焦亚硫酸钠对大鼠背根节神经元L-型钙电流的影响

为了探讨二氧化硫(SO2)及其衍生物对背根节神经元的生理调节作用,应用全细胞膜片钳技术,研究了SO2衍生物焦亚硫酸钠(sodiummetabisulfite,SMB)对大鼠背根节神经元L-型钙电流(ICa,L)的影响.结果表明,SMB可增大ICa,L,且具有剂量依赖性和电压依赖性的特征.SMB可使ICa,L的激活和失活过程均向去极化方向移动,但对失活的影响要大于对激活的影响,从而可导致背根节神经元钙离子内流增大,引起细胞内钙离子浓度增加.这说明SO2及其衍生物对背根节神经元的生理功能有调节作用,当其浓度过高时也可能引起该神经元的病理生理改变.

Modulation of sodium metabisulfite on L-type calcium current in rat dorsal root ganglion neurons

To explore the regulating role of SO2 and its derivatives on the physiological function of dorsal root ganglion (DRG) neurons, the effect of sodium metabisulfite (SMB), a common sulfur dioxide (SO2) derivative and food preservative, on the L-type calcium current (ICa,L) of rat DRG neurons was studied using the whole cell configuration by patch-clamp technique. The present results show that SMB increased the ICa,L in a concentration-and voltage-dependent manner. SMB shifted both the steady-state activation and the inactivation curves of ICa,L to more positive potentials, and the shift of the inactivation curves was more pronounced than that of the activation curves. The increase of ICa,L by SMB might cause an increase of intracellular calcium concentration via voltage-gated L-type calcium channels. These results lead to the conclusion that SO2 and its derivatives could regulate the physiological function of DRG neurons, and these chemicals at high concentrations could also cause pathophysiologic changes of the neurons.