Basic researches on the high altitude training : mechanism of vascular and pulmonary systems

低碳酸低氧暴露（10% 02在N2中持续8周）后，观察了3种失神经大鼠颈动脉小体的形态学变化。鼻窦和交感神经同时失神经的大鼠颈动脉小体（SD+S）随着血管扩张而明显增大。而单纯窦神经去神经组（SD）或窦神经、交感神经和迷走神经去神经组（SD+S+V）的颈动脉小体无明显变化。上述结果表明，交感神经和迷走神经失神经大鼠或交感神经和迷走神经完好大鼠（SD大鼠）颈动脉体均无形态学改变。这表明在缺氧条件下颈动脉体的扩大可能依赖于良好平衡的交感神经和副交感神经控制。观察了自发性高血压大鼠（SHR）、年龄匹配的正常血压Wistar大鼠（NWR）和年龄匹配的遗传可比性Wistar大鼠（WKY）颈动脉小体的形态学特征。SHR组颈动脉体积大于NWR组和WKY组。SHR颈动脉小体VIP静脉曲张纤维密度小于WKY颈动脉小体，但SP、CGRP、NPY纤维密度与NWR、WKY颈动脉小体相似。这些结果提示高血压大鼠颈动脉体扩大的机制与缺氧大鼠不同。

Morphological changes in the carotid bodies of three types of denervated rats were examined after hypocapnic hypoxic exposure (10% 02 in N2 for 8 weeks). The carotid bodies of rats denervated of both sinus and sympathetic nerves (SD+S) were significantly enlarged with vascular expansion. But there were no significant changes in the carotid bodies of rats denervated of the sinus nerve alone (SD) or rats denervated of the sinus, sympathetic, and vagal nerves (SD+S+V). These findings indicate that there would be no morphological changes in the carotid bodies of rats denervated of the sympathetic and vagal nerves rats or rats with these two nerves intact (SD rats). This suggests that the enlargement of the carotid body in hypoxic conditions may depend on well-balanced sympathetic and para-sympathetic control.Morphological characteristics in the carotid bodies of spontaneously hypertensive rats (SHR) and those of age-matched normotensive Wistar rats (NWR) as well as age-matched genetically comparable Wistar rats (WKY) were examined. The carotid bodies of SHR were greater than those of NWR and WKY. The density of VIP varicose fibers in the carotid bodies of SHR were smaller than that in the carotid bodies of WKY, although that of SP, CGRP, and NPY fibers was similar to that in the carotid bodies of NWR and WKY. These findings suggest that the mechanisms of carotid body enlargement in hypertensive rats are different from those in hypoxic rats.