Effects of high O2 and N2-O2 pressures on the physical performance of deer mice: preliminary studies.

Exposure of deer mouse colonies to oxygen tensions of 0.8, 1.0 and 1.5 ATA are accompanied by reductions in wheel-running activity. The magnitude of the reductions was correlated with the partial pressure of oxygen and duration of exposure. Efforts to minimize the toxic effects of high-pressure oxygen by simultaneous exposure to a high nitrogen tension were not effective. Earlier studies (8) showed that exposure to 13.8 atm nitrogen under normoxic conditions reduced running activity by 10%. When this same nitrogen tension was provided in each of the elevated oxygen environments, wheel-running activity deteriorated in a manner comparable to that observed in the absence of added nitrogen. Visual observations of social behavior and respiratory distress suggest that a nitrogen tension of 13.8 atm does not provide protection against oxygen toxicity.