Journal of Applied Physiology, Vol 65, Issue 2 633-639, Copyright © 1988 by American Physiological Society
Responses of pulmonary vagal mechanoreceptors to high-frequency oscillatory ventilation
J. A. Wozniak, P. W. Davenport and P. C. Kosch
Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610.
The discharge of 57 slowly adapting pulmonary stretch receptors (PSR's) and
16 rapidly adapting receptors (RAR's) was recorded from thin vagal
filaments in anesthetized dogs. The receptors were localized and separated
into three groups: extrathoracic tracheal, intrathoracic tracheal, and
intrapulmonary receptors. The influence of high-frequency oscillatory
ventilation (HFO) at 29 Hz on receptor discharge was analyzed by separating
the response to the associated shift in functional residual capacity (FRC)
from the oscillatory component of the response. PSR activity during HFO was
increased from spontaneous breathing (49%) and from the static FRC shift
(25%). PSR activity during the static inflation was increased 19% over
spontaneous breathing. RAR activity was also increased with HFO. These
results demonstrate that 1) the increased activity of PSR and RAR during
HFO is due primarily to the oscillating action of the ventilator and
secondarily to the shift in FRC associated with HFO, 2) the increased PSR
activity during HFO may account for the observed apneic response, and 3)
PSR response generally decreases with increasing distance from the tracheal
opening.
