Slow to fast alterations in skeletal muscle fibers caused by clenbuterol, a beta 2-receptor agonist.
Slow to fast alterations in skeletal muscle fibers caused by clenbuterol, a beta 2-receptor agonist.
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克伦特罗（一种 β2 受体激动剂）引起骨骼肌纤维从慢到快的变化。
DOI：
10.1152/ajpendo.1988.254.6.e726
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Etlinger,JD
中科院分区：
文献类型：
--
作者：
Zeman,RJ;Ludemann,R;Easton,TG;Etlinger,JD
用盐酸克仑特罗（一种β 2受体激动剂）慢性治疗大鼠（8-12周），引起比目鱼肌内组织化学鉴定的快肌纤维肥大，而不是慢肌纤维，而指长伸肌（EDL）中两种纤维的平均面积都增加。相比之下，用- 2受体拮抗剂丁胺治疗，减少了两块肌肉的快肌纤维大小。在solei和edl中，克伦特罗增加了快肌纤维与慢肌纤维的数量之比，但在较小程度上增加了edl，而butoxamine则相反。在EDL中观察到的肌纤维肥大伴随着最大强直张力和肌肉横截面积的平行增加，而在solei中，也观察到向典型的快速收缩肌肉的力量发展和松弛率的渐进增加。我们的研究结果表明β 2受体在调节肌纤维类型组成和生长中的作用。
Chronic treatment of rats with clenbuterol, a beta 2-receptor agonist (8–12 wk), caused hypertrophy of histochemically identified fast- but not slow-twitch fibers within the soleus, while the mean areas of both fiber types were increased in the extensor digitorum longus (EDL). In contrast, treatment with the beta 2-receptor antagonist, butoxamine, reduced fast-twitch fiber size in both muscles. In the solei and to a lesser extent in the EDLs, the ratio of the number of fast- to slow-twitch fibers was increased by clenbuterol, while the opposite was observed with butoxamine. The muscle fiber hypertrophy observed in the EDL was accompanied by parallel increases in maximal tetanic tension and muscle cross-sectional area, while in the solei, progressive increases in rates of force development and relaxation toward values typical of fast-twitch muscles were also observed. Our results suggest a role of beta 2-receptors in regulating muscle fiber type composition as well as growth.