焦亚硫酸钠对大鼠海马CA1区神经元钾电流的影响  

EFFECTS OF SODIUM METABISULFITE ON POTASSIUM CURRENTS IN ACUTELY ISOLATED RAT HIPPOCAMPAL CA1 NEURONS

作　　者：孟紫强[1] 聂爱芳[1] 

机构地区：[1]山西大学环境医学与毒理学研究所,山西太原030006

出　　处：《中国应用生理学杂志》2005年第3期241-246,共6页Chinese Journal of Applied Physiology

基　　金：国家自然科学基金重点项目(30230310);国家自然科学基金面上基金项目(20477023)

摘　　要：目的:探讨焦亚硫酸钠(SMB)、二氧化硫(SO2)及其体内衍生物(亚硫酸盐和亚硫酸氢盐)对中枢神经元钾通道的影响及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)及谷胱甘肽过氧化物酶(GPx)相应的保护作用。方法:采用全细胞膜片钳技术研究了SMB对大鼠海马CA1区神经元瞬间外向钾电流(IA)和延迟整流钾电流(IK)的影响。结果:①焦亚硫酸钠可增大全细胞IA和IK,且具剂量依赖性和电压依赖性,使IA和IK增大50%的剂量分别为15.8μmol/L和11.5μmol/L;②10μmol/L的SMB均可显著影响IA和IK的激活过程,给药前后IA的半数激活电压分别为(-12.6±1.6)mV和(-7.0±1.3)mV(n=8,P<0.01),IK的半数激活电压分别为(10.8±0.9)mV和(21.6±0.7)mV(n=8,P<0.01),但不改变其斜率因子;③10μmol/L的SMB还非常显著地影响IA的失活过程,给药前后其半数失活电压分别为(-97.0±1.1)mV和(-84.4±3.3)mV(n=8,P<0.01),但也不改变其斜率因子;④抗氧化酶SOD(1×106U/L)、CAT(2×106U/L)及GPx(105U/L)均可使SMB(10μmol/L)增大的IA和IK部分恢复。结论:SMB可显著增大IA和IK,抑制IA和IK的激活过程及IA的失活过程,从而导致胞内K+的外流增加,使胞内K+浓度降低,从而对中枢神经元功能产生不利影响。Aim： To investigate the effects of sodium metabisulfite（SMB）, sulfur dioxide（SO2） and its derivatives in vivo, sodium bisulfite and sulfite on K^＋ channels of the central neurons and its mechanisms. Methods： By using whole-cell patch-clamp techinique, the effects of SMB on transient outward K^＋ （IA） and delayed rectifier K^＋ currents（IK） were observed. Results： ① SMB can increase the amplitudes of IA and IK in a dose-dependent and vohage-dependent manner. Their half-increase doses were 15.8 μmol/L and 11.5 μmol/L respectively. ② SMB（ 10 μmol/L） significantly shifted the activation curves of IA and IK to more positive potentials. Before and after application of 10μmol/L SMB , the half-activation voltages of IA and IK were （ - 12.6 ± 1.6）mV and （ - 7.0 ± 1.3）mV, （10.8 ± 0.9）mV and （21.6 ± 0.7）mV（ P〈 0.01, n = 8）, respectively, but the slope factors were not changed. ③ The inactivation curve of IA was shifted to positive potentials, the half-inactivation voltage of IA were（ - 97.0 ± 1.1）mV and（ - 84.4 ± 3.3）mV （ P 〈 0.01, n = 8） before and after application of SMB（ 10μmol/L） , without changing the slope factors. ④ SOD, CAT and GPx could partly inhibit the incremental effect of SMB on IA and IK. Conclusion： SMB, SO2 and its derivatives in vivo, sodium bisulfite and sulfite have the damage effects on the central nervous system, and they can cause extracelluar K＋ increase and induce the disturbance of the central neuronal functions. Its mechanism may involve oxidation damage in the rat hippocampal CA1 neurons, caused by sulfurand oxygen-centered free radicals formed in the process of sulfite or bisulfite oxidation.

关 键 词：海马神经元 全细胞膜片钳技术 焦亚硫酸钠 二氧化硫 瞬间外向钾电流(IA) 延迟整流钾电流(IK) 

分 类 号：Q346[生物学—遗传学]