模拟失重对大鼠后肢动脉血管床血管反应性的影响

Effects of Simulated Weightlessness on Vasoreactivity of Hindlimb Arterial Bed in Rats.

目的观察模拟失重对大鼠后肢血管床血管反应性的影响。方法采用尾部悬吊大鼠模型模拟失重，利用离体后肢恒流灌流技术测定模拟失重２ｗｋ后动脉血管床血管反应性的变化。结果后肢血管床的压力－流量关系在悬吊大鼠与对照大鼠间无明显差别，在对ＫＣｌ（２０～１００ｍＭ）与ＰＥ（１０－８～１０－４Ｍ）的收缩反应中，悬吊大鼠后肢血管床的灌流阻力增加幅度明显小于对照大鼠。结论后肢小动脉的收缩能力在模拟失重状态下明显降低，提示由此所致外周阻力增加的能力受损在飞行后立位耐力不良的发生机制中可能具有一定的作用。

Objective To investigate the alterations in vasoreactivity of hindlimb arterial bed after simulated weightlessness. Method The tail suspended rat model was used to simulate weightlessness, and the alterations in vasoreactivity of arterial bed were examined in vitro using isolated, constant flow perfused hindlimb of 2 wk suspended rats and control rats. Result Perfusion flow pressure relationship of hindlimb arterial bed showed no significant differences between suspended rats and control rats; but vascular responses to KCl(20～100 mM) and PE(10 -8 ～10 -4 M) were decreased in hindlimb arterial bed of suspended rats as compared with that of control rats. Conclusion Contractile ability of resistance vessels was diminished in simulated weightlessness rats, and a compromised ability of resistance vessels to increase peripheral resistance may play an important role in occurrence of orthostatic intolerance.