钾对小鼠星形胶质细胞和神经元原代培养物中阴离子和阳离子含量的影响。

Effects of potassium on the anion and cation contents of primary cultures of mouse astrocytes and neurons.

作者信息

Chow S Y, Yen-Chow Y C, White H S, Hertz L, Woodbury D M

机构信息

Department of Physiology, University of Utah, Salt Lake City 84108.

出版信息

Neurochem Res. 1991 Dec;16(12):1275-83. doi: 10.1007/BF00966658.

DOI:10.1007/BF00966658

PMID:1784325

Abstract

In astrocytes, as [K+]o was increased from 1.2 to 10 mM, [K+]i and [Cl-]i were increased, whereas [Na+]i was decreased. As [K+]o was increased from 10 to 60 mM, intracellular concentration of these three ions showed no significant change. When [K+]o was increased from 60 to 122 mM, an increase in [K+]i and [Cl-]i and a decrease in [Na+]i were observed. In neurons, as [K+]o was increased from 1.2 to 2.8 mM, [Na+]i and [Cl-]i were decreased, whereas [K+]i was increased. As [K+]o was increased from 2.8 to 30 mM, [K+]i, [Na+]i and [Cl-]i showed no significant change. When [K+]o was increased from 30 to 122 mM, [K+]i and [Cl-]i were increased, whereas [Na+]i was decreased. In astrocytes, pHi increased when [K+]o was increased. In neurons, there was a biphasic change in pHi. In lower [K+]o (1.2-2.8 mM) pHi decreased as [K+]o increased, whereas in higher [K+]o (2.8-122 mM) pHi was directly related to [K+]o. In both astrocytes and neurons, changes in [K+]o did not affect the extracellular water content, whereas the intracellular water content increased as the [K+]o increased. Transmembrane potential (Em) as measured with Tl-204 was inversely related to [K+]o between 1.2 and 90 mM, a ten-fold increase in [K+]o depolarized the astrocytes by about 56 mV and the neurons about 52 mV. The Em values measured with Tl-204 were close to the potassium equilibrium potential (Ek) except those in neurons at lower [K+]o. However, they were not equal to the chloride equilibrium potential (ECl) at [K+]o lower than 30 mM in both astrocytes and neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

摘要

在星形胶质细胞中，随着细胞外钾离子浓度（[K⁺]o）从1.2 mM增加到10 mM，细胞内钾离子浓度（[K⁺]i）和氯离子浓度（[Cl⁻]i）升高，而细胞内钠离子浓度（[Na⁺]i）降低。当[K⁺]o从10 mM增加到60 mM时，这三种离子的细胞内浓度无显著变化。当[K⁺]o从60 mM增加到122 mM时，观察到[K⁺]i和[Cl⁻]i增加，[Na⁺]i降低。在神经元中，随着[K⁺]o从1.2 mM增加到2.8 mM，[Na⁺]i和[Cl⁻]i降低，而[K⁺]i升高。当[K⁺]o从2.8 mM增加到30 mM时，[K⁺]i、[Na⁺]i和[Cl⁻]i无显著变化。当[K⁺]o从30 mM增加到122 mM时，[K⁺]i和[Cl⁻]i升高，而[Na⁺]i降低。在星形胶质细胞中，当[K⁺]o升高时细胞内pH值（pHi）增加。在神经元中，pHi有双相变化。在较低的[K⁺]o（1.2 - 2.8 mM）时，pHi随着[K⁺]o升高而降低，而在较高的[K⁺]o（2.8 - 122 mM）时，pHi与[K⁺]o直接相关。在星形胶质细胞和神经元中，[K⁺]o的变化均不影响细胞外水含量，而细胞内水含量随着[K⁺]o升高而增加。用铊 - 204测量的跨膜电位（Em）在1.2 mM至90 mM的[K⁺]o范围内与[K⁺]o呈负相关，[K⁺]o增加10倍使星形胶质细胞去极化约56 mV，使神经元去极化约52 mV。除了在较低[K⁺]o时的神经元外，用铊 - 204测量的Em值接近钾离子平衡电位（Ek）。然而，在[K⁺]o低于30 mM时，星形胶质细胞和神经元的Em值均不等于氯离子平衡电位（ECl）。（摘要截选至250字）