Tokunaka S, Okamura K, Fujii H, Yachiku S
Department of Urology, Asahikawa Medical College, Japan.
Urol Res. 1990;18(5):341-4. doi: 10.1007/BF00300784.
The proportions of fast and slow myosin molecules in external urethral sphincter specimens from ten urodynamically normal male bladder carcinoma patients were estimated from the contents of fast and slow myosin light chains in two-dimensional electrophoretic gels. The percentages of fast and slow myosin molecules ranged from 5.0% to 61.4% with a mean of 35.5% and from 38.6% to 95.0% with a mean of 65.5% respectively. It is therefore concluded that the human external urethral sphincter is composed of both fast and slow muscle fibers as well as other voluntary muscles. The human external urethral sphincter is considered to be a highly fatigue-resistant muscle with a very high proportion of slow muscle fibers. In the cases studied so far, there is a great diversity in the proportions of fast and slow myosin molecules; the reason for this remains unknown.
从二维电泳凝胶中快、慢肌球蛋白轻链的含量，估算了10例尿动力学正常的男性膀胱癌患者尿道外括约肌标本中快、慢肌球蛋白分子的比例。快、慢肌球蛋白分子的百分比分别为5.0%至61.4%，平均为35.5%；以及38.6%至95.0%，平均为65.5%。因此得出结论，人类尿道外括约肌由快、慢肌纤维以及其他随意肌组成。人类尿道外括约肌被认为是一种具有高比例慢肌纤维、高度抗疲劳的肌肉。在目前所研究的病例中，快、慢肌球蛋白分子的比例存在很大差异，其原因尚不清楚。
