豚鼠耳蜗单离Hensen细胞钾电流特性及三磷酸腺苷对其影响

The properties of potassium currents in isolated Hensen cells and effects of ATP on ion currents

目的 研究豚鼠耳蜗单离Hensen细胞的钾离子电流及其特性以及三磷酸腺苷(adenosinetriphosphate ,ATP)对Hensen细胞电生理特性的影响。 方法 采用传统全细胞膜片钳技术 ,对单离Hensen细胞进行记录。ATP通过压力注射仪对单离Hensen细胞给药。结果 Hensen细胞的钾电流呈明显的外向整流性 ,只有延迟整流性钾电流 (delayedrectificationpotassiumcurrent,IK) ,没有瞬间外向性钾电流 (transientoutwardpotassiumcurrent ,IA)。低浓度 ( 0 1 μmol/L ,1 μmol/L ,1 0μmol/L)ATP可以使Hensen细胞的钾电流的幅度明显降低 ,且呈浓度依赖性 ,浓度越高 ,降幅越大。高浓度ATP( 1 0 0 μmol/L ,1mmol/L ,1 0mmol/L)可以引起Hensen细胞的内向离子流 ,呈浓度依赖性 ,浓度越高 ,升幅越大。ATP的这两种作用均可被ATP受体拮抗剂 ( 1 0 0 μmol/L舒拉明 )所逆转。结论对Hensen细胞不同电压的刺激可以诱发出延迟整流性钾电流 ,低浓度ATP对Hensen细胞的钾电流有明显抑制作用 ,且呈浓度依赖性。高浓度ATP可以引起Hensen细胞的非选择性内向离子流 ,为钾离子依赖性 。

Objective To study potassium currents and their properties in isolated Hensen cells and observe effects of ATP on ion currents Methods The whole cell patch clamp technique was used to record K + currents in Hensen cells ATP was applied directly to the single Hensen cell by using a pressure injector with microtubules Results The outward K + rectification currents indicated delayed rectified, TEA sensitive potassium currents (I K), not rapidly inactive, 4 AP sensitive potassium currents (I A) In low concentrations(0 1 μmol/L,1 μmol/L,10 μmol/L),the amplitude of potassium current was reduced by ATP In high concentrations(100 μmol/L,1 mmol/L,10 mmol/L)ATP evoked an inward current with dose dependence These could be reversed by the purinergic antagonist (100 μmol/L suramin) Conclusion Delayed rectified potassium currents were evoked in Hensen cells The amplitude of potassium current was reduced by ATP in low concentrations An inward current was evoked by ATP in high concentrations The inward current was sensitive to potassium ion and might act on purinergic receptor