豚鼠耳蜗单离外毛细胞和Deiters细胞的钾离子电流及其生理功能

Potassium Currents and Their Possible Functions in Isolated Outer Hair Cells and Deiters′ Cells of Guinea Pig Cochlea

目的 研究豚鼠耳蜗单离外毛细胞 (OHC)和Deiters细胞的钾离子电流及其特性 ,观察乙酰胆碱(ACh)和三磷酸腺苷 (ATP)对离子电流的影响。方法 运用全细胞膜片钳技术 ,分别记录单离OHC和Deiters细胞的离子电流。结果 OHC的长度不同 ,其钾离子电流表达具有差异性 ,短OHC具有较大外向电流和内向电流。ACh对短OHC钾离子电流的影响较大 ,其作用是使OHC超极化。ATP介导的OHC内向电流是非选择性的阳离子电流。ATP介导Deiters细胞出现内向离子电流。结论 K+ 电流在OHC的电谐振中非常重要。Deiters细胞能够通过减少K+ 外流、增加K+ 内流来缓冲周围环境中K+ 浓度的变化。

Objective To study potassium currents and their properties in isolated outer hair cells (OHC) and Deiters′ cells of guinea pig cochlea and observe effects of ACh and ATP on ion currents. Methods The whole cell patch-clamp technique was used to record potassium currents in OHC and Deiters′ cells, respectively.Results Potassium currents were expressed differentially in OHC with different length and the amplitudes of outward current and inward current were larger in short OHC.ACh induced greater effects on outwardly rectifying potassium currents in short OHCs. Effect of ACh was to hyperpolarize the membrane potential of OHCs from rest. ATP-induced inward current in OHC was through non-selective cations channel. Conclusion The potassium currents in OHC play an important role in electric resonance of OHC. Deiters′ cell could buffer K + concentration around the cells through decreased K + efflux and increased K + influx. Effects of ACh and ATP on ion currents in OHC significantly contribute to the cochlear mechanism.