Effects Of Low-intensity Low-frequency Magnetic Field On The Electrophysiological Characteristics Of Neurons In Hippocampal CA1 Region Of Rats

Modern lifcestyle exposes nearly all humans to electromagnetic fields,particularly to extremely low fi-equency electromagnetic fields(ELF-EMFs).People are more and more dependent on electronic products,and the environment is exposed.Geomagnetic environment,personal communication equipment and electrical equipment are all important sources of ELF-EMF.In addition,rTMS,as a noninvasive method for the treatment of neuropatlhic diseases,shows that magnetic stimulation does have a certain effect on the human brain.However,the effcct of ELF-EMF on the electrical activity and mechanism of microcells has not been determined.This is also the focus of researchers at present.The sim of this study is to explore the mechanism of ELF-EMF stimulation on the electrical activity of the voltage gated Na+ and voltage gated K+ channels in rat hippocampal neurons.In this paper,patch clamp online ELF-EMF magnetic exposure device was used to stimulated the pyramidal cells of the radiation layer in the hippocampus of the rat.The stimulation frequency was 15 Hz and 50 Hz,and the stimulation intensity was 0.5mT,1 mT and 2mT respectively.The stimulation time was 10min,20min and 30min/A total of two experiments,one is for the voltage gated Nat channels.4-AP was used to block transient outward potassium channel.TEA-Cl was used to blcock delayed rectifier potassium channel.CdCl2 was used to block calcium channel.The current,activation characteristics and deactivation characteristics of the sodium ion channel are recorded with the curves of depolarization potential.Then we recorded the current curve of the sodium channel with TTX.The current disappeared,indicating that the sodium current has been completely blocked.At this time,the brain slices were stimulated by ELF-EMF.The change of the curve with depolarization potential was recorded.But there is no channel current.It is concluded that ELF-EMF stimulation can not be used as an inducer and can not remove the effect of blockers to make the channel gate open again.The same method records the transient outward potassium current and the delayed rectifier potassium current as well as the activation inactivation.The result is that ELF-EMF does not have the inducer effect.The second experiment is to explore the regulation mechanism of ELFF-EMF.4-AP was used to block transient outward potassium channel.TEA-Cl was used to block delayed rectifier potassium channel.CdCl2 was used to block calcium channel.The current,activation characteristics and deactivation characteristics of the sodium ion channel are recorded with the curves of depolarization potential.Then the ELF-EMF of different stimulation time,magnetic field intensity and magnetic field frequency was applied to observe the changes of sodium current and activation inactivation.Finally,the I-V curve,the activation curve and inactivation curve.were analyzed.The adjustment trend of ELF-EMF was found.In the same way,the regulation trend of the transient outward potassium channel and delayed rectifier potassium channel by ELF-EMF was recorded.The results showed that ELF-EMF had a promoting effect on INa and had inhibitory effect on IA and IK.This is mainly because ELF-EMF changes the conversion probability of the channel,that is,the activation character and inactivation character.The regulation mechanism of ELF-EMF on the channel of neuron pyramidal cell is different,which is related to the time of magnetic stimulation,the intensity of magnetic field,the frequency of magnetic field and the type of channel.