ELASTIC ENERGY-STORAGE IN RIGORED SKELETAL-MUSCLE CELLS UNDER PHYSIOLOGICAL LOADING CONDITIONS
ELASTIC ENERGY-STORAGE IN RIGORED SKELETAL-MUSCLE CELLS UNDER PHYSIOLOGICAL LOADING CONDITIONS
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DOI：
10.1152/ajpregu.1986.250.1.r56
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发表时间：
1986-01-01
影响因子：
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通讯作者：
DANIEL, TL
中科院分区：
文献类型：
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作者：
TIDBALL, JG;DANIEL, TL
之前已经研究过重粒肌球蛋白（HMM）在可逆变形中储存能量的能力；然而，HMM 是否是骨骼肌细胞中最具弹性能量储存的部位尚未确定。我们在肌节长度的生理范围内对单个严格的肌肉细胞进行了动态负载测试。这些测试使我们能够计算在每个振荡周期期间存储在可逆变形中或在电池中耗散的能量。我们的研究结果表明这些细胞能够存储.apprx。 0.5 J .cntdot。在激动剂体内最后 50 mg 被动伸展期间以及在其自身主动收缩之前，弹性能为 kg-1。这种能量存储的可能位置是 HMM 亚基 2、HMM 亚基 1 的近端部分和平行结构。然而，随着肌丝重叠在生理范围内减少，能量储存单调增加。这种负相关表明 HMM 亚基不是弹性能量存储的主要位置。我们的电子显微镜观察表明，细胞表面的胶原纤维在能量储存增加的肌节长度范围内变得与细胞长轴平行。这提供了观察到的弹性能量存储增加的机制。
The capability of heavy meromyosin (HMM) to store energy in reversible deformations has been investigated previously; yet, whether HMM is the site of most elastic energy storage in skeletal muscle cells has not been established. We conducted dynamic loading tests on single rigored muscle cells over the physiological range of sarcomere lengths. These tests enabled us to calculate the energy stored in reversible deformations or dissipated in the cell during each cycle of oscillation. Our findings show that these cells are capable of storing .apprx. 0.5 J .cntdot. kg-1 of elastic energy during the last 50 mg of passive extension in vivo by agonists and before their own active contractions. Possible sites of this energy storage are HMM subunit 2, the proximal portion of HMM subunit 1, and parallel structures. However, energy storage increases monotonically as myofilament overlap decreases in the physiological range. This negative correlation suggests that HMM subunits are not the primary sites of elastic energy storage. Our electron-microscopic observations show that collagen fibrils at the cell''s surface become oriented parallel to the cell''s long axis over the range of sarcomere lengths where energery storage increases. This provides a mechanism for the observed increases in elastic energy storage.