Enhancement of mechanical performance by stretch during tetanic contractions of vertebrate skeletal muscle fibres.
Enhancement of mechanical performance by stretch during tetanic contractions of vertebrate skeletal muscle fibres.
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通过脊椎动物骨骼肌纤维强直收缩期间的拉伸来增强机械性能。
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
M. Noble
中科院分区：
文献类型：
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作者：
K. Edman;G. Elzinga;M. Noble
1.从半腱肌蛙temporaria单纤维拉伸融合强直收缩和张力和肌节长度（激光衍射）的反应记录。2.纤维的拉伸导致肌节长度成比例增加。力增加到在拉伸期间维持的平台值或增加到在拉伸期间维持的平台值或略微增加。3.拉伸过程中的力的平台值取决于拉伸的速度，是独立的拉伸的振幅，并不成比例的厚和薄的长丝的重叠。4.与等长强直时相同肌节长度的肌节相比，牵张后肌节产生的力有所增强。这种力的增强与施加拉伸的速度无关。5.肌节长度在1.9和2.3微米之间时，拉伸后的力增强迅速下降，与每个肌节约25 nm以上的拉伸幅度无关，与力-速度曲线的偏移无关。在肌节长度超过2.3微米时，拉伸后的力增强衰减非常缓慢，并且在长强直中4秒后仍然存在。6.在肌节长度大于2.3微米时，拉伸后的力增强随着拉伸幅度的增加而增加，并且对于任何给定的拉伸幅度随着肌节长度而增加。因此，拉伸后记录的力与粗长丝和细长丝的重叠不成比例。7.在肌节长度超过2.3微米时，拉伸后的力增强与力-速度曲线向更高力值的偏移相关。通过力-速度曲线的双曲线外推得出的缩短速度和零载荷（Vmax）不受影响。8.牵张过程中和牵张后的张力增强在防止肌节长度分散方面具有稳定作用，特别是在长度-张力曲线的下降支上。
1. Single fibres from the semitendinosus muscle of Rana temporaria were stretched during fused tetanic contractions and tension and sarcomere length (laser diffraction) responses were recorded. 2. Stretch of the fibres caused proportional increases in length of the sarcomeres. The force increased to a plateau value which was maintained during stretch or increased to a plateau value which was maintained during stretch or increased slightly. 3. The plateau value of force during stretch was dependent upon the velocity of stretch, was independent of the amplitude of stretch and was not proportional to overlap of thick and thin filaments. 4. There was enhancement of force after stretch compared with that produced at the same sarcomere length during isometric tetani. This force enhancement was independent of the velocity at which the stretch had been applied. 5. At sarcomere lengths between 1.9 and 2.3 micrometer, the force enhancement after stretch declayed rapidly, was independent of amplitude of stretch above approximately 25 nm per sarcomere not associated with a shift of the force‐‐velocity curve. At sarcomere lengths above 2.3 micrometer the force enhancement after stretch decayed very slowly and was still present after 4 sec in long tetani. 6. At sarcomere lengths above 2.3 micrometer, force enhancement after stretch increased with amplitude of stretch and increased for any given stretch amplitude with sarcomere length. The force recorded after stretch was thus not proportional to overlap of thick and thin filaments. 7. At sarcomere lengths above 2.3 micrometer, the force enhancement after stretch was associated with a shift towards higher force value of the force‐‐velocity curve. The velocity of shortening and zero load (V max) derived by hyperbolic extrapolation of the force‐‐velocity curve was not affected. 8. Tension enhancement during and after stretch has a stabilizing effect in preventing dispersion of sarcomere length, particularly on the descending limb of the length‐‐tension curve.