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Momose-Sato Y, Sato K. Large-scale synchronized activity in the embryonic brainstem and spinal cord. Front Cell Neurosci 2013; 7:36. [PMID: 23596392 PMCID: PMC3625830 DOI: 10.3389/fncel.2013.00036] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 03/20/2013] [Indexed: 01/09/2023] Open
Abstract
In the developing central nervous system, spontaneous activity appears well before the brain responds to external sensory inputs. One of the earliest activities is observed in the hindbrain and spinal cord, which is detected as rhythmic electrical discharges of cranial and spinal motoneurons or oscillations of Ca(2+)- and voltage-related optical signals. Shortly after the initial expression, the spontaneous activity appearing in the hindbrain and spinal cord exhibits a large-scale correlated wave that propagates over a wide region of the central nervous system, maximally extending to the lumbosacral cord and to the forebrain. In this review, we describe several aspects of this synchronized activity by focusing on the basic properties, development, origin, propagation pattern, pharmacological characteristics, and possible mechanisms underlying the generation of the activity. These profiles differ from those of the respiratory and locomotion pattern generators observed in the mature brainstem and spinal cord, suggesting that the wave is primordial activity that appears during a specific period of embryonic development and plays some important roles in the development of the central nervous system.
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Affiliation(s)
- Yoko Momose-Sato
- Department of Health and Nutrition, College of Human Environmental Studies, Kanto Gakuin UniversityYokohama, Japan
| | - Katsushige Sato
- Department of Health and Nutrition Sciences, Faculty of Human Health, Komazawa Women's UniversityTokyo, Japan
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Champagnat J, Morin-Surun MP, Fortin G, Thoby-Brisson M. Developmental basis of the rostro-caudal organization of the brainstem respiratory rhythm generator. Philos Trans R Soc Lond B Biol Sci 2009; 364:2469-76. [PMID: 19651648 DOI: 10.1098/rstb.2009.0090] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Hox genetic network plays a key role in the anteroposterior patterning of the rhombencephalon at pre- and early-segmental stages of development of the neural tube. In the mouse, it controls development of the entire brainstem respiratory neuronal network, including the pons, the parafacial respiratory group (pFRG) and the pre-Bötzinger complex (preBötC). Inactivation of Krox20/Egr2 eliminates the pFRG activity, thereby causing life-threatening neonatal apnoeas alternating with respiration at low frequency. Another respiratory abnormality, the complete absence of breathing, is induced when neuronal synchronization fails to develop in the preBötC. The present paper summarizes data on a third type of respiratory deficits induced by altering Hox function at pontine levels. Inactivation of Hoxa2, the most rostrally expressed Hox gene in the hindbrain, disturbs embryonic development of the pons and alters neonatal inspiratory shaping without affecting respiratory frequency and apnoeas. The same result is obtained by the Phox2a(+/-) mutation modifying the number of petrosal chemoafferent neurons, by eliminating acetylcholinesterase and by altering Hox-dependent development of the pons with retinoic acid administration at embryonic day 7.5. In addition, embryos treated with retinoic acid provide a mouse model for hyperpnoeic episodic breathing, widely reported in pre-term neonates, young girls with Rett's syndrome, patients with Joubert syndrome and adults with Cheyne-Stokes respiration. We conclude that specific respiratory deficits in vivo are assignable to anteroposterior segments of the brainstem, suggesting that the adult respiratory neuronal network is functionally organized according to the rhombomeric, Hox-dependent segmentation of the brainstem in embryos.
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Affiliation(s)
- J Champagnat
- Centre de Recherche de Gif, UPR 2216 (Neurobiologie Génétique et Intégrative), IFR 2118 (Institut de Neurobiologie Alfred Fessard), CNRS, 91198 Gif-sur-Yvette, France.
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Thoby-Brisson M, Karlén M, Wu N, Charnay P, Champagnat J, Fortin G. Genetic identification of an embryonic parafacial oscillator coupling to the preBötzinger complex. Nat Neurosci 2009; 12:1028-35. [PMID: 19578380 DOI: 10.1038/nn.2354] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 05/29/2009] [Indexed: 11/08/2022]
Abstract
The hindbrain transcription factors Phox2b and Egr2 (also known as Krox20) are linked to the development of the autonomic nervous system and rhombomere-related regulation of breathing, respectively. Mutations in these proteins can lead to abnormal breathing behavior as a result of an alteration in an unidentified neuronal system. We characterized a bilateral embryonic parafacial (e-pF) population of rhythmically bursting neurons at embryonic day (E) 14.5 in mice. These cells expressed Phox2b, were derived from Egr2-expressing precursors and their development was dependent on the integrity of the Egr2 gene. Silencing or eliminating the e-pF oscillator, but not the putative inspiratory oscillator (preBötzinger complex, preBötC), led to an abnormally slow rhythm, demonstrating that the e-pF controls the respiratory rhythm. The e-pF oscillator, the only one active at E14.5, entrained and then coupled with the preBötC, which emerged independently at E15.5. These data establish the dual organization of the respiratory rhythm generator at the time of its inception, when it begins to drive fetal breathing.
