Dong Lei, Li Gang, Gao Yang, Lin Ling, Zheng Yu, Cao Xue-Bin
State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin, China.
Tianjin Key Laboratory of Biomedical Detecting Techniques & Instruments, Tianjin University, Tianjin, China.
Eur J Neurosci. 2020 Aug;52(4):3166-3180. doi: 10.1111/ejn.14705. Epub 2020 Mar 9.
Low-frequency electromagnetic field (LF-EMF) stimulation is an emerging neuromodulation tool that is attracting more attention because of its non-invasive and well-controlled characteristics. However, the effect of different LF-EMF features including the forms and the time of addition on neuronal activity has not been completely understood. In this study, we used multi-electrode array (MEA) systems to develop a flexible in vitro magnetic stimulation device with plug-and-play features that allows for real-time delivery of LF-EMFs to biological tissues. Crucially, the method enables different forms of LF-EMF to be added at any time to a long-term potentiation (LTP) experiment without interrupting the process of LTP induction. We demonstrated that the slope of field excitatory postsynaptic potentials (fEPSPs) decreased significantly under post or priming uninterrupted sine LF-EMFs. The fEPSPs slope would continue to decline significantly when LF-EMFs were added two times with a 20-min interval. Paired-pulse ratio (PPR) was analyzed and the results reflected that LF-EMFs induced LTP was expressed postsynaptically. The results of pharmacological experiments indicated that AMPA receptor activity was involved in the process of LTP loss caused by post-LF-EMFs. Moreover, the effect of priming sine or Quadripulse stimulation (QPS)-patterned LF-EMFs depended on the time interval between the end of LF-EMF and the beginning of baseline recording. Interestingly, the effect of sine LF-EMFs on LTP would not disappear within 120 min, while the impact of QPS-patterned LF-EMFs on LTP might disappear after 90 min. These results indicated that LF-EMF might have a form- and time-dependent effect on LTP.
低频电磁场（LF-EMF）刺激是一种新兴的神经调节工具，因其非侵入性和良好的可控性而备受关注。然而，不同LF-EMF特征（包括形式和施加时间）对神经元活动的影响尚未完全明确。在本研究中，我们使用多电极阵列（MEA）系统开发了一种具有即插即用功能的灵活体外磁刺激装置，该装置能够将LF-EMF实时传递至生物组织。至关重要的是，该方法能够在不中断长时程增强（LTP）诱导过程的情况下，随时向LTP实验中添加不同形式的LF-EMF。我们证明，在施加后或预激发不间断正弦LF-EMF时，场兴奋性突触后电位（fEPSP）的斜率显著降低。当以20分钟的间隔添加两次LF-EMF时，fEPSP斜率将继续显著下降。分析了配对脉冲比率（PPR），结果表明LF-EMF诱导的LTP是在突触后表达的。药理学实验结果表明，AMPA受体活性参与了LF-EMF施加后导致的LTP丧失过程。此外，预激发正弦或四脉冲刺激（QPS）模式的LF-EMF的效果取决于LF-EMF结束与基线记录开始之间的时间间隔。有趣的是，正弦LF-EMF对LTP的影响在120分钟内不会消失，而QPS模式的LF-EMF对LTP的影响可能在90分钟后消失。这些结果表明，LF-EMF可能对LTP具有形式和时间依赖性效应。
