GATING AND IONIC CURRENTS OF CLONED POTASSIUM CHANNELS

钾通道在调节心肌细胞活性中起着不可或缺的作用。 神经和肌肉等细胞的兴奋性。当钾离子通道 是开放的，钾从内部沿着浓度梯度向下流动 在牢房外。这会使薄膜远离射击阈值。 从而降低细胞的兴奋性。开业和闭幕 电压依赖性钾通道由膜调节 随着膜的去极化，电势通道打开。电压 通道开放的依赖性来自构象变化，其中 有一个电荷的净运动穿过电场。 薄膜。这种电荷移动可以作为瞬变的“门控”来测量 电流“在电压钳实验中。这项研究的长期目标 建议是定义耦合这一电荷的结构域 电压依赖性钾的开通和闭合运动 频道。 该提案主要集中在两个方面：1)具有以下特点的药理制剂 与电压依赖性钾的门控机制相互作用 通道和2)两个以不同方式耦合的钾通道克隆 电荷运动和通道闭合由内部检测 四乙基铵。实验同时采用膜片钳和切割法 开放卵母细胞凡士林间隙技术测量离子电流和门控电流 来自克隆的钾通道。这些研究应该提供有意义的 对钾通道活性的机制的洞察 由膜电位调制，并可能揭示其作用机制 监管。

Potassium channels play an integral role in regulating the activity of excitability of cells such as nerve and muscle. When potassium channels are open, potassium flows down its concentration gradient from inside to outside the cell. This draws the membrane away from the firing threshold and thereby decreases cell excitability. The opening and closing of voltage dependent potassium channels is regulated by the membrane potential channels open as the membrane is depolarized. The voltage dependence of channel opening arises from conformational changes in which there is a net movement of charge across the electric field of the membrane. This charge movement can be measured as a transient "gating currents" in voltage clamp experiments. The long term goal of this proposal is to define the structural domains that couple this charge movement to the opening and closing of voltage dependent potassium channels. This proposal focuses on two main aspects: 1) pharmacological agents that interact with the gating mechanism of voltage dependent potassium channels and 2) two potassium channel clones that couple differently charge movement and channel closing as assayed by internal tetraethylammonium. The experiments employ both the patch clamp and cut open oocyte Vaseline gap techniques to measure ionic and gating current from cloned potassium channels. These studies should provide meaningful insight to the mechanisms by which potassium channel activity is modulated by membrane potential and may reveal mechanisms for their regulation.