醋酸铅对人和小鼠瞬时受体电位A1离子通道的抑制作用

摘要

OBJECTIVE To investigate the inhibitory effect of lead acetate on transient receptor potential A1(TRPA1)channel. METHODS TRPA1-mediated calcium influx in mice dorsal root ganglion(DRG) neurons and HEK293 cells expressing nouse TRP1 (mTRPA1) and human TRPA1 (hTRPA1) was recorded by intracellular calcium imaging. TRPA1-mediated currents were detected by two-electrode voltage clamp. RESULTS Lead acetate 3.0 and 10.0μmol·L-1 inhibited external calcium influx in DRG neurons by(36.7 ± 4.1)% and(79.4 ± 3.1)%(n=5),respectively. The inhibitory effect of lead acetate on hTRPA1-mediated current was concentration-dependent. Lead acetate 0.3, 1.0, 3.0, 10.0 and 30.0μmol · L-1 inhibited the amplitudes of currents by(1.0 ± 0.7)%,(11.6 ± 0.8)%,(57.7 ± 3.2)%,(93.6 ± 2.6)%and(91.2±2.0)%(n≥4),respectively,with the IC50 2.4μmol·L-1. CONCLUSION TRPA1 channel may be an endogenous target of lead. Lead acetate inhibits TRPA1 channel at a very low concentration.%目的：研究醋酸铅对瞬时受体电位A1（TRPA1）通道的影响。方法应用细胞内钙荧光成像系统检测原代培养的小鼠背根神经节（DRG）神经元上TRPA1（mTRPA1）通道和外源性表达在HEK293细胞上的人源TRPA1（hTRPA1）和mTRPA1通道介导的细胞外钙内流；应用双电极电压钳技术记录外源性表达在爪蟾卵母细胞上的hTRPA1通道介导的电流。结果醋酸铅3.0和10.0μmol·L-1对TRPA1介导的小鼠DRG神经元外钙内流的抑制率分别为（36.7±4.1）%和（79.4±3.1）%；醋酸铅浓度依赖性地抑制爪蟾卵母细胞上hTRPA1通道介导的电流，醋酸铅0.3，1.0，3.0，10.0和30.0μmol·L-1对+80 mV处电流的抑制率分别为（1.0±0.7）%，（11.6±0.8）%，（57.7±3.2）%，（93.6±2.6）%和（93.2±2.7）%，其IC50为2.4μmol·L-1。结论 TRPA1通道是铅的内源性作用靶点，低浓度醋酸铅可抑制TRPA1通道。