Journal of Applied Physiology, Vol 55, Issue 2 400-408, Copyright © 1983 by American Physiological Society
Influence of ischemia and hypoxia on breathing in ducks
R. S. Lillo and D. R. Jones
We examined the influence of whole and lower body hypoxia and lower body
ischemia on breathing in White Pekin ducks, Anas platyrhynchos, excluding
pathways involving the carotid bodies. Carotid body denervated birds
breathing 10 or 5% O2 developed a tachypnea after a latency of 30-100 s.
The tachypnea was more pronounced with the more severe hypoxia, resulting
in almost a doubling of minute ventilation (VE). Occlusion of the abdominal
aorta in unanesthetized ducks produced immediate development of
hypertension. Ventilation was unaffected for the 1st min; a tachypnea then
developed rapidly and persisted for the duration of the occlusion resulting
in a 25% increase in VE. After thoracic spinal section, all ventilatory
responses to occlusion were eliminated. Experimental perfusion of the brain
and single intact carotid body in unanesthetized ducks with hyperoxic blood
during low O2 breathing (6-9% O2) resulted in tachypnea, also after a
considerable latency. These results suggest that severe hypoxia can affect
breathing in birds via pathways other than those involving the carotid
bodies.
