摘要
目的研究并探讨硝普钠(sodiumnitroprusside,SNP)对豚鼠耳蜗外毛细胞(outerhaircells,OHC)全细胞电流的影响及其作用机制。方法利用急性分离的OHC和特异性的离子通道阻断剂作为工具药,通过膜片钳电压钳记录技术观察了SNP对豚鼠耳蜗OHC全细胞电流的影响,结果①在以+40mV的指令电压刺激时,10-3mol/L的SNP抑制15.34±6.59%的细胞电流(n=5);②SNP对全细胞电流的抑制作用有电压依赖性,在刺激高于0mV时作用明显,10-2mol/L的SNP在+10mV时抑制率为4.97±1.74%,而在+40mV时的抑制率为33.82±1.61%;③SNP对全细胞电流的抑制呈量效关系,在浓度大于10-3mol/L时,抑制作用逐渐明显,10-1mol/L的SNP时接近达到最大抑制效应;④分离离子电流成分后,SNP仅对Ca2+电流有抑制作用。结论SNP对豚鼠耳蜗外毛细胞的全细胞电流的抑制作用,主要通过抑制细胞外Ca2+的内流,进而影响Ca2+依赖性K+通道而实现。
Objective To study the effects of sodium nitroprusside(SNP) on whole cell currents of outer hair cells(OHCs)in the cochlea of guinea pigs and to find the underlying mechanism. Method By using the whole cell patch clamp recording technique, the effects of SNP on whole cell curents of OHCs were investigated. Results SNP could affect OHCs'whole cell currents in voltage-dependent and dose-response manner. 1mmol/L SNP inhibited the whole cell currents by 15.34±6.59%. Under different voltage stimuli of +40mV and +10mV, 10mmol/L SNP inhibited OHC whole cell currents by 33.82±1.61% and 4.97±1.74%, respectively(n=5). When the concentration of SNP was higher than 1mmol/L, the inhibitory effect became more apparent. By alternating the components of ions in the medium, it was found that only the calcium currents were inhibited by SNP. Conclusion SNP could inhibit the whole cell currents of OHCs in the cochlea of guinea pigs by preventing the extracellular calcium from influx into the cells.
出处
《中华耳科学杂志》
CSCD
2005年第2期121-125,共5页
Chinese Journal of Otology
基金
国家自然科学基金项目
批准号:39670781
国家杰出青年科学基金项目
批准号:39925035
教育部"高等学校骨干教师资助计划"项目(2000-65)
