ABSTRACT

To investigate the effects of extremely low-frequency electromagnetic fields (ELF-EMFs) stimulation on sodium channel currents (I_Na), transient outward potassium channel currents (I_A) and delayed rectifier potassium channel currents (I_K) on hippocampal CA1 pyramidal neurons of young Sprague–Dawley rats. CA1 pyramidal neurons of rat hippocampal slices were subjected to ELF-EMFs stimulation with different frequencies (15 and 50 Hz), intensities (0.5, 1 and 2 mT) and durations (10, 20 and 30 min). The I_Na, I_A and I_K of neurons were recorded by a whole-cell patch-clamp method. ELF-EMFs stimulation enhanced I_Na densities, and depressed I_A and I_K densities. In detail, I_Na was more sensitive to the variation of intensities and frequencies of ELF-EMFs, whereas I_A and I_K were mainly affected by the variation of the duration of ELF-EMFs. ELF-EMFs stimulation altered activation and deactivation properties of I_Na, I_A and I_K. ELF-EMFs stimulation plays a role as a regulator rather than an inducer for ion channels. It might change the transition probability of ion channel opening or closing, and might also change the structure and function of the ion channel which need to be proved by the further technical method.

摘要

研究极低频电磁场 (ELF-EMFs) 刺激对钠通道电流 (I _Na )、瞬时外向钾通道电流 (I _A ) 和延迟整流钾通道电流 (I _K ) 对海马 CA1 锥体神经元的影响年轻的 Sprague-Dawley 大鼠。大鼠海马切片的 CA1 锥体神经元受到不同频率 (15 和 50 Hz)、强度 (0.5、1 和 2 mT) 和持续时间 (10、20 和 30 分钟) 的 ELF-EMF 刺激。采用全细胞膜片钳法记录神经元的I _Na、I _A和I _K值。ELF-EMFs 刺激增强了 I _Na密度，并降低了 I _A和 I _K密度。具体而言，I _Na对 ELF-EMF 的强度和频率的变化更为敏感，而 I _A和 I _K主要受 ELF-EMF 持续时间变化的影响。ELF-EMFs 刺激改变了 I _Na、 I _A和 I _{K 的}激活和失活特性。ELF-EMFs 刺激起到调节剂的作用，而不是离子通道的诱导剂。它可能会改变离子通道打开或关闭的跃迁概率，也可能会改变离子通道的结构和功能，需要进一步的技术方法来证明。