The Influence of Static Magnetic Fields on Brain tissue

静磁场对脑组织的影响

• 批准号: 6518219
• 负责人: ANDRZEJ WIERASZKO
• 金额: $ 12.68万
• 依托单位: COLLEGE OF STATEN ISLAND
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-12 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6518219
• 关键词: biological transport; calcium flux; cell membrane; evoked potentials; glutamates; hippocampus; laboratory mouse; magnetic field; membrane permeability; protein kinase C; radiobiology

Epidemiological studies have suggested that exposure to electromagnetic fields generated by high-voltage, alternating current (AC) transmission line systems may have adverse effects on the biological systems. Although most of the work on magnetic field effects focused on AC fields, static magnetic fields (SMF) are also present in human environment. They are used in the industry and medicine and number of reports describes the effects of static magnetic fields (SMF) on biological systems. The current in high-voltage DC transmission lines, in opposite to AC lines, do not vary rapidly and is unable to induce current in conducting objects. Therefore, their possible interaction with biological systems would be different than AC fields. The objective of proposed research is to evaluate the influence of SMF on the evoked potentials recorded from mouse hippocampal slices. Hippocampus has been selected since presurgical evaluation of human subjects demonstrated that SMF may trigger epileptic activity in the hippocampus. Additionally, basic hippocampal electrophysiology and morphology is well known and arrangement of cells and fibers creates an environment potentially prone to magnetic fields action. Our preliminary results show that SMF (2-3 mT of intensity) modulate the magnitude of the population spike recorded from mouse hippocampal slices. The initial decline in the potential observed during exposure of the slices to SMF was followed by a recovery/amplification phase, which began after terminating the SMF action. During that phase the population spike exceeded the amplitude observed before application of the magnetic fields. The pattern of magnetic fields influence was not affected by antagonists of NMDA receptor. The inhibition of the rising phase of the potential by dantrolene, an inhibitor of intracellular Cat+ channels suggests that intracellular calcium channels participate in the mechanism of SMF action. The SMF effects were limited to orthodromically driven potentials. Our hypothesis is that SMF modulate the movement of Ca2+ ions through cellular membranes. The accumulation of radioactive Ca2+ by slices exposed to SMF will be determined. The influence of SMF on the activity of protein kinase C (PKC) which participates in synaptic mechanisms will be determined. Studies are planned to compare release and uptake of glutamate (a neurotransmitter in a tested pathway) in control and SMF-treated slices. The influence of SMF on individual neurons activity using intracellular recordings are planned. The cell excitability, synaptic efficiency and action potentials recorded from the slices exposed to SMF will be studied. The directions of alternative and future research are delineated.

流行病学研究表明，暴露于高压交流 (AC) 传输线系统产生的电磁场可能会对生物系统产生不利影响。 尽管大多数关于磁场效应的工作都集中在交流场上，但静磁场 (SMF) 也存在于人类环境中。 它们用于工业和医学，许多报告描述了静磁场 (SMF) 对生物系统的影响。 与交流线路相反，高压直流输电线路中的电流变化不大，无法在导电物体中感应出电流。 因此，它们与生物系统可能的相互作用将不同于交流场。 本研究的目的是评估 SMF 对小鼠海马切片记录的诱发电位的影响。 之所以选择海马体，是因为对人类受试者的术前评估表明，SMF 可能会引发海马体的癫痫活动。 此外，基本的海马电生理学和形态学是众所周知的，细胞和纤维的排列创造了一个可能容易受到磁场作用的环境。 我们的初步结果表明，SMF（2-3 mT 强度）调节从小鼠海马切片记录的群体峰值的幅度。 在切片暴露于 SMF 期间观察到的电位最初下降，随后是恢复/放大阶段，该阶段在终止 SMF 作用后开始。 在此阶段，种群数量峰值超过了施加磁场之前观察到的幅度。磁场影响的模式不受NMDA受体拮抗剂的影响。 丹曲林（一种细胞内 Cat+ 通道抑制剂）对电位上升阶段的抑制表明细胞内钙通道参与了 SMF 的作用机制。 SMF 效应仅限于顺向驱动电位。 我们的假设是 SMF 调节 Ca2+ 离子穿过细胞膜的运动。 将确定暴露于 SMF 的切片中放射性 Ca2+ 的积累。将确定SMF对参与突触机制的蛋白激酶C（PKC）活性的影响。 计划进行研究来比较对照切片和 SMF 处理切片中谷氨酸（测试途径中的一种神经递质）的释放和吸收。 计划使用细胞内记录来研究 SMF 对单个神经元活动的影响。 将研究暴露于 SMF 的切片记录的细胞兴奋性、突触效率和动作电位。 描绘了替代和未来研究的方向。