Xu Yuan, Wang Lidan, Liu Yu-Zhang, Yang Yan, Xue Xiaolin, Wang Zhiru
Institute and Key Laboratory of Brain Functional Genomics of The Ministry of Education of China, Shanghai Key Laboratory of Brain Functional Genomics, School of Life Sciences, East China Normal University, Shanghai, 200062, China.
Neurosci Bull. 2016 Aug;32(4):363-73. doi: 10.1007/s12264-016-0049-2. Epub 2016 Jul 20.
Neuronal oscillations are fundamental to hippocampal function. It has been shown that GABAergic interneurons make an important contribution to hippocampal oscillations, but the underlying mechanism is not well understood. Here, using whole-cell recording in the complete hippocampal formation isolated from rats at postnatal days 14-18, we showed that GABAA receptor-mediated activity enhanced the generation of slow CA1 oscillations. In vitro, slow oscillations (0.5-1.5 Hz) were generated in CA1 neurons, and they consisted primarily of excitatory rather than inhibitory membrane-potential changes. These oscillations were greatly reduced by blocking GABAA receptor-mediated activity with bicuculline and were enhanced by increasing such activity with midazolam, suggesting that interneurons are required for oscillation generation. Consistently, CA1 fast-spiking interneurons were found to generate action potentials usually preceding those in CA1 pyramidal cells. These findings indicate a GABAA receptor-based mechanism for the generation of the slow CA1 oscillation in the hippocampus.
神经元振荡是海马体功能的基础。已有研究表明，γ-氨基丁酸（GABA）能中间神经元对海马体振荡有重要贡献，但其潜在机制尚不清楚。在此，我们利用全细胞膜片钳记录技术，对出生后14至18天大鼠分离出的完整海马结构进行研究，结果表明GABAA受体介导的活动增强了CA1区慢振荡的产生。在体外实验中，CA1神经元产生了慢振荡（0.5-1.5赫兹），这些振荡主要由兴奋性而非抑制性膜电位变化组成。用荷包牡丹碱阻断GABAA受体介导的活动可使这些振荡大幅减少，而用咪达唑仑增强该活动则可使振荡增强，这表明中间神经元是振荡产生所必需的。一致的是，我们发现CA1区快发放中间神经元产生动作电位的时间通常早于CA1区锥体细胞。这些发现表明，海马体中CA1区慢振荡的产生存在一种基于GABAA受体的机制。
