Friedrich M, Benndorf K, Schwalb M, Hirche H
Institut für Vegetative Physiologie, Universität zu Köln, Federal Republic of Germany.
Pflugers Arch. 1990 Apr;416(1-2):207-9. doi: 10.1007/BF00370244.
Whole cell currents were measured in isolated cardiocytes of guinea pig under anoxic conditions (pO2 less than 0.5 torr). After 2 to 32 (mean 11.2) minutes of anoxia, time independent outward currents developed gradually which had a linear current-voltage relation between -100 and +20 mV and reversed at the resting potential of the cells (-82 to -90 mV). After 20 to 170 (mean 38) seconds, the amplitude of these outward currents saturated (3.6 +/- 0.5 nA at +10 mV, n = 23). Reoxygenation within one minute after the appearance of the first extra outward currents led in most cells (greater than 90%) to their complete disappearance in 2 to 4 (mean 2.87, n = 15) seconds. Ca currents were not affected at the time when the first extra outward currents occurred. It is concluded that (i) the anoxia-induced outward current is carried by K+ ions probably through KATP channels which open at intracellular ATP concentrations below 1 mmol/l (Noma and Shibasaki 1985) and (ii) this degree of ATP depletion does not affect normal Ca channel function.
在缺氧条件下（pO2小于0.5托），对豚鼠分离心肌细胞的全细胞电流进行了测量。缺氧2至32分钟（平均11.2分钟）后，逐渐出现与时间无关的外向电流，该电流在-100至+20 mV之间呈线性电流-电压关系，并在细胞静息电位（-82至-90 mV）处反转。20至170秒（平均38秒）后，这些外向电流的幅度达到饱和（在+10 mV时为3.6±0.5 nA，n = 23）。在首次出现额外外向电流后一分钟内复氧，在大多数细胞（大于90%）中，这些电流在2至4秒（平均2.87秒，n = 15）内完全消失。当首次出现额外外向电流时，钙电流未受影响。结论是：（i）缺氧诱导的外向电流可能由K+离子通过KATP通道携带，该通道在细胞内ATP浓度低于1 mmol/l时开放（野间和柴崎，1985年）；（ii）这种程度的ATP耗竭不影响正常的钙通道功能。
