Wroblewski R, Edström L, Jakobsson F
Department of Pathology, Karolinska Hospital, Stockholm, Sweden.
J Submicrosc Cytol Pathol. 1989 Oct;21(4):685-90.
Fast twitch extensor digitorum longus (EDL) and slow twitch soleus (S) muscles were studied after 5 and 16 days of denervation. Elemental contents of single muscle fibres were obtained with energy dispersive X-ray microanalyses (XRMA) applied on cryosections visualised in the scanning or scanning-transmission mode of electron microscopy. Cross sections in series with those produced for analytical electron microscopy were stained for enzyme histochemical fibre typing. A similar increase of Na and Cl was observed in EDL and S fibres after 16 days of denervation and a decrease of K was observed as well in EDL. This time after denervation is known to correspond to the maximal acetylcholine receptor synthesis extrajunctionally. There were no changes of elemental content after 5 days and thus the early membrane changes as i.a. fall in resting membrane potential and increased permeability for Na as well as increased endocytosis did not correspond to changes detectable by XRMA. Time course of atrophy differed between histochemical fibre types in EDL. In S all the muscle fibres atrophied earlier than in EDL and without any difference between fibre types. Then changes in elemental composition of muscle fibres after denervation do not seem to be related to degree and time course of muscle fibre atrophy.
在去神经支配5天和16天后，对快肌趾长伸肌（EDL）和慢肌比目鱼肌（S）进行了研究。通过对在扫描或扫描透射电子显微镜模式下观察的冷冻切片应用能量色散X射线微分析（XRMA），获得了单根肌纤维的元素含量。与用于分析电子显微镜的切片系列的横断面进行酶组织化学纤维分型染色。去神经支配16天后，在EDL和S纤维中观察到Na和Cl有类似的增加，并且在EDL中也观察到K的减少。已知去神经支配后的这段时间对应于接头外乙酰胆碱受体合成的最大值。5天后元素含量没有变化，因此早期的膜变化，如静息膜电位下降、对Na的通透性增加以及内吞作用增加，与XRMA可检测到的变化不对应。EDL中组织化学纤维类型之间的萎缩时间进程不同。在S中，所有肌纤维比EDL更早萎缩，并且纤维类型之间没有任何差异。因此，去神经支配后肌纤维元素组成的变化似乎与肌纤维萎缩的程度和时间进程无关。
