Journal of Applied Physiology, Vol 42, Issue 6 845-851, Copyright © 1977 by American Physiological Society
Effect of pentobarbital sodium on respiratory control in newborn rabbits
M. S. Goldberg and J. Milic-Emili
Using the airway occlusion pressure technique, control of breathing was
studied in unanesthetized and anesthetized newborn rabbits breathing
various gas mixtures under steady-state conditions. Independent of the gas
mixture breathed, barbiturate anesthesia resulted in a reduction of
ventilation. This was not due to a change in inspiratory drive since for
each gas mixture breathed the pressure generated by the inspiratory muscles
0.3 s after the onset of the occluded inspiration (P0.3) remained virtually
unchanged, nor could this be attributed to changes in respiratory mechanics
as indicated by the fact that the relation between P0.3 and V0.3 (the
volume generated 0.3 s after onset of the immediately preceding unoccluded
inspiration) did not change. On the other hand, during anesthesia
inspiratory time was slightly shortened as a result of a change in both
central (bulbopontine) and peripheral (volume-related vagal reflex)
modulation, while expiratory duration was markedly prolonged. This
disproportionate increase in expiratory duration with respect to
inspiratory duration was responsible for most of the depression of
ventilation found in the newborn rabbits during barbiturate anesthesia.
