摘要
目的 :通过对模拟微重力 (SM)、肺动脉 (PA)和胸主动脉 (TA)局部调节机理研究 ,为大小循环动脉对SM适应机理和SM后立位耐力降低机理研究积累资料。方法 :XXH 2 0 0 0型小循环心功能检测仪检测人体头低位 6°卧床(HDT) 7d心肺循环功能变化。 - 30°尾部悬吊 (TS)大鼠模拟微重力 (microgravity ,M)的生理效应 ,测量 7d、1 4dPA和TA的反应性。结果 :人体HDT初期每搏PA(hz)、静脉 (hc)容量和左心前负荷 (hc/hz)均显著增加 ,96～ 1 4 4h大小循环均出现超调现象 ,前者出现时间早、幅度大。 7d尾部悬吊大鼠 (TS7)与对照组 (CON)比PA舒张反应显著增强 ,TS1 4有降低趋势。TS7TA与CON比舒张反应显著增强 ,TS1 4轻度升高。TS7PA收缩反应与CON比轻度降低 ,TS1 4显著降低。TS1 4TA收缩反应显著降低。去VECPA对KCl、苯肾上腺素和硝普钠的反应在所有组间无差异。结论 :SM对大小循环动脉影响不同 ,可能是SM时局部调节功能降低的重要表现 ,主要由于动脉血管内皮细胞功能变化 。
Aim:Through studying local regulatory mechanisms in pulmonary arteries (PA) and thoracic aortae (TA) under simulated microgravity (SM), to collect some data for the researches of adaptive mechanisms in pulmonary and systemic arteries and for the mechanisms accounting for orthostatic intolerance after SM. Methods: Cardiopulmonary circulatory function during 7 day 6° head down bed rest (HDT) in male young volunteers was measured with a XXH 2000 pulmonary circulation and cardiac function instrument. -30℃ tail suspended(TS) rats were used as the model to simulate the physiological effects of M. The PA and TA changes of vasoreactivity were respectively observed by vitro vessel rings perfusion. Results: The changes in volume of PA and pulmonary vein during a cardiac cycle and the preload in left cardiac ventricle in men increased significantly in the initial HDT. The super regulatory phenomena appeared in both pulmonary and systemic circulation, but earlier and more obviously in pulmonary circulation than systemic circulation during 96～144 h. The dilatory reactivity in TS7 PA increased significantly, tended to decrease in TS14. The dilatory reactivity of TA in TS7 had a significant increase, had a slight increase in TS14. The contractile reactivity of PA decreased slightly in TS7 from CON, and were attenuated significantly in TS14. The contractile reactivity of TA in TS14 decreased significantly. The responsiveness to KCl, phenylephrine and sodium nitroprussiate in VEC removed PA had no differences among all groups. Conclusion: The differences in changes between pulmonary and systemic arteries under SM could be an important sign of depressed local regulatory function, which might be mainly due to dilatory function in VEC and contribute to the occurrence of orthostatic intolerance after SM.
出处
《中国应用生理学杂志》
CAS
CSCD
北大核心
2003年第3期269-273,共5页
Chinese Journal of Applied Physiology
基金
中国人民解放军总装备部重点技术课题 ( 0 110 130 7)
关键词
模拟微重力
肺动脉
胸主动脉
外周阻力
立位耐力
simulated microgravity
thoracic aorta
pulmonary artery
peripheral resistance
orthostatic tolerance
