STUDY ON EFFECTS OF EXTRA LOW FREQUENCY ELECTROMAGNETIC FIELD ON GENERATOR OF BIORHYTHM

研究了特低频电磁场对生物节律产生源视交叉上核（SCN）电活动的影响。首先，我开发了一个可以在几天内测量昼夜节律的支架。进行了50 Hz磁场对SCN活动影响的实验。将玻璃包覆的双极金属微电极立体定向插入麻醉大鼠的SCN中，以测量SCN的细胞外活性。手术后两周，将大鼠放入屏蔽室，将其头部水平固定在线圈系统中心的支架上，线圈系统可以产生均匀的磁场。实验大鼠分别沿垂直轴（z轴）、平行于头部纵轴（x轴）和垂直于x轴水平面（y轴）施加50 Hz正弦磁场。结果表明，在x轴和y轴磁场暴露实验中，观察到SCN活动节律的相位延迟。研究了极低频磁场对游离SCN活性的影响。手术后，这只大鼠在暗室里饲养了两个多星期。在极低频磁场暴露次日，观察到SCN电活动昼夜节律的畸变。

How extra low frequency (ELF) electromagnetic field affects the electrical activity of suparachiasmatic nucleus (SCN) which is the generator of the biorhythrn was investigated. First, I developed a holder with which circadian rhythm can be measured over days. I carried out the experiments about effects of 50 Hz magnetic field to the SCN activity. A glass-coated bipolar metal microelectrode was inserted stereotaxically into the SCN of an anesthetized rat in order to measure the extracellular activity of SCN. Two weeks after the surgical operation, the rat was put into the shielded room and its head was fixed horizontally with the holder at the center of the coil system which can produce uniform magnetic field. The experimental rats were exposed with 50 Hz sinusoidal magnetic field along the vertical axis (z-axis), parallel to the longitudinal axis of the head (x-axis) or perpendicular to x-axis in horizontal plane (y-axis) respectively. The result shows that the phase delay of rhythm of SCN activity was observed in the experiments of magnetic field exposure along x-axis and y-axis. The ettect ot ELF magnetic field to the free-running SCN activity was also investigated. The rat was bred uva dark room for more than two weeks after the surgical operation. The distortion of the circadian rhythm of SCN electrical activity was observed on the next day of the exposure of ELF magnetic field.