Krüppel T, Westermann R, Lueken W
Fachbereich Biologie/Chemie, Universität Osnabrück, F.R.G.
Biochim Biophys Acta. 1991 Feb 25;1062(2):193-8. doi: 10.1016/0005-2736(91)90392-l.
In the marine hypotrichous ciliate Euplotes vannus, the transient K+ outward current, IK fast, was studied by use of a single-microelectrode voltage-clamp equipment. Activation and inactivation kinetics, and steady-state inactivation are comparable to the properties of A-currents. Not typical for this type of current is its insensitivity to either 4-AP or 3,4-AP and its Ca2+ dependence which was derived from its inhibition by either extracellular Cd2+, La3+, D-600, or by intracellular BAPTA. Actual amplitudes of IK fast were obtained from a composite current, by subtraction of early parts of a slowly activating K+ current, IK slow, and of the early, transient Ca2+ inward current, ICa fast, that is typical for ciliates. IK fast counteracts ICa fast during the first milliseconds after onset of depolarization such that the composite current is purely outward directed.
在海洋腹毛目纤毛虫扇形游仆虫中，利用单微电极电压钳设备研究了瞬时钾离子外向电流IK fast。其激活和失活动力学以及稳态失活与A电流的特性相当。这种电流的非典型特征是它对4-AP或3,4-AP均不敏感，以及它对钙离子的依赖性，这种依赖性源于细胞外Cd2+、La3+、D-600或细胞内BAPTA对它的抑制作用。IK fast的实际幅度是通过从复合电流中减去缓慢激活的钾离子电流IK slow的早期部分以及纤毛虫典型的早期瞬时钙离子内向电流ICa fast的早期部分而获得的。在去极化开始后的最初几毫秒内，IK fast抵消ICa fast，使得复合电流完全向外。
