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目的 研究模拟微重力 (SM)时大小循环动脉血管舒张反应性随时间变化的过程 ,为SM时大小循环血管局部调节的适应机理和立位耐力降低机理的研究积累资料。 方法 采用 - 30°尾部悬吊大鼠模型模拟微重力的生理效应 ,研究对照组 (CON组 )、悬吊 7d组 (TS7组 )和悬吊 14d组(TS14组 )离体灌流的胸主动脉 (TA)和肺动脉 (PA)环的反应性。 结果 TS7组 TA和 PA舒张反应显著增强 ;TS14组 PA反应有减弱趋势而 TA仍有增强。去内皮 PA对硝普钠的舒张反应 3组间无显著性意义。 结论 模拟微重力时大小循环动脉舒张反应的不同变化 ,是局部调节功能降低的表现 ,可能对 SM后立位耐力降低有贡献
OBJECTIVE: To study the process of the changes of the circulatory vasorelaxation of large and small arterial blood vessels (SMCs) during simulated microgravity (SM) with time, and to accumulate data for the study of the adaptive mechanism of local regulation of the size of circulating blood vessels in SM and the mechanism of the reduction of standing endurance. Methods The physiological effects of microgravity were simulated in a rat model of - 30 ° tail suspension. The effects of isolated rat perfused thoracic aorta in control group (CON group), suspension 7d group (TS7 group) and suspension 14d group (TS14 group) (TA) and pulmonary artery (PA) rings. Results The relaxation of TA and PA in TS7 group was significantly enhanced. The PA response in TS14 group was attenuated and TA increased. There was no significant difference between the three groups in the diastolic response of sodium nitroprusside to endothelium PA. Conclusions Different changes in the diastolic responses of the circulatory arteries during simulated microgravity are indicative of a decrease in local regulatory function and may contribute to the reduction of post-SME standing stamina