Moorman J R, Kirsch G E, VanDongen A M, Joho R H, Brown A M
Department of Medicine, University of Texas Medical Branch, Galveston 77550.
Neuron. 1990 Feb;4(2):243-52. doi: 10.1016/0896-6273(90)90099-2.
We investigated the kinetics of rat brain type III Na+ currents expressed in Xenopus oocytes. We found distinct patterns of fast and slow gating. Fast gating was characterized by bursts of longer openings. Traces with slow gating occurred in runs with lifetimes of 5 and 30 s and were separated by periods with lifetimes of 5 and 80 s. Cycling of fast and slow gating was present in excised outside-out patches at 10 degrees C, suggesting that metabolic factors are not essential for both forms of gating. It is unlikely that more than one population of channels was expressed, as patches with purely fast or purely slow gating were not observed. We suggest that structural mechanisms for fast and slow gating are encoded in the primary amino acid sequence of the channel protein.
我们研究了非洲爪蟾卵母细胞中表达的大鼠脑III型钠离子电流的动力学。我们发现了快速门控和慢速门控的不同模式。快速门控的特征是较长时间的开放脉冲。具有慢速门控的电流记录出现在寿命为5秒和30秒的时段中，且被寿命为5秒和80秒的时段分隔开。在10摄氏度下的外翻式膜片上存在快速门控和慢速门控的循环，这表明代谢因素对于两种门控形式并非必不可少。不太可能表达了不止一种通道群体，因为未观察到具有纯快速或纯慢速门控的膜片。我们认为，快速门控和慢速门控的结构机制编码在通道蛋白的一级氨基酸序列中。
