不同温度条件对药物作用hERG钾通道的影响研究

Effects of drugs on hERG potassium channels at different temperatures

目的:建立生理温度下hERG钾通道评价方法,研究非温度敏感型药物和温度敏感型药物对人类果蝇相关基因-hERG(human ether-a-go-go-related gene)编码的心脏hERG钾通道的作用。方法:在室温或生理温度(33℃和35℃)条件下,采用全细胞膜片钳技术记录不同浓度的温度敏感型(红霉素、氧化苦参碱)和非温度敏感型药物(西沙必利、昂丹司琼、E-4031)作用于HEK293细胞后hERG钾电流的变化,研究不同温度条件下上述药物对hERG钾电流作用的浓度依赖性以及半数抑制浓度(IC50)。结果:非温度敏感型药物西沙必利、E-4031、昂丹司琼在不同温度条件下均对快速激活延迟整流钾电流(Ikr)有浓度依赖性的抑制作用;温度敏感型药物红霉素、氧化苦参碱在室温、33℃和35℃下对Ikr均有浓度依赖性的抑制作用,且测定温度越高,其IC50值越小。结论:在生理温度条件下采用全细胞膜片钳技术可以测定人胚肾细胞(HEK293)转染表达的hERG钾通道电流,非温度敏感型药物在不同温度条件下对hERG钾电流阻断作用差异不显著,温度敏感型药物在不同温度条件下对hERG钾电流的作用略有差异,提示在生理温度条件下测定药物对hERG钾电流的作用可以更准确地反应温度敏感型药物在人体内对hERG钾通道的作用。

Objective: To establish an evaluation method for hERG potassium channel at physiological temperature, and study the effects of non-temperature-sensitive drugs and temperature-sensitive drugs on hERG potassium channel, which was encored by the human ether-a-go-go-related gene. Methods: At room temperature or physiological temperature(33 ℃ and 35 ℃), whole-cell patch clamp technology was used to record the changes of hERG potassium currents after treatment on HEK293 cells with different concentrations of temperature-sensitive drugs(erythromycin, oxymatrine) and non-temperature-sensitive drugs(cisapride, ondansetron, E-4031) to study the concentration dependence and the half inhibitory concentration of the effects(IC50) of the above drugs on hERG potassium currents under different temperature conditions. Results: The non-temperature-sensitive drugs cisapride, E-4031, and ondansetron all had a concentration-dependent inhibitory effect on the rapidly activated delayed rectifier potassium currents(Ikr) under different temperature conditions;the temperature-sensitive drugs erythromycin and oxymatrine had a concentration-dependent inhibitory effect on Ikrat room temperature, 33 ℃ and 35 ℃, and the higher the measurement temperature, the lower its IC50. Conclusion: The whole-cell patch clamp technique can be used to measure the hERG potassium channel currents transfected and expressed by human embryonic kidney cells(HEK293) under physiological temperature conditions. There is no significant difference in the blocking effects of non-temperature-sensitive drugs on hERG potassium currents under different temperature conditions. The effects of temperature-sensitive drugs on hERG potassium currents under different temperature conditions are slightly different, suggesting that measuring the effects of drugs on hERG potassium currents under physiological temperature conditions can more accurately reflect the effects of temperature-sensitive drugs on hERG potassium channels in human body.