大白鼠大脑视区皮质棘器的微细结构

用电镜对大鼠大脑视区皮质内锥体细胞树突侧棘的棘器作了观察,并分析了其微细结构。棘器是大脑皮质内侧棘结构的一个显著特点,系由被嗜锇性的致密带或颗粒分隔的一些囊或管组成的,它们是复杂多形态的结构。棘器一般位于侧棘小头内,本文也报导了小柄内的棘器。突触后膜和棘器间可见有微丝连接,偶见棘器附近有核糖体。棘器膜性囊或管的形态与滑而内质网相似,说明二者系同源结构。几种形态的棘器中,Gray氏棘器和管形棘器仅见于哺乳动物大脑皮质内,未能在低位中枢神经系统内见到,因而认为棘器可能与脑新皮质的特异性功能有特殊的关系。

THE FINE STRUCTURE OF SPINE APPARATUS IN THE VISUAL CORTEX OF THE RAT

The dendritic spine apparatus of the pyramidal cell in the visual cortex of the rat cerebrum has been observed with the electron microscope after fixation by glutaraldehyde-osmium tetroxide and double staining with uranyl acetate and lead citrate. The present study analyzed the fine structure of the spine apparatus. It was found that the spine apparatus is a prominent character of the structure of the dendritic spine in the cerebral cortex. The spine apparatus of visual cortex consists of a series of sacs or channels separated by several bands or granules of osmophilic dense material These special organoids are complicated and polymorphous structure. Usually, the spine apparatus located mainly in the head of the spine, but some were encountered within the stalk of the spine. In the postsynaptic element, some microfilaments connected the spine apparatus and the postsynaptic membrane. Occasionally, some ribosomes occurred near the spine apparatus. As the membrane-bound sac of the spine apparatus is morphologically similar to the smooth endoplasmic reticulum, it was suggested that both organelles are homologous structures. Although there are several types of spine apparatus in the cerebral cortex, the Gray's and channel-like spine apparatuses have never been found in the lower regions of the central nervous system. Thus they might be unique to the cerebral cortex of the mammals and that they are in particular related to the specialized functions of the neocortex was considered.