Carbon monoxide stimulates a potassium-selective current in rabbit corneal epithelial cells.
Carbon monoxide stimulates a potassium-selective current in rabbit corneal epithelial cells.
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DOI：
10.1152/ajpcell.1994.267.2.c435
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发表时间：
1994-08
期刊：
影响因子：
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通讯作者：
A. Rich;Gianrico Farrugia;James L. Rae
中科院分区：
文献类型：
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作者：
A. Rich;Gianrico Farrugia;James L. Rae
应用穿孔膜片全细胞电压钳技术研究了CO对新鲜分散的兔角膜上皮细胞离子电流的影响。用1%CO进行浴灌注导致钾电流（IK）增加84 +/- 18%（平均值+/- SE，n = 14），膜超极化从-42 +/- 4 mV增加至-51 +/- 4 mV。CO刺激的电流在-64 +/-7 mV下反转[反转电位（EK）= -87 mV]。1 mM奎尼丁或1 mM地尔硫卓（抑制兔角膜上皮细胞IK的试剂）阻断刺激电流。在细胞贴附构型中测量的单钾通道电流表明，在保持电位为-40 mV时，外源性CO使稳态开放概率从0.003增加到0.156。CO不影响切除斑块的开放概率。在-40至+40 mV范围内测量的单通道电导不受影响。用放射免疫分析法测定细胞内环磷酸鸟苷（cGMP）浓度，发现加入1%CO后，cGMP浓度从0.41 ± 0.24增加到0.55 ± 0.27 pmol/10（6）个细胞（P < 0.05）。数据表明，浴灌注外源性CO激活IK和超极化的静息膜电位，数据还表明，CO调节细胞内cGMP浓度。
The effects of CO on ion currents in freshly dispersed rabbit corneal epithelial cells were assessed using the perforated patch whole cell voltage-clamp technique. Bath perfusion with 1% CO resulted in a 84 +/- 18% (mean +/- SE, n = 14) increase in potassium current (IK) and a membrane hyperpolarization from -42 +/- 4 to -51 +/- 4 mV. The CO-stimulated current reversed at -64 +/- 7 mV [reverse potential (EK) = -87 mV]. The stimulated current was blocked by 1 mM quinidine or 1 mM diltiazem, agents that inhibit IK in rabbit corneal epithelial cells. Single potassium-channel currents measured in the cell-attached configuration showed that exogenous CO increased the steady-state open probability from 0.003 to 0.156 at a holding potential of -40 mV. CO did not affect open probability in excised patches. The single-channel conductance measured from -40 to +40 mV was unaffected. Intracellular guanosine 3',5'-cyclic monophosphate (cGMP) concentration measured with radioimmunoassay techniques was found to increase from 0.41 +/- 0.24 to 0.55 +/- 0.27 pmol/10(6) cells after the addition of 1% CO (P < 0.05). The data show that bath perfusion with exogenous CO activates IK and hyperpolarizes the resting membrane potential; the data also suggest that CO modulates intracellular cGMP concentration.