Miller C
Biophys J. 1987 Jul;52(1):123-6. doi: 10.1016/S0006-3495(87)83196-X.
Single Ca++-activated K+ channels from rat muscle plasma membranes are inhibited by Ba++. A single Ba++ entering the channel's conduction pore induces a long-lived blocked state. This study employs Ba++ as a probe of the channel's conduction pathway to show that the channel can be forced to close with a single Ba++ ion inside the pore. A Ba++ ion inside the closed channel is trapped and cannot escape until the channel opens. The results demonstrate that in the channel's closed state, the cytoplasmic side of the conduction pore is obstructed to the passage of ions.
来自大鼠肌细胞膜的单个钙离子激活的钾通道受到钡离子的抑制。单个进入通道传导孔的钡离子会诱导一个长寿命的阻断状态。本研究采用钡离子作为通道传导途径的探针，以表明通道孔内有单个钡离子时可被迫关闭。封闭通道内的钡离子被困住，直到通道打开才能逸出。结果表明，在通道的关闭状态下，传导孔的细胞质侧对离子的通过有阻碍作用。
