Variability in the measurement of hERG potassium channel inhibition: Effects of temperature and stimulus pattern
Variability in the measurement of hERG potassium channel inhibition: Effects of temperature and stimulus pattern
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DOI：
10.1016/j.vascn.2004.06.003
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发表时间：
2004-09-01
影响因子：
1.9
通讯作者：
Brown, Arthur M.
中科院分区：
文献类型：
--
作者：
Kirsch, Glenn E.;Trepakova, Elena S.;Brown, Arthur M.
简介：药物对hERG K+通道作用的体外评价是在药物安全性试验中识别潜在促肾上腺皮质激素副作用的有价值的工具。膜片钳记录哺乳动物细胞中的hERG K+电流可以准确地评估药物作用，但方法尚未标准化，结果差异很大。我们的目的是评估两个潜在的变异性来源：进行记录的温度和用于激活HEK 293细胞中表达的hERG K+通道的电压脉冲方案。研究方法：使用几种膜片钳电压方案，在室温和接近生理温度下评价了一组15种药物，这些药物涵盖了hERG抑制和药理学类别的广泛效力。浓度响应分析进行了三个刺激协议：0.5和2秒的步进脉冲，或步进斜坡模式。结果：15种药物中的2种，D，L-索他洛尔（抗血小板药物）和红霉素（抗生素）的阻断具有明显的温度敏感性。使用2秒阶跃脉冲方案测量的hERG抑制与使用阶跃斜坡方案获得的结果相比低估了红霉素效力。使用保守的验收标准和阶梯式方案，15种药物的hERG阻断IC 50值差异小于2倍。讨论内容：在接近生理温度下使用步进-斜坡模式获得的数据具有高度可重复性，并提供了hERG抑制的保守安全性评价。(C)2004年爱思唯尔公司All rights reserved.
Introduction: In vitro evaluation of drug effects on hERG K+ channels is a valuable tool for identifying potential proarrhythmic side effects in drug safety testing. Patch-clamp recording of hERG K+ current in mammalian cells can accurately evaluate drug effects, but the methodology has not been standardized, and results vary widely. Our objective was to evaluate two potential sources of variability: the temperature at which recordings are performed and the voltage pulse protocol used to activate hERG K+ channels expressed in HEK293 cells. Methods: A panel of 15 drugs that spanned a broad range of potency for hERG inhibition and pharmacological class was evaluated at both room and near-physiological temperatures using several patch-clamp voltage protocols. Concentration-response analysis was performed with three stimulus protocols: 0.5- and 2-s step pulses, or a step-ramp pattern. Results: Block by 2 of the 15 drugs tested, D,L-sotalol (antiarrhythmic) and erythromycin (antibiotic), was markedly temperature sensitive. hERG inhibition measured using a 2-s step-pulse protocol underestimated erythromycin potency compared with results obtained with a step-ramp protocol. Using conservative acceptance criteria and the step-ramp protocol, the IC50 values for hERG block differed by less than twofold for 15 drugs. Discussion: Data obtained at near-physiological temperatures using a step-ramp pattern are highly repeatable and provide a conservative safety evaluation of hERG inhibition. (C) 2004 Elsevier Inc. All rights reserved.