Characterization of K+ currents using an in situ patch clamp technique in body wall muscle cells from Caenorhabditis elegans
Characterization of K+ currents using an in situ patch clamp technique in body wall muscle cells from Caenorhabditis elegans
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DOI：
10.1113/jphysiol.2002.022293
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发表时间：
2002-10-15
影响因子：
5.5
通讯作者：
Allard, B
中科院分区：
文献类型：
--
作者：
Jospin, M;Mariol, MC;Allard, B
采用原位膜片钳技术在宏观和单一水平上研究了急性解剖的秀丽隐杆线虫体壁肌细胞中K+通道的特性。在全细胞结构中，电位正至-40 mV的去极化产生外向电流，这是由两个动力学上不同的电压依赖的K+电流激活引起的：一个快速激活和灭活4-氨基吡啶敏感成分，一个缓慢激活和维持四乙基铵敏感成分。在细胞贴片中，电压依赖性的K+通道，在5和140 mm的外部K+存在下，分别具有34和80 pS的统一电导，在正至-40 mV的膜电位下被激活。切除发现这些通道对应于Ca2+激活的K+通道，对内部Cl-表现出异常的敏感性，其活性在内向外的条件下逐渐降低。在这些通道完全关闭后，三分之一的由内向外的斑块显示出另一个较小的统一电导的Ca2+激活的K+通道的活性（在5mm外部K+存在的情况下，0 mV下6ps）。通过详细描述秀丽隐杆线虫体壁肌肉细胞中的天然K+电流，本工作为进一步与突变体进行比较，以评估这种模式生物中高度适合分子和经典遗传学的K+通道功能奠定了基础。
The properties of K+ channels in body wall muscle cells acutely dissected from the nematode Caenorhabditis elegans were investigated at the macroscopic and unitary level using an in situ patch clamp technique. In the whole-cell configuration, depolarizations to potentials positive to -40 mV gave rise to outward currents resulting from the activation of two kinetically distinct voltage-dependent K+ currents: a fast activating and inactivating 4-aminopyridine-sensitive component and a slowly activating and maintained tetraethylammonium-sensitive component. In cell-attached patches, voltage-dependent K+ channels, with unitary conductances of 34 and 80 pS in the presence of 5 and 140 mm external K+, respectively, activated at membrane potentials positive to -40 mV. Excision revealed that these channels corresponded to Ca2+-activated K+ channels exhibiting an unusual sensitivity to internal Cl- and whose activity progressively decreased in inside-out conditions. After complete run-down of these channels, one third of inside-out patches displayed activity of another Ca2+-activated K+ channel of smaller unitary conductance (6 pS at 0 mV in the presence of 5 mm external K+). In providing a detailed description of native K+ currents in body wall muscle cells of C. elegans, this work lays the basis for further comparisons with mutants to assess the function of K+ channels in this model organism that is highly amenable to molecular and classical genetics.