INSERMU975, CHU Pitié-Salpêtrière, 105 bd de l'Hôpital, Paris, France.
J Physiol. 2010 Jun 15;588(Pt 12):2077-90. doi: 10.1113/jphysiol.2009.185918. Epub 2010 Apr 19.
Glickfeld and colleagues (2009) suggested that single hippocampal interneurones generate field potentials at monosynaptic latencies. We pursued this observation in simultaneous intracellular and multiple extracellular records from the CA3 region of rat hippocampal slices. We confirmed that interneurones evoked field potentials at monosynaptic latencies. Pyramidal cells initiated disynaptic inhibitory field potentials, but did not initiate detectable monosynaptic excitatory fields. We confirmed that inhibitory fields were GABAergic in nature and showed they were suppressed at low external Cl(-), suggesting they originate at postsynaptic sites. Field potentials generated by a single interneuron were detected at multiple sites over distances of more than 800 mum along the stratum pyramidale of the CA3 region. We used arrays of extracellular electrodes to examine amplitude distributions of spontaneous inhibitory fields recorded at sites orthogonal to or along the CA3 stratum pyramidale. Cluster analysis of spatially distributed inhibitory field events let us separate events generated by interneurones terminating on distinct zones of somato-dendritic axis. Events generated at dendritic sites had similar amplitudