肌细胞发育过程中间隙连接的变化

THE APPEARANCE AND CHANGES OF GAP JUNCTIONS DURING MYOGENESIS OF CYNOPS EMBRYOS

用石蜡切片、超薄切片和冰冻蚀刻技术研究了东方蝾螈胚胎肌细胞发育过程中间隙连接的变化。间隙连接最初出现于原肠后期的体节中胚层细胞中,到原肠末期,体节中胚层细胞间的间隙连接数量骤增,从神经板期到鼻窝出现期,间隙连接数量保持在一个相当高的水平,肌效应期后,其数量明显下降,直到肌细胞发育成熟,神经-肌肉连接充分发育,间隙连接才消失。间隙连接大小的变化与数量的变化表现为平行的现象。此外,细胞融合之前,正是间隙连接的数量和大小达到最高峰的时间。这些结果说明细胞通讯与胚胎肌细胞发育密切相关。对细胞通讯在细胞决定和分化以及细胞融合中的可能作用进行了讨论。

The appearance and changes of gap junc-tions during the development of striatedmuscle cells of Cynops orientalis have beenstudied by paraffin section,ultrathin-sectionand freeze-etching techniques.Gap junctionsfirst appear between the somitic mesodermcells in the late gastrula.A marked increaseof the number of gap junctions occurs at theend of gastrulation.The number of gap junc-tions remains at a high level from neuralplate stage up to nasal pit stage.After thestage of muscle contraction,the number ofgap junctions decreases.Gap junctions do notdisappear until muscle cells have attainedtheir final differentiation and neuromuscularjunctions have fully developed.The changesof size of gap junctions parallel with thechanges in number.In addition,the numberand size of gap junctions are both at the highlevel before cell fusion.Therefore,it is pos-sible to conclude that cell communication isclosely correlated with the development ofstriated muscle cells.The role of communi-cations in cell determination and differentia-tion and in cell fusion of muscle cells arediscussed.