Ionic dependence of the extracellular ATP-induced permeabilization of transformed mouse fibroblasts: role of plasma membrane activities that regulate cell volume.
Ionic dependence of the extracellular ATP-induced permeabilization of transformed mouse fibroblasts: role of plasma membrane activities that regulate cell volume.
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细胞外 ATP 诱导的转化小鼠成纤维细胞透化的离子依赖性：质膜活性调节细胞体积的作用。
DOI：
10.1002/jcp.1041380221
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发表时间：
1989
影响因子：
5.6
通讯作者：
Pritchard,RS
中科院分区：
文献类型：
--
作者：
Weisman,GA;De,BK;Pritchard,RS
细胞外ATP使转化的小鼠成神经细胞的质膜对通常不渗透的分子具有渗透性。这种渗透性的变化，防止通过增加离子强度的等渗介质与NaCl。相反，当NaCl浓度降低到等渗性以下时，当KCl浓度增加到5 mM以上同时保持等渗性时，以及当培养基的pH升高到7.0以上时，细胞表现出对ATP的敏感性增加。这些条件以及ATP本身的添加导致细胞肿胀。然而，ATP的作用与细胞体积无关，而取决于离子强度，而不是介质的渗透压，因为（1）在等渗介质中加入蔗糖并不能阻止透化作用，尽管用蔗糖或NaCl使介质高渗引起细胞体积减小;（2）低渗培养基中加入蔗糖或NaCl可使细胞体积减小，但只有NaCl能降低细胞对ATP的反应。已被证明抑制质膜蛋白，在细胞体积调节中发挥相互作用的条件下，具有相互作用的透化过程中，即使ATP的效果是独立的细胞体积。例如，哇巴因对Na+，K+-ATP酶的抑制增加了细胞对ATP的敏感性，而抑制Na+，K+，Cl−-协同转运蛋白活性的条件，如用利尿剂呋塞米或布美他尼处理细胞或用硝酸钠或硫氰酸钠代替培养基中的氯化钠，则抑制了透化作用。抑制透化的呋塞米浓度大于抑制Na+，K+，Cl−-协同转运蛋白介导的86 Rb+（K+）摄取的浓度，表明呋塞米对透化过程的影响可能不是Na+，K+，Cl−-协同转运蛋白特异性的。
Extracellular ATP rendered the plasma membrane of transformed mouse fibro‐blasts permeable to normally impermeant molecules. This permeability change was prevented by increasing the ionic strength of the isotonic medium with NaCl. Conversely, the cells exhibited increased sensitivity to ATP when the NaCl concentration was decreased below isotonicity, when the KCl concentration was increased above 5 mM while maintaining isotonicity, and when the pH of the medium was raised above 7.0. These conditions as well as the addition of ATP itself caused cell swelling. However, the effect of ATP was independent of cell volume and dependent upon the ionic strength and not the osmolarity of the medium since (1) addition of sucrose to isotonic medium did not prevent permeabilization although media made hypertonic with either sucrose or NaCl caused a decrease in cell volume; and (2) addition of sucrose or NaCl to hypotonic media caused a decrease in cell volume, but only NaCl addition decreased the response to ATP. Conditions that have been shown to inhibit plasma membrane proteins that play a reciprocal role in cell volume regulation had reciprocal effects on the permeabilization process, even though the effect of ATP was independent of cell volume. For example, inhibition of the Na+, K+‐ATPase by ouabain increased sensitivity of cells to ATP while conditions which inhibit Na+, K+, Cl−‐cotransporter activity, such as treatment of the cells with the diuretics furosemide or bumetanide or replacement of sodium chloride in the medium with sodium nitrate or thiocyanate, inhibited permeabilization. The furosemide concentration that inhibited permeabilization was greater than the concentration that inhibited Na+, K+, Cl−‐cotransporter‐mediated86Rb+(K+) uptake, suggesting that the effect of furosemide on the permeabilization process may not be specific for the Na+, K+, Cl−‐cotransporter.