Ventilation induced apnea and its effect on dorsal brainstem inspiratory neurones in the rat

Hari H. Subramanian*, Ron J. Balnave, Chin M. Chow

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    3 Citations (Scopus)

    Abstract

    The purpose of this study was to examine the effect of mechanical ventilation (MV) on inherent breathing and on dorsal brainstem nucleus tractus solitarius (NTS) respiratory cell function. In pentobarbitone-anaesthetised rats, application of MV at combined high frequencies and volumes (representing threshold levels) produced apnea. The apnea persisted as long as MV was maintained at or above the threshold frequency and volume. Following removal of MV, inherent breathing did not resume immediately, with the diaphragm exhibiting post-mechanical ventilation apnea. The fall in arterial P-CO2, (Pa-CO2) levels evoked by MV-engendered hyperventilation was shown not to be the trigger for initiation of apnea. MV-induced apnea was immediately reversed by bilateral vagotomy. Further, MV-induced apnea could not be evoked in bilaterally vagotomized animals suggesting that vagal feedback is the critical pathway for its initiation. NTs inspiratory neurones were inhibited during both MV-induced apnea and post-mechanical ventilation apnea, implying the involvement of central neural mechanisms in mediating this effect. (c) 2007 Elsevier B.V. All rights reserved.

    Original languageEnglish
    Pages (from-to)252-261
    Number of pages10
    JournalRespiratory physiology & neurobiology
    Volume157
    Issue number2-3
    DOIs
    Publication statusPublished - 1-Aug-2007

    Keywords

    • mechanical apneic thresholds
    • vagal memory
    • NTS inspiratory neurones
    • post-mechanical ventilation apnea
    • HIGH-FREQUENCY VENTILATION
    • NUCLEUS-TRACTUS-SOLITARIUS
    • STRETCH-RECEPTOR ACTIVITY
    • RESPIRATORY MOTOR OUTPUT
    • KOLLIKER-FUSE NUCLEUS
    • BREUER-HERING REFLEX
    • MECHANICAL VENTILATION
    • OSCILLATORY VENTILATION
    • SLEEPING HUMANS
    • CARBON-DIOXIDE

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