Ruth L. Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Patrice G. Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
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19
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Burnstock G, Brouns I, Adriaensen D, Timmermans JP. Purinergic signaling in the airways. Pharmacol Rev 2012; 64:834-68. [PMID: 22885703 DOI: 10.1124/pr.111.005389] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Evidence for a significant role and impact of purinergic signaling in normal and diseased airways is now beyond dispute. The present review intends to provide the current state of knowledge of the involvement of purinergic pathways in the upper and lower airways and lungs, thereby differentiating the involvement of different tissues, such as the epithelial lining, immune cells, airway smooth muscle, vasculature, peripheral and central innervation, and neuroendocrine system. In addition to the vast number of well illustrated functions for purinergic signaling in the healthy respiratory tract, increasing data pointing to enhanced levels of ATP and/or adenosine in airway secretions of patients with airway damage and respiratory diseases corroborates the emerging view that purines act as clinically important mediators resulting in either proinflammatory or protective responses. Purinergic signaling has been implicated in lung injury and in the pathogenesis of a wide range of respiratory disorders and diseases, including asthma, chronic obstructive pulmonary disease, inflammation, cystic fibrosis, lung cancer, and pulmonary hypertension. These ostensibly enigmatic actions are based on widely different mechanisms, which are influenced by the cellular microenvironment, but especially the subtypes of purine receptors involved and the activity of distinct members of the ectonucleotidase family, the latter being potential protein targets for therapeutic implementation.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Royal Free Campus, London, UK.
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20
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Ohtomo K, Shatos MA, Vrouvlianis J, Li D, Hodges RR, Dartt DA. Increase of intracellular Ca2+ by purinergic receptors in cultured rat lacrimal gland myoepithelial cells. Invest Ophthalmol Vis Sci 2011; 52:9503-15. [PMID: 22039237 DOI: 10.1167/iovs.11-7809] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
PURPOSE To isolate and characterize cultured myoepithelial cells (MECs) from rat lacrimal gland and determine which purinergic receptor subtypes are present and functional in MECs. METHODS Rat lacrimal glands were subjected to collagenase digestion, and MECs were grown. RT-PCR was performed for the purinergic receptors P2X(7), P2Y(1), P2Y(11), and P2Y(13) on RNA isolated from the MECs. Immunofluorescence experiments were performed with antibodies against MEC markers and P2X(7), P2Y(1), P2Y(11), and P2Y(13) purinergic receptors. Proteins from MECs were separated using Western blot analysis techniques. In addition, cells were incubated with Fura 2 tetra acetoxymethyl ester, and intracellular [Ca(2+)] ([Ca(2+)](i)) was determined in response to P2 purinergic agonists. RESULTS MECs expressed the MEC proteins α-smooth muscle actin, vimentin, α-actinin, and adenylyl cyclase II. RT-PCR, Western blot, and immunofluorescence techniques demonstrated the presence of the purinergic receptors P2X(7), P2Y(1), P2Y(11), and P2Y(13). The purinergic agonists ATP, benzoylbenzoyl ATP (BzATP), α,β methylene ATP, UTP, 2-methylthioATP (MeSATP), and ATPγS increased [Ca(2+)](i). As BzATP binds to the P2X(7) receptor, specific characteristics of this receptor were investigated. Neither inhibitors of P2X(7) receptors nor removal of extracellular Mg(2+) or Ca(2+) had an effect on the BzATP-stimulated increase in [Ca(2+)](i). Repeated applications of BzATP desensitized this response. Inhibitors for P2Y(1), P2Y(11), and P2Y(13) each decreased the BzATP-stimulated increase in [Ca(2+)](i) with the P2Y(1) inhibitor most effective. CONCLUSIONS MECs can be isolated from rat lacrimal glands, and they express P2X(7), P2Y(1), P2Y(11), and P2Y(13) purinergic receptors. Surprisingly, BzATP binds the P2Y(1) receptor, which is primarily responsible for the BzATP-stimulated increase in [Ca(2+)](i).
