Block of stretch-activated ion channels in Xenopus oocytes by gadolinium and calcium ions.
Block of stretch-activated ion channels in Xenopus oocytes by gadolinium and calcium ions.
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DOI：
10.1126/science.2466333
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发表时间：
1989-02
期刊：
影响因子：
56.9
通讯作者：
Xian-Cheng Yang;Frederick Sachs
中科院分区：
文献类型：
--
作者：
Xian-Cheng Yang;Frederick Sachs
钆离子在爪蟾卵母细胞中产生三种不同类型的拉伸激活（SA）离子通道阻滞：通道打开时间的浓度依赖性减少，开放通道电流的浓度依赖性减少，以及独特的，高度浓度依赖性的可逆通道打开抑制。最后一种效应将通道打开的概率从5微米时的10（-1）降低到10微米钆时的10（-5）以下。钙对通道开启时间和电流的影响与钆相似，但该通道对钙具有渗透性，钙不能完全抑制通道活性。SA离子通道阻滞剂的可用性可能有助于确定其生理功能，并将简化卵母细胞作为离子通道表达系统的使用。
Gadolinium ions produce three distinct kinds of block of the stretch-activated (SA) ion channels in Xenopus oocytes: a concentration-dependent reduction in channel open time, a concentration-dependent reduction in open channel current, and a unique, steeply concentration-dependent, reversible inhibition of channel opening. This last effect reduces the probability of a channel being open from about 10(-1) at 5 microM to less than 10(-5) at 10 microM gadolinium. Calcium has effects on open time and current similar to that of gadolinium, but this channel is permeable to calcium and calcium does not completely inhibit channel activity. The availability of a blocker for SA ion channels may help to define their physiological function, and will simplify the use of oocytes as an expression system for ion channels.