Martin R, Schilling K, Fritz W, Giuditta A
Sekt. Elektronenmikroskopie, Universität Ulm, F.R.G.
Neuroscience. 1990;37(2):553-62. doi: 10.1016/0306-4522(90)90423-2.
When inelastically scattered electrons with an energy loss specific for interaction with phosphorus atoms were used for visualization of sections of squid axons, bead-like domains of elongated proteins, presumably neurofilaments, exhibited distinct phosphorus signals. A marked asymmetry of these phosphorus signals was detectable between the pre- and the postsynaptic cytoskeleton of the giant synapse. Signals were very numerous and intense in the presynaptic terminal, while rare and weak in the postsynaptic axoplasm. The giant axon revealed a delayed appearance of phosphorus signals in its course from the cell bodies in the giant fibre lobe to its exit from the stellate ganglion. Numerous and intense phosphorylation signals were evident only in the peripheral giant axon. Asymmetry in the distribution of phosphorus signals between pre- and postsynaptic axoplasm paralleled differences in Ca(2+)-buffering mechanisms, as shown in a previous study. In the presynaptic terminal patterns of phosphorus signals correlated with precipitates which had formed after intra-axonal injection of calcium. Our observations suggest a role of phosphorylated neurofilaments in binding of calcium in the squid synapse.
当使用因与磷原子相互作用而具有特定能量损失的非弹性散射电子来观察鱿鱼轴突切片时，细长蛋白质的珠状结构域（可能是神经丝）呈现出明显的磷信号。在巨大突触的突触前和突触后细胞骨架之间可检测到这些磷信号的明显不对称性。信号在突触前终末非常多且强烈，而在突触后轴浆中则稀少且微弱。巨大轴突在从巨大纤维叶中的细胞体到其从星状神经节穿出的过程中，磷信号出现延迟。大量且强烈的磷酸化信号仅在周围的巨大轴突中明显。如先前研究所示，突触前和突触后轴浆中磷信号分布的不对称与钙缓冲机制的差异平行。在突触前终末，磷信号模式与轴突内注射钙后形成的沉淀物相关。我们的观察结果表明磷酸化神经丝在鱿鱼突触中钙结合方面发挥作用。
