| This dissertation is focused on the underlying mechanisms involved in the effects of electromagnetic fields on the excitable cells,neurons to be more exact.Although many investigators have conducted a wide range of experiments on this topic,the underlying mechanisms remain undefined.By consulting a large nunmber of papers related to this area,I classified the past researches into two main categories:the physical model and bio-trigger model.The former is based on the physical laws and the other is phenomenological models.The first part of this dissertation is about theoretical calcualting.Although there have been many calculating models about the transmemebrane currents or potentials induced by the applied fields,their model is somewhat simple.In most previous papers,the cells are often considered three-compartment models with different electroconductivities in different regions(the three compartments are often intracellular regions,membrane,and extracellular regions).However,models like that did not take dynamic ion channels into consideration.Therefore,one cannot obtain concrete ionic current changes such as potassium current change or sodium current change by these models.So a new calculating model were introduced into our models.Most equations used in the present paper originate from Nernst-Plank equations,which are ionic current related equations.The main work is to calculate ionic current changes induced by EMF exposure,and then transmembrane potential changes are calculated with Hodgkin-Huxley model.The second part of this paper is about a series of whole-cell patch clamping experiments,by which we want to investigate the possible mechanisms of low frequency magnetic fields could have on the rat hippocampal CA1 pyramidal neurons.Then the inactivation and activation properties of sodium and potassium channels are analysed based on the two-state ion channel mdoels to uncover the biological mechanisms responsible for the electrophysiological modifications. |
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