Force-velocity and power characteristics of rat soleus muscle fibers after hindlimb suspension.
Force-velocity and power characteristics of rat soleus muscle fibers after hindlimb suspension.
复制标题
后肢悬吊后大鼠比目鱼肌纤维的力-速度和功率特性。
DOI：
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发表时间：
1994
影响因子：
3.3
通讯作者：
R. Fitts
中科院分区：
文献类型：
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作者：
K. McDonald;C. Blaser;R. Fitts
本文观察了后肢悬吊1、2和3周对大鼠比目鱼肌单纤维力-速度和功率特性的影响。HS 1、2或3周后，分离小纤维束，置于剥皮溶液中，并储存在-20 ℃下直至研究。单纤维被隔离，并放置在电机臂和力传感器，功能特性进行了研究，和纤维蛋白质含量进行了分析，随后通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）。从对照组和HS后1周和3周的比目鱼肌中分离出额外的纤维，并通过SDS-PAGE分析确定纤维类型分布和肌球蛋白轻链化学计量。HS 1周后，I型纤维百分比从82%下降到74%，而混合纤维从10%增加到18%。快II型纤维百分比从对照组和HS 1周的8%增加到HS 3周的26%。大多数肌纤维无负荷最大缩短速度（Vo）增加，但肌球蛋白重链仍完全为慢I型。Vo增加的机制尚不清楚。HS后1、2和3周，纤维直径（14、30和38%）和峰值力（38、56和63%）分别逐渐下降。HS 1周导致力-速度曲线移动，HS 2 - 3周之间，曲线进一步移动，使得Vo在所有相对负荷< 45%峰值等长力时均高于对照组。比目鱼肌纤维的峰值绝对功率输出在HS的2周内逐渐下降，但在3周时没有进一步的变化。（250字处删节）
The effects of 1, 2, and 3 wk of hindlimb suspension (HS) on force-velocity and power characteristics of single rat soleus fibers were determined. After 1, 2, or 3 wk of HS, small fiber bundles were isolated, placed in skinning solution, and stored at -20 degrees C until studied. Single fibers were isolated and placed between a motor arm and force transducer, functional properties were studied, and fiber protein content was subsequently analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Additional fibers were isolated from soleus of control and after 1 and 3 wk of HS, and fiber type distribution and myosin light chain stoichiometry were determined from SDS-PAGE analysis. After 1 wk of HS, percent type I fibers declined from 82 to 74%, whereas hybrid fibers increased from 10 to 18%. Percent fast type II fibers increased from 8% in control and 1 wk of HS to 26% by 3 wk of HS. Most fibers showed an increased unloaded maximal shortening velocity (Vo), but myosin heavy chain remained entirely slow type I. The mechanism for increased Vo is unknown. There was a progressive decrease in fiber diameter (14, 30, and 38%) and peak force (38, 56, and 63%) after 1, 2, and 3 wk of HS, respectively. One week of HS resulted in a shift of the force-velocity curve, and between 2 and 3 wk of HS the curve shifted further such that Vo was higher than control at all relative loads < 45% peak isometric force. Peak absolute power output of soleus fibers progressively decreased through 2 wk of HS but showed no further change at 3 wk.(ABSTRACT TRUNCATED AT 250 WORDS)