Chow S Y, White H S, Yen-Chow Y C, Woodbury D M
Department of Physiology, Toxicology University of Utah, Salt Lake City 84108.
Neurochem Res. 1989 Oct;14(10):963-9. doi: 10.1007/BF00965930.
Primary cultures of both mouse astrocytes and neurons accumulate more 125I- than 36Cl- from the medium. The average cell/medium ratio of 125I- of astrocytes (1.01) is greater than that of neurons (0.74), whereas the ratio of 36Cl- of neurons (0.47) is greater than that of astrocytes (0.25). The equilibrium potentials of both 125I- and 36Cl- calculated from the cell/medium ratios in astrocytes and neurons are significantly lower than their corresponding resting transmembrane potentials which suggest that both iodide and chloride are actively transported into both cell types. With respect to different transport inhibitors, thiocyanate is more effective in inhibiting 125I- uptake whereas furosemide is more effective in inhibiting 36Cl- uptake. Radioiodide uptake by mouse astrocytes was directly proportional to the [Na+]o but was not significantly affected by changes of [Cl-]o or [HCO3-]o, except that it is low in bicarbonate-free medium. Radiochloride uptake by astrocytes was inversely related to [Cl-]o and [HCO3-]o and was not affected [Na+]o, except that it was low in sodium-free medium. Radioiodide uptake by neurons was directly related to [Na+]o between 60 and 140 mM and inversely related to [HCO3-]o between 10 and 40 mM, but it was not affected by [Cl-]o. Radiochloride uptake by neurons was directly related to [Cl-]o and to [Na+]o between 60 and 140 mM and was not affected by [HCO3-]o. However, in sodium-free medium both 125I- and 36Cl- uptakes into neurons were higher than those in [Na+]o between 5 and 60 mM. These results indicate that uptake of 125I- and 36Cl- into astrocytes and neurons are different in their ion dependence and that they are under separate regulation.
小鼠星形胶质细胞和神经元的原代培养物从培养基中积累的¹²⁵I⁻比³⁶Cl⁻更多。星形胶质细胞¹²⁵I⁻的平均细胞/培养基比率（1.01）大于神经元（0.74），而神经元³⁶Cl⁻的比率（0.47）大于星形胶质细胞（0.25）。根据星形胶质细胞和神经元中的细胞/培养基比率计算出的¹²⁵I⁻和³⁶Cl⁻的平衡电位均显著低于它们相应的静息跨膜电位，这表明碘化物和氯离子都被主动转运到这两种细胞类型中。关于不同的转运抑制剂，硫氰酸盐在抑制¹²⁵I⁻摄取方面更有效，而呋塞米在抑制³⁶Cl⁻摄取方面更有效。小鼠星形胶质细胞对放射性碘的摄取与细胞外[Na⁺]直接成正比，但不受细胞外[Cl⁻]或[HCO₃⁻]变化的显著影响，只是在无碳酸氢盐的培养基中摄取量较低。星形胶质细胞对放射性氯的摄取与[Cl⁻]和[HCO₃⁻]呈负相关，不受[Na⁺]的影响，只是在无钠培养基中摄取量较低。神经元对放射性碘的摄取在60至140 mM的[Na⁺]之间与[Na⁺]直接相关，在10至4 mM的[HCO₃⁻]之间与[HCO₃⁻]呈负相关，但不受[Cl⁻]的影响。神经元对放射性氯的摄取与[Cl⁻]以及60至140 mM的[Na⁺]直接相关，不受[HCO₃⁻]的影响。然而，在无钠培养基中，神经元对¹²⁵I⁻和³⁶Cl⁻的摄取均高于5至60 mM的[Na⁺]条件下的摄取。这些结果表明，¹²⁵I⁻和³⁶Cl⁻进入星形胶质细胞和神经元的摄取在离子依赖性方面存在差异，并且它们受到不同的调节。
