Effects of SO2 derivatives on sodium currents in acutely isolated rat hippocampal lead-exposed neurons

Abstract

In this study, the effects of acute SO2 derivatives and chronic lead exposure together on sodium currents (I(Na)) were investigated in acutely isolated rat hippocampal neurons by using the whole-cell patch clamp techniques. We found that chronic lead exposure hardly reduced the amplitudes of I(Na). In the normal condition, sodium current started to appear at around -70 mV, and reached the peak current at around -40 mV. After chronic lead exposure, the data changed to -70 and -30 mV. After adding SO2 derivatives, the data changed to -80 and -40 mV, respectively. SO2 derivatives caused a significant increase of I(Na) in hippocampal chronic-lead exposed neurons. Chronic lead exposure induced a right shift of the activation curve and a left shift of the inactivation curve of sodium channels. SO2 derivatives caused negative shifts of the activation and inactivation curves of I(Na) in hippocampal chronic-lead exposed neurons. Lead exposure put off the time reaching the peak of I(Na) activation. SO2 derivatives increased the time constants of inactivation after lead exposure. The interaction of lead and SO2 derivatives with voltage-dependent sodium channels may lead to changes in electrical activity and contribute to worsening the neurotoxicological damage.

二氧化硫衍生物对铅引起的大鼠海马神经元钠电流变化的影响

“…CdCl 2 0.2 mmol/L. 电极内液(mmol/L): CsCl 75, NaF 7.5, MgCl 2 2, HEPES 10, EGTA 2.5, Na 2 ATP 3, pH 7.5 [7] . 二氧化硫代谢衍生物的配制: 将 2.5 mmol/L NaHSO 3 和 7.5 mmol/L Na 2 SO 3 [6] .…”