Electrophysiologicalestudy on the cardiac ryanodine receptor operating the Ca-induced Ca-release mechanisms.

在为期两年的“心脏ryanodine受体（RyR）运行ca诱导ca释放机制的电生理研究”项目中，我们获得了以下结果。心脏RyR的单通道活性被重组成平面脂质双层。(1)我们通过磷酸化探索了RyR通道活性的调节机制。RyR被蛋白激酶A亚基激活。磷酸化的RyR通道打开/关闭的频率更高，打开的时间更长，关闭的时间更短。进一步证明，这种活化是由于对胞质阻断配体Mg离子的敏感性降低所致。关于这项工作的一篇论文最近被Pflugers档案库接受。(2)研究了膜脂（如鞘脂）的病理生理代谢产物对RyR通道活性的另一种调节机制。虽然这种物质是脂质，但它很可能与通道分子的特定细胞质位点结合并阻断通道活性。关于这项工作的一篇论文已经提交给了某杂志。(3)我们还分析了RyR真实电流抑制ca诱导的ca释放的失活机制。我们正在准备一份关于这项工作的文件。因此，心肌细胞胞质代谢物对钙诱导的钙释放中发挥核心作用的RyR的一些新的调控机制已经被阐明。

Performing the two-year project on "Electrophysiological study on the cardiac ryanodine receptor (RyR) operating the Ca-induced Ca-release mechanisms", we obtained the following results. The single-channel activity from the cardiac RyR was reconstituted into planar lipid bilayers.(1) We explored a modulation mechanism of the channel activity of the RyR via a phosphorylation. The RyR was activated by the protein kinase A subunit. The phosphorylated RyR channels open/close more frequently, stay open longer, stay closed for shorter periods. It was improved that the activation is ascribable to the decrease in sensitivity to the cytosolic blocking ligarid of Mg ion. A paper on this work was recently accepted by Pflugers Archiv.(2) We investigated another modulation mechanism of the channel activity of the RyR by the pathophysiological metabolytes from membrane lipids such as sphingolipids. Although this substance is lipid, it is likely to bind to the specific cytoplasmic site of the channel molecule and to block the channel activity. A paper on this work was already submitted to some journal.(3) We also analysed the inactivation mechanism of the real current of the RyR to inhibit the Ca-induced Ca-release. We are now preparing a paper on this work.Thus, some novel regulation mechanisms by cytoplasmic metabolites of the cardiac myocytes on RyR which exerts a central role of the Ca-induced Ca release have been elucidated.