|
|
||||||||
Journal of Applied Physiology, Vol 69, Issue 6 1998-2003, Copyright © 1990 by American Physiological Society
ARTICLES |
J. P. Praud, E. Canet, D. Dalle, A. Bairam and M. Bureau
Centre Jeremy Rill, Departement de Pediatrie, Universite de Sherbrooke, Quebec, Canada.
It is generally accepted that hypoxia in early life results in active laryngeal braking of expiratory airflow via the recruitment of glottic adductor muscles. We examined the electromyogram expiratory activity of the thyroarytenoid muscle in seven 11- to 18-day-old awake nonsedated lambs exposed to an inspired O2 fraction of 0.08 for 18 min. The lambs breathed through a face mask and a pneumotachograph. During baseline prehypoxic breathing, the thyroarytenoid muscle was largely inactive in each awake lamb. Unexpectedly, no recruitment of the thyroarytenoid muscle was recorded during hypoxia in any of the seven lambs; simultaneous examination of the flow-volume curves revealed an absence of expiratory airflow braking. Also unexpectedly, marked expiratory activity of the thyroarytenoid muscle was recorded, with each expiration occurring within less than 10 s after the return to room air. The resulting delay of expiration was apparent in the flow-volume loops. Thus, in awake 11- to 18-day-old lambs, 1) active expiratory glottic adduction is absent during hypoxia and 2) a return from hypoxia to room air results in prolonged expiration as well as active glottic adduction that controls end-expiratory lung volume.
This article has been cited by other articles:
![]() |
J. Arsenault, F. Moreau-Bussiere, P. Reix, T. Niyonsenga, and J.-P. Praud Postnatal maturation of vagal respiratory reflexes in preterm and full-term lambs J Appl Physiol, May 1, 2003; 94(5): 1978 - 1986. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. M. Bissonnette Mechanisms regulating hypoxic respiratory depression during fetal and postnatal life Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2000; 278(6): R1391 - R1400. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. R. Feroah, H. V. Forster, L. G. Pan, and T. Rice Reciprocal activation of hypopharyngeal muscles and their effect on upper airway area J Appl Physiol, February 1, 2000; 88(2): 611 - 626. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |