Mizutani Makoto, Nakae Yoshiko, Ohno Norikazu
Department of Anatomy, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusaku, Nagoya 464-8650, Japan.
Okajimas Folia Anat Jpn. 2007 May;84(1):19-24. doi: 10.2535/ofaj.84.19.
The quantitative assessment of enzyme activities in situ in single muscle fibres is essential for understanding the functions of skeketal muscles. The function of the lateral pterygoid muscle (LPM) is not fully understood because it is a deeply located masticatory muscle and cannot be dissected in an intact configuration. Here we report how to measure the activities of mitochondrial succinate dehydrogenase (SDH) in single muscle fibres in situ in the LPM in sections of rat heads. Unfixed head sections were incubated on gel films containing SDH substrate and nitroblue tetrazolium. During incubation, images of the section due to deposition of the final reaction products, formazans, were captured at intervals of 10 s using a real-time image analysis system for absorbance measurements. We found that the belly of the LPM consisted of four areas with different mean activities of SDH. The lateral and upper areas of the muscle showed similarly high SDH activities. Mean activity in the lower area was the lowest, about half of those of the lateral and upper areas. These results agree with the hypothesis that the superior head of the LPM participates in more continuous contraction and is more resistant to fatigue than the inferior head.
对单根肌纤维中的酶活性进行原位定量评估对于理解骨骼肌的功能至关重要。翼外肌（LPM）的功能尚未完全明确，因为它是一块位置较深的咀嚼肌，无法以完整形态进行解剖。在此，我们报告了如何在大鼠头部切片的翼外肌中对单根肌纤维中的线粒体琥珀酸脱氢酶（SDH）活性进行原位测量。未固定的头部切片在含有SDH底物和硝基蓝四唑的凝胶膜上孵育。孵育过程中，使用实时图像分析系统每隔10秒采集一次切片因最终反应产物甲臜沉积而产生的图像，用于吸光度测量。我们发现翼外肌肌腹由四个具有不同SDH平均活性的区域组成。肌肉的外侧和上部区域显示出相似的高SDH活性。下部区域的平均活性最低，约为外侧和上部区域的一半。这些结果与以下假设一致，即翼外肌上头比下头参与更持续的收缩且更抗疲劳。
