Study of reversibility of effects of hypoxia in airway smooth muscle.

We have shown in the past that hypoxia impairs contractile activity in tracheal smooth muscle (TSM). This was associated with partial uncoupling of mitochondria. It remained to be determined whether these changes were reversible. The TSM model was felt to be superior to the isolated mitochondria since it was likely to be free from artefacts inherent in procedures involving homogenisation and extraction. We report here that the oxygen uptake rates of the isolated, mechanically active TSM were increased in the posthypoxia recovery period when compared with the prehypoxia active muscle. Mechanical recovery was complete.