摘要：
目的：探讨氟西汀对hERG( ether-a-go-go-related gene)钾通道的作用及蛋白激酶C( PKC)激动剂佛波酯( PMA )对氟西汀作用的影响。方法采用全细胞膜片钳技术记录氟西汀0.01,0.1,1和10μmol·L－1处理后稳定表达hERG钾通道的HEK293细胞( hERG-HEK293稳态细胞)上hERG钾通道电流(IKr)的变化,研究氟西汀对IKr作用的浓度依赖性和电压依赖性,并观察氟西汀1μmol·L－1处理后hERG钾通道激活、失活和复活动力学的变化。在此基础上,观察PMA 1μmol·L－1对氟西汀1μmol·L－1作用IKr后的影响。结果氟西汀0.01,0.1,1和10μmol·L－1对hERG-HEK293稳态细胞上IKr具有浓度依赖性和电压依赖性的抑制作用,半数抑制浓度( lC50)约为0.8μmol·L－1,Hill系数约为1.1。氟西汀1μmol·L－1可以减小IKr激活、失活和复活电流,并影响hERG钾通道的激活和复活过程。在氟西汀对IKr电流的抑制作用达到稳态后,PMA 1μmol·L－1可抑制氟西汀对hERG钾通道的阻断作用。结论氟西汀对hERG-HEK293稳态细胞上hERG钾通道具有明显的阻断作用,该作用可被PKC激动剂PMA抑制。%OBJECTlVE To investigate the action mechanism of antidepressant fluoxetine on hERG ( ether-a-go-go-related gene ) potassium channel, and the effect of protein kinase C ( PKC ) agonist phorbol-12-myristate-13-acetate ( PMA) on fluoxetine inhibition. METHODS The whole cell patch clamp technique was used to record the change in hERG potassium current ( IKr ) on HEK293 cells that stably expressed hERG potassium channel ( hERG-HEK293 steady-state cells) , which was treated with fluoxe-tine 0.01, 0.1, 1 and 10μmol·L-1 , to study the concentration-and voltage-dependence of the effects on IKr, and to observe the changes in activation, inactivation and recovery dynamics of hERG potassium channel treated with fluoxetine 1μmol·L-1 . On this basis, the effect of PMA of 1μmol·L-1 on inhibition of fluoxetine 1 μmol·L-1 was explored. RESULTS Fluoxetine 0.01, 0.1, 1 and 10 μmol·L-1 inhibited IKr on hERG-HEK293 steady-state cells in a concentration- and voltage-dependent manner. The half maximal inhibitory concentration ( lC50 ) was about 0. 8 mmol·L-1 , and the Hill coefficient was about 1. 1. Fluoxetine 1 μmol·L-1 could reduce the activation, deactivation and recovery currents of IKr and affect the activation and recovery of hERG potassium channel. After fluoxetine inhibition of IKr became stable, PMA 1 μmol·L-1 could inhibit the blocking effect of fluoxetine on hERG potassium channels. CONCLUSlON Fluoxetine has obvious inhibitory effect on IKr of hERG-HEK293 steady-state cells, but the effect could be inhibited by PKC agonist PMA.
