在稳定转染的 HEK293 细胞中，changrolin 对人 ether-a-go-go 相关基因 (hERG) K(+) 通道的状态依赖性阻断。
State-dependent blockade of human ether-a-go-go-related gene (hERG) K(+) channels by changrolin in stably transfected HEK293 cells.
机构信息
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
出版信息
Acta Pharmacol Sin. 2010 Aug;31(8):915-22. doi: 10.1038/aps.2010.84.
AIM
To study the effect of changrolin on the K(+) channels encoded by the human ether-a-go-go-related gene (hERG).
METHODS
hERG channels were heterologously stably expressed in human embryonic kidney 293 cells, and the hERG K(+) currents were recorded using a standard whole-cell patch-clamp technique.
RESULTS
Changrolin inhibited hERG channels in a concentration-dependent and reversible manner (IC(50)=18.23 mumol/L, 95% CI: 9.27-35.9 mumol/L; Hill coefficient=-0.9446). In addition, changrolin shifted the activation curve of hERG channels by 14.3+/-1.5 mV to more negative potentials (P<0.01, n=9) but did not significantly affect the steady-state inactivation of hERG (n=5, P>0.05). The relative block of hERG channels by changrolin was close to zero at the time point of channel opening by the depolarizing voltage step and quickly increased afterwards. The maximal block was achieved in the inactivated state, with no further development of the open channel block. In the "envelope of tails" experiments, the time constants of activation were found to be 287.8+/-46.2 ms and 174.2+/-18.4 ms, respectively, for the absence and presence of 30 mumol/L changrolin (P<0.05, n=7). The onset of inactivation was accelerated significantly by changrolin between -40 mV and +60 mV (P<0.05, n=7).
CONCLUSION
The results demonstrate that changrolin is a potent hERG blocker that preferentially binds to hERG channels in the open and inactivated states.
目的
研究樟柳碱对人 ether-a-go-go 相关基因（hERG）编码的 K(+)通道的影响。
方法
采用标准全细胞膜片钳技术，在人胚肾 293 细胞中异源稳定表达 hERG 通道，记录 hERG K(+)电流。
结果
樟柳碱呈浓度依赖性和可恢复性抑制 hERG 通道（IC(50)=18.23 mumol/L，95%CI：9.27-35.9 mumol/L；Hill 系数=-0.9446）。此外，樟柳碱将 hERG 通道的激活曲线向更负的电位移动 14.3+/-1.5 mV（P<0.01，n=9），但对 hERG 的稳态失活没有显著影响（n=5，P>0.05）。在去极化电压阶跃引起通道开放的时间点，hERG 通道被樟柳碱的相对阻断接近于零，随后迅速增加。最大阻断发生在失活状态，开放通道阻断无进一步发展。在“尾迹包络”实验中，发现激活时间常数分别为 287.8+/-46.2 ms 和 174.2+/-18.4 ms，在不存在和存在 30 mumol/L 樟柳碱的情况下（P<0.05，n=7）。失活开始时，樟柳碱显著加速（P<0.05，n=7）。
结论
结果表明，樟柳碱是一种有效的 hERG 阻断剂，优先结合开放和失活状态的 hERG 通道。
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