Structural limits on force production and shortening of smooth muscle.
Structural limits on force production and shortening of smooth muscle.
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DOI：
10.1007/s10974-012-9333-6
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发表时间：
2013-02
影响因子：
2.7
通讯作者：
Butler, Thomas M.
中科院分区：
文献类型：
--
作者：
Siegman, Marion J.;Davidheiser, Sandra;Mooers, Susan U.;Butler, Thomas M.
关键词：
这项研究确定了限制两个平滑肌中的力产生和缩短的因素，这两个平滑肌具有作为肌肉长度的函数的主动力和被动力之间的非常不同的关系。大鼠肛尾肌在0.2 - 2.0×最佳产力长度（Lo）的长度范围内产生主动力。由于静止肌肉的伸展引起的被动张力仅在超过Lo的长度时发生。相比之下，兔结肠带在0.4- 1.1 Lo的长度范围内产生力，在0.56 Lo时可检测到的被动力在Lo时增加到约0.45的最大主动力，并且随着进一步延伸而急剧增加。肛尾肌缩短至0.2Lo，结肠带缩短至0.4Lo。在短肌肉长度的动态刚度和能量的使用表明，限制缩短在结肠带，相反，肛尾肌，是不是由于跨桥相互作用的失败。磷酸化的调节肌球蛋白轻链在完整的肌肉减少到一个小的程度，在短的长度相比，减少生产力。即使在透化后，肌球蛋白轻链被ATPγS不可逆地磷酸化，两种肌肉在力产生和缩短程度上的差异仍然存在，表明激活差异几乎没有作用。休息和激活肌肉的超微结构研究表明，结肠带，这是丰富的结缔组织（不像肛尾肌）经历了显着的细胞扭曲和收缩丝错位在短长度与压缩的细胞外基质。结果，力不在肌肉的纵轴上传递，而是抵抗由压缩的细胞外基质提供的内部负荷而消散。对两种非常不同的正常平滑肌的这些观察揭示了主动和被动结构元件的相对贡献的差异如何决定它们的机械行为，以及如何通过疾病中发生的重塑和响应功能需求的变化来潜在地修改。
This study determined the factors that limit force production and shortening in two smooth muscles having very different relationships between active and passive force as a function of muscle length. The rat anococcygeus muscle develops active force over the range of lengths 0.2 – 2.0× the optimum length for force production (Lo). Passive tension due to extension of the resting muscle occurs only at lengths exceeding Lo. In contrast, the rabbit taenia coli develops force in the range of lengths 0.4– 1.1 Lo, and passive force which is detectable at 0.56 Lo, increases to ~0.45 maximum active force at Lo, and increases sharply with further extension. The anococcygeus muscle can shorten to 0.2 Lo and the taenia coli to 0.4 Lo. Dynamic stiffness and energy usage at short muscle lengths suggest that the limit of shortening in the taenia coli, in contrast to the anococcygeus muscle, is not due to a failure of cross bridge interaction. Phosphorylation of the regulatory myosin light chains in intact muscles decreased to a small extent at short lengths compared to the decrease in force production. The differences in force production and the extent of shortening in the two muscles was maintained even when, following permeabilization, the myosin light chains were irreversibly phosphorylated with ATPγS, indicating that differences in activation played little, if any role. Ultrastructural studies on resting and activated muscles show that the taenia coli, which is rich in connective tissue (unlike the anococcygeus muscle) undergoes marked cellular twisting and contractile filament misalignment at short lengths with compression of the extracellular matrix. As a result, force is not transmitted in the longitudinal axis of the muscle, but is dissipated against an internal load provided by the compressed extracellular matrix. These observations on two very different normal smooth muscles reveal how differences in the relative contribution of active and passive structural elements determine their mechanical behavior, and how this is potentially modified by remodeling that occurs in disease and in response to changes in functional demand.
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影响因子：
1.6
作者：
GOSLING, JA;DIXON, JS
通讯作者：
DIXON, JS
DOI：
10.1111/j.1748-1716.1978.tb06060.x
发表时间：
1978-01-01
期刊：
ACTA PHYSIOLOGICA SCANDINAVICA
影响因子：
--
作者：
CORNELIUS, F;LOWY, J
通讯作者：
LOWY, J
DOI：
10.1007/bf00304599
发表时间：
1983-01-01
期刊：
ANATOMY AND EMBRYOLOGY
影响因子：
--
作者：
GABELLA, G
通讯作者：
GABELLA, G
影响因子：
5.6
作者：
ASHTON, FT;SOMLYO, AV;SOMLYO, AP
通讯作者：
SOMLYO, AP
影响因子：
--
作者：
GORDON, AR;SIEGMAN, MJ
通讯作者：
SIEGMAN, MJ