Characterization of the Na/K pump current in N20.1 oligodendrocytes.
Characterization of the Na/K pump current in N20.1 oligodendrocytes.
复制标题
N20.1 少突胶质细胞中 Na/K 泵电流的表征。
DOI：
10.1016/0006-8993(96)00171-0
复制
发表时间：
1996
期刊：
影响因子：
2.9
通讯作者：
Stimers,JR
中科院分区：
文献类型：
--
作者：
Dobretsov,M;Stimers,JR
Glial cell Na,K-ATPase is suggested to participate in extracellular K+concentration ([K+]o) control by being activated when [K+]orises in the brain. The extent of that activation directly depends on the Na/K pump affinity to [K+]o, intracellular Na+([Na+]iand, indirectly on pump cycle regulation by membrane potential (Vm). In the present investigation, these Na/K pump properties were studied with the whole-cell patch-clamp technique in cultured mouse oligodendrocytes (N20.1 cell line). N20.1 cells possess ouabain-sensitive Na/K pump current (Ip) with a maximal density of 0.5-0.6 pA/pF (estimated for conditions of Na/K pump stimulation by saturating [Na+]i, [ATP]i, [K+]oand at positive Vm. This current was half-inhibited at 83 ± 31 μM ouabain, and half-activated by [Na+]iof 9.6 ± 1.1 mM, by [K+]oof 2.0 ± 0.1 mM and by membrane potential at about −65 mV. High levels of nervous activity may increase [K+]ofrom 3 to 12 mM which would only increase Na/K pump current by 40% due to the direct effect of [K+]o. However, elevated [K+]owould also depolarize the glial cell membrane which would indirectly activate Ipand together with the direct effect of [K+]owould increase IPas much as 2–2.5-fold. These data suggest that glial cell Na/K pump regulation by Vmmay be an important factor in determining the participation of the Na/K pump in [K+]ohomeostasis in the nervous system.