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Affiliation(s)
- Kaori Ohtomo
- Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
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21
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Zwicker JD, Rajani V, Hahn LB, Funk GD. Purinergic modulation of preBötzinger complex inspiratory rhythm in rodents: the interaction between ATP and adenosine. J Physiol 2011; 589:4583-600. [PMID: 21788352 DOI: 10.1113/jphysiol.2011.210930] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
ATP signalling in the CNS is mediated by a three-part system comprising the actions of ATP (and ADP) at P2 receptors (P2Rs), adenosine (ADO) at P1 receptors (P1Rs), and ectonucleotidases that degrade ATP into ADO. ATP excites preBötzinger complex (preBötC) inspiratory rhythm-generating networks where its release attenuates the hypoxic depression of breathing. Its metabolite, ADO, inhibits breathing through unknown mechanisms that may involve the preBötC. Our objective is to understand the dynamics of this signalling system and its influence on preBötC networks. We show that the preBötC of mouse and rat is sensitive to P2Y(1) purinoceptor (P2Y(1)R) activation, responding with a >2-fold increase in frequency. Remarkably, the mouse preBötC is insensitive to ATP. Only after block of A(1) ADORs is the ATP-evoked, P2Y(1)R-mediated frequency increase observed. This demonstrates that ATP is rapidly degraded to ADO, which activates inhibitory A(1)Rs, counteracting the P2Y(1)R-mediated excitation. ADO sensitivity of mouse preBötC was confirmed by a frequency decrease that was absent in rat. Differential ectonucleotidase activities are likely to contribute to the negligible ATP sensitivity of mouse preBötC. Real-time PCR analysis of ectonucleotidase isoforms in preBötC punches revealed TNAP (degrades ATP to ADO) or ENTPDase2 (favours production of excitatory ADP) as the primary constituent in mouse and rat, respectively. These data further establish the sensitivity of this vital network to P2Y(1)R-mediated excitation, emphasizing that individual components of the three-part signalling system dramatically alter network responses to ATP. Data also suggest therapeutic potential may derive from methods that alter the ATP-ADO balance to favour the excitatory actions of ATP.
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Affiliation(s)
- J D Zwicker
- Departments of Physiology and Pediatrics, Centre for Neuroscience, Women and Children’s Health Research Institute (WCHRI), Faculty of Medicineand Dentistry, University of Alberta, Edmonton, Alberta, Canada, T6G 2H7
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22
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Abstract
Long regarded as mere structural support for neurons, neuroglial cells are now considered pivotal for brain metabolism, the blood-brain barrier, cerebral hemodynamics, and neuronal function. Multitasking by glia involves numerous signaling and effector pathways that control various processes, including neurotransmitter uptake and release of gliotransmitters, such as glutamate or adenosine 5'-triphosphate (ATP). Acidosis of cerebrospinal fluid causes ATP release from astrocytic glia at the ventral brainstem surface, which excites neighboring brainstem neurons that stimulate neurons in the pre-Bötzinger complex (preBötC), which controls inspiratory breathing movements. New insights into glial regulation of complex behavior, and particularly into respiratory circuit function, are evolving from application of genetically engineered optical stimulation and Ca(2+) imaging tools, combined with other molecular and electrophysiological approaches. These advances in technology will enable direct analyses of respiratory-related neuron-glia interactions not only at the ventral brainstem surface but also within the preBötC, which generates a vital brain rhythm.
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Affiliation(s)
- Klaus Ballanyi
- Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
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23
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Abstract
Glia modulate neuronal activity by releasing transmitters in a process called gliotransmission. The role of this process in controlling the activity of neuronal networks underlying motor behavior is unknown. ATP features prominently in gliotransmission; it also contributes to the homeostatic ventilatory response evoked by low oxygen through mechanisms that likely include excitation of preBötzinger complex (preBötC) neural networks, brainstem centers critical for breathing. We therefore inhibited glial function in rhythmically active inspiratory networks in vitro to determine whether glia contribute to preBötC ATP sensitivity. Glial toxins markedly reduced preBötC responses to ATP, but not other modulators. Furthermore, since preBötC glia responded to ATP with increased intracellular Ca(2+) and glutamate release, we conclude that glia contribute to the ATP sensitivity of preBötC networks, and possibly the hypoxic ventilatory response. Data reveal a role for glia in signal processing within brainstem motor networks that may be relevant to similar networks throughout the neuraxis.
