POTASSIUM FLUXES IN VOLTAGE CLAMPED PURKINJE FIBRES
POTASSIUM FLUXES IN VOLTAGE CLAMPED PURKINJE FIBRES
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DOI：
10.1007/bf00362653
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发表时间：
1966-01-01
期刊：
影响因子：
--
通讯作者：
KERN, R
中科院分区：
文献类型：
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作者：
HAAS, HG;KERN, R
1.分离的羊浦肯野纤维股已被用来测量K42流出电压钳条件下。K流出数据作为稳态值获得，即作为膜电位的函数而不是时间的函数。2.根据K流出量数据，利用Hodgkin和Keynes（1955）的通量关系计算了相应的K流入量和K净流IK值。3.稳态K电流-电压关系为单调的S形曲线。斜率[delta]IK/[delta]V始终为正，并在V =[长划线]50和[长划线]90 mV之间达到最小值。4.从K电流-电压关系计算K弦电导gK。从静息电位开始，电导-电压关系显示在去极化（超极化）的情况下降低（增加），最小值在V =[长划线]50 mV，最大值在V =[长划线]110 mV。5. K电流-电压关系与在无Na溶液中通过电测量获得的膜电流-电压关系定性一致（Hall、Hutter和Noble，1963; Deck和Trautwein，1964）。在去极化的范围内，膜电流的电学方法所确定的似乎是小于K电流。6.将心脏动作电位过程中膜电导G的时程（Weidmann，1951，1956）与对应于瞬时膜电位的gK值进行比较。最后复极和舒张期缓慢去极化有充分的一致性。
1. Isolated strands of sheep Purklnje fibers have been used to measure K42 efflux under voltage clamp conditions. K efflux data were obtained as steady-state values i.e. as a function of membrane potential but not of time. 2. From the K efflux data the corresponding values of K influx and K net current IK were calculated using the flux relation of Hodgkin and Keynes (1955). 3. The steady-state K current-voltage relationship is a monotonous S-shaped curve. The slope [delta]IK/[delta]V is always positive and reaches a minimum between V =[long dash]50 and[long dash]90 mV. 4. From the K current-voltage relationship the K chord conductance gK was calculated. Starting from the resting potential the conductance-voltage relationship shows a decrease (increase) in case of depolarization (hyperpolarlzation) with a minimum at V =[long dash]50 mV and a maximum at V =[long dash]110 mV. 5. The K current-voltage relationship is in qualitative agreement with the membrane current-voltage relationships obtained from electrical measurements in Na-free solutions (Hall, Hutter, and Noble, 1963; Deck and Trautwein, 1964). In the range of depolarization, the membrane current as determined by electrical methods appears to be smaller than the K current. 6. The time course of membrane conductance G during a cardiac action potential (Weidmann, 1951, 1956) was compared with the gK values corresponding to the instantaneous membrane potential. A sufficient agreement was found for the final repolarization and the slow diastolic depolarization.