Effect of Discontinuous Decompression on Blood Pressure in the Rat

Abstract

Rats exposed to discontinuous decompression equivalent to an altitude of 30,000 ft. for 2 hrs./day for 19 wks. became progressively hypertensive. When returned to ordinary air pressure for 8 wks. following the period of decompression, the blood pressure remained elevated. Rats treated with the drugs strychnine, epinephrine, and papaverine daily during the decompression period showed no significant difference from the untreated but decompressed animals. Erythrocyte numbers did not change during the decompression period, indicating that no hypoxia resulted and therefore the hypertension was entirely due to the physical pressure reduction. Histopathological changes were restricted to the lungs and kidneys, the former showing enlargement of the alveolar sacs with narrowing of the walls, while the latter showed some uriniferous tubule dilation. Some distention of veins occurred but the arteries were not visibly affected.