去神经对快,慢肌纤维肌球蛋白ATPase影响的组织化学观察

本文用组织化学方法观察了豚鼠比目鱼肌(SOL)和腓骨第三肌(PT)在去神经后其快、慢纤维肌球蛋白ATPase特性的变化。在正常肌肉中Ⅰ型(慢)纤维和Ⅱ型(快)纤维分别具有酸和碱稳定ATPase活性。慢纤维在去神经后出现了碱稳定ATPase活性,而快纤维则无明显变化。结果表明,只有慢纤维的肌球蛋白ATPase特性才与神经支配有关。

HISTOCHEMICAL STUDIES ON MYOSIN ATP are OF SLOW AND FAST MUSCLE FIBERS AFTER DENERVATION

The effect of denervation on the myosin ATPase property of fast and slow fibers in so-leus muscle (SOL) and peroneal muscle third (PT) of adult guinea-pig was histochemically monitered, based on the fact that slow (type I) and fast (type II) fibers will display notable acid-stable and alkali-stable myosin ATPase activities respectively. The observations were made in animals denervated 1-6 weeks. (1) SOL, as a homogeneous slow twitch muscle, was constructed only by type 1 fibers, but PT, composed of type II (94%), type I (6%) and a very few intermediate type fibers, was a heterogeneous fast twitch muscle. (2) In SOL, alkalistable activity generated and enhanced gradually after denervation as follows: On the seventh day, the activity had clearly appeared in a few fibers. In following weeks, such kind of fibers increased and in the meantime the activity in the single fiber also developed obviously. By three weeks, alkali-stable fibers could reach approximately 90% of total fibers (3) However, even to six weeks, acidstable ATPase activity still remained at a rather high level in all fibers. It may suggest that both slow and fast myosin isozymes coexisted in denervated slow muscle. (4) Similarly, the slow fibers in denervated PT were found to have the alteration as same as those of SOL, but the fast fibers seemed to have not changed apparently. (5) Some fibers in contra-lateral SOL altered in the way of denervated lateral SOL. In sum, the enzymic property of myosin ATPase of slow fiber, but not fast fiber, is dependent upon the functional activity of the nervous system, and it is worthy to note this method allows us to illustrate a early process of modification of myosin ATPase.