PDF(Pubmed)
Abstract：
High-frequency magnetic stimulation (HFMS) applied directly to the hippocampal slice preparation in vitro induces activity-dependent synaptic plasticity and metaplasticity. In addition, changes in synaptic transmission following HFMS involve the activation of N-methyl-D-aspartate and metabotropic glutamate receptors (mGluR). Here, we asked whether a short period of HFMS (5 × 10 delta-burst trains, duration of ~1 min) could alter mGluR5-mediated depression at Schaffer collateral-CA1 synapses in the acute brain slice preparation at 30 min after HFMS. To this end, we obtained field excitatory postsynaptic potential (fEPSP) slopes from Schaffer collateral-CA1 synapses after HFMS or control. First, we demonstrated that activity-dependent plasticity following HFMS depends on the slice orientation towards the magnetic coil indicating specific ion fluxes induced by magnetic fields. Second, we found that the mGluR5-specific agonist (RS)-2-chloro-5-hydroxyphenylglycine reduced the field excitatory postsynaptic potential (fEPSP) slopes in control slices but rather enhanced them in HFMS-treated slices. In contrast, the compound (S)-3,5-dihydroxyphenylglycine acting at both mGluR1 and mGluR5 reduced fEPSP slopes in both control and HFMS-treated slices. Importantly, the mGluR-dependent effects were independent from the slice-to-coil orientation indicating that asynchronous glutamate release could play a role. We conclude that a short period of HFMS inhibits subsequently evoked mGluR5-dependent depression at Schaffer collateral-CA1 synapses. This could be relevant for repetitive transcranial magnetic stimulation in psychiatric disorders such as major depression.
摘要：
直接应用于体外海马切片制备的高频磁刺激(HFMS)诱导活性依赖性突触可塑性和复可塑性。此外,HFMS后突触传递的变化涉及N-甲基-D-天冬氨酸和代谢型谷氨酸受体（mGluR）的激活。这里,我们询问短期HFMS(5×10三角形突发列车，持续时间约1分钟）可以在HFMS后30分钟改变急性脑切片制备中Schaffer侧支CA1突触处mGluR5介导的抑郁。为此,我们从HFMS或对照后的Schaffer侧支-CA1突触获得了场兴奋性突触后电位（fEPSP）斜率。首先,我们证明了HFMS之后的活动依赖性可塑性取决于朝向磁线圈的切片方向，表明磁场引起的特定离子通量。第二,我们发现mGluR5特异性激动剂(RS)-2-氯-5-羟基苯基甘氨酸降低了对照切片中的场兴奋性突触后电位(fEPSP)斜率,但在HFMS处理的切片中却增强了它们.相比之下,作用于mGluR1和mGluR5的化合物(S)-3,5-二羟基苯基甘氨酸降低了对照和HFMS处理的切片中的fEPSP斜率。重要的是,mGluR依赖性效应与切片-盘卷方向无关,表明谷氨酸异步释放可能起作用.我们得出的结论是，短时间的HFMS抑制了随后在Schaffer侧支CA1突触上引起的mGluR5依赖性抑郁。这可能与重性抑郁症等精神疾病的重复经颅磁刺激有关。
