Novel myosin isoform in nuclear chain fibers of rat muscle spindles produced in response to endurance swimming.
Novel myosin isoform in nuclear chain fibers of rat muscle spindles produced in response to endurance swimming.
复制标题
大鼠肌梭核链纤维中因耐力游泳而产生的新型肌球蛋白亚型。
DOI：
10.1152/jappl.1992.73.5.1925
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发表时间：
1992
影响因子：
3.3
通讯作者：
N. Fujitsuka
中科院分区：
文献类型：
--
作者：
A. Yoshimura;C. Fujitsuka;K. Kawakami;N. Ozawa;H. Ojala;N. Fujitsuka
利用肌球蛋白腺苷三磷酸酶（ATPase）和免疫荧光染色方法，在大鼠比目鱼肌（SOL）和伸指长肌（EDL）肌肉的冰冻切片中研究了梭内和梭外纤维对耐力游泳的适应性反应。糖原消耗证实了标准化运动结束时的肌肉疲劳。在任何纤维中均未检测到肌球蛋白同种型的显着年龄依赖性变化。 12 周的训练使 SOL 中的 I 型纤维增加了 10.9%，EDL 中的 IIa 型纤维增加了 16.6%。在训练过的肌肉切片中，两种染色方法都鉴定出排列的链纤维，其表达与 bag2 纤维中的肌球蛋白亚型相同。然而，在 bag1 和 bag2 纤维中没有发现运动引起的肌球蛋白异构体谱的变化。肌球蛋白 ATP 酶（和免疫荧光）染色显示，训练 6 周后，排列链纤维的百分比从 0 增加到 6.7% (5.6%)，训练 12 周后增加到 19.2% (14.1%)，训练后 10 周仍保持在 6.1% (4.2%)。因此，通过肌梭的重复募集，可以在核链纤维中表达一种新的肌球蛋白亚型。
With the use of myosin adenosinetriphosphatase (ATPase) and immunofluorescence staining methods, the adaptive responses of intrafusal and extrafusal fibers to endurance swimming were studied in frozen sections of rat soleus (SOL) and extensor digitorum longus (EDL) muscles. Glycogen depletion confirmed muscle fatigue at the end of a standardized bout of exercise. No significant age-dependent changes in myosin isoforms were detected in any fibers. The 12-wk training increased type I fibers by 10.9% in the SOL and type IIa fibers in the EDL by 16.6%. In trained muscle sections, both staining methods identified a permuted chain fiber, expressed the same as the myosin isoform in the bag2 fiber. However, no exercise-induced change of myosin isoform profile was found in the bag1 and bag2 fibers. Myosin ATPase (and immunofluorescence) staining showed the percentage of permuted chain fibers increased from 0 to 6.7% (5.6%) after 6 wk of training and to 19.2% (14.1%) after 12 wk of training and that it was still at 6.1% (4.2%) 10 wks after training. A novel myosin isoform may thus be expressed in nuclear chain fibers by repetitive recruitment of muscle spindles.