Development Of An Extremely Low Frequency Magnetic Field Generator And Its Application In Nerve Cell Electrophysiological Characteristics Research

Electrophysiological activity is an important activity of organisms. Neurons spark and ion channel in patch clamp are two important areas. Since electrophysiological activity is electricity; it will be some affected by external electromagnetic activity. Using electromagnetic fields to stimulate nerve cells and tumor cells are two important subjects in bioelectromagnetics research studies. The appropriate magnetic stimulation on diseases of the nervous system plays a certain role in treatment, such as Parkinson's disease, neuropathic pain, epilepsy, depression, schizophrenia, etc. Hippocampal is an important region in brain for learning and memorization; it is very important lesions region in Parkinsson's disease. In this paper we study hippocampal cells characteristics by magnetic field stimulation. Through research we had analyzed the potassium-ion-channel and neural discharge signals before and after magnetic stimulation to study the changes in its physiological characteristics. This study gave great theoretical and practical values.In this theses, at first we have designed a generic extremely low-frequency magnetic field generator for electrophysiology experiments in bioelectromagnetics. The equipment can generate a variety of waveforms, frequencies and intensities magnetic field which is constant distribution in spatial. Then we did the experiment on Rat hippocampal by two ways a) ion channel patch clamp b) and neurons spark. In this experiment some neurons has been stimulated by low-frequency magnetic fields, and the others haven't stimulated. Finally we compared two results.The main research results we obtained are as follows:(1)A Low-frequency multi-waveform magnetic field stimulator has been developed, which Suitable for the bioelectromagnetics research studies. The apparatus is characterized by:a) Magnetic field strength has upgraded from several millitesla (mT) to 100 mT;b) Adoption of hardware and compensation software, to overcome the limitations of decreasing the intensity while increasing the frequency of the magnetic waveforms, producing constant magnetic field intensity from 1 Hz to 500 Hz;c) The Developed triangular magnetic field waveform can generate a short time constant electric field, which can be used for special researches.(2)A wavelet noise reduction algorithm has been created to do with specific electrophysiological signals. The electrophysiological signals have two characteristics: a11 or none law; it has short refractory period. In noise reduction methods we used a generating function called haar function as a wavelet basis function. Through testing, this method can enhance the effect significantly than the traditional of low-pass filter method.(3)An algorithm certification standards of ion single-channel noise reduction was been rose. Noting that ion channel has a characteristic of full or off. So we constructed a standard signal waveform to measure noise reduction effects.(4) Signals of discharge are more rhythm when hippocampus cells are stimulated by extremely low frequency magnetic field. The AR model spectrum analysis shows that signals spectrum of discharge are smoother when hippocampus cells stimulated by magnetic field, the decrease of the frequency components means signals are more rhythm.(5) The activities of the hippocampus cells electrophysiological become more active when they are stimulated by magnetic fields stimulation. Using AR model spectral analysis method we found that the electrophysiological signals in the AR spectrum will move to high frequency section. This means signals frequencies of electrophysiological activity are increased, the electrophysiological activities are more frequent. Stochastic processes and statistical analysis methods, which have been used showed that extremely low frequency magnetic stimulation hippocampus cells increased the number of action potentials, decreases ISI, increased the potassium channel opening time and decreased close time. These results are consistent with the conclusions of the relevant literature reported.In this paper, two experimental methods are used; concluded that the specific magnetic field can promote the activities of electrophysiological characteristics. From the view of physiology, Na~+ ion channels in the primary role of neurons discharge, but potassium channel opener will become more active. So it seems that we can draw the following inference: the specific magnetic stimulation played a role in promote Na~+-K~+ pump activity. Although K~+ flow the opposite direction in Na~+-K~+ pump flow and ion channels. This is consistent some literatures which reported magnetic field direct effect Na~+-K~+ pump activity and enhance membrane. By experiment we have proved in a certain way that the magnetic field can play a role in the treatment of nervous system diseases.