Maximum tension and force‐velocity properties of fatigued, single Xenopus muscle fibres studied by caffeine and high K+.
Maximum tension and force‐velocity properties of fatigued, single Xenopus muscle fibres studied by caffeine and high K+.
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通过咖啡因和高 K+ 研究疲劳的单爪爪蟾肌纤维的最大张力和力速度特性。
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
H. Westerblad
中科院分区：
文献类型：
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作者：
J. Lännergren;H. Westerblad
1. 使用钾和咖啡因挛缩作为工具，研究了骨骼肌疲劳发展中最大发力能力降低的重要性。2. 从爪蟾的蚓状肌和髂腓肠肌中分离出单个完整的纤维，通过反复的强直刺激使其疲劳，直到它们产生接近原始强直张力（P0）的40%。使用这种刺激方案可以区分三种主要类型的纤维：易疲劳（1型）、抗疲劳（2型）和非常抗疲劳（3型）纤维（Westerblad & Lännergren, 1986）。3. 当被8 - 15 mM -咖啡因-林格溶液激活时，所有三种类型的疲劳纤维都产生了与对照组相似的张力（分别为81.0 +/‐6.6 vs. 83.9 +/‐4.2%的P0；平均值+/‐sd）。4. 当疲劳纤维用190 mM‐K+溶液去极化时，张力输出也显著增加。在这种情况下产生的张力与纤维类型有关：纤维类型1、2和3分别为P0的71.4 +/‐6.6、81.3 +/‐2.5和95.0 +/‐4.4%。5. 在疲劳髂腓骨纤维（类型1和类型2）的咖啡因收缩期间进行力速度测量，以获得有关过桥功能状态的更多信息。6. 在疲劳的1型纤维中，缩短速度降低到对照组的25%左右，而在2型纤维中，缩短速度没有明显降低。7. 结论是，疲劳纤维的十字桥可以产生几乎完全的张力，但在这种状态下，它们的工作速度可能要慢得多。8. 1型和2型纤维在恢复期大多表现出一种持久的、可逆的严重抑制张力产生的状态，这种状态被称为收缩后抑制，PCD （Westerblad & Lännergren, 1986）。在这种状态下测试的纤维产生完全的咖啡因激活张力，缩短速度没有明显降低。然而，K+收缩期间的张力输出明显下降（12.4 +/‐4.1%）。9. 综上所述，如果交叉桥被完全激活，那么在PCD和疲劳状态下，交叉桥都能够产生接近完全的张力。然而，在这两种情况下，功能损害的形式似乎并不相同。
1. The importance of reduced maximum force‐generating capacity in the development of skeletal muscle fatigue has been studied using potassium and caffeine contractures as tools. 2. Single, intact fibres isolated from the lumbrical and iliofibularis muscles of Xenopus were fatigued by repeated tetanic stimulations until they produced close to 40% of the original tetanic tension (P0). Using this stimulation scheme three major types of fibres can be distinguished: easily fatigued (type 1), fatigue resistant (type 2), and very fatigue‐resistant (type 3) fibres (Westerblad & Lännergren, 1986). 3. When activated by 8‐15 mM‐caffeine‐Ringer solutions fatigued fibres of all three types developed tensions similar to those of controls (81.0 +/‐ 6.6 vs. 83.9 +/‐ 4.2% of P0, respectively; means +/‐ S.D.). 4. Tension output also increased markedly when fatigued fibres were depolarized by 190 mM‐K+ solution. The tension produced was in this case fibre type dependent: 71.4 +/‐ 6.6, 81.3 +/‐ 2.5 and 95.0 +/‐ 4.4% of P0 in fibre types 1, 2 and 3, respectively. 5. Force‐velocity measurements were performed during caffeine contractures in fatigued iliofibularis fibres (types 1 and 2) to obtain more information about the functional state of cross‐bridges. 6. In fatigued type 1 fibres the shortening velocity was reduced to about 25% of that in controls, while it was not significantly depressed in type 2 fibres. 7. It is concluded that cross‐bridges of fatigued fibres can produce nearly full tension, but they may work at a much slower rate in this state. 8. Fibre types 1 and 2 mostly display a long‐lasting, reversible state of severely depressed tension production during the recovery period, which has been named post‐contractile depression, PCD (Westerblad & Lännergren, 1986). Fibres tested in this state generated full caffeine‐activated tension and the shortening velocity was not significantly reduced. The tension output during K+ contractures was, however, markedly depressed (12.4 +/‐ 4.1% of P0). 9. In conclusion, cross‐bridges are able to produce close to full tension during PCD as well as in the fatigued state if they are fully activated. The form of functional impairment seems, however, not to be the same in the two cases.
它是二质子化的无机磷酸盐，可抑制带皮骨骼肌纤维的力量。
DOI：
10.1126/science.3563496
发表时间：
1987
期刊：
Science (New York, N.Y.)
影响因子：
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作者：
Nosek,TM;Fender,KY;Godt,RE
通讯作者：
Godt,RE