Measurement of intracellular chloride activity in mouse liver slices with microelectrodes.
Measurement of intracellular chloride activity in mouse liver slices with microelectrodes.
复制标题
用微电极测量小鼠肝脏切片中细胞内氯离子的活性。
DOI：
10.1016/0005-2736(87)90155-6
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Armstrong,WM
中科院分区：
文献类型：
--
作者：
Lyall,V;Croxton,TL;Armstrong,WM
稳态膜电位（Vm）和细胞内Cl−活性（aCli）在小鼠肝切片中用双管Cl−选择性微电极测量。在含有丙酮酸盐、谷氨酸盐、富马酸盐和葡萄糖的浴液（33.8° C）中，VmandaCl分别为−27.6 ± 1.0 mV和32.6 ± 1.5 mM。这一表观值比该离子被动分布所需的水平（aCleq= 26.4 ± 1.3 mM）高出6.2 ± 1.0 mM。在（i）Na+被胆碱替代，（ii）HCO3−被去除，（iii）Cl−被葡萄糖酸盐替代的实验中，这一差异基本上没有变化。这些数据反对在小鼠肝细胞质膜中存在Na+或HCO3−耦合的Cl−转运机制。这意味着aCliq实际上处于平衡状态，细胞内阴离子对Cl−选择性微电极响应的干扰是aCliq和aCleq之间明显差异的原因。我们发现含有Corning 477315配体的Cl−选择性微电极对牛磺胆酸盐（一种代表性的胆汁盐）敏感。它们对牛磺胆酸盐的选择性约为它们对Cl−的选择性的60倍。这表明，肝细胞中正常浓度的胆汁酸干扰了对aCli −aCleq的测定。
Steady-state membrane potential (Vm) and intracellular Cl−activity (aCli) were measured with double-barreled Cl−-selective microelectrodes in mouse liver slices. In bathing solutions (33.8° C) containing pyruvate, glutamate, fumarate, and glucose,VmandaCliwere −27.6 ± 1.0 mV and 32.6 ± 1.5 mM, respectively. This apparent value ofaCliexceeded the level required for passive distribution of this ion (aCleq= 26.4 ± 1.3 mM) by 6.2 ± 1.0 mM. This difference was essentially unchanged in experiments where (i) Na+was replaced by choline, (ii) HCO3−was removed, and (iii) Cl−was replaced by gluconate. These data argue against the presence of Na+- or HCO3−-coupled Cl−transport mechanisms in the plasma membrane of mouse liver cells. This implies thataCliis in fact at equilibrium and interference with the response of Cl−-selective microelectrodes by intracellular anions is responsible for the apparent difference betweenaCliandaCleq. We found that Cl−-selective microelectrodes containing Corning 477315 ligand are sensitive to taurocholate, a representative bile salt. Their selectivity to taurocholate is about 60-times their selectivity towards Cl−. This suggests that interference of bile acids at concentrations normally present in hepatocytes with determinations ofaClican account for the apparent differenceaCli−aCleq.