大鼠心肌细胞的肌浆网与闰盘间偶联的电镜观察

本实验对大鼠心房心肌细胞的肌浆网与閏盘间的关系进行了超微结构观察。结果表明,肌浆网与閏盘的非特化肌膜存在偶联,为区别于一般的周围偶联,而将它们之间的偶联称为閏盘偶联。它具有周围偶联及内部偶联的形态结构特征,即(1)在偶联区域内存在胞浆间隙,宽约11～18nm;(2)在胞浆间隙内有连接突或连足;(3)肌浆网腔内含有电子致密物质。在偶联区域,肌浆网膜不仅与閏盘的非特化肌膜形成偶联,而且与线粒体外膜紧密并置。此外,心肌缝隙连接与肌浆网可形成缝隙连接-肌浆网偶联,其超微结构特点与心肌偶联相同。本文对肌浆网与閏盘的偶联的功能意义进行了讨论。

Electron Micoscopic Observation on Coupling of Sarcoplasmic Reticulum with the Intercalated Disk in Myocardial Cells of Rat

The ultrastructure of the relationship between the sarcoplasmic (SR) and the intercalated disk in the atrial myocardial cells of the heart is studied. The results reveal: a coupling exists between the SR and the unspecializsd sarcolem-ma of the intercalated disk. In order to differentiate it from a general peripheral coupling it is called intercalated disk coupling. It possesses 3 morphological features of the peripheral and interior couplings, i. e., the cytoplasmic gap in coupling region is about 11-18 nm in width; the jnctional processes or junc-tional feet are located in the cytoplasmic gap; and the SR contains electronic dense material in its lumen. In the coupling region the RS membranes are not only coupling with the unspecialized membrane of the intercalated disk but also closely apposed to the external membrane of mitochondria. In addition, the gap junction-sarcoplasmic reticulum couplings are formed between the cardial gap junction and the SR. Its ultrastructural characteristics are the same as the cardial couplings. The functional significance of the couplings of the SR with the intercalated disk is discussed.