Hypotonically activated chloride current in HSG cells.
Hypotonically activated chloride current in HSG cells.
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HSG 细胞中低渗激活的氯电流。
DOI：
10.1007/bf00234940
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Belton,CM
中科院分区：
文献类型：
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作者：
Fatherazi,S;Izutsu,KT;Wellner,RB;Belton,CM
利用全细胞、膜片钳和Coulter计数技术分别研究了低压诱导的HSG克隆细胞系全细胞电流和细胞体积的变化。当使用含K+和Cl−的溶液测量时，暴露于10%至50%的低渗溶液诱导全细胞电导的剂量依赖性增加。在0毫伏时检测到的向外电流对应于瞬时激活的K+电流（通常在内向电流激活之前），并且与我们之前在这些细胞中描述的Ca2+激活的K+电流具有几个共同特征。低电压诱导的内向电流具有Cl−电流的特征。该电流被NPPB（5-硝基-2-（3-苯基-丙基氨基）-苯甲酸酯）和sit（4-乙酰氨基-4 ' -异硫氰二苯乙烯）抑制，其反转电位对应于高和低外部Cl -浓度下的Cl -平衡电位。当电压大于+ 80mv时，感应电流失活，其i - v曲线向外整流。在膜片移液管中加入BAPTA或去除GTP不影响电流，但去除ATP或细胞外花生四烯酸、醌、去甲二氢木尿酸和细胞松弛素d会抑制电流。此外，HSG细胞暴露于低渗介质中会导致它们膨胀，然后经历调节体积减少（RVD）反应。NPPB、sit和奎宁单独作用均不能抑制RVD，但NPPB和奎宁联合作用完全抑制RVD。这些特性，加上感应电流的大小，表明低电压诱导的K+和Cl−电流可能是RVD响应的基础。细胞松弛素D也阻断了RVD反应，表明激活当前电流可能需要完整的细胞骨架f -肌动蛋白。因此，我们的研究结果表明，低渗应激激活了这些细胞中的K+和Cl -传导，并且K+传导的激活途径显然涉及[Ca2+]，而Cl -传导的激活途径不涉及[Ca2+]和脂氧合酶代谢，但确实需要完整的细胞骨架f -肌动蛋白。
Hypotonically induced changes in whole-cell currents and in cell volume were studied in the HSG cloned cell line using the whole-cell, patch clamp and Coulter counter techniques, respectively. Exposures to 10 to 50% hypotonic solutions induced dose-dependent increases in whole-cell conductances when measured using K+and Cl−containing solutions. An outward current detected at 0 mV, corresponded to a K+current which was transiently activated, (usually preceding activation of an inward current and had several characteristics in common with a Ca2+-activated K+current we previously described in these cells. The hypotonically induced inward current had characteristics of a Cl−current. This current was inhibited by NPPB (5-nitro-2-(3-phenyl-propylamino)-benzoate) and SITS (4-acetamido-4′-isothiocyanostilbene), and its reversal potentials corresponded to the Cl−equilibrium potentials at high and low external Cl−concentrations. The induced current inactivated at voltages greater than +80 mV, and theI-Vcurve was outwardly rectifying. The current was unaffected by addition of BAPTA or removal of GTP from the patch pipette, but was inhibited by removal of ATP or by the presence of extracellular arachidonic acid, quinacrine, nordihydroguairetic acid, and cytochalasin D. Moreover, exposure of HSG cells to hypotonic media caused them to swell and then to undergo a regulatory volume decrease (RVD) response. Neither NPPB, SITS or quinine acting alone could inhibit RVD, but NPPB and quinine together totally inhibited RVD. These properties, plus the magnitudes of the induced currents, indicate that the hypotonically induced K+and Cl−currents may underlie the RVD response. Cytochalasin D also blocked the RVD response, indicating that intact cytoskeletal F-actin may be required for activation of the present currents. Hence, our results indicate that hypotonic stress activates K+and Cl−conductances in these cells, and that the activation pathway for the K+conductance apparently involves [Ca2+], while the activation pathway for the Cl−conductance does not involve [Ca2+] nor lipoxygenase metabolism, but does require intact cytoskeletal F-actin.