A chloride current associated with swelling of cultured chick heart cells.
A chloride current associated with swelling of cultured chick heart cells.
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DOI：
10.1113/jphysiol.1993.sp019974
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发表时间：
1993-12
期刊：
影响因子：
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通讯作者：
Jianping Zhang;R. Rasmusson;S. K. Hall;M. Lieberman
中科院分区：
文献类型：
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作者：
Jianping Zhang;R. Rasmusson;S. K. Hall;M. Lieberman
1. 受到低渗应激的培养鸡心脏细胞经历了调节体积减少（RVD），这种减少因细胞内氯离子的先前耗尽而减弱。 2. 在低渗肿胀期间，细胞聚集体经历了自发收缩活动的最初增加，随后最终静止。传统的微电极研究揭示了自发电活动的潜在增加，随后持续去极化超过阈值。 3. K+电流被阻断的全细胞膜片钳研究表明，细胞暴露于低渗溶液（氯化钠还原）导致渗透性快速膨胀，随后全细胞电导大幅增加，这种增加在低渗暴露期间持续存在，并且在返回等渗浴溶液时几乎完全逆转。 4. 对于各种 Cl- 浓度，测量的膨胀激活电流的反转电位 (Erev) 与计算的 Cl- 平衡电位 (ECl) 密切相关，线性回归斜率为 0.82。当通过 Nernst 方程估计时，Erev 和 [Cl-]i/[Cl-]o 比率之间的关系与浓度比每十年变化 51 mV 的斜率吻合，与 Cl(-) 选择性电导一致。 5. 膨胀激活电导对氯离子、甲磺酸盐（MSA）和天冬氨酸盐（Asp）的渗透率计算为 PCl:PMSA:PASP = 1:0.36:0.02，离子选择性顺序为 Cl->MSA->>Asp-，这表明膨胀激活电导对其他阴离子有轻微的渗透性。 6. 应用 Cl-通道阻滞剂二苯胺-2-羧酸盐（DPC，200 µM）可显着抑制溶胀激活电流，而不会改变该电流的 Erev。 DPC 的作用与膜电位无关。 7. 该证据表明，培养鸡心细胞的低渗肿胀会激活通道介导的 Cl 电导，这可能与容量调节机制的综合反应有关。
1. Cultured chick heart cells challenged by hyposmotic stress underwent regulatory volume decrease (RVD) that was attenuated by prior depletion of intracellular chloride. 2. During hyposmotic swelling, cell aggregates experienced an initial increase in spontaneous contractile activity followed by eventual quiescence. Conventional microelectrode studies revealed an underlying increase in spontaneous electrical activity, followed by a sustained depolarization beyond threshold. 3. Whole‐cell patch clamp studies, with K+ currents blocked, indicated that exposure of cells to hyposmotic solution (NaCl reduction) resulted in a rapid osmotic swelling followed by a substantial increase in whole‐cell conductance which persisted for the duration of hyposmotic exposure and was almost completely reversed on return to isosmotic bath solution. 4. For a variety of Cl‐ concentrations, the reversal potentials (Erev) of the measured swelling‐activated current closely followed the calculated Cl‐ equilibrium potential (ECl) with a linear regression slope of 0.82. When estimated by the Nernst equation, the relationship between Erev and the [Cl‐]i/[Cl‐]o ratio fitted well with a slope of 51 mV per decade change in the concentration ratio, consistent with a Cl(‐)‐selective conductance. 5. The permeability ratios of this swelling‐activated conductance to chloride, methanesulphonate (MSA) and aspartate (Asp) were calculated as PCl:PMSA:PASP = 1:0.36:0.02, with the ion selectivity sequence of Cl‐ > MSA‐ >> Asp‐, which suggests the swelling‐activated conductance is slightly permeable to other anions. 6. Application of a Cl‐ channel blocker, diphenylamine‐2‐carboxylate (DPC, 200 microM), substantially suppressed the swelling‐activated current without shifting the Erev of this current. The effect of DPC was independent of membrane potential. 7. This evidence demonstrates that hyposmotic swelling of cultured chick heart cells activates a channel‐mediated Cl‐ conductance which may be associated with the integrated response of volume‐regulatory mechanisms.