Crider J Y, Williams G W, Yorio T, Sharif N A, Griffin B W
Molecular Pharmacology Unit, Alcon Laboratories, Inc., Fort Worth, TX 76134, USA.
Ophthalmic Res. 1997;29(3):117-23. doi: 10.1159/000268005.
A new method for measuring cellular rubidium (Rb+) uptake activities based on cation chromatography was developed and compared with the standard technique, uptake of the radioisotope 86Rb+, using cultured bovine retinal pigment epithelial (RPE) cells. The Rb+ response was strictly linear from 0.25 nmol (detection limit) to 25 nmol. The Na+/K(+)-ATPase inhibitor ouabain inhibited Rb+ uptake with IC50 values of 128.7 +/- 23.5 nM (n = 8; radioactive method) and 56.6 +/- 9.3 nM (n = 9; non-radioactive method, p < 0.01). The latter value is identical to the IC50 value of 54.4 +/- 16.2 nM (n = 3) for ouabain binding to the intact RPE cells. Ouabain and bumetanide, an inhibitor of the Na+/K+/Cl(-)-cotransporter, each inhibited Rb+ uptake maximally by 66 and 30%, respectively. This new technique allows sensitive measurement of intracellular Rb+, as well as K+ and Na+, and, thus, should prove useful for studying the effects of pharmacologic agents and simulated disease conditions on cation transport and cation balance in RPE and other cell types.
开发了一种基于阳离子色谱法测量细胞铷（Rb+）摄取活性的新方法，并将其与标准技术（使用培养的牛视网膜色素上皮（RPE）细胞摄取放射性同位素86Rb+）进行比较。Rb+响应在0.25 nmol（检测限）至25 nmol范围内严格呈线性。Na+/K(+)-ATP酶抑制剂哇巴因抑制Rb+摄取，放射性方法的IC50值为128.7±23.5 nM（n = 8），非放射性方法的IC50值为56.6±9.3 nM（n = 9，p < 0.01）。后一值与哇巴因与完整RPE细胞结合的IC50值54.4±16.2 nM（n = 3）相同。哇巴因和Na+/K+/Cl(-)-共转运体抑制剂布美他尼分别最大程度地抑制Rb+摄取66%和30%。这种新技术能够灵敏地测量细胞内的Rb+以及K+和Na+，因此，对于研究药物制剂和模拟疾病状况对RPE及其他细胞类型中阳离子转运和阳离子平衡的影响应是有用的。
