Tourneur Y, Marion A, Gautier P
Laboratoire de Physiologie des Eléments Excitables, C.N.R.S. U.R.A. 180, Université Claude Bernard, Villeurbanne, France.
J Membr Biol. 1994 Dec;142(3):337-47. doi: 10.1007/BF00233440.
(i) We studied the effects of a new cromakalim analogue, SR47063, in guinea-pig ventricular cells. The experiments were carried out in whole-cell patch clamp with internal and external solutions supposedly similar to the physiological ones. (ii) SR47063 reversibly activated a time-independent current reversing near the potassium equilibrium potential, and a time-dependent current reversing at a more positive potential. Both currents were blocked by application of glibenclamide. (iii) The time-independent and the time-dependent currents were activating for the same concentration of agonist in every cell, this concentration being very different from cell to cell. (iv) The amplitude of the time-dependent current was shown to depend directly neither on agonist concentration nor on potential, but rather on the amplitude of the current flowing during the prepulse before the test pulse. (v) We conclude that SR47063 is a potent KATP channel opener acting at concentrations lower than one micromolar, and that the time-dependent current is likely due to accumulation and depletion of potassium in restricted areas of the cells.
（i）我们研究了一种新型克罗卡林类似物SR47063对豚鼠心室细胞的作用。实验采用全细胞膜片钳技术，使用的细胞内液和细胞外液被认为与生理溶液相似。（ii）SR47063可逆地激活了一种在钾平衡电位附近反转的非时间依赖性电流，以及一种在更正电位处反转的时间依赖性电流。两种电流都可被格列本脲阻断。（iii）在每个细胞中，非时间依赖性电流和时间依赖性电流对相同浓度的激动剂均有激活作用，且该浓度在不同细胞间差异很大。（iv）时间依赖性电流的幅度既不直接依赖于激动剂浓度，也不依赖于电位，而是取决于测试脉冲前预脉冲期间流动的电流幅度。（v）我们得出结论，SR47063是一种强效的KATP通道开放剂，作用浓度低于1微摩尔，且时间依赖性电流可能是由于细胞受限区域内钾的积累和消耗所致。
