FIG. 9.

Hyperoxia exposure increases PDE5 activity in small PA from adult mice. Male C57Bl6 mice were placed into three experimental groups: 1) room air, nonventilated (21NV), 2) mechanically ventilated with 100% O₂ for 45 min (100V), and 3) 90% O₂ exposure for 45 min in an animal hyperoxia chamber (Biospherix; 90NV). (A) PDE5-specific cGMP hydrolytic activity in the small PA is measured using a commercially available colorimetric assay (n=5 per group, read in duplicate). Data are shown as mean±SEM pmol cGMP hydrolyzed/mg protein/min. (B) cGMP content of lung tissue was measured via EIA, and cGMP was normalized to milligrams of tissue. Data are shown as mean±SEM (n=5, read in duplicate). *p<0.05 vs. 21NV animals.