ACTION OF TETRAETHYLAMMONIUM ON CALCIUM-ACTIVATED POTASSIUM CHANNELS IN PIG PANCREATIC ACINAR-CELLS STUDIED BY PATCH-CLAMP SINGLE-CHANNEL AND WHOLE-CELL CURRENT RECORDING
ACTION OF TETRAETHYLAMMONIUM ON CALCIUM-ACTIVATED POTASSIUM CHANNELS IN PIG PANCREATIC ACINAR-CELLS STUDIED BY PATCH-CLAMP SINGLE-CHANNEL AND WHOLE-CELL CURRENT RECORDING
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DOI：
10.1007/bf01870780
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发表时间：
1985-01-01
影响因子：
2.4
通讯作者：
PETERSEN, OH
中科院分区：
文献类型：
--
作者：
IWATSUKI, N;PETERSEN, OH
采用膜片钳单通道和全细胞电流记录技术，研究了四乙基铵离子（TEA）对猪胰腺腺泡细胞高电导电压激活和钙激活钾通道电流的影响。在切除的外向膜补丁TEA（1-2 mM）添加到浴溶液中几乎废除单位电流活动，除了在非常积极的膜电位时，单位电流对应于一个显着降低的电导观察。TEA在较低的浓度（0.2 mM）显着降低了开放状态的概率，并导致一些单通道电导减少。在由内而外的膜贴片浴中，浓度高达2 mM的TEA对单通道电流没有影响。在较高浓度（10 mM）下，单通道电导发生轻微降低。在全细胞电流记录实验中，添加到浴溶液中的TEA（1-2 mM）完全抑制与去极化电压跳变到OmV的膜电位相关的外向电流，并且即使在非常正的膜电位（30-40 mV）下也阻断外向电流的主要部分（70-90%）。相反，TEA（2 mM）加入到细胞内部（移液管溶液）对外向K+电流没有影响。低浓度（1-2 mM）的TEA特异性作用于质膜外侧，阻断通过高电导Ca 2+和电压激活的K+通道的电流。
The effects of tetraethylammonium ions [TEA] on currents through high-conductance voltage- and Ca2+-activated K+ channels were studied with the help of patch-clamp single-channel and whole-cell current recording on pig pancreatic acinar cells. In excised outside-out membrane patches TEA (1-2 mM) added to the bath solution virtually abolishes unitary current activity except at very positive membrane potentials when unitary currents corresponding to a markedly reduced conductance are observed. TEA in a lower concentration (0.2 mM) markedly reduces the open-state probability and causes some reduction of the single-channel conductance. In inside-out membrane patches bath application of TEA in concentrations up to 2 mM has no effect on single-channel currents. At a higher concentration (10 mM) slight reductions in single-channel conductance occur. In whole-cell current recording experiments TEA (1-2 mM) added to the bath solution completely suppresses the outward currents associated with depolarizing voltage jumps to membrane potentials of 0 mV and blocks the major part (70-90%) of the outward currents even at very positive membrane potentials (30-40 mV). In contrast TEA (2 mM) added to the cell interior (pipette solution) has no effect on the outward K+ current. TEA in low concentrations (1-2 mM) acts specifically on the outside of the plasma membrane to block current through the high-conductance Ca2+ and voltage-activated K+ channels.