Levenson R, Housman D, Cantley L
Proc Natl Acad Sci U S A. 1980 Oct;77(10):5948-52. doi: 10.1073/pnas.77.10.5948.
The effect of amiloride (an inhibitor of passive Na+ transport in many tissues) on the differentiation of murine erythroleukemia cells was investigated. Amiloride completely blocked the dimethyl sulfoxide (Me2SO)-induced erythroid differentiation of cells at a concentration (10 microgram/ml) that did not affect cell proliferation. Amiloride also prevented the decrease in cell volume normally observed afte a 20-hr exposure to Me2SO. The ratio of total cell Na+ to total cell water was essentially the same for control cells, Me2SO-treated cells, and cells treated with Me2SO plus amiloride. However, cells treated for 24 hr with Me2SO had a rate of Ca2+ uptake that was twice that of untreated cells and a similarly higher Ca2+ content. Addition of amiloride plus Me2SO prevented both the increase in Ca2+ uptake rate and the increase in Ca2+ content. Cells grown in the presence of Me2SO plus amiloride initiated differentiation immediately after removal of amiloride or addition of the Ca2+ ionophore A23187 (1 microgram/ml). Addition of sufficient ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid to reduce free extracellular Ca2+ to submicromolar levels prevented Me2SO-induced differentiation while only slightly affecting cell proliferation. These results suggest that an increase in in the Ca2+ level is an essential step in Me2SO induction, that amiloride either directly or indirectly inhibits this process, and that Me2SO has an early effect on cells that is necessary for differentiation and is not mimicked by A23187.
研究了氨氯吡咪（一种在许多组织中抑制被动性钠离子转运的抑制剂）对小鼠红白血病细胞分化的影响。氨氯吡咪在浓度为10微克/毫升时可完全阻断二甲基亚砜（Me2SO）诱导的细胞红系分化，该浓度不影响细胞增殖。氨氯吡咪还可阻止通常在暴露于Me2SO 20小时后观察到的细胞体积减小。对照细胞、经Me2SO处理的细胞以及经Me2SO加氨氯吡咪处理的细胞的总细胞钠与总细胞水的比率基本相同。然而，经Me2SO处理24小时的细胞的钙离子摄取速率是未处理细胞的两倍，钙离子含量也同样更高。添加氨氯吡咪加Me2SO可同时阻止钙离子摄取速率的增加和钙离子含量的增加。在Me2SO加氨氯吡咪存在下生长的细胞在去除氨氯吡咪或添加钙离子载体A23187（1微克/毫升）后立即开始分化。添加足够的乙二醇双（β-氨基乙醚）-N，N，N'，N'-四乙酸以将细胞外游离钙离子降低至亚微摩尔水平可阻止Me2SO诱导的分化，而仅轻微影响细胞增殖。这些结果表明，钙离子水平的升高是Me2SO诱导过程中的一个关键步骤，氨氯吡咪直接或间接抑制该过程，并且Me2SO对细胞有一个早期影响，这是分化所必需的，且不能被A23187模拟。
