Hypotonicity activates a native chloride current in Xenopus oocytes.
Hypotonicity activates a native chloride current in Xenopus oocytes.
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DOI：
10.1085/jgp.103.2.153
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发表时间：
1994-02
影响因子：
3.8
通讯作者：
Clapham, D E
中科院分区：
文献类型：
--
作者：
Ackerman, M J;Wickman, K D;Clapham, D E
爪蟾卵母细胞经常被用于细胞蛋白的体内表达，尤其是离子通道蛋白。深入了解内源性电导及其调控对于正确表征表达通道蛋白至关重要。在这里，我们详细介绍了一种新的氯化物电流（ICl.swell）响应低张力在非洲爪蟾卵母细胞使用双电极电压钳技术。将细胞外渗透压降低50%会产生与钙无关的氯离子电流，其阴离子电导率序列与上皮细胞中观察到的肿胀诱导的氯离子电流相同。低张力激活电流被氯离子通道阻滞剂、三价镧系元素和核苷酸阻断。G-蛋白、cAMP-PKA和花生四烯酸信号级联不参与ICl。膨胀激活。ICl。卵母细胞内的膨胀通道不同于拉伸激活的非选择性阳离子通道和钙激活的氯离子电流，可能在爪蟾卵母细胞的体积调节中起关键作用。
Xenopus oocytes are frequently utilized for in vivo expression of cellular proteins, especially ion channel proteins. A thorough understanding of the endogenous conductances and their regulation is paramount for proper characterization of expressed channel proteins. Here we detail a novel chloride current (ICl.swell) responsive to hypotonicity in Xenopus oocytes using the two-electrode voltage clamp technique. Reducing the extracellular osmolarity by 50% elicited a calcium-independent chloride current having an anion conductivity sequence identical with swelling-induced chloride currents observed in epithelial cells. The hypotonicity-activated current was blocked by chloride channel blockers, trivalent lanthanides, and nucleotides. G- protein, cAMP-PKA, and arachidonic acid signaling cascades were not involved in ICl.swell activation. ICl.swell is distinct from both stretch-activated nonselective cation channels and the calcium- activated chloride current in oocytes and may play a critical role in volume regulation in Xenopus oocytes.