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TASK channels contribute to the K+-dominated leak current regulating respiratory rhythm generation in vitro. J Neurosci 2010; 30:4273-84. [PMID: 20335463 DOI: 10.1523/jneurosci.4017-09.2010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Leak channels regulate neuronal activity and excitability. Determining which leak channels exist in neurons and how they control electrophysiological behavior is fundamental. Here we investigated TASK channels, members of the two-pore domain K(+) channel family, as a component of the K(+)-dominated leak conductance that controls and modulates rhythm generation at cellular and network levels in the mammalian pre-Bötzinger complex (pre-BötC), an excitatory network of neurons in the medulla critically involved in respiratory rhythmogenesis. By voltage-clamp analyses of pre-BötC neuronal current-voltage (I-V) relations in neonatal rat medullary slices in vitro, we demonstrated that pre-BötC inspiratory neurons have a weakly outward-rectifying total leak conductance with reversal potential that was depolarized by approximately 4 mV from the K(+) equilibrium potential, indicating that background K(+) channels are dominant contributors to leak. This K(+) channel component had I-V relations described by constant field theory, and the conductance was reduced by acid and was augmented by the volatile anesthetic halothane, which are all hallmarks of TASK. We established by single-cell RT-PCR that pre-BötC inspiratory neurons express TASK-1 and in some cases also TASK-3 mRNA. Furthermore, acid depolarized and augmented bursting frequency of pre-BötC inspiratory neurons with intrinsic bursting properties. Microinfusion of acidified solutions into the rhythmically active pre-BötC network increased network bursting frequency, halothane decreased bursting frequency, and acid reversed the depressant effects of halothane, consistent with modulation of network activity by TASK channels. We conclude that TASK-like channels play a major functional role in chemosensory modulation of respiratory rhythm generation in the pre-Bötzinger complex in vitro.
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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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Purinergic signalling in autonomic control. Trends Neurosci 2009; 32:241-8. [PMID: 19359051 DOI: 10.1016/j.tins.2009.03.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 03/16/2009] [Accepted: 03/17/2009] [Indexed: 02/07/2023]
Abstract
Intercellular purinergic signalling, which utilizes ATP as a transmitter, is fundamental for the operation of the autonomic nervous system. ATP is released together with 'classical' transmitters from sympathetic and parasympathetic nerves supplying various peripheral targets, modulates neurotransmission in autonomic ganglia, has an important role in local enteric neural control and coordination of intestinal secretion and motility, and acts as a common mediator for several distinct sensory modalities. Recently, the role of ATP-mediated signalling in the central nervous control of autonomic function has been addressed. Emerging data demonstrate that in the brain ATP is involved in the operation of several key cardiorespiratory reflexes, contributes to central processing of viscerosensory information, mediates central CO(2) chemosensory transduction and triggers adaptive changes in breathing, and modulates the activities of the brainstem vagal preganglionic, presympathetic and respiratory neural networks.
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Hu DY, Li Q, Li B, Dai RJ, Geng LN, Deng YL. Normobaric hypoxia-induced brain damage in wistar rat. ACTA ACUST UNITED AC 2009. [DOI: 10.4236/jbise.2009.28092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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McCrimmon DR, Mitchell GS, Alheid GF. Overview: the neurochemistry of respiratory control. Respir Physiol Neurobiol 2008; 164:1-2. [PMID: 18721910 PMCID: PMC2642897 DOI: 10.1016/j.resp.2008.07.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Accepted: 07/23/2008] [Indexed: 01/25/2023]
Abstract
This special issue of Respiratory Physiology and Neurobiology surveys a broad range of topics focused on the neurochemical control of breathing. A variety of approaches have integrated the neurochemistry of breathing with the physiology of individual neurons, with the neuroanatomy of brainstem and forebrain respiratory circuits, and with the clinical pathology of respiratory disorders all of which has been fueled by the ongoing explosion of information in the molecular biology of the nervous system. Accordingly, substantial progress has identified neurotransmitters, neuromodulators, receptors, signaling cascades, trophic factors, hormones, and genes mediating normal and pathological breathing. Dynamic changes in the neurochemistry of breathing are addressed with respect to brainstem development, environmental challenges such as intermittent or chronic hypoxia, and as a function of the sleep-wake cycle. Respiratory disruption has also been identified in an increasing variety of genetic-based disorders and remarkable progress has been made in determining the affected genes and their mutations that negatively impact respiration.
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Affiliation(s)
- Donald R. McCrimmon
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA 60611−3088
| | - Gordon S. Mitchell
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA, 53706
| | - George F. Alheid
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA 60611−3088
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