Two types of voltage-gated K channels in carotid body cells of adult cats
Two types of voltage-gated K channels in carotid body cells of adult cats
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DOI：
10.1016/s0006-8993(96)00987-0
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发表时间：
1996-12-02
期刊：
影响因子：
2.9
通讯作者：
Shirahata, M
中科院分区：
文献类型：
--
作者：
Chou, CL;Shirahata, M
本研究的目的是调查是否氧敏感性钾通道存在于成年猫的颈动脉体细胞，如果所有的颈动脉体细胞表达的氧敏感性钾通道。一个标准的膜片钳技术与全细胞配置应用于培养的颈动脉体细胞从成年猫。在室温下用5%CO2/空气或5%CO2/氩气平衡的Krebs连续灌注细胞。结果表明，培养的猫颈动脉体细胞在电生理上至少存在两种类型的细胞。一种表达氧敏感性钾通道，另一种表达氧不敏感性钾通道。氧敏感性钾通道具有电压依赖性，阈值电位为-30 mV。在30 ms的刺激期间未观察到失活。稳态电流-电压曲线的斜率在-30 ~+50 mV范围内几乎呈线性。缺氧（pO（2）= 25 mmHg）可逆地抑制钾电流22%。该电流被4-氨基吡啶（10 mM）和四乙基铵（4-25 mM）抑制，但对Charybdotoxin（100 nM）不敏感。氧不敏感钾通道与氧敏感钾通道在激活阈值、激活速度和I-V曲线形状等方面具有相似的特性。猫是第三个在颈动脉体中发现氧敏感性K通道的物种。钾通道对氧的敏感性可能是化学感受细胞的独特特征，但猫、大鼠和兔的氧敏感性钾通道的性质不同。
The purpose of this study was to investigate if the oxygen-sensitive K channel is present in the carotid body cells of adult cats, and if all carotid body cells express the oxygen-sensitive K channel. A standard patch-clamp technique with a whole-cell configuration was applied to cultured carotid body cells from adult cats. The cells were continuously perfused with Krebs equilibrated with 5% CO2/air or 5% CO2/argon at room temperature. The results showed that electrophysiologically at least two types of cells existed in cultured cat carotid body cells. One type expressed the oxygen sensitive K channel and the other expressed the oxygen-insensitive K channel. The oxygen-sensitive K channel was voltage-dependent with a threshold potential of -30 mV. No inactivation was observed during 30 ms of stimulation. The slope of the steady-state current-voltage curve was almost linear in the range from -30 mV to +50 mV. Hypoxia (pO(2) = 25 mmHg) reversibly depressed the K current by 22%. The current was inhibited by 4-aminopyridine (10 mM) and tetraethylammonium (4-25 mM), but insensitive to charybdotoxin (100 nM). The oxygen-insensitive K channel showed similar characteristics to that of the oxygen-sensitive K channel in the threshold and the speed of activation, and the shape of I-V curve. The cat is the third species in which the oxygen-sensitive K channel was found in the carotid body. The sensitivity of K channels to oxygen may be a unique feature of chemosensory cells, but the properties of the oxygen-sensitive K channels are different among cats, rats, and rabbits.