磁场对神经元动作电位产生与传导的影响

The electromagnetic field can affect the function of the nervous system. Existing researches showed that temporarily nerve dysfunction such as dizziness, nausea, and magnetic phosphene can be caused by exercise in the high intensity magnetic field. Transcranial magnetic stimulation (TMS) can be used for the treatment of diseases such as epilepsy, depression by their effects on the central nervous system. In addition, TMS can affect peripheral acupoints and then caused the change of brain electrical. The results showed that magnetic field has clear role on the nervous system, and the influence can be passed through the neural network. Other researches showed that the movement of charge in organisms can be changed by electromagnetic fields due to the magnetic induction mechanism. Therefore, the electromagnetic field can affect neuronal electrical activity and thus change the motivation of nervous system. However, it is not clear that how neuron feel and response to electromagnetic field. Based on previous studies, this project intends to study the effects of static magnetic field and pulse electromagnetic field on action potential generation in cell body and action potential transmission along axon by patch clamp technique in building of neurons, the primary cortical neurons of rats, and cortex tissue slices of rats respectively. At the same time, the role of myelin structure in electromagnetic field affects neuronal electrical impulse transmission would be explored. This project aims to reveal the mechanism of influence of electromagnetic field on the generation and transmission of neuronal action potential. The results can provide experimental basis for the study of the biological mechanisms under electromagnetic field, as well as the application of electromagnetic field in medicine.

外界电磁场可影响神经系统的功能。已有研究表明在高强度磁场中运动可导致眩晕、恶心、磁光幻视等暂时神经功能紊乱；经颅磁刺激（TMS）可作用于中枢神经系统，用于癫痫、抑郁等疾病的治疗；此外，TMS作用于外周穴位可引起脑电的变化。说明磁场对神经系统具有明确作用，且其作用可通过神经网络进行传递。另有研究表明由于磁感应机制的存在，电磁场会对生物体内电荷的运动产生影响。因此，电磁场可通过影响神经元电活动从而影响神经系统激励发生改变。然而，神经元感受和响应电磁场的方式目前尚不清楚。本项目拟在前期研究基础上，利用膜片钳技术研究建系神经元、大鼠原代皮层神经元，及大鼠皮层组织脑片在外界恒定磁场和脉冲电磁场作用下胞体动作电位产生及其在轴突传导的变化；同时探索髓鞘结构在电磁场影响神经元电冲动传递中的作用，旨在揭示电磁场对神经元动作电位产生和传导的作用机制，为电磁场生物学机制的研究及电磁场在医学中的应用提供实验依据。

外界电磁场可影响神经系统功能，经颅磁刺激作为一种物理干预措施，在临床上被用于癫痫、抑郁症等疾病的治疗。但是，经颅磁刺激作为一种电磁场，其作用机理和最佳作用方式目前尚不清楚。神经细胞感受和响应外界电磁场的方式目前仍不清楚。本项目拟从神经细胞电特性入手，研究电磁场作用后神经元动作电位的产生和发放的变化。分别开展重复经颅磁刺激对雌性昆明小鼠自然老化过程中认知能力和海马神经元兴奋性的影响；重复经颅磁刺激对雌性幼年昆明小鼠认知能力和海马神经元兴奋性的影响；不同频率经颅磁刺激对小鼠学习记忆和海马神经元动作电位的影响及磁刺激对体外培养神经细胞生长的影响的实验。.结果显示重复经颅磁刺激能够显著改善认识功能障碍与神经元电特性指标的退化，尤其是老化导致的认知功能障碍和海马齿状回区域神经元电生理特性指标的改变，提高神经元兴奋性或许是重复经颅磁刺激改善认知功能的机制之一。重复经颅磁刺激对认识功能的改善作用需要一定时间积累的，15天的作用可使幼年小鼠在行为上产生显著的提高。不同频率经颅磁刺激对小鼠认知功能和神经元兴奋性的影响不同，其中高频（5Hz、10Hz）刺激作用显著，低频（1Hz）刺激作用不显著。且θ节律的重复性经颅磁刺激效果优于标准的重复经颅磁刺激。这些研究结果表明外界脉冲电磁场对脑认知功能的调节可能与相关神经元电特性的改变有关。.本项目研究的结果有助于从细胞电特性角度理解磁场对生物体的作用，尤其是从神经元兴奋性角度理解脉冲磁场对神经功能的作用。同时为磁刺激在脑功能健康领域的应用提供潜在的实验和理论依据。