Reconstitution in lipid bilayers of an ATP-sensitive K+ channel from pig coronary smooth muscle.
Reconstitution in lipid bilayers of an ATP-sensitive K+ channel from pig coronary smooth muscle.
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猪冠状平滑肌 ATP 敏感 K 通道的脂质双层重建。
DOI：
10.1007/s002329900123
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Toro,L
中科院分区：
文献类型：
--
作者：
Ottolia,M;Toro,L
一个主要电导为29 pS的K+通道被记录后，冠状动脉膜囊泡纳入脂质双层。该通道被鉴定为ATP敏感性K+通道（KATP），因为其活性被50-250 μ mATP-Na 2的内部应用所减弱。外用10-50 μmpinacidil可使其开放。单通道记录揭示了几个（子）电导状态的存在。在0 mV和5/250 KCl梯度下，KATP通道的主电导为29 pS。其他（子）电导状态频率较低，离散值为12，17和22 pS。吡那地尔主要在29 pS电导水平稳定通道开放状态;而ATP抑制所有电导水平。一般来说，KATP通道的特征是短暂的开放，随后是长时间的关闭（开放概率，Po ≥ 0.02）;只有偶尔（12个实验中的3个）KATP通道具有高开放概率（Po≥ 0.7）。在通道内侧加入2.5-10 mmUDP-TRIS和0.5-2 mmMgCl 2可增加或挽救通道活性。
A K+channel with a main conductance of 29 pS was recorded after the incorporation of coronary artery membrane vesicles into lipid bilayers. This channel was identified as an ATP-sensitive K+channel (KATP) because its activity was diminished by the internal application of 50–250 μmATP-Na2. Moreover, it was opened when 10–50 μmpinacidil was externally applied. Single-channel records revealed the existence of several (sub)conductance states. At 0 mV and with a 5/250 KCl gradient, the main conductance of the KATPchannel was 29 pS. The other (sub)conductance states were less frequent and had discrete values of 12, 17 and 22 pS. Pinacidil stabilized the channel open state primarily in the 29 pS conductance level; whereas ATP inhibited all the conductance levels. In general, KATPchannels were characterized by brief openings followed by long closings (open probability,Po≈ 0.02); only occasionally (3 out of 12 experiments) did the KATPchannels have a high open probability (Po≥ 0.7). Channel activity could be increased or rescued by adding 2.5–10 mmUDP-TRIS and 0.5–2 mmMgCl2to the internal side of the channel.