工频磁场对皮层神经元离子通道的影响

发布时间：2018-10-08 09:21

【摘要】： 随着现代科技的进步和社会经济的迅猛发展,各种电子产品、电力设备被大量的应用到人们生活环境中,人为产生的电磁场已逐渐成为威胁人体以及其他生物体健康和安全的环境污染因子。工频磁场就是由输电线及家用电器所产生的一种极低频电磁场,其对人体的影响日趋广泛但作用机理尚不清楚,有待于进一步探索。而在人体各系统中,中枢神经系统是对电磁辐射最敏感的系统,神经元是神经系统结构和功能的基本单位,要深入探讨工频磁场对神经系统的生物学作用,就必须开展工频磁场对神经元作用的研究。本文从细胞层次上观察了在较低强度的工频磁场环境下,小鼠皮层神经元电压门控钠、钾离子通道特性的变化。实验采用频率为50Hz、平均强度为2.0mT较低强度的工频磁场对小鼠的脑皮层神经元进行刺激,而后应用全细胞膜片钳技术测量其钠、钾离子通道特性。结果显示:较低强度工频磁场可使神经元电压门控离子通道特性改变,可显著影响皮层神经元离子通道通道电流、激活和失活电位,对INa、IA、IK的作用具有时间依赖性和电压依赖性。工频磁场作用于小鼠皮层神经元使钠通道峰值电流INa明显增大,并且改变了钠通道的激活特性,从而影响动作电位的去极化过程,进而会引起神经元的生理功能发生变化。同时工频磁场对瞬时外向钾电流IA和延迟整流外向钾电流IK有显著的抑制作用,工频磁场作用可显著地改变钾通道的激活与失活过程,从而影响动作电位的形成和发放频率,改变神经元的生理功能。这些结果提示工频磁场的生物刺激作用可能与细胞膜离子通道构象及功能有关。膜片钳技术为细胞和分子水平探讨较低强度工频磁场的生物刺激效应提供了一个全新的方法,本文的研究成果为探索工频磁场的生物刺激效应机理机制奠定了理论和实验基础。
[Abstract]:With the progress of modern science and technology and the rapid development of social economy, a variety of electronic products and power equipment are widely used in people's living environment. Anthropogenic electromagnetic fields have become environmental pollution factors threatening the health and safety of human body and other organisms. Power frequency magnetic field is a kind of extremely low frequency electromagnetic field produced by transmission lines and household appliances. The influence of power frequency magnetic field on human body is more and more extensive, but the mechanism of action is not clear, so it needs to be further explored. The central nervous system is the most sensitive system to electromagnetic radiation, and the neuron is the basic unit of the structure and function of the nervous system. It is necessary to study the action of power frequency magnetic field on neurons. The characteristics of voltage-gated sodium and potassium channels in mouse cortical neurons under low intensity power frequency magnetic field were observed at the cellular level. In the experiment, 50 Hz power frequency magnetic field with average intensity of 2.0mT was used to stimulate the cortical neurons of mice. The characteristics of sodium and potassium channels were measured by whole-cell patch clamp technique. The results show that the low intensity power frequency magnetic field can change the characteristics of the voltage-gated ion channel of neurons, and can significantly affect the ion channel current, activation and inactivation potential of cortical neurons. The effect on INa,IA,IK is time-and voltage-dependent. The peak current (INa) of sodium channel in mouse cortical neurons was obviously increased by power frequency magnetic field, and the activation characteristics of sodium channel were changed, which affected the depolarization process of action potential and resulted in the changes of physiological function of neurons. At the same time, the transient outward potassium current (IA) and the delayed rectifier outward potassium current (IK) were significantly inhibited by the power frequency magnetic field. The activation and inactivation process of potassium channel were significantly changed by the power frequency magnetic field, which affected the formation and release frequency of the action potential. Change the physiological function of neurons. These results suggest that the biological stimulation of power frequency magnetic field may be related to the conformation and function of ion channel. Patch clamp technique provides a new method for the study of biological stimulation effect of low intensity power frequency magnetic field at cell and molecular level. The research results in this paper have laid a theoretical and experimental foundation for exploring the mechanism of biological stimulation effect of power frequency magnetic field.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R35

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