Intracellular Po2 and Its Regulation in Resting Skeletal Muscle of the Guinea Pig
Intracellular Po2 in the gracilis muscle of lightly anesthetized guinea pigs was measured by means of an O2 microelectrode to see (a) whether the Po2 was low enough that it might limit O2 consumption, and (b) whether it would increase with high O2 breathing. The resting cell membrane potential was used to localize the electrode tip. Of 184 cells tested in 26 animals, 70 cells had a Po2 of less than 1 mm Hg. Mean intracellular Po2 was about 4 mm Hg. When 100% O2 or 98% O2-2% CO2 was administered while the electrode was in a cell, 60 of 89 cells tested (20 animals) showed no change in Po2. In the other 29 cells, the Po2 increased by 5% or more. We have concluded that blood flow in resting skeletal muscle in the anesthetized guinea pig is regulated so as to maintain a low Po2-low enough that it could limit O2 consumption.
- intracellular O2 electrode
- transmembrane potential
- inhalation of O2
- cell respiration
- critical Po2
- Accepted July 17, 1967.
- © 1967 American Heart Association, Inc.