Electrophysiological study of the functional structure of the Na channel.

Na通道功能结构的电生理研究。

• 批准号: 61570044
• 负责人: SEYAMA Issei
• 金额: $ 1.54万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61570044/
• 关键词: Na channel; Squid axon; Blocking action; Cyclic polyamine; グラヤノトキシン; Na透性; グアニディニウム基; 不活性化過程; イカ巨大神経

In this series of experiments using the internal perfusion and the voltage clamp method on squid giant axon, an attempt was made to elucidate the functional structure Na channel by using the newly found biological toxins and chemicals. The experiments were categorized as follows; 1) The mechanism of block of the Na channel from the internal surface of cell membrane by cyclic-polyamine derivatives. cyclam and its analogue having the alkylguanidunium side chain (G-cyclam) have shown to block the Na channel only from the internal surface. Mode of the block is voltage- as well as time-dependent. In the case of G-cyclam, time course of the block is governed by a single exponential function. While, cyclam blocks Na channel with a double exponential function. The enhancement of blocking action occurred when [Na]_i increased from 50 to 200 mM. Two state three barrier model well explains all these blocking actions in the Na channel. from the molecular consideration of these cyclic aolyamine ana … More logues, it is reasonable to assume that alkyl guanidinium group freely moves inside the na channel, thereby attaching the negative charged site and in ture blocking the Na channel. 2) Similar finding also obtained, when two spider toxins, JSTX-3 and NSTX-3, were applied intra-cellularly. These spider toxins have a common 2,4 dihydrooxy-phenylacethyl-aspargynil-cadabelino-ptreamine. Difference in molecular structure is recognized in the terminal where JSTX-3 has gpysine and NSTX-3 arginine residues. Since NSTX-3 exerts stronger blocking action than JSTX-3 does, again freely movable terminal group having a permanent positive charge is assumed to play an important role in blocking the Na channel. 3) Externally applied grayanotoxin (GTX), Na channel modifier, appeared in the intracellu lar phase and induced much bigger depolarization in the non-perfusion of intracellular phase than in the continuous perfusion. Thus, it has been concluded that the site of action is in the intracellular phase. Less

在鱿鱼巨轴突上采用内部灌注和电压钳法进行的这一系列实验中，试图利用新发现的生物毒素和化学物质来阐明Na通道的功能结构。实验分类如下； 1）环状多胺衍生物阻断细胞膜内表面Na通道的机制。仙客来及其具有烷基胍侧链的类似物 (G-仙客来) 已显示仅从内表面阻断 Na 通道。模块的模式与电压和时间相关。在 G-cyclam 的情况下，块的时间过程由单个指数函数控制。同时，cyclam以双指数函数阻断Na通道。当[Na]_i从50 mM增加到200 mM时，阻断作用增强。二态三势垒模型很好地解释了Na通道中的所有这些阻塞作用。从这些环状胺类的分子角度考虑，可以合理地假设烷基胍基团在 Na 通道内自由移动，从而连接带负电的位点并最终阻断 Na 通道。 2)当两种蜘蛛毒素JSTX-3和NSTX-3应用于细胞内时，也得到了类似的发现。这些蜘蛛毒素有一个共同的2,4二羟基-苯乙酰-天冬氨酰-卡达贝利诺-ptreamine。分子结构的差异可在末端发现，其中 JSTX-3 具有 gpysine，而 NSTX-3 具有精氨酸残基。由于NSTX-3比JSTX-3发挥更强的阻断作用，因此具有永久正电荷的可自由移动的末端基团再次被认为在阻断Na通道中发挥重要作用。 3)外用Na通道调节剂灰藻毒素(GTX)出现在细胞内期,在细胞内非灌注期比连续灌注期诱导更大的去极化。因此，可以得出结论，作用位点是在细胞内阶段。较少的

项目成果

Seyama,I.: J.Physiol.Soc.Japan.48(2,3). 183 (1986)

Seyama，I.：J.Physiol.Soc.Japan.48(2,3)。

Yamaoka,K.: J.Physiol.Soc.Japan.48(2,3). 342 (1986)

Yamaoka,K.：J.Physiol.Soc.Japan.48(2,3)。

Seyama,I.: Natural Products and Biological Activitties.University of Tokyo Press.101-109 (1986)

Seyama,I.：天然产物和生物活性。东京大学出版社.101-109 (1986)

Seyama,I.Ed.Hiroo,I.et al.: Natural Products and Biological Activities.University of Tokyo Press.101-109 (1986)

Seyama,I.Ed.Hiroo,I.et al.：天然产物和生物活性。东京大学出版社.101-109 (1986)

Seyama, I.: "Mechanism of the Na channel block with trypargine and guanidyl-side armed cyclam." Natural products and biological activities.101-109 (1986)

Seyama，I.：“用色精和胍基侧武装仙客来阻断 Na 通道的机制。”