Removal of sodium inactivation and block of sodium channels by chloramine-T in crayfish and squid giant axons.
Removal of sodium inactivation and block of sodium channels by chloramine-T in crayfish and squid giant axons.
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氯胺-T 消除小龙虾和鱿鱼巨轴突中的钠失活和钠通道阻断。
DOI：
10.1016/s0006-3495(87)83203-4
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发表时间：
1987
影响因子：
3.4
通讯作者：
J. Yeh
中科院分区：
文献类型：
--
作者：
J. Huang;J. Tanguy;J. Yeh
采用双蔗糖间隙法和轴向丝法分别研究了氯胺- t对电压钳定内灌注小龙虾和鱿鱼巨轴突钠通道的修饰作用。新制备的氯胺- t溶液对钠通道有两个主要作用：(a)不可逆地去除快速的Na失活，(b)可逆地阻断Na电流。当氯胺- t在轴突内部或外部（5-10 mM）施加时，观察到这两种效应。第一种效应是在小龙虾轴突中研究的。我们发现快速Na失活的去除并不取决于通道的状态，因为通道可以被氯胺- t在保持电位（从-80到-100 mV）或在-30 mV的去极化电位下修饰。去除快速Na失活后，缓慢Na失活机制仍然存在，更多的通道可以经历缓慢Na失活。这一结果表明，在小龙虾轴突中，快速失活状态的转变并不是缓慢失活状态发生的先决条件。在氯胺- t治疗期间，发生了明显的阻断期，在冲洗药物后恢复。本文详细研究了氯胺- t在鱿鱼轴突中的第二种作用。24 h后，氯胺- t溶液失去了快速失活的去除能力，但保留了阻断作用。在去除快速Na失活后，新鲜和陈化的氯胺- t溶液都以相似的效力和电压依赖的方式阻断Na电流，在较低的去极化电位下更为明显。（摘要删节250字）
Modification of sodium channels by chloramine-T was examined in voltage clamped internally perfused crayfish and squid giant axons using the double sucrose gap and axial wire technique, respectively. Freshly prepared chloramine-T solution exerted two major actions on sodium channels: (a) an irreversible removal of the fast Na inactivation, and (b) a reversible block of the Na current. Both effects were observed when chloramine-T was applied internally or externally (5–10 mM) to axons. The first effect was studied in crayfish axons. We found that the removal of the fast Na inactivation did not depend on the states of the channel since the channel could be modified by chloramine-T at holding potential (from -80 to -100 mV) or at depolarized potential of -30 mV. After removal of fast Na inactivation, the slow inactivation mechanism was still present, and more channels could undergo slow inactivation. This result indicates that in crayfish axons the transition through the fast inactivated state is not a prerequisite for the slow inactivation to occur. During chloramine-T treatment, a distinct blocking phase occurred, which recovered upon washing out the drug. This second effect of chloramine-T was studied in detail in squid axons. After 24 h, chloramine-T solution lost its ability to remove fast inactivation but retained its blocking action. After removal of the fast Na inactivation, both fresh and aged chloramine-T solutions blocked the Na currents with a similar potency and in a voltage-dependent manner, being more pronounced at lower depolarizing potentials.(ABSTRACT TRUNCATED AT 250 WORDS)
N-溴乙酰胺和链霉酶对钠失活的电压依赖性去除。
影响因子：
3.4
作者：
Salgado,VL;Yeh,JZ;Narahashi,T
通讯作者：
Narahashi,T