Effect of chronic respiratory load on cytochrome oxidase activity in diaphragmatic fibers.
Effect of chronic respiratory load on cytochrome oxidase activity in diaphragmatic fibers.
复制标题
慢性呼吸负荷对膈肌细胞色素氧化酶活性的影响。
DOI：
10.1152/jappl.1992.72.1.266
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Kim,YJ
中科院分区：
文献类型：
--
作者：
Bazzy,AR;Kim,YJ
To determine whether the increase in oxidative capacity after respiratory muscle training with chronic inspiratory loads in sheep is specific to a particular fiber type, we measured cytochrome c oxidase (COX) activity in type I and type II fibers. COX activity in individual fibers was examined histochemically and measured as relative optical density by use of an image processing system. Fiber types were differentiated by the myosin adenosine-triphosphatase reaction. We found that COX activity was higher in both fiber types in the trained diaphragms than in the control diaphragms (P less than 0.01). The increase with training was greater in type II (39%) than in type I fibers (21%), resulting in relatively homogeneous COX activity in all diaphragmatic fibers. The proportion of type I fibers increased from 43.4 +/- 5.4% in the control diaphragm to 53.1 +/- 2.9% in the trained diaphragm, whereas the proportion of type II fibers decreased (P less than 0.001). We conclude that respiratory muscle training activates oxidative enzyme activity in both diaphragmatic fiber types; this activation is differentially more in type II fibers, which also decrease in proportion, and less in type I fibers, which increase in proportion.
