Carbenoxolone-sensitive and cesium-permeable potassium channel in the rod cells of frog taste discs.
Carbenoxolone-sensitive and cesium-permeable potassium channel in the rod cells of frog taste discs.
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DOI：
10.1016/j.bbrep.2015.09.010
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发表时间：
2015-12
影响因子：
2.7
通讯作者：
Toda K
中科院分区：
文献类型：
--
作者：
Okada Y;Miyazaki T;Fujiyama R;Toda K
在内源性K+被Cs+取代的条件下，蛙味盘中的视杆细胞呈现外向电流，并维持负的静息电位。我们分析了棒状电池中Cs+的渗透电导特性。由电压斜坡得到的电流-电压(I/V)关系在Cs+内溶液下呈钟形。电压阶跃引起的稳态I/V关系也表现为钟形外向电流。电流的激活随着去极化的进行而加速，在正电压下出现失活。即使在对称条件下(Cs+外部和内部解决方案)，电流的门控也保持不变。翼细胞没有表现出这些特性。K+离子的渗透率略大于Cs+离子。内源性Na+和NMDG+不能诱发钟状外向电流。Carbenoxolone呈剂量依赖性抑制钟状外向Cs+电流(IC50：27μM)。花生四烯酸(20μM)不能引起双孔结构域K+通道(K2P)的线性电流-电压(I-V)关系。结果提示，视杆细胞的静息膜电位是由电压门控性K+通道维持的。在Cs+内液作用下，蛙类味觉细胞呈现钟状外向电流。即使在对称离子条件下，电流的门控也保持不变。对外向Cs+电流的抑制作用呈剂量依赖性(IC50：27μM)。静息电位可以通过电压门控的K+通道来维持。
The rod cells in frog taste discs display the outward current and maintain the negative resting potential in the condition where internal K+ is replaced with Cs+. We analyzed the properties of the Cs+-permeable conductance in the rod cells. The current–voltage (I/V) relationships obtained by a voltage ramp were bell-shaped under Cs+ internal solution. The steady state I/V relationships elicited by voltage steps also displayed the bell-shaped outward current. The activation of the current accelerated with the depolarization and the inactivation appeared at positive voltage. The gating for the current was maintained even at symmetric condition (Cs+ external and internal solutions). The wing cells did not show the properties. The permeability for K+ was a little larger than that for Cs+. Internal Na+ and NMDG+ could not induce the bell-shaped outward current. Carbenoxolone inhibited the bell-shaped outward Cs+ current dose dependently (IC50: 27 μM). Internal arachidonic acid (20 μM) did not induce the linear current–voltage (I–V) relationship which is observed in two-pore domain K+ channel (K2P). The results suggest that the resting membrane potentials in the rod cells are maintained by the voltage-gated K+ channels. Frog taste cells displayed bell-shaped outward current under Cs+ internal solution. The gating for the current was maintained even at symmetric ionic condition. Carbenoxolone inhibited the outward Cs+ current dose dependently (IC50: 27 μM). The resting potentials may be maintained by the voltage-gated K+ channels.