EFFECTS OF ACTIVATION OF ATP-SENSITIVE K+ CHANNELS IN MAMMALIAN VENTRICULAR MYOCYTES
EFFECTS OF ACTIVATION OF ATP-SENSITIVE K+ CHANNELS IN MAMMALIAN VENTRICULAR MYOCYTES
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DOI：
10.1152/ajpheart.1989.257.5.h1551
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发表时间：
1989-11-01
影响因子：
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通讯作者：
CORABOEUF, E
中科院分区：
文献类型：
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作者：
FINDLAY, I;DEROUBAIX, E;CORABOEUF, E
色满卡林类似物SR 44866可打开心室肌细胞中ATP敏感性K+通道。SR 44866开放的通道被内部ATP关闭，并具有与ATP敏感性K+通道相同的电流-电压关系;被ATP关闭的通道可以被SR 44866打开。SR 44866在应用于切除的膜贴片的任一侧时以及在细胞附着膜记录期间包含在移液器中时有效。当SR 44866应用于移液器外部的细胞膜时，其还打开了细胞附着膜贴片中的通道。SR 44866在全细胞记录中诱发的电流被甲苯磺丁脲抑制。SR 44866降低了豚鼠乳头肌中动作电位的持续时间以及诱发肌肉收缩的幅度和持续时间，解离常数在24 ℃下为6.8 μ M，在34 ℃下为1.9 μ M，希尔系数分别为1.72和1.71。我们的结论是ATP敏感性K+通道的开放对心肌的电活动和机械活动具有深刻的抑制作用。
A cromakalim analogue, SR 44866, is shown to open ATP-sensitive K+ channels in ventricular myocytes. The channels opened by SR 44866 were closed by internal ATP and had the same current-voltage relationship as ATP-sensitive K+ channels; channels closed by ATP could be opened by SR 44866. SR 44866 was effective when applied to either side of excised membrane patches and when included in the pipette during cell-attached membrane recordings. SR 44866 also opened channels in cell-attached membrane patches when it was applied to the cell membrane outside of the pipette. The current evoked by SR 44866 in whole cell recordings was inhibited by tolbutamide. SR 44866 reduced the duration of action potentials and the amplitude and duration of evoked muscle contractions in guinea pig papillary muscle, with dissociation constants of 6.8 microM at 24 degrees C and 1.9 microM at 34 degrees C and Hill coefficients of 1.72 and 1.71, respectively. We conclude that the opening of ATP-sensitive K+ channels has profound inhibitory effects on the electrical and mechanical activity of cardiac muscle.