The cloned cardiac Na channel alpha-subunit expressed in Xenopus oocytes show gating and blocking properties of native channels.
The cloned cardiac Na channel alpha-subunit expressed in Xenopus oocytes show gating and blocking properties of native channels.
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在非洲爪蟾卵母细胞中表达的克隆心脏 Na 通道 α 亚基显示出天然通道的门控和阻断特性。
DOI：
10.1007/bf00233735
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Fozzard,HA
中科院分区：
文献类型：
--
作者：
Satin,J;Kyle,JW;Chen,M;Rogart,RB;Fozzard,HA
卵母细胞中新生大鼠心脏 Na 通道 α 亚基定向电流显示出心脏对河豚毒素 (TTX) 阻滞的特征性相对抵抗力。通过在大鼠脑 (BrnIIa) 和成人骨骼肌 (μI) Na 通道的 α 亚基的爪蟾细胞中表达获得的 TTX 敏感电流显示出异常缓慢的衰减动力学。为了确定心脏α亚基（RHI）引导的电流在卵母细胞中是否表现出像天然电流一样的动力学，我们将卵母细胞中的RHI引导电流与新鲜分离的新生大鼠肌细胞中的Na电流进行了比较。 RHI电流的衰减速率接近新生儿肌细胞的衰减速率，并且比卵母细胞中的BrnIIa和μI电流更快。可用性和激活的电压依赖性与大鼠肌细胞相同，除了去极化方向有 12-19 mV 的偏移。 RHI Na电流对Cd2+阻滞敏感，并且它们表现出与天然电流类似的TTX和利多卡因阻滞的使用依赖性。注射编码心脏Na通道α亚基的cRNA后，卵母细胞中表达的电流具有天然心脏Na电流的大部分特征动力学和药理学特性。
The neonatal rat cardiac Na channelα-subunit directed currents in oocytes show characteristic cardiac relative resistance to tetrodotoxin (TTX) block. TTX-sensitive currents obtained by expression inXenopusoocytes of theα-subunits of the rat brain (BrnIIa) and adult skeletal muscle (μI) Na channels show abnormally slow decay kinetics. In order to determine if currents directed by the cardiacα-subunit (RHI) exhibit kinetics in oocytes like native currents, we compared RHI-directed currents in oocytes to Na currents in freshly isolated neonatal rat myocytes. The decay rate of RHI currents approached that of neonatal myocytes and was faster than BrnIIa and μI currents in oocytes. The voltage dependence of availability and activation was the same as that in the rat myocytes except for a 12–19 mV shift in the depolarizing direction. The RHI Na currents were sensitive to Cd2+block, and they showed use dependence of TTX and lidocaine block similar to native currents. The current expressed in oocytes following injection of the cRNA encoding for theα-subunit of the cardiac Na channel possesses most of the characteristic kinetic and pharmacological properties of the native cardiac Na current.