迅速激活,慢慢地灭活克隆人类心脏钾通道。功能分析后稳定的哺乳动物细胞培养的表情。
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斯奈德DJ, Tamkun MM,贝内特PB
迅速激活,慢慢地灭活克隆人类心脏钾通道。功能分析后稳定的哺乳动物细胞培养的表情。
J创杂志。1993年4月,101 (4):513 - 43。
- PubMed ID
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8505626 (在PubMed]
- 文摘
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HK2的电生理特性(Kv1.5), K +通道克隆人类心室进行调查后稳定表达鼠标Ltk -细胞系。细胞系HK2 mRNA表达显示电流和延迟整流特性在23摄氏度,而虚假的转染细胞系显示特定HK2 mRNA杂交和voltage-activated完整的细胞条件下电流。HK2电流的表达式在两年内已经稳定了。当前的逆转潜力的依赖外部K +浓度(55 mV /十年)证实了K +选择性,和尾巴信封测试很满意,指示表达式一个人口K +通道。激活时间进程是快速和s形(时间常数从10 ms下降到< 2 0到60 + mV女士)。中点和激活曲线的斜率因子呃= -14 + / - 5 mV和k = 5.9 + / - 0.9 (n = 31),分别。观察慢部分失活特别是在大去极化(20 + / - 2%在250 ms + 60 mV, n = 32),和是不完整的5 s (69 + / - 3%, n = 14)。这慢失活似乎是一个真正的控制过程,而不是由于K +积累,因为它是现在不管电流的大小与140毫米甚至观察外部K +浓度。慢失活与主要voltage-independent biexponential时间课程时间常数的大约240和-10年间2700 ms + 60 mV。缓慢的电压依赖性失活重叠与激活:呃= -25 + / - 4 mV和k = 3.7 + / - 0.7 (n = 14)。 The fully activated current-voltage relationship displayed outward rectification in 4 mM external K+ concentration, but was more linear at higher external K+ concentrations, changes that could be explained in part on the basis of constant field (Goldman-Hodgkin-Katz) rectification. Activation and inactivation kinetics displayed a marked temperature dependence, resulting in faster activation and enhanced inactivation at higher temperature. The current was sensitive to low concentrations of 4-aminopyridine, but relatively insensitive to external TEA and to high concentrations of dendrotoxin. The expressed current did not resemble either the rapid or the slow components of delayed rectification described in guinea pig myocytes. However, this channel has many similarities to the rapidly activating delayed rectifying currents described in adult rat atrial and neonatal canine epicardial myocytes.(ABSTRACT TRUNCATED AT 400 WORDS)