Elsevier

Developmental Brain Research

Volume 91, Issue 1, 22 January 1996, Pages 121-130
Developmental Brain Research

Research report
Perinatal developmental changes in respiratory activity of medullary and spinal neurons: an in vitro study on fetal and newborn rats

https://doi.org/10.1016/0165-3806(95)00170-0Get rights and content

Abstract

Experiments were performed in vitro on fetal and newborn rat brainstem-spinal cord preparations to analyse the perinatal developmental changes in inspiratory motor output. The amplitude of the inspiratory bursts of the whole C4 ventral root (global extracellular recording), the firing patterns of 80 medullary inspiratory neurons (unitary extracellular recording) and the firing and membrane properties of 71 respiratory neurons in the C4 ventral horn (whole-cell recording) were analysed at embryonic day 18 (E18), 21 (E21) and post natal days 0 to 3 (P0–3). At E18, the amplitude of the C4 bursts was weak and variable from one respiratory cycle to the next, as well as the discharge pattern of most of the medullary inspiratory neurons. C4 motoneurons were immature, very excitable and displaying variable inspiratory discharges, but already able to deliver sustained bursts of potentials when depolarised. At E21 and P0–3, the amplitude of the C4 bursts was increased and stable, most of the medullary inspiratory neurons already were able to generate a stable firing pattern and C4 motoneurons showed maturational changes in terms of the resting potential, spike amplitude and input membrane resistance. This work suggests that the short period extending from E18 to E21 is a critical maturational period for the medullary respiratory network which becomes able to elaborate a stable respiratory motor output.

References (35)

  • H. Rigatto

    Maturation of breathing

    Clin. Perinatol.

    (1992)
  • J.C. Smith et al.

    Intracellular recording from phrenic motoneurons receiving respiratory drive in vitro

    Neurosci. Lett.

    (1988)
  • F. Viana et al.

    Postnatal changes in rat hypoglossal motoneuron membrane properties

    Neuroscience

    (1994)
  • L. Ziskind-Conhaim

    Electrical properties of motoneurons in the spinal cord of rat embryos

    Dev. Biol.

    (1988)
  • A.L. Bianchi

    Localisation et etude des neurones respiratoires bulbaires. Mise en jeu antidromique par stimulation spinale ou vagale

    J. Physiol. (Paris)

    (1971)
  • W.E. Cameron et al.

    Electrophysiological properties of developing phrenic motoneurons in the cat

    J. Neurophysiol.

    (1991)
  • C.L. Cleland et al.

    Respiratory-modulated and phrenic afferent-driven neurons in the cervical spinal cord (C4–C6) of the fluorocarbon-perfused guinea pig

    Exp. Brain Res.

    (1993)
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