Hamon B, Stanton P K, Heinemann U
Neurosci Lett. 1987 Mar 31;75(2):240-5. doi: 10.1016/0304-3940(87)90304-1.
Partial reduction of [Mg2+]o from 2 to 1 mM markedly enhanced neuronal responses evoked by Schaffer collateral-commissural fiber stimulation in the CA1-region of rat hippocampal slices. The amplitude of extracellular population potentials recorded in the CA1-pyramidal cell layer and maximum dV/dt of extracellular population EPSP's recorded in the CA1-pyramidal apical dendritic layer were both increased. However, unlike findings from slices where Mg2+ was completely removed from the bathing medium, there was no spontaneous or evoked epileptiform activity, and the N-methyl-D-aspartate (NMDA) receptor antagonist 2-amino-5-phosphonovalerate (2-APV) did not antagonize the enhancement of evoked responses. These results indicate that, in addition to the participation of NMDA receptors in the epileptiform activity observed when Mg2+ is completely removed from the bathing medium, there is also an NMDA receptor-independent excitatory action of partial reduction of [Mg2+]o in hippocampal slices.
将细胞外液中镁离子浓度（[Mg2+]o）从2 mM 部分降低至1 mM，可显著增强大鼠海马脑片CA1区由Schaffer侧支-联合纤维刺激诱发的神经元反应。记录于CA1锥体细胞层的细胞外群体电位的幅度以及记录于CA1锥体顶端树突层的细胞外群体兴奋性突触后电位（EPSP）的最大dV/dt均增加。然而，与将镁离子从灌流液中完全去除的脑片实验结果不同，该实验中未出现自发或诱发的癫痫样活动，且N-甲基-D-天冬氨酸（NMDA）受体拮抗剂2-氨基-5-磷酸戊酸（2-APV）并未拮抗诱发反应的增强。这些结果表明，除了NMDA受体参与在灌流液中完全去除镁离子时所观察到的癫痫样活动外，海马脑片中[Mg2+]o的部分降低还存在一种不依赖NMDA受体的兴奋性作用。
