Journal of Applied Physiology, Vol 44, Issue 5 659-665, Copyright © 1978 by American Physiological Society
Inhibition of rat bronchiolar oxygen consumption by plasma proteins
R. M. Navari and J. L. Patterson Jr
The oxygen consumption of rat bronchioles suspended in a physiological salt
solution containing plasma proteins was measured with the Cartesian diver
microrespirometer. The oxygen consumption of the bronchiolar tissue 100-300
and 300-400 micrometer in diam was significantly (P greater than 0.01)
reduced as the protein concentration of the suspending solution was
increased from the low to the high extreme of the normal plasma
physiological range and as the diffusion distance through the suspending
medium was increased from 25 to 50 micrometer. The reduction in the
bronchiolar oxygen consumption was significantly (P greater than 0.01)
reversed by using 95% oxygen-5% nitrogen instead of air as the diffusing
gas in the Cartesian diver. Measurements of the oxygen diffusivity in the
protein solutions using a diaphragm diffusion cell showed a large decrease
in the diffusivity as the plasma protein concentration was increased over
the same concentration range used in the oxygen consumption studies. These
results suggest that the reduction in oxygen consumption was secondary to a
decrease in oxygen diffusion and may provide at least a partial explanation
for the diffusion abnormalities which exist in noncardiogenic pulmonary
edema in which there is an increase in microvascular membrane permeability
to proteins.
