THE DISTRIBUTION OF MOBILE AND STRUCTURAL COMPONENTS AT CHEMICAL SYNAPSES

该项目旨在确定细胞内的分布 轴突、树突、胶质细胞内的可扩散成分和结构成分， 和突触。这项工作之所以重要，是因为 在细胞成分的局部化和移动之间 以及它们在突触传递中的作用。定量x射线 钙离子和钙离子在细胞内分布的微观分析 平行纤维/浦肯野细胞小脑突触的其他成分 表明在所有突触前和突触后细胞器中 光滑型内质网显著积聚 生理条件下的钙，而这种积累 作为突触的功能发生于细胞外来源 活动。蓄水池中吸收的钙量 浦肯野细胞树突棘--从700个增加到3倍 离子到2100个离子--与钙进入脊椎一致 通过配基门控离子通道。互补的新项目 利用视觉系统，神经元和神经胶质细胞的模型已经开始屈服 关于细胞内钙储存的身份和活动的数据。 活体冰冻切片的免疫细胞化学研究 周围神经髓鞘形成的电子显微镜观察 已经证明了细胞骨架的共同定位 肌动蛋白和血影蛋白与雪旺细胞黏附 施万氏特定胞质结构域中的MAG分子 手机。这些结果支持髓鞘形成的机制。 MAG介导的髓鞘定向附着形成 通过细胞骨架的运动。因此，该项目继续提供 关于两国之间详细关系的新信息 神经元和神经胶质的可扩散和结构成分，以及如何 它们调节神经元的活动。

This project aims to determine the intracellular distribution of diffusible and structural components within axons, dendrites, glia, and synapses. This work is important because of the relationship between the localization and movement of cellular constituents and their role in synaptic transmission. Quantitative x-ray microanalysis of the intracellular distribution of calcium and other elements in parallel fiber/Purkinje cell cerebellar synapses indicates that among all the pre- and postsynaptic organelles only the smooth endoplasmic reticulum accumulates significant calcium under physiological conditions, and that this accumulation occurs from extracellular sources as a function of synaptic activity. The amount of calcium taken up in the cisterns of the Purkinje cell dendritic spines -- a three fold increase from 700 ions to 2100 ions -- is consistent with calcium entry into spines via a ligand-gated ion channel. Complementary new projects using visual system models of neurons and glia have begun to yield data on the identity and activity of intracellular calcium stores. Immunocytochemical studies using frozen sections of actively myelinating peripheral nerve at the electron microscope level have demonstrated the co-localization of the cytoskeletal proteins actin and spectrin and the Schwann cell adhesion molecule MAG in specific cytoplasmic domains of the Schwann cell. These results support a mechanism for myelin sheath formation involving MAG-mediated myelin attachment directed by cytoskeletal motility. Thus, this project continues to provide new information on the detailed relationship between the diffusible and structural components of neurons and glia, and how these regulate neuronal activity.