Tiras N R, Pavlik L L, Moshkov D A
Institute of Biological Physics, USSR Academy of Sciences, Pushchino.
Acta Histochem Suppl. 1991;41:249-56.
The ultrastructural changes in the cytoskeleton of the goldfish Mauthner cells (M-cells) at various functional states induced by intracerebral microinjections of biologically active substances were studied. Under the action of kainic acid, a structural analog of the excitatory neurotransmitter of glutamate, the density of the cytoplasmic matrix increased. Cytotoxin II from the cobra toxin, which blocks acetylcholine transmission, had an opposite effect upon the M-cell cytoskeleton. Simultaneously, in some areas of the neural cytoplasm strands of an electron-dense material of various shapes appeared. They had an unique structure which did not resemble any known cytoskeleton element. The molecular composition of the strands is unknown, but similar strands appeared after injections of phalloidin or cytochalasin B, both disturbing the microfilamental component of the cytoskeleton. Decoration with myosin subfragment-1 revealed actin in intact M-cells which was organized as crossing loose filaments and bundles of parallel fibers. The morphology of the fiber bundles resembles the helical part of the strands appearing after the treatment with phalloidin, cytochalasin B, or cytotoxin II. It is suggested that the cytoplasmic matrix of M-cells is a dynamic system which responds to the functional changes by thickening or loosening of its cytoskeletal elements or by formation of new structures.
研究了脑室内微量注射生物活性物质诱导金鱼莫氏细胞（M细胞）在不同功能状态下细胞骨架的超微结构变化。在谷氨酸兴奋性神经递质的结构类似物红藻氨酸的作用下，细胞质基质密度增加。阻断乙酰胆碱传递的眼镜蛇毒素细胞毒素II对M细胞骨架有相反的作用。同时，在神经细胞质的某些区域出现了各种形状的电子致密物质的细丝。它们具有独特的结构，与任何已知的细胞骨架成分都不相似。这些细丝的分子组成尚不清楚，但在注射鬼笔环肽或细胞松弛素B后也出现了类似的细丝，这两种物质都会干扰细胞骨架的微丝成分。用肌球蛋白亚片段-1进行标记显示，完整的M细胞中存在肌动蛋白，其组织形式为交叉的松散细丝和平行纤维束。纤维束的形态类似于用鬼笔环肽、细胞松弛素B或细胞毒素II处理后出现的细丝的螺旋部分。研究表明，M细胞的细胞质基质是一个动态系统，它通过细胞骨架成分的增厚或松弛或通过形成新结构来响应功能变化。
