MECHANICAL-PROPERTIES AND REACTIVITY OF VESSELS IN ISOLATED PERFUSED LUNGS OF CHRONICALLY HYPOXIC RATS
MECHANICAL-PROPERTIES AND REACTIVITY OF VESSELS IN ISOLATED PERFUSED LUNGS OF CHRONICALLY HYPOXIC RATS
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DOI：
10.1042/cs0610569
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发表时间：
1981-01-01
期刊：
影响因子：
6
通讯作者：
BARER, GR
中科院分区：
文献类型：
--
作者：
EMERY, CJ;BEE, D;BARER, GR
慢性缺氧大鼠保持在10%（体积/体积）的O_2 3-6周，与同窝对照组大鼠进行了比较。肺血管阻力，测量的压力-流量关系的斜率在离体肺灌注正常细胞压积的血液是高于慢性缺氧比对照组大鼠，即使在常氧。慢性缺氧大鼠体重低于对照组大鼠，但他们的肺血管容积，与标记白蛋白测量是类似的对照组大鼠。这与毛细血管前血管数量没有减少的证据一起，并不表明慢性缺氧时血管床大量减少。异丙肾上腺素和腺苷在慢性缺氧肺中的血管舒张作用比对照肺更大，表明了更高的常氧血管张力。这种较高的张力并不是慢性缺氧肺阻力增加的唯一原因，因为最大血管舒张并没有降低阻力至对照水平。其主要原因可能是新生肌侵入小血管管腔所致。肺动脉顺应性在慢性低氧肺降低。反应性的血管通气缺氧，在很宽的范围内的O2张力，血管紧张素II（ANG II）和ATP是显着更大的慢性缺氧比对照肺，但这些刺激的阈值没有降低。
Chronically hypoxic rats kept in 10% (vol/vol) O2 for 3-6 wk, were compared with littermate control rats. Pulmonary vascular resistance, measured from the slope of the pressure-flow relationship in isolated lungs perfused with blood of normal packed cell volume was higher in chronically hypoxic than control rats even during normoxia. Chronically hypoxic rats weighed less than control rats but their pulmonary vascular volume, measured with labeled albumin was similar to control rats. This, together with evidence that the number of precapillary vessels is not reduced, does not suggest a large reduction in the vascular bed in chronic hypoxia. A greater vasodilator action of isoprenaline and adenosine in chronically hypoxic than control lungs suggested a higher normoxic vascular tone. This higher tone was not the sole cause of increased resistance in chronically hypoxic lungs, since maximal vasodilatation did not reduce resistance to control levels. The chief cause was probably encroachment of new muscle on the vascular lumen of small vessels. Pulmonary arterial compliance was reduced in chronically hypoxic lungs. Reactivity of vessels to ventilation hypoxia, over a wide range of O2 tension, to angiotensin II (ANG II) and to ATP was significantly greater in chronically hypoxic than control lungs, but thresholds to these stimuli were not reduced.