Studies on molecular mechanism of neural calcium signaling

细胞内钙离子在神经信号传导和神经可塑性中起着重要作用。近年来，分子生物学技术在神经生物学中的应用极大地促进了对神经系统钙代谢分子机制的研究，并导致对作为功能元件的蛋白质的功能和性质的阐明。另一方面，我们对大脑高级功能的了解也在迅速增加，特别是由于非侵入性测量方法的出现。然而，在了解大脑分子和了解大脑高级功能之间仍然存在很大的差距。为了填补这一空白，我们在这个项目中研究了以下主题。我们通过电生理和药理学测量在培养细胞中表达的重组钙通道，研究了通过gtp结合蛋白调节电压依赖性钙通道的分子机制。我们获得了新的观察结果，表明g蛋白的多种调节模式。我们研究了电压依赖性钙通道和良胺受体在良胺受体缺乏小鼠骨骼肌细胞中表达的分子相互作用。我们证明了在兴奋-收缩耦合机制中，骨型和心脏型ryanodine受体之间的功能不平等。我们一直在尝试克隆一个编码一种新型非电压依赖性钙渗透通道的cdna家族。到目前为止，我们已经获得了这个家族几个成员的cdna，现在正在研究组织分布和功能特性。为了满足小鼠脑钙成像的需要，我们制作了一套专门用于脑片制备的装置，并开发了相应的软件环境。小鼠神经元钙代谢的基本数据与大鼠神经元基本一致，但由于小鼠大脑体积小，难以处理更小的结构或未成熟的大脑。

Intracellular calcium ion plays critical roles in neural signaling and neural plasticity. Recently, application of molecular biological techniques into neurobiology has dramatically accelerated studies on molecular mechanism of calcium metabolism in the nervous system, and led to elucidation of functions and properties of proteins which work as functional elements. On the other hand, our knowledge of higher brain functions is also rapidly increasing, especially owing to non-invasive measurement methods. However, there still remains a big gap between understanding molecules in brain and understanding higher brain functions. In order to fill the gap, we studied following subject in this project.We studied molecular mechanism of modulation of voltage-dependent calcium channels through GTP-binding proteins, by electrophysiological-and pharmacological measurements of recombinant calcium channels expressed in cultured cells. We obtained novel observation indicating showing multiple mode of G-protein modulation. We investigated molecular interaction between voltage-dependent calcium channels and ryanodine receptors expressed in skeletal muscle cells derived from ryanodine receptor-deficient mice. We demonstrated functional non-equality between skeletal type and cardiac type of ryanodine receptors in the excitation-contraction coupling mechanism. We have been trying to clone a family of cDNAs encoding a novel type of non-voltage-dependent calcium permeable channels. So far we have obtained cDNAs of several members of this family, and now are now studying tissue distribution and functional properties. To meet the need for calcium imaging of mouse brain, we have made a setup designed for brain slice preparation and developed a software environment. The basic data of calcium metabolism of mouse neurons corresponds well to those of rat neurons, however, the small size of mouse brain makes it difficult to handle smaller structures or immature brains.