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Article Dans Une Revue European Journal of Neuroscience Année : 2003

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

Résumé

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.
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Dates et versions

hal-00285953 , version 1 (06-06-2008)

Identifiants

  • HAL Id : hal-00285953 , version 1
  • PUBMED : 12670311

Citer

Jean-Charles Viemari, Henri Burnet, Michelle Bévengut, Gérard Hilaire. Perinatal maturation of the mouse respiratory rhythm-generator: in vivo and in vitro studies.. European Journal of Neuroscience, 2003, 17 (6), pp.1233-44. ⟨hal-00285953⟩

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