Resistance to fatigue of individual Xenopus single skeletal muscle fibres is correlated with mitochondrial volume density.
Resistance to fatigue of individual Xenopus single skeletal muscle fibres is correlated with mitochondrial volume density.
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个体爪蟾单骨骼肌纤维的抗疲劳性与线粒体体积密度相关。
DOI：
10.1113/expphysiol.2004.027763
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Hogan,MichaelC
中科院分区：
文献类型：
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作者：
Stary,CreedM;Mathieu-Costello,Odile;Hogan,MichaelC
本研究的目的是使用直接组织学形态测定法来比较分离的单骨骼肌纤维的个体疲劳特征及其线粒体体积密度（MVD）。从成年雌性非洲爪蟾的蚓状肌中显微解剖单肌纤维（n = 14），并在以逐渐增加的频率（在 0.25、0.33、0.5 和 1 次收缩 s−1 下每次 2 分钟）刺激纤维（9 V 下 70 Hz 刺激，200 毫秒的强直性收缩训练）时测量力，直至疲劳（<50% 初始最大力）已经成立。疲劳方案结束后，通过电子显微镜测定 MVD。各个纤维的疲劳时间各不相同，从 3.3 分钟到 10 分钟不等。单个纤维的 MVD 范围为 3.0% 至 9.2%，并且与相应纤维的疲劳时间呈正相关（r=0.93）。这些结果使用 MVD 的直接组织学测量：（1）在单细胞基础上支持氧化能力是肌肉抗疲劳性的主要决定因素的观点； (2)表明单个细胞的疲劳曲线可用于预测氧化能力。
The purpose of the present study was to compare the individual fatigue characteristics of isolated single skeletal muscle fibres with their mitochondrial volume density (MVD), using direct histological morphometry. Single muscle fibres (n= 14) were microdissected from lumbrical muscle of adult femaleXenopus laevis, and force was measured while fibres were stimulated (tetanic contractions of 200 ms trains with 70 Hz stimuli at 9 V) at progressively increasing frequencies (2 min each at 0.25, 0.33, 0.5 and 1 contractions s−1) until fatigue (<50% initial maximal force) had been established. Following the end of the fatigue protocol, MVD was determined by electron microscopy. Time to fatigue varied among the individual fibres from 3.3 to 10 min. MVD of individual fibres ranged from 3.0 to 9.2% and was positively correlated (r= 0.93) with time to fatigue of corresponding fibres. These results, using direct histological measurements of MVD: (1) support on a single cell basis the notion that oxidative capacity is a major determinant of muscle fatigue resistance; and (2) show that the fatigue profile of a single cell can be used to predict oxidative capacity.