Inwardly rectifying potassium channels (Kir) in central nervous system glia: a special role for Kir4.1 in glial functions.
Inwardly rectifying potassium channels (Kir) in central nervous system glia: a special role for Kir4.1 in glial functions.
复制标题
DOI：
10.1111/j.1582-4934.2006.tb00289.x
复制
发表时间：
2006-01
影响因子：
5.3
通讯作者：
Kalsi A
中科院分区：
文献类型：
--
作者：
Butt AM;Kalsi A
中枢神经系统（CNS）的胶质细胞表达多种内向整流钾通道（Kir）。Kir的主要功能是建立神经胶质细胞膜的高钾（K+）选择性和强负静息膜电位（RMP），这是神经胶质细胞的特征性生理特性。Kir的经典性质是当RMP相对于K+的平衡电位（Ek）为负时，K+向内流动，但在更正的电位下，外向电流被抑制。这通过“K+空间缓冲”和“K+虹吸”过程为神经元活动期间释放的K+的神经胶质摄取提供了驱动力，这被认为是星形胶质细胞（CNS中的主要神经胶质细胞类型）的关键功能。胶质细胞表达多种Kir通道亚型，这些亚型可能具有与其电导差异相关的不同功能作用，以及对细胞内和细胞外因子的敏感性，包括pH、ATP、G蛋白、神经递质和激素。CNS神经胶质细胞的一个特征是其Kir4.1亚型的特异性表达，Kir4.1亚型是神经胶质细胞膜中的主要K+传导，并且在设定神经胶质RMP中具有关键作用。Kir4.1与Kir5.1、可能还有Kir2.0亚型共同参与了钾离子的调节，既有同聚体通道，也有异聚体通道。值得注意的是，Kir4.1也由少突胶质细胞（CNS的髓鞘形成细胞）表达，并且Kir4.1的遗传消融也由少突胶质细胞（CNS的髓鞘形成细胞）表达，并且Kir4.1的遗传消融导致严重的髓鞘形成不足。因此，Kir，特别是Kir4.1，是神经胶质功能的关键调节因子，而神经胶质功能又决定了神经元的兴奋性和轴突传导。
Glia in the central nervous system (CNS) express diverse inward rectifying potassium channels (Kir). The major function of Kir is in establishing the high potassium (K+) selectivity of the glial cell membrane and strongly negative resting membrane potential (RMP), which are characteristic physiological properties of glia. The classical property of Kir is that K+ flows inwards when the RMP is negative to the equilibrium potential for K+ (Ek), but at more positive potentials outward currents are inhibited. This provides the driving force for glial uptake of K+ released during neuronal activity, by the processes of “K+ spatial buffering” and “K+ siphoning”, considered a key function of astrocytes, the main glial cell type in the CNS. Glia express multiple Kir channel subtypes, which are likely to have distinct functional roles related to their differences in conductance, and sensitivity to intracellular and extracellular factors, including pH, ATP, G-proteins, neurotransmitters and hormones. A feature of CNS glia is their specific expression of the Kir4.1 subtype, which is a major K+ conductance in glial cell membranes and has a key role in setting the glial RMP. It is proposed that Kir4.1 have a primary function in K+ regulation, both as homomeric channels and as heteromeric channels by co-assembley with Kir5.1 and probably Kir2.0 subtypes. Significantly, Kir4.1 are also expressed by oligodendrocytes, the myelin-forming cells of the CNS, and the genetic ablation of Kir4.1 are also expressed by Oligodendrocytes, the myelin-forming cells of the CNS, and the genetic ablation of Kir4.1 results in severe hypomyelination. Hence, Kir, and in particular Kir4.1, are key regulators of glial functions, which in turn determine neuronal excitability and axonal conduction.
登录
查看更多内容
影响因子：
2.5
作者：
D'Ambrosio, R;Gordon, DS;Winn, HR
通讯作者：
Winn, HR
影响因子：
2.9
作者：
Dunn-Meynell, AA;Rawson, NE;Levin, BE
通讯作者：
Levin, BE
DOI：
10.1152/ajpcell.2001.281.3.c922
发表时间：
2001-09-01
影响因子：
5.5
作者：
Higashi, K;Fujita, A;Kurachi, Y
通讯作者：
Kurachi, Y
影响因子：
56.9
作者：
CONNORS, BW;RANSOM, BR;GUTNICK, MJ
通讯作者：
GUTNICK, MJ
影响因子：
6.2
作者：
Britz, FC;Hirth, IC;Deitmer, JW
通讯作者：
Deitmer, JW