L-TYPE CALCIUM CHANNELS, POTASSIUM CHANNELS, AND NOVEL NONSPECIFIC CATION CHANNELS IN A CLONAL MUSCLE-CELL LINE DERIVED FROM EMBRYONIC RAT VENTRICLE
L-TYPE CALCIUM CHANNELS, POTASSIUM CHANNELS, AND NOVEL NONSPECIFIC CATION CHANNELS IN A CLONAL MUSCLE-CELL LINE DERIVED FROM EMBRYONIC RAT VENTRICLE
复制标题
DOI：
10.1161/01.res.69.6.1487
复制
发表时间：
1991-12-01
影响因子：
20.1
通讯作者：
MARBAN, E
中科院分区：
文献类型：
--
作者：
SIPIDO, KR;MARBAN, E
我们的特点是在H9C2克隆肌细胞系来自胚胎大鼠心室的膜电流。Hescheler及其同事发现，通过选择性连续传代和克隆增殖建立的这些细胞表达对β-肾上腺素能刺激有反应的二氢吡啶敏感性钙通道。我们用标准的膜片钳方法研究了这些细胞中的宏观电流和基元电流。在保持汇合3 - 4周的细胞中，我们已经证实了L型钙通道的表达，并且还确定了许多但不是所有这些通道的单位电导（在70 mM钡中为25 pS）等于心肌而不是骨骼肌的单位电导。当细胞快速增殖时，钙通道稀少或不存在，但至少观察到两个不同的钾通道和一个非特异性阳离子通道。非特异性通道在生理盐水中表现出30 pS的电导率，并以几乎相同的功效传导钠、钾和钙。几个不寻常的属性区分这种非特异性通道从以前描述的其他人。门控是电压依赖性的，具有缓慢激活和在正电位下开放概率的显著增加。与电压不同，[Ca2 +]或膜拉伸的变化不会明显影响活动。总之，我们的工作和Hescheler等人的工作表明，H9c2细胞是研究离子通道调节和肌肉基因表达的潜在有价值的替代物。
We have characterized the membrane currents in the H9c2 clonal muscle cell line derived from embryonic rat ventricle. These cells, established by selective serial passage and clonal proliferation, have been found by Hescheler and coworkers to express dihydropyridine-sensitive calcium channels that respond to beta-adrenergic stimulation. We have investigated the macroscopic and elementary currents in these cells by using standard patch-clamp methods. In cells that are kept confluent for 3-4 weeks, we have confirmed the expression of L-type calcium channels and additionally establish that the unitary conductance of many, but not all, of these channels (25 pS in 70 mM barium) is equal to that of cardiac rather than skeletal muscle. When the cells are proliferating rapidly, calcium channels are sparse or absent, but at least two distinct potassium channels and a nonspecific cation channel are observed. The nonspecific channel exhibits a conductance of 30 pS in physiological saline and conducts sodium, potassium, and calcium with nearly equal efficacy. Several unusual properties distinguish this nonspecific channel from others described previously. Gating is voltage dependent, with slow activation and marked increases in open probability at positive potentials. Unlike voltage, changes in [Ca2+] or in membrane stretch do not noticeably influence activity. In conclusion, our work and that of Hescheler et al indicate that H9c2 cells are potentially valuable surrogates for the investigation of ion channel regulation and muscular gene expression.