二氧化硫衍生物对背根神经元钙通道的影响

Effects of SO_2 Derivatives on Calcium Channels in DRG Neurons

应用全细胞膜片钳技术研究了SO2衍生物对大鼠DRG(背根神经节)神经元不同亚型钙通道的影响.结果表明,1μmol/LSO2衍生物对不同电压下的钙电流均有增大作用,在-10 mV时可使钙电流增幅达到63.4%±5.7%.在细胞外液中加入不同亚型钙通道的阻滞剂并经过修正计算发现,1μmol/L SO2衍生物使L型钙电流增长了82.2%,N型钙电流增长了95.3%,r型(非L型、非N型)钙电流增长了9.4%,说明高阈值激活的N型和L型钙电流对SO2衍生物特别敏感,推测SO2衍生物诱发神经性疼痛,引起神经毒性,可能主要通过增大DRG神经元上N型和L型钙通道发生电流介导.

The effects of SO2 derivatives on L-type and N-type calcium currents in freshly isolated rat dorsat root ganglion neurons were investigated using the whole-cell configuration of the path-clamp technique. The results showed： first, it was found that 1μmol/L SO2 derivatives could increase the amplitudes of calcium currents in a voltage-dependent manner. The average increase of high-voltage- activated calcium currents was 63.4% ＋5.7% at - 10 mV. Second, the sensitivity of SOs derivatives on channel subtypes was quantitatively estimated based on the different ratios of L-, N-, r-（ non-L- and non-N-types） types expressed in total high-voltage-activated calcium channels when the corresponding selective channel blockers were applied and the calcium currents were recorded. The data showed that 1 lxmol/L SO2 derivatives increased L-type current by 82.2% , increased N-type by 95.3% , and increased residual r type Ca^2＋ currents by 9.4% , which indicated that both N- and L-type Ca^2＋ channels were sensitive to SO2 derivatives. It was suggested that SO2 derivatives could enhance both types of Ca^2＋ currents in dorsal root ganglion neurons and then lead to neuropathic pain.