BK通道
SK通道
钙激活钾通道
T型钙通道
伸展激活离子通道
生物物理学
化学
心脏动作电位
海马结构
R型钙通道
后超极化
细胞生物学
P型钙通道
膜片钳
离子通道
电压依赖性钙通道
内向整流钾离子通道
钙
配体门控离子通道
钾通道
去极化
细胞外
细胞内
钙通道
膜电位
电生理学
NMDA受体
神经科学
谷氨酸受体
复极
生物
生物化学
受体
有机化学
作者
Neil V. Marrion,Steven J. Tavalin
出处
期刊:Nature
[Springer Nature]
日期:1998-10-01
卷期号:395 (6705): 900-905
被引量:526
摘要
Calcium entry through voltage-gated calcium channels can activate either large- (BK) or small- (SK) conductance calcium-activated potassium channels. In hippocampal neurons, activation of BK channels underlies the falling phase of an action potential and generation of the fast afterhyperpolarization (AHP). In contrast, SK channel activation underlies generation of the slow AHP after a burst of action potentials. The source of calcium for BK channel activation is unknown, but the slow AHP is blocked by dihydropyridine antagonists, indicating that L-type calcium channels provide the calcium for activation of SK channels. It is not understood how this specialized coupling between calcium and potassium channels is achieved. Here we study channel activity in cell-attached patches from hippocampal neurons and report a unique specificity of coupling. L-type channels activate SK channels only, without activating BK channels present in the same patch. The delay between the opening of L-type channels and SK channels indicates that these channels are 50-150 nm apart. In contrast, N-type calcium channels activate BK channels only, with opening of the two channel types being nearly coincident. This temporal association indicates that N and BK channels are very close. Finally, P/Q-type calcium channels do not couple to either SK or BK channels. These data indicate an absolute segregation of coupling between channels, and illustrate the functional importance of submembrane calcium microdomains.
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