Influence of temperature on oxygen diffusion in hamster retractor
muscle.
Bentley, Timothy B., and Roland N. Pittman.
Department of Physiology, Medical College of Virginia, Virginia
Commonwealth University, Richmond, Virginia
APStracts 3:0361H, 1996.
A mathematical analysis of in vivo data on arteriolar O2 loss
suggested that Krogh's diffusion coefficient (KO2 = [alpha] DO2) in
vivo could be an order of magnitude larger than that calculated from
DO2 values measured in vitro at 22oC and extrapolated to 37oC (24).
In this study, to eliminate potential extrapolation errors, we
utilized a miniature hyperbaric chamber with 1-2 atm of O2 to
maintain tissue oxygenation and allow DO2 measurements directly at
37oC while utilizing a non-steady state technique. The need for
metabolic poisons that had been required by earlier experimental
techniques was thereby eliminated. DO2 measured directly at 37oC
(2.42 x 10-5 cm2 sec-1) and the increase with temperature of DO2
between 30 and 41oC (4.61%/oC) were unexpectedly higher than the
values we found at lower temperatures. O2 was also higher than
expected at 37 and 40oC. An analysis of the activation energy for DO2
suggests that at higher temperatures there is a change in the
diffusion pathway from that existing at lower temperatures, perhaps
due to phase transitions in the lipid membranes.
Received 15 February 1994; accepted in final form 5 August 1996.
APS Manuscript Number H149-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 August 1996