21d模拟失重家兔股静脉血管反应性的变化

目的研究模拟失重对下肢静脉系统的影响。方法将雄性新西兰家兔 2 4只 ,随机分为对照组、水平限动组和头低位限动组 ,每组 8只。利用离体血管环灌流技术 ,测量了 2 1d水平限动及 - 2 0°头低位限动家兔股静脉对组胺 (Ht)、苯肾上腺素 (PE)和氯化钾 (KCl)的收缩反应以及对乙酰胆碱 (ACh)和硝普钠(SNP)的舒张反应。结果 2 1d水平限动及头低位限动家兔股静脉对较高浓度PE和KCl的收缩反应均显著下降 (P <0 .0 5 ) ;对Ht的收缩反应有下降趋势 ,但无统计学意义 ;对ACh和SNP的舒张反应无显著变化。结论 2 1d模拟失重后家兔后肢深静脉对血管活性物质的收缩反应性下降 ,提示这可能是失重或模拟失重后立位耐力下降的原因之一

Changes of Reactivity of Rabbit Femoral Venous Rings after 21 d Simulated Weightlessness

Objective To study the effects of simulated weightlessness on reactivity of leg veins. Method Vascular bathing technique was used to measure the contractile responses of rabbit femoral venous rings to Ht, PE and KCl, and the dilatory responses to ACh and SNP after horizontal confinement or head down tilt confinement for 21 d. Result After simulated weightlessness for 21 d, the contractile response of rabbit femoral venous rings to higher concentrations of PE and KCl decreased significantly(P<0.05); the contractile response to Ht also decreased, but not significantly(P>0.05); the dilatory responses to ACh and SNP did not change significantly in both groups. Conclusion Contractile response of rabbit femoral vein decreased after simulated weightlessness for 21 d, which might partly explain the occurrence of orthostatic intolerance in men after space flight.