The effects of SO2 derivatives on L-type and N-type calcium currents in freshly isolated rat dorsal root ganglion neurons were investigated using the whole-cell configuration of the path-clamp technique. The results showed: first,it was found that 1 μmol/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 SO2 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 μmol/i SO2 derivatives increased L-type current by 82.2% ,increased N-type by 95.3% ,and increased residual r type Ca2+ currents by 9.4% ,which indicated that both N- and L-type Ca2+ channels were sensitive to SO,derivatives. It was suggested that SO2 derivatives could enhance both types of Ca2+ currents in dorsal root ganglion neurons and then lead to neuropathic pain.%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.
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