Quinidine blocks adenosine 5'-triphosphate-sensitive potassium channels in heart.
Quinidine blocks adenosine 5'-triphosphate-sensitive potassium channels in heart.
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奎尼丁阻断心脏中腺苷 5-三磷酸敏感的钾通道。
DOI：
10.1152/ajpheart.1990.259.5.h1609
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Rosenshtraukh,LV
中科院分区：
文献类型：
--
作者：
Undrovinas,AI;Burnashev,N;Eroshenko,D;Fleidervish,I;Starmer,CF;Makielski,JC;Rosenshtraukh,LV
在20-23 ℃下，在大鼠心室肌细胞的由内而外的膜片上研究ATP敏感性钾通道电流（IK-ATP）。浴溶液含有140 mM KF，移液管溶液含有140 mM KCl和1.2 mM MgCl 2。浴中的ATP（0.5mM）抑制IK-ATP。在不存在ATP的情况下，10 μ M奎尼丁在-50 mV下降低开放概率67 +/- 1%（n = 6），在-130 mV下降低开放概率28 +/- 12%（n = 5），而不影响单通道电导（48-52 pS）。25和50 μ M奎尼丁可增加阻滞，清洗奎尼丁几分钟可逆转阻滞。奎尼丁增加了爆发（关闭）间隔，而开放和关闭的时间分布内爆发没有改变。我们的结论是奎尼丁阻断IK-ATP在一个“缓慢”和电压依赖性的方式在临床相关的浓度。由于IK-ATP在心肌缺血中的假定作用，奎尼丁阻断该通道可能在缺血性心律失常中起作用。
The ATP-sensitive potassium channel current (IK-ATP) was studied in excised inside-out patches from rat ventricular cells at 20-23 degrees C. The bath solution contained 140 mM KF, and the pipette solution contained 140 mM KCl and 1.2 mM MgCl2. ATP (0.5 mM) in the bath inhibited IK-ATP. In the absence of ATP, 10 microM quinidine decreased open probability 67 +/- 1% (n = 6) at -50 mV and 28 +/- 12% at -130 mV (n = 5) without affecting single channel conductance (48-52 pS). The block increased with 25 and 50 microM quinidine and could be reversed on washing quinidine for several minutes. Interburst (closed) intervals were increased by quinidine, whereas open and closed time distributions within bursts were not changed. We conclude that quinidine blocks IK-ATP in a "slow" and voltage-dependent manner in clinically relevant concentrations. Because of the postulated role for IK-ATP in cardiac ischemia, quinidine block of this channel may play a role in ischemic arrhythmias.