Sonoda M, Moriya H, Shimada Y
Department of Anatomy/Cell Biology, School of Medicine, Chiba University, Japan.
Microsc Res Tech. 1993 Apr 1;24(5):423-8. doi: 10.1002/jemt.1070240507.
The 3-dimensional distribution of transverse (T) tubules at myotendinous junctions (MTJs) was studied by intermediate voltage (400 kV) electron microscopy of thick sections of rat vastus intermedius and chicken pectoralis muscles stained with lanthanum nitrate. Transversely oriented T tubules were seen to run at the level of A-I junctions (the rat vastus intermedius) and Z bands (the chicken pectoralis), but were absent from such levels adjacent to the end of MTJ processes. These tubules opened to the lateral wall of sarcolemmal infoldings of MTJs and to the lateral cell surface. Longitudinally running T tubules were seen to connect with the transverse T tubules and to open at the bottom of junctional folds. The lack of T tubules at the final sarcomeric regions seems to indicate that the terminal sarcomeric half in close proximity to MTJs may be activated from the sarcoplasmic reticulum which forms couplings with the MTJ sarcolemma and/or longitudinal tubules in the MTJ processes.
通过对硝酸镧染色的大鼠股中间肌和鸡胸肌厚切片进行中压（400 kV）电子显微镜观察，研究了肌腱连接点（MTJ）处横管（T管）的三维分布。可见横向排列的T管在A-I连接点（大鼠股中间肌）和Z带（鸡胸肌）水平处走行，但在MTJ突起末端相邻的此类水平处不存在。这些小管通向MTJ肌膜内褶的侧壁和细胞外侧表面。可见纵向走行的T管与横向T管相连，并在连接褶底部开口。在最终的肌节区域缺乏T管似乎表明，紧邻MTJ的末端肌节半部可能由肌浆网激活，肌浆网与MTJ肌膜和/或MTJ突起中的纵向小管形成连接。
