关键词: 失重模拟;大鼠;心肌/细胞学;钙;膜片钳;受体，肾上腺素能β

    摘 要:目的 研究模拟失重大鼠心肌细胞钙电流(ICa )对β-肾上腺素受体激动剂的反应性变化. 方法 用尾部悬吊大鼠模型模拟失重(4wk)，胶原酶分离心肌细胞，用膜片钳全细胞方式记录单个心肌细胞的膜电容和I Ca 等.给予β-肾上腺素受体激动剂(异丙肾上腺素)，记录观察ICa 的反应性. 结果 对照组与悬吊组的ICa 密度无明显差别(P>0.05)，ICa 电流密度-电压曲线基本一致;加入异丙肾上腺素后，两组ICa 密度均明显增大，但是两组的增加幅度不同，悬吊组的增加幅度(84.3±8.2)%明显小于对照组(109.3±7.9)%(P<0.05). 结论 模拟失重4wk大鼠心肌细胞的ICa 密度无明显改变;模拟失重后心肌细胞ICa 对β-肾上腺素受体激动剂的反应性降低.

    Responsiveness of calcium currents toβ┐receptor ag┐onist in cardiac myocytes of simulated weightless rats

    CHENG Hong-Wei，ZHANG Li-Fan，FENG Han-Zhong，CHENG Jiu-Hua，YU Zhi-Bin

    Department of Aerospace Physiology，Faculty of Aerospace Medicine，Fourth Military Medical Uni-versity，Xi'an710033，China

    Keywords:weightlessness simulation;rats;myocardium/cy-tology;calcium;patch-clamp techniques;recep-tors，adrenergic，beta

    Abstract:AIM To investigate the changes of responsiveness of calcium currents(I

    Ca )toβ-adrenergic receptor agonist in cardiac myocytes of simulated ightless rats.METHODS The rat tail-suspension model was used to simulate weight-lessness(4wk).Cardiac myocytes were isolated with colla-genase.Under whole cell recording mode of patch clamp technique ......