Bee D, Barer G, Wach R, Pallot D, Emery C, Jones S
University Department of Medicine, Royal Hallamshire Hospital, Sheffield.
Q J Exp Physiol. 1989 Sep;74(5):691-701. doi: 10.1113/expphysiol.1989.sp003321.
Morphology of the carotid body and the ventilatory response to hypoxia were compared in New Zealand genetically hypertensive rats and 'normotensive' control rats from the same genetic stock. Hypertensive rats grew more slowly, had higher blood pressure from 6 weeks of age and developed left ventricular hypertrophy. Carotid bodies of both groups were similar in size but larger than those of a common Wistar strain. Intimal damage and proliferation were seen in 1st- and 2nd-order branches of the carotid body artery in hypertensive rats and point-counting showed that the volume proportion of Type 1 cell nuclei and vascular lumen was reduced and vascular wall increased. In age-matched anaesthetized rats, minute ventilation per 100 g was greater in hypertensives than 'normotensive' when inspiring O2 concentrations of 30, 21, 18, 15, 12, 10 and 8%. However, at each inspired O2 concentration, arterial Pa.O2 was higher and Pa.CO2 lower in hypertensive than in 'normotensive' rats. Hypertensive rats were hyperventilating. The shape of the ventilation/O2 tension curve was similar in hypertensive and 'normotensive' rats; thus carotid body sensitivity to hypoxia was probably unchanged. Possible causes of hyperventilation and the relation of carotid body morphology to hypertension are discussed.
对来自同一遗传种群的新西兰遗传性高血压大鼠和“正常血压”对照大鼠的颈动脉体形态及对低氧的通气反应进行了比较。高血压大鼠生长较慢，6周龄起血压较高，并出现左心室肥厚。两组大鼠的颈动脉体大小相似，但比普通Wistar品系大鼠的颈动脉体大。在高血压大鼠的颈动脉体动脉一级和二级分支中可见内膜损伤和增殖，点计数显示1型细胞核和血管腔的体积比例降低，血管壁增加。在年龄匹配的麻醉大鼠中，当吸入氧气浓度为30%、21%、18%、15%、12%、10%和8%时，高血压大鼠每100克体重的分钟通气量比“正常血压”大鼠大。然而，在每个吸入氧气浓度下，高血压大鼠的动脉血氧分压较高，二氧化碳分压较低。高血压大鼠存在通气过度。高血压大鼠和“正常血压”大鼠的通气/氧分压曲线形状相似；因此，颈动脉体对低氧的敏感性可能未发生变化。本文讨论了通气过度的可能原因以及颈动脉体形态与高血压的关系。
