Perinatal maturation of the mouse respiratory rhythm-generator: in vivo and in vitro studies

Autor: Viemari, Jean-Charles, Burnet, Henri, Bévengut, Michelle, Hilaire, Gérard
Přispěvatelé: Groupe d'étude des réseaux moteurs - GERM (GERMG), Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique (CNRS), Centre de recherche en neurobiologie - neurophysiologie de Marseille (CRN2M), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Dumonceaud, Corinne
Jazyk: angličtina
Rok vydání: 2003
Předmět:
Zdroj: European Journal of Neuroscience
European Journal of Neuroscience, 2003, 17 (6), pp.1233-44
European Journal of Neuroscience, Wiley, 2003, 17 (6), pp.1233-44
ISSN: 0953-816X
1460-9568
Popis: In vivo (plethysmography) and in vitro (en bloc preparations) experiments were performed from embryonic day 16 (E16) to postnatal day 9 (P9) in order to analyse the perinatal maturation of the respiratory rhythm-generator in mice. At E16, delivered foetuses did not ventilate and survive but at E18 they breathed at about 110 cycles/min with respiratory cycles of variable individual duration. From E18 to P0-P2, the respiratory cycles stabilised without changes in the breathing parameters. However, these increased several-fold during the next days. Hypoxia increased breathing frequency from E18-P5 and only significantly affected ventilation from P3 onwards. At E16, in vitro medullary preparations (pons resection) produced rhythmic phrenic bursts at a low frequency (about 5 cycles/min) with variable cycle duration. At E18, their frequency doubled but cycle duration remained variable. After birth, the frequency did not change although cycle duration stabilised. At E18 and P0-P2, the in vitro frequency decreased by around 50% under hypoxia, increased by 40-50% under noradrenaline or substance P and was permanently depressed by the pontine A5 areas. At E16 however, hypoxia had no effects, both noradrenaline and substance P drastically increased the frequency and area A5 inhibition was not expressed at this time. At E18 and P0-P2, electrical stimulation and electrolytic lesion of the rostral ventrolateral medulla affected the in vitro rhythm but failed to induce convincing effects at E16. Thus, a major maturational step in respiratory rhythmogenesis occurs between E16-E18, in agreement with the concept of multiple rhythmogenic mechanisms.
Databáze: OpenAIRE
Externí odkaz: