Into deepest lung with drug and camera

Alveoli of guinea pigs subjected to high partial pressures of oxygen (pO2 500 mmHg) for 6 days were studied with the scanning electron microscope. After six days the alveoli of untreated guinea pigs were engorged with an increased volume of alveolar type II cells and macrophages resulting in death of approximately half of the animals. Guinea pigs that had been pretreated with reserpine and phenoxybenzamine catecholamine inhibitors did not show the damaging ultrastructural changes seen in the untreated controls, although phenoxybenzamine was less effective in preventing the changes than reserpine. The results support previous experiments implicating the sympathetic nervous system in the production of pulmonary pathology due to oxygen toxicity.