间断性头高位对抗尾部悬吊大鼠脑动脉血管反应性变化的影响

Counteracting effects of intermittent head-up tilt on changes in responsiveness of basilar arteries of tail suspended rats

目的 间断性人工重力被认为是对抗长期失重下心血管系统脱适应的最有效、合理措施之一 .本实验拟探讨其对抗模拟失重下大鼠脑基底动脉血管反应性改变的影响 .方法 每日给予 3 wk尾部悬吊大鼠不同持续时间 (2 h或 4h)的头高位倾斜 (HUT) ,测定大鼠离体基底动脉血管环对KCl的收缩反应性 .结果 悬吊组大鼠基底动脉血管环对KCl的最大反应 (7.0 7± 0 .49) m N较对照组 (4.83± 0 .36 )m N显著升高 (P <0 .0 5 ) ;HUT组大鼠基底动脉血管环对KCl的最大反应 [HUT4:(4.78± 0 .5 1) m N;HUT2 :(5 .5 6± 0 .2 8) m N]较悬吊组显著减弱 (P<0 .0 5 ) ,与对照组无显著差异 .

AIM Artificial gravity is considered one of the most effective and rational countermeasures to cardiovascular deconditioning after spaceflight. The purpose of this work isto investigate counteracting effects of intermittent artificial gravity on changes in responsiveness of basilar arteries of tail suspended rats. METHODS Three wk Tail suspended rats were subjected to head up tilt (HUT) of various duration (2 h or 4 h, respectively) daily and their responses of perfused isolated basilar arterial rings to KCl were examined. RESULTS Maximal isometric contractile responses to KCl were significantly enhanced in arterial rings isolated from 3 wk tail suspended rats (7.07±0.49) mN as compared with those from simultaneous control rats (4.83±0.36) mN ( P <0.05). However, maximal isometric contractile responses to KCl in arterial rings isolated from 3 wk tail suspended plus daily HUT rats [HUT 4: (4.78±0.51) mN; HUT 2: (5.56±0.28) mN] were the same no different as compared with those from simultaneous control rats, and were significantly decreased ( P <0.05) as compared with those from 3 wk tail suspended rats. CONCLUSION Daily using the intermittent artificial gravity produced by HUT as a countermeasure can prevent the effects of simulated weightless on changes in responsiveness of basilar arteries of tail suspended rats is valid.