AJP - Regulatory, Integrative and Comparative Physiology, Vol 244, Issue 1 15-R22, Copyright © 1983 by American Physiological Society
Diffusion of oxygen in slices of rat brain
L. D. Homer, J. B. Shelton and T. J. Williams
A new method for the joint determination in tissue slices of the diffusion
coefficient of oxygen (D) and the fluorescence-quenching coefficient (K')
of pyrenebutyric acid (PBA) is introduced. Values of D and K' in rat brain
at temperatures (Tc) from 20 to 40 degrees C were determined and referred
to the values in water. D = DH2O (0.72 - 0.0074 Tc) +/- 0.079 X 10(-5)
cm2/s for 80-microns slices. D = DH2O (1.01 - 0.0074 Tc) +/- 0.12 X 10(-5)
cm2/s for 160-microns slices. K' = K'H2O (0.72 + 0.025 Tc) +/- 0.56 X
10(-4) mmHg-1. The temperature dependence of both these parameters in
tissue is different from their temperature dependence, and comparison with
parameter values obtained with other methods leads us to conclude that
factors affecting the diffusion of oxygen in tissue are heterogenous rather
than homogenous. The variation in the different parameters, D and K',
probably exceeds a twofold range.
