Validation of the use of the lipophilic thiocyanate anion for the determination of membrane potential in Ehrlich ascites tumor cells.
Validation of the use of the lipophilic thiocyanate anion for the determination of membrane potential in Ehrlich ascites tumor cells.
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验证使用亲脂性硫氰酸盐阴离子测定艾利希腹水肿瘤细胞的膜电位。
DOI：
10.1007/bf01871722
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Robinson,SC
中科院分区：
文献类型：
--
作者：
Smith,TC;Robinson,SC
通过与直接电生理测量进行比较，评估了亲脂性阴离子硫氰酸盐 (SCN+) 作为间接估计艾利希腹水肿瘤细胞细胞膜电位 (Vm) 的探针的效用。 SCN 积累与单一动力学可识别细胞区室的一级摄取一致，在 22°C 下 20-30 分钟内实现稳态分布。生理盐水中的稳态分配比（[SCN−]c/[SCN−]e）为0.44±0.02。用 Ca2+ 依赖性 K+ 通道激活剂普萘洛尔 (0.13 mM) 处理细胞，可将稳态分布比降低至 0.19±0.02。相反，用该途径的拮抗剂BACl2(10 mM)处理，将SCN-分布比增加至0.62±0.01。在这些条件下计算的平衡电位(VSCN)实际上与在相同条件下对Vm进行的直接电生理测量相同。还测试了在恒定 [Na+]e=100 mM 存在下不同细胞外 [K+]([K+]e) 的影响。在对照细胞中，[K+]e从6 mM升高至60 mM使VSCN从-20.6±1.0降低至-13.2±1.2 mV。同样，微电极测量给出了极好的定量一致性。普萘洛尔可增加细胞对不同 [K+]e 的敏感性，因此升高 10 倍可使 VSCN 降低约 31 mV。 BaCl2 极大地降低了这种响应：[K+] 升高 10 倍，仅在 VSCN 中产生 4 mV 的反射。结论是，可以通过 SCN 分布测量准确估计艾利希细胞的膜电位。
The utility of the lipophilic anion thiocyanate (SCN+) as a probe for the indirect estimation of the cell membrane potential (Vm) in Ehrlich ascites tumor cells has been evaluated by comparison to direct electrophysiological measurements. SCN accumulation is consisten with first-order uptake into a single kinetically-identifiable cellular compartement, achieving steadystate distribution in 20–30 min at 22°C. The steady-state distribution ratio ([SCN−]c/[SCN−]e) in physiological saline is 0.44±0.02. Treatment of the cells with proparanolol (0.13 mM), an activator of Ca2+dependent K+channels, reduces the steady-state distribution ratio to 0.19±0.02. Conversely, treatmetn with BACl2(10 mM), an antagonist of the pathway, increases the SCN−distribution ratio to 0.62±0.01. The equilibrium potentials (VSCN) calculated under these conditions are virtually identical to direct electrophysiological measurements of theVmmade under the same conditions. The effect of varing extracellular [K+]([K+]e) in the presence of constant [Na+]e=100 mM has also been tested. In control cells, elevation of [K+]efrom 6 to 60 mM reducesVSCNfrom −20.6±1.0 to −13.2±1.2 mV. Again, microelectrode measurements give excellent quantitative agreement. Propranolol increases the sensitivity of the cells to varying [K+]e, so that a 10-fold elevation reducesVSCNby approximately 31 mV. BaCl2greatly reduces this reponse: a 10-fold elevation in [K+]eyielding only a 4-mV rediction inVSCN. It is concluded that the membrane potential of Ehrlich cells can be estimated accurately from SCN−distribution measurements.