家兔某种神经细胞的核膜皱折及其有关现象

INVAGINATION OF NUCLEAR MEMBRANE AND ITS RELATED PHENOMENA IN CERTAIN NERVE CELLS OF RABBIT

用电子显微镜观察到,中枢神经系统中,特别是斜方体核中,某些神经细胞显示特有的核膜皱折。其中有一些是深的内析,也有一些只是沿着核边缘的浅陷。核膜内折腔中含有内质网和成堆浓颗粒,后者与胞浆中核糖核蛋白类似。在内折腔中有时看见体积较大的球形致密体,其中含有高电子密度的细粒,它们可能是溶酶体。内折中还有成组的大小不同球形空泡,其性质不明。凡核膜有深内折处,在其口部几乎总是具有线粒体的大量聚集。但是,在内折腔中的深部极少看见线粒体。核膜浅陷所形成的袋内常装有成堆的颗粒、粗面内质网和线粒体。成堆的核仁物质和一些核膜皱折(包括浅陷和深折)有互相接近的趋势。我们认为,某些神经细胞的核膜皱折代表一种动态变化,它在整个生命期中周期性地出现,这可能是与尼氏体的生物合成有关的一种生理过程。

Certain nerve cells in the central nervous system and especially in the trapezoid nucleus as examined under electron microscope show characteristic infoldings of the nuclear membrane.The infolding formations may appear as deep invaginations or as simple depressions and indentations along the border of the nucleus.Substances in the lumen of the invaginations of the nuclear membrane consist of profiles of endoplasmic reticulum and clusters of dense particles,which are regarded as ribonucleoprotein similar to that found in the cytoplasm.Large spherical dense bodies containing electron-opaque fine grains suggesting lysosomes have occasionally been found in the invagination.Aggregates of various sized spherical vacuoles of unknown nature are also present.Whenever there is a deep invagination of the nuclear membrane there is almost al-ways a large concentration of mitochondria around its opening.Mitochondria,however,have rarely been found in the depth of the nuclear invagination.The pockets formed by shallow depressions and indentations of the nuclear membrane are often loaded with clustered ribosomes,granular endoplasmic reticulum and mitochondria,Clumps of nucleo-lar substances and some of the infoldings of the nuclear membrane.deep or shallow,tend to approach each other.The infoldings of the nuclear membrane of certain nerve cells are thought to be a dynamic change occurring periodically throughout life as a physiological process concerned with the biosynthesis of Nissl substance.