The frequency response of smooth muscle stiffness during Ca2+-activated contraction.
The frequency response of smooth muscle stiffness during Ca2+-activated contraction.
复制标题
Ca2 激活收缩过程中平滑肌硬度的频率响应。
DOI：
10.1016/s0006-3495(99)77393-5
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Brozovich,FV
中科院分区：
文献类型：
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作者：
Shue,GH;Brozovich,FV
为了研究平滑肌收缩的机制，研究了松弛状态下单个β-七叶皂苷透化平滑肌细胞的肌肉刚度的频率响应。此外，从松弛溶液开始交换到活化溶液，连续监测响应3分钟，然后以5分钟的间隔监测长达20分钟。频率响应（30 Hz带宽，0.33Hz（或0.2Hz）分辨率）是根据频率递增（1- 32 Hz）正弦波的3 s（或5 s）恒定振幅长度扰动期间采样的傅里叶变换力和长度计算的。在松弛状态下，观察到一个大的负相位角，这表明存在的附加能量产生的横桥。随着激活的进行，肌肉刚度和相位角稳步增加;这些增加逐渐扩展到更高的频率，并在激活后100 s或刚度开始增加后1040 s达到稳定状态。结果表明，一个固定的分布的跨桥状态后，40秒的钙激活和跨桥循环速率没有改变力的维持期间。
To investigate the mechanism of smooth muscle contraction, the frequency response of the muscle stiffness of singleβ-escin permeabilized smooth muscle cells in the relaxed state was studied. Also, the response was continuously monitored for 3min from the beginning of the exchange of relaxing solution to activating solution, and then at 5-min intervals for up to 20min. The frequency response (30Hz bandwidth, 0.33Hz (or 0.2Hz) resolution) was calculated from the Fourier-transformed force and length sampled during a 3-s (or 5-s) constant-amplitude length perturbation of increasing-frequency (1–32Hz) sine waves. In the relaxed state, a large negative phase angle was observed, which suggests the existence of attached energy generating cross-bridges. As the activation progressed, the muscle stiffness and phase angle steadily increased; these increases gradually extended to higher frequencies, and reached a steady state by 100s after activation or ∼40s after stiffness began to increase. The results suggest that a fixed distribution of cross-bridge states was reached after 40s of Ca2+activation and the cross-bridge cycling rate did not change during the period of force maintenance.