| With the increasingly popularity of various of communicating devices, household appliances and the application of many physiotherapy equipments, people are suffering more and more from the effects of electromagnetic fields. There are many research about the biological effects of electromagnetic fields, however, its mechanism is unclear, so it needs to be further explored. Therefore, it is necessary to study the influences and functions of the electromagnetic fields with different parameters on human being, especially on the cellular level, which will help to remove the effect of individual difference in the previous epidemiological study, and be more beneficial to reveal the biological mechanism of electromagnetic fields at a deeper level. From the aspects of the characters of ion channels and the electric activity of the cells, the influence of the magnetic field of different intensity, frequency and effect time to the channel characters of the animal neurons were researched using whole-cell patch-clamp technique. In this thesis, the dependences of the time, voltage, magnetic field intensity and frequency of the magnetic fields to the sodium and potassium channel currents of the neurons of the mouse and the influences of the magnetic fields to the activation and inactivation characteristics of the channels were researched. This will be able to explore the effects and rules of magnetic fields on animal neurons at cellular and molecular level.The main research contents of the dissertation are as follows:1. At the cellular level, using patch-clamp technique, we investigated the effects of static magnetic fields on the survival time (i.e. the viability of the cell) after the formation of the whole-cell mode. In the exposure process of 30mT and 100mT static magnetic field, the sodium channel currents were recorded. The experiments revealed that 30mT static magnetic field could increase the average survival time of the neurons one time longer than the cell which was not exposed under magnetic field. However, the average survival time of neurons exposed under the 100mT static magnetic field had no significant differences with the control group.2. Most of the previous researches about the effects of biological tissues inflicted by magnetic fields are at the levels of entire body or organs. The effects of 3mT, 30mT, 100mT static magnetic fields and 3mT power frequency magnetic fields on the properties of sodium channel in cortex neurons of a mouse were studied using the patch-clamp technique at the level of cells in this thesis. The results revealed that the magnetic fields of different intensities and frequencies had different influences on the activation and inactivation properties of neuronal sodium channel with the dependences of voltage, time, intensity and frequency of magnetic field.3. The effects of series of magnetic fields (3mT, 30mT, 100mT static magnetic field and 3mT power frequency magnetic field) were studied on the properties of transient outward potassium channel and delayed rectifier potassium channel of cortex neurons. The results show that the magnetic fields of different parameters produced different effects on two potassium channel properties of neurons.4. At present, most researches choose the rat as the animal specimens, but the mouse have their own advantages can not be replaced by the rat. A simple and fast acute isolation method preparing a large number of neurons was obtained by a lot of experiments in this paper. The neurons obtained by this method have good morphological and typical electrophysiological characteristics, which can be used for patch-clamp experiments. Thus the method can broaden the choice of cell samples.
|
PDF Full Text Request