50Hz磁场暴露对大鼠海马单胺类神经递质的影响

The Effects of 50 Hz Magnetic Field on the Monoamine Neurotransmitters Contents in the Hippocampus of Rats

目的探讨50Hz磁场不同强度、不同暴露时间对不同年龄大鼠海马组织中单胺类神经递质含量的影响。方法将学习记忆能力基本同等的32只雄性SD青龄(2～3月)大鼠随机分为4组(50Hz磁场暴露剂量分别为0.1、1.2、1.6mT的暴露组和对照组),每组8只。暴露组大鼠每天在游迷宫之前进行磁场暴露2h,对照组假暴露2h,连续10d。按照上述方法,另设1.2mT的暴露组和对照组,连续暴露90d;1.6mT的暴露组和对照组,连续暴露10d后,停止暴露30d;大龄(18个月)大鼠0.1mT暴露组和对照组熏连续暴露8个月。采用高效液相色谱电化学法熏检测大鼠海马组织中单胺类神经递质眼去甲肾上腺素(NE)、肾上腺素(E)、多巴胺(DA)和5-羟色胺(5-HT)演的含量。结果10d暴露结果显示,1.2和1.6mT组大鼠海马组织中NE、E和DA含量高于对照组(P<0.05),1.6mT组的5-HT含量高于对照组(P<0.05)。1.2mT组青龄大鼠经过90d的较高强度的磁场暴露后,NE、DA和5-HT含量降低有统计学意义(P<0.05)。1.6mT10d磁场暴露的青龄大鼠停止磁场暴露30d后,再检测大鼠海马组织的单胺类神经递质,发现NE、E、DA和5-HT含量与对照组比较,差异均没有统计学意义。大龄大鼠0.1mT磁场暴露8个月,海马组织NE、DA及5-HT含量都在不同程度上低于对照组(P<0.05),E的变化不明显。结论短期(10d)的磁场暴露对青龄大鼠海马组织中单胺类神经递质含量的影响存在强度效应关系,较高强度(1.2mT、1.6mT)的磁场暴露可以提高青龄大鼠海马组织中NE、DA和5-HT的含量,但促进作用是暂时、可恢复的;随着较高强度暴露时间的延长(1.2mT,90d),促进作用可逆转为抑制作用。50Hz磁场暴露可引起海马组织中单胺类神经递质含量的改变,可能与磁场暴露引起的大鼠学习记忆能力改变有关。

Objective To investigate the effect of 50Hz magnetic field on the monoamine neurotransmitters contents in the hippocampus of rats. Methods 32 male SD rats were divided into 4 groups, exposed to 50 Hz magnetic field at the density of 0, 0.1, 1.2, and 1.6 mT, 2 h a day for a certain time. The contents of NE, E, DA and 5-HT were measured by HPLC. Results The contents of NE, DA and 5-HT in hippocampus were increased when the young rats were exposed to 1.2 and 1.6 mT for 10 days, the changes of monoamine neurotransmitters in 0.1 mT exposed group was not significant. The increase in monoamine neurotransmitters was disappeared when the 1.6 mT exposed group stop being exposed to the magnetic field for 30 days, while the monoamine neurotransmitters contents were decreased when the young rats were continuously exposed to 1.2 mT for 90 days. The contents of NE, DA and 5-HT, except E, in the old rats were decreased significantly when exposed to 0.1 mT intensity for 8 months. Conclusion Magnetic field exposure may affect the monoamine neurotransmitters content in the hippoeampus, which may be responsible for the changes of learning and memory of rats induced by 50 Hz magnetic field exposure.