Finlayson K, Pennington A J, Kelly J S
Fujisawa Institute of Neuroscience, Department of Neuroscience, University of Edinburgh, 1 George Square, EH8 9JZ, Edinburgh, UK.
Eur J Pharmacol. 2001 Feb 2;412(3):203-12. doi: 10.1016/s0014-2999(01)00731-2.
The pharmacological characteristics of [3H]dofetilide binding in SHSY5Y, HEK293 and CHO-K1 cells were examined, and in parallel whole cell recordings used to characterise HERG-like K+ currents. Dofetilide affinity was similar in the human cell lines, SHSY5Y (Kd=99.6 nM) and HEK293 (Kd=102.9 nM), but 10 times lower in CHO-K1 cells (Kd=1200 nM). In contrast, clofilium and E4031 had a similar affinity in all three cell lines, whereas WAY 123,398 had no effect. Electrophysiological studies showed that SHSY5Y cells contained a HERG-like K+ current blocked by application of dofetilide to either side of the membrane. Block was faster when dofetilide was applied intracellularly. In contrast, HEK293 and CHO-K1 cells contained no such current, despite the presence of a partial cDNA for HERG in the former. That [3H]dofetilide is specific for I(Kr)/HERG may be questionable, as HEK293 and CHO-K1 cells contain no such functional K+ current.
研究了[3H]多非利特在SHSY5Y、HEK293和CHO-K1细胞中的结合药理学特性，并同时使用全细胞记录来表征类HERG钾电流。多非利特在人细胞系SHSY5Y（Kd = 99.6 nM）和HEK293（Kd = 102.9 nM）中的亲和力相似，但在CHO-K1细胞中低10倍（Kd = 1200 nM）。相比之下，氯非铵和E4031在所有三种细胞系中的亲和力相似，而WAY 123,398没有作用。电生理研究表明，SHSY5Y细胞含有一种类HERG钾电流，在膜的两侧施加多非利特均可阻断该电流。当在细胞内施加多非利特时，阻断速度更快。相比之下，尽管HEK293细胞中存在HERG的部分cDNA，但HEK293和CHO-K1细胞中不存在这种电流。由于HEK293和CHO-K1细胞中不存在这种功能性钾电流，[3H]多非利特对I(Kr)/HERG的特异性可能存在疑问。
