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[目的]通过分析石英作用后大鼠背根神经元(DRG)高电压激活(HVA)钙电流的变化,探讨石英对钙离子通道结构和功能的影响。[方法]原代培养DRG,分0、5、15、45、135μg/mL5个石英浓度组进行体外染尘,运用全细胞膜片钳记录技术记录不同染尘时间DRGHVA钙电流,每组记录约6个DRG。[结果]135μg/mL剂量组石英作用于DRG后HVA钙电流密度峰值为(-95.9±38.8)pA/pF,大于对照组和低剂量组,差异有统计学意义(P<0.05),HVA钙电流从30%升至70%的速率明显快于对照组和其他染尘组,差异有统计学意义(P<0.01),但达峰时间差异无统计学意义(P>0.05);135μg/mL剂量组钙电流平均失活速率明显快于对照组和其他染尘组,差异有统计学意义(P=0.000),电流从峰值到记录结束时的下降率高于对照组和其他染尘组,差异有统计学意义(P<0.05)。45、135μg/mL组的DRG膜电导值分别为(1420.0±655.6)pS/μm2和(2257.4±454.2)pS/μm2,均高于对照组和低剂量染尘组,差异有统计学意义(P<0.05)。石英可使DRGHVA钙电流稳态激活曲线V1/2向正值方向移动约6.0～6.5mV,大于对照组,差异有统计学意义(P<0.05),移动的幅度与染尘浓度关系不明显(P>0.05);斜率k变化不明显(P>0.05)。石英作用后DRGHVA电流-电压(I-V)曲线形状改变不明显,对DRGHVA钙电流时间依赖性也没有明显影响。[结论]石英作用后DRGHVA钙通道结构和功能发生变化,使钙电流显著增大,呈激活快、失活也快的特征;另外,石英可使HVA钙通道在高刺激电压状况下(-10mV左右)更容易被激活。
[Objective] The purpose of this study was to investigate the effect of quartz on the structure and function of calcium channels by analyzing the changes of high voltage activated (HVA) calcium currents in rat dorsal root ganglion (DRG) induced by quartz. [Method] Primary cultured DRG were divided into 5, 5, 15, 45 and 135μg / mL quartz concentration groups to infect dust in vitro. Whole-cell patch clamp recording technique was used to record the DRGHVA calcium current at different dusting times, DRG. [Results] The peak current density of HVA in the group treated with 135μg / mL quartz was (-95.9 ± 38.8) pA / pF greater than that of the control group and the low dose group, the difference was statistically significant (P <0.05) The rate of current increase from 30% to 70% was significantly faster than that of the control group and other dyed groups (P <0.01), but there was no significant difference between peak time and peak value (P> 0.05) The average inactivation rate of calcium current in the dose group was significantly faster than that in the control group and other dyed groups (P = 0.000). The decreasing rate of current from the peak to the end of recording was higher than that of the control and other dyed groups, The difference was statistically significant (P <0.05). The conductivity of DRG in 45 and 135μg / mL groups were (1420.0 ± 655.6) pS / μm2 and (2257.4 ± 454.2) pS / μm2, respectively, which were significantly higher than those in control and low dose groups <0.05). Quartz can make DRGHVA calcium current steady state activation curve V1 / 2 move toward the positive direction about 6.0 ~ 6.5mV, which is larger than the control group, the difference is statistically significant (P <0.05), the movement amplitude and the dust concentration is not obvious P> 0.05); slope k did not change significantly (P> 0.05). The change of shape of current-voltage (I-V) curve of DRGHVA after quartz was insignificant, and had no significant effect on the time dependence of DRGHVA calcium current. [Conclusion] The structure and function of calcium channel of DRGHVA changed after quartz exposure, which increased the calcium current significantly and showed the characteristics of fast activation and inactivation. In addition, quartz could make HVA calcium channel under high stimulation voltage (-10mV Left and right) easier to be activated.