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Affiliation(s)
- Muriel Thoby-Brisson
- Institut de Neurobiologie Alfred Fessard, Centre National de la Recherche Scientifique UPR2216, Gif sur Yvette, France
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Kubin L, Volgin DV. Developmental profiles of neurotransmitter receptors in respiratory motor nuclei. Respir Physiol Neurobiol 2009; 164:64-71. [PMID: 18514591 DOI: 10.1016/j.resp.2008.04.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 04/18/2008] [Accepted: 04/18/2008] [Indexed: 10/22/2022]
Abstract
We discuss the time course of postnatal development of selected neurotransmitter receptors in motoneurons that innervate respiratory pump and accessory respiratory muscles, with emphasis on other than classic respiratory signals as important regulatory factors. Functions of those brainstem motoneurons that innervate the pharynx and larynx change more dramatically during early postnatal development than those of spinal respiratory motoneurons. Possibly in relation to this difference, the time course of postnatal expression of distinct receptors for serotonin differ between the hypoglossal (XII) and phrenic motoneurons. In rats, distinct developmental patterns include a decline or increase that extends over the first 3-4 postnatal weeks, a rapid increase during the first 2 weeks, or a transient decline on postnatal days 11-14. The latter period coincides with major changes in many transmitters in brainstem respiratory regions that may be related to a brain-wide reconfiguration of sensorymotor processing resulting from eye and ear opening and beginning of a switch from suckling to mature forms of food seeking and processing. Such rapid neurochemical changes may impart increased vulnerability on the respiratory system. We also consider rapid eye movement sleep as a state during which some brain functions may revert to conditions typical of perinatal period. In addition to normal developmental processes, changes in the expression or function of neurotransmitter receptors may occur in respiratory motoneurons in response to injury, perinatal stress, or disease conditions that increase the load on respiratory muscles or alter the normal levels and patterns of oxygen delivery.
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Affiliation(s)
- Leszek Kubin
- Department of Animal Biology, School of Veterinary Medicine and Center for Sleep and Respiratory Neurobiology, University of Pennsylvania, Philadelphia, PA 19104-6046, USA.
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Chatonnet F, Wrobel LJ, Mézières V, Pasqualetti M, Ducret S, Taillebourg E, Charnay P, Rijli FM, Champagnat J. Distinct roles of Hoxa2 and Krox20 in the development of rhythmic neural networks controlling inspiratory depth, respiratory frequency, and jaw opening. Neural Dev 2007; 2:19. [PMID: 17897445 PMCID: PMC2098766 DOI: 10.1186/1749-8104-2-19] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 09/26/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Little is known about the involvement of molecular determinants of segmental patterning of rhombomeres (r) in the development of rhythmic neural networks in the mouse hindbrain. Here, we compare the phenotypes of mice carrying targeted inactivations of Hoxa2, the only Hox gene expressed up to r2, and of Krox20, expressed in r3 and r5. We investigated the impact of such mutations on the neural circuits controlling jaw opening and breathing in newborn mice, compatible with Hoxa2-dependent trigeminal defects and direct regulation of Hoxa2 by Krox20 in r3. RESULTS We found that Hoxa2 mutants displayed an impaired oro-buccal reflex, similarly to Krox20 mutants. In contrast, while Krox20 is required for the development of the rhythm-promoting parafacial respiratory group (pFRG) modulating respiratory frequency, Hoxa2 inactivation did not affect neonatal breathing frequency. Instead, we found that Hoxa2-/- but not Krox20-/- mutation leads to the elimination of a transient control of the inspiratory amplitude normally occurring during the first hours following birth. Tracing of r2-specific progenies of Hoxa2 expressing cells indicated that the control of inspiratory activity resides in rostral pontine areas and required an intact r2-derived territory. CONCLUSION Thus, inspiratory shaping and respiratory frequency are under the control of distinct Hox-dependent segmental cues in the mammalian brain. Moreover, these data point to the importance of rhombomere-specific genetic control in the development of modular neural networks in the mammalian hindbrain.
