Sorota S, Du X Y
Department of Pharmacology, Columbia University, New York, New York 10032, USA.
J Cardiovasc Electrophysiol. 1998 Aug;9(8):825-31. doi: 10.1111/j.1540-8167.1998.tb00122.x.
A lag phase has been reported for the activation of cardiac swelling-induced chloride currents. Prior demonstrations of this lag used methods that produce gradual changes in cell size, making interpretation and quantification of the time course problematic.
Isolated dog atrial cells were studied using the whole cell, patch clamp technique. Step changes in cell size were produced by application of transient pulses of positive pressure, and the time course for activation of the swelling-induced chloride current was observed. There was a distinct temporal dissociation between size changes and current activation that was temperature sensitive. Activation half-times were 98 +/- 31 seconds and 586 +/- 112 seconds at 36 degrees C and room temperature, respectively. Swelling-induced chloride currents were evoked in a higher percentage of cells at 36 degrees C (83%) compared with room temperature (50%).
Cardiac swelling-induced chloride current activates with a distinct lag after step changes in cell size. The activation time course is temperature sensitive. These observations are consistent with the notion that signal transduction events, and not simply membrane stretch, are required for the activation of cardiac swelling-induced chloride current.
据报道，心脏肿胀诱导的氯离子电流激活存在一个延迟期。此前对该延迟期的证明采用的方法会使细胞大小逐渐变化，这使得对时间进程的解释和量化存在问题。
使用全细胞膜片钳技术对分离的犬心房细胞进行研究。通过施加短暂的正压脉冲使细胞大小发生阶跃变化，并观察肿胀诱导的氯离子电流的激活时间进程。细胞大小变化与电流激活之间存在明显的时间分离，且这种分离对温度敏感。在36℃和室温下，激活半衰期分别为98±31秒和586±112秒。与室温（50%）相比，在36℃时更高比例的细胞（83%）诱发了肿胀诱导的氯离子电流。
在细胞大小发生阶跃变化后，心脏肿胀诱导的氯离子电流会有明显延迟激活。激活时间进程对温度敏感。这些观察结果与以下观点一致，即心脏肿胀诱导的氯离子电流的激活需要信号转导事件，而不仅仅是膜拉伸。
