培养细胞中被动呋塞米敏感性跨膜钾转运的发生情况。

Occurrence of passive furosemide-sensitive transmembrane potassium transport in cultured cells.

作者信息

Aiton J F, Chipperfield A R, Lamb J F, Ogden P, Simmons N L

出版信息

Biochim Biophys Acta. 1981 Sep 7;646(3):389-98. doi: 10.1016/0005-2736(81)90307-2.

Abstract

Furosemide (1 x 10(-4) M) inhibits a proportion of the total passive (ouabain-insensitive) K+ influx into primary chick heart cell cultures (85%), BC3H1 cells (75%), MDCK cells (40%) and HeLa cells (57%). This action of furosemide upon K+ influx is independent of (Na+ + K+)-pump inhibition since the furosemide-sensitive component of the K+ influx is identical in the presence and absence of ouabain (1 x 10(-3) M). For HeLa cells the passive, furosemide-sensitive component of K+ influx is markedly dependent upon the external K+, Na+ and Cl- content. Acetate, iodide and nitrate are ineffective as substitutes for Cl-, whereas Br- is partially effective. Partial Cl- replacement by NO3- gave an apparent affinity of 100 mM [Cl]. Na+ replacement by choline+ abolishes the furosemide-sensitive component, whereas Li+ replacement reduces this component by 48%. Partial Na+ replacement by choline+ gives an apparent affinity of 25 mM [Na+]. Variation in the external K+ content gives an affinity for the furosemide-sensitive component of approx. 1.0 mM. Furosemide inhibition of the passive K+ influx is of high affinity, half-maximal inhibition being observed at 5 x 10(-6) M furosemide. Piretanide (1 x 10(-4) M) and phloretin (1 x 10(-4) M) inhibit the same component of passive K+ influx as furosemide; ethacrynic acid and amiloride (both 1 x 10(-4) M) partially so. The stilbene, SITS (1 x 10(-6) M), was ineffective as an inhibitor for the furosemide-sensitive component.

摘要

呋塞米（1×10⁻⁴ M）可抑制原代鸡心脏细胞培养物（85%）、BC3H1细胞（75%）、MDCK细胞（40%）和HeLa细胞（57%）中总的被动（哇巴因不敏感）钾离子内流的一部分。呋塞米对钾离子内流的这种作用与（钠⁺ + 钾⁺）泵抑制无关，因为在有和没有哇巴因（1×10⁻³ M）的情况下，钾离子内流中对呋塞米敏感的成分是相同的。对于HeLa细胞，钾离子内流中被动的、对呋塞米敏感的成分明显依赖于细胞外钾离子、钠离子和氯离子的含量。醋酸根、碘离子和硝酸根不能有效替代氯离子，而溴离子部分有效。用硝酸根部分替代氯离子时，表观亲和力为100 mM [Cl]。用胆碱⁺替代钠离子可消除对呋塞米敏感的成分，而用锂离子替代则使该成分减少48%。用胆碱⁺部分替代钠离子时，表观亲和力为25 mM [Na⁺]。细胞外钾离子含量的变化对呋塞米敏感成分的亲和力约为1.0 mM。呋塞米对被动钾离子内流的抑制具有高亲和力，在5×10⁻⁶ M呋塞米时观察到半数最大抑制。吡咯他尼（1×10⁻⁴ M）和根皮素（1×10⁻⁴ M）与呋塞米一样抑制被动钾离子内流的相同成分；依他尼酸和阿米洛利（均为1×10⁻⁴ M）则部分抑制。二苯乙烯类化合物SITS（1×10⁻⁶ M）对呋塞米敏感成分无抑制作用。