水杨酸钠对豚鼠单离外毛细胞外向钾电流和静息电位及膜电容影响

Effects of sodium salicylate on outward potassium current, resting potential and membrane electric capacitance of the outer hair cell isolated from guinea pig cochlea

目的 探讨水杨酸钠对豚鼠单离外毛细胞（ｏｕｔｅｒｈａｉｒｃｅｌｌ，ＯＨＣ） 钾电流（ｐｏｔａｓｓｉｕｍ ｃｕｒｒｅｎｔ，ＩＫ）、静息电位（ｒｅｓｔｉｎｇ ｐｏｔｅｎｔｉａｌ，ＲＰ） 和膜电容（ｍｅｍｂｒａｎｅ ｅｌｅｃｔｒｉｃ ｃａｐａｃｉｔａｎｃｅ，ＭＥＣ） 的影响，分析水杨酸钠影响毛细胞功能的细胞电生理机制。方法 应用膜片钳全细胞记录技术，测试０．１ 和１ ．０ ｍｍｏｌ／Ｌ水杨酸钠用药前后ＯＨＣ的ＩＫ、ＲＰ和ＭＥＣ 变化。结果 水杨酸钠对ＩＫ 的影响具有时效和量效关系，即用药后有ＩＫ 先增加后降低的双相作用，而高浓度水杨酸钠无论是对ＩＫ 的增加作用还是降低作用都比低浓度时明显。ＲＰ平均约为－６０ ｍＶ，ＭＥＣ 平均约为３９ ｐＦ。水杨酸钠有降低ＲＰ和ＭＥＣ的作用，且均存在着量效关系，即高浓度时的作用大于低浓度时。水杨酸钠对ＲＰ和ＭＥＣ影响的时效关系不明显。结论 水杨酸钠具有影响ＯＨＣ两侧膜的Ｋ＋ 电导和细胞内外Ｋ＋ 分布的作用，并通过对ＩＫ、ＲＰ和ＭＥＣ的影响改变ＯＨＣ的兴奋性和机械活动特性，可能是水杨酸影响毛细胞功能的耳蜗机制之一。

Objectives To study effects of sodium salicylate on the outward potassium current (I K), resting potential (RP) and membrane electric capacitance (MEC) of outer hair cells isolated from guinea pig cochleas and the cytoelectrophysiological mechanisms of effects of sodium salicylate on functions of hair cells Methods Using the patch clamp whole cell recording technique, I K, RP and MEC were measured before and after the administration of sodium salicylate at concentration of 0 1 or 1 0 mmol/L The effects of sodium salicylate on I K, RP and MEC were observed Results The effects of sodium salicylate on I K had time and dosage effect relations, of which the former meant I K increasing and then decreasing after administration, the later meant that the effects of sodium salicylate being much more dominant during either increasing or decreasing I K in higher concentration than in lower concentration The mean RP was approximately -60mV and the mean MEC was approximately 39 pF Sodium salicylate could decrease RP and MEC, which possessed a dosage effect relation, that is, the effect was stronger in higher concentration than in lower concentration, and there was no clear evidence for time effect relation Conclusions The sodium salicylate might affect the K + conduction at the lateral membrane and internal and external distribution of K + in the outer hair cell Sodium salicylate might affect the excitability and mechanical activity of the outer hair cell by means of affecting I K, RP and MEC, which might be one of the cochlear mechanisms of the effects of sodium salicylate on the functions of hair cells