PULMONARY-ARTERIES AND VEINS IN EXPERIMENTAL HYPOXIA - ULTRASTRUCTURAL-STUDY

  • 1 January 1978
    • journal article
    • research article
    • Vol. 93  (2) , 353-368
Abstract
Pulmonary vessels of rats were studied by EM after 4 days to 4 wk of hypoxia and were compared with those of control rats and of regression rats that, after a period of hypoxia, were allowed to survive in normal air for up to 4 wk. Both hypoxic and regression rats had medial hypertrophy of both arteries and arterioles and of veins and venules. In contrast to the control and the regression rats, many hypertrophic vessels of the hypoxic rats showed signs of constriction (i.p., crenation of the wall), indentations of medial smooth muscle cell nuclei and excrescences of smooth muscle cell cytoplasm, often protruding deeply into the endothelium. Vasoconstriction due to hypoxia occurs in pulmonary arteries, arterioles, veins and venules. Medial hypertrophy may be found in the absence of vasoconstriction; this is especially evident during recovery from hypoxia.