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Affiliation(s)
- Fabrice Chatonnet
- NGI, UPR 2216, Institut de Neurobiologie Alfred Fessard IFR2218, Centre National de la Recherche Scientifique, F-91198 Gif sur Yvette Cedex, France
- IGFL UMR 5242 CNRS/INRA/UCB/École Normale Supérieure de Lyon, allée d'Italie, 69364 Lyon Cedex 07, France
| | - Ludovic J Wrobel
- NGI, UPR 2216, Institut de Neurobiologie Alfred Fessard IFR2218, Centre National de la Recherche Scientifique, F-91198 Gif sur Yvette Cedex, France
| | - Valérie Mézières
- NGI, UPR 2216, Institut de Neurobiologie Alfred Fessard IFR2218, Centre National de la Recherche Scientifique, F-91198 Gif sur Yvette Cedex, France
| | - Massimo Pasqualetti
- IGBMC, UMR 7104, CNRS/INSERM/ULP/Collège de France, CU de Strasbourg, F-67404 Illkirch Cedex, France
- Laboratori di Biologia Cellulare e dello Sviluppo, Università di Pisa, Via G Carducci, Pisa, Italy
| | - Sébastien Ducret
- IGBMC, UMR 7104, CNRS/INSERM/ULP/Collège de France, CU de Strasbourg, F-67404 Illkirch Cedex, France
| | - Emmanuel Taillebourg
- INSERM, U 784, Ecole Normale Supérieure, rue d'Ulm, 75230 Paris Cedex 05, France
- CEA, Laboratoire de Biochimie et Biophysique des Systèmes Intégrés, 38054 Grenoble, France
| | - Patrick Charnay
- INSERM, U 784, Ecole Normale Supérieure, rue d'Ulm, 75230 Paris Cedex 05, France
| | - Filippo M Rijli
- IGBMC, UMR 7104, CNRS/INSERM/ULP/Collège de France, CU de Strasbourg, F-67404 Illkirch Cedex, France
| | - Jean Champagnat
- NGI, UPR 2216, Institut de Neurobiologie Alfred Fessard IFR2218, Centre National de la Recherche Scientifique, F-91198 Gif sur Yvette Cedex, France
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Guimarães L, Domínguez-del-Toro E, Chatonnet F, Wrobel L, Pujades C, Monteiro LS, Champagnat J. Exposure to retinoic acid at the onset of hindbrain segmentation induces episodic breathing in mice. Eur J Neurosci 2007; 25:3526-36. [PMID: 17610572 DOI: 10.1111/j.1460-9568.2007.05609.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hyperpnoeic episodic breathing (HEB), a cyclic waxing and waning of breathing, has been widely reported in pre-term neonates, patients with Joubert syndrome and adults (Cheyne-Stokes respiration) with congestive heart failure and brainstem infarction. We now provide a developmental mouse model of neonatal HEB. We used retinoic acid (RA) (0.5-10 mg/kg of maternal weight) to alter embryonic development of the respiratory neuronal network at the onset of hindbrain segmentation (7.5 days post-coitum). HEB was observed in vivo after RA treatment during post-natal days 1-7 but not in control animals. HEB persisted after reduction of the chemoafferent input by hypocapnic hyperoxia (100% O(2)). A large increase and decrease of the rhythm resembling an HEB episode was induced in vitro by stimulating the parafacial respiratory oscillator in treated but not in control neonates. Post-natal localization of the superior cerebellar peduncle and adjacent dorsal tegmentum was found to be abnormal in the pons of RA-treated juvenile mice. Thus, early developmental specifications in the rostral hindbrain are required for the development of neurones that stabilize the function of the respiratory rhythm generator, thereby preventing HEB during post-natal maturation.
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Affiliation(s)
- Laura Guimarães
- Neurobiologie Génétique et Intégrative, UPR 2216, CNRS, Gif-sur-Yvette, France
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Borday C, Vias C, Autran S, Thoby-Brisson M, Champagnat J, Fortin G. The pre-Bötzinger oscillator in the mouse embryo. ACTA ACUST UNITED AC 2007; 100:284-9. [PMID: 17628453 DOI: 10.1016/j.jphysparis.2007.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Studies of the sites and mechanisms involved in mammalian respiratory rhythm generation point to two clusters of rhythmic neurons forming a coupled oscillator network within the brainstem. The location of these oscillators, the pre-Bötzinger complex (preBötC) at vagal level, and the para-facial respiratory group at facial level, probably result from regional patterning schemes specifying neural types in the hindbrain during embryogenesis. Here, we report evidence that the preBötC oscillator (i) is first active at embryonic stages, (ii) originates in the post-otic hindbrain neural tube and (iii) requires the glutamate vesicular transporter 2 for rhythm generation.
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Affiliation(s)
- C Borday
- Neurobiologie Génétique et Intégrative, Institut de Neurobiologie Alfred Fessard, CNRS, 1 av. de la terrasse, 91198 Gif sur Yvette, France
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