Sah Pankaj, Faber E S Louise
Division of Neuroscience, John Curtin School of Medical Research, Australian National University, G.P.O. Box 334, Canberra, ACT 2601, Australia.
Prog Neurobiol. 2002 Apr;66(5):345-53. doi: 10.1016/s0301-0082(02)00004-7.
In many cell types rises in cytosolic calcium, either due to influx from the extracellular space, or by release from an intracellular store activates calcium dependent potassium currents on the plasmalemma. In neurons, these currents are largely activated following calcium influx via voltage gated calcium channels active during the action potentials. Three types of these currents are known: I(c), I(AHP) and I(sAHP). These currents can be distinguished by clear differences in their pharmacology and kinetics. Activation of these potassium currents modulates action potential time course and the repetitive firing properties of neurons. Single channel studies have identified two types of calcium-activated potassium channel which can also be separated on biophysical and pharmacological grounds and have been named BK and SK channels. It is now clear that BK channels underlie I(c) whereas SK channels underlie I(AHP). The identity of the channels underlying I(sAHP) are not known. In this review, we discuss the properties of the different types of calcium-activated potassium channels and the relationship between these channels and the macroscopic currents present in neurons.
在许多细胞类型中，胞质钙的升高，要么是由于从细胞外空间流入，要么是通过从细胞内储存库释放，从而激活质膜上的钙依赖性钾电流。在神经元中，这些电流在很大程度上是在动作电位期间通过电压门控钙通道流入钙后被激活的。已知有三种类型的这些电流：I(c)、I(AHP) 和 I(sAHP)。这些电流可以通过它们的药理学和动力学的明显差异来区分。这些钾电流的激活调节动作电位的时间进程和神经元的重复放电特性。单通道研究已经确定了两种类型的钙激活钾通道，它们也可以根据生物物理和药理学依据进行区分，并被命名为BK和SK通道。现在很清楚，BK通道是I(c)的基础，而SK通道是I(AHP)的基础。I(sAHP)所基于的通道身份尚不清楚。在这篇综述中，我们讨论了不同类型的钙激活钾通道的特性以及这些通道与神经元中存在的宏观电流之间的关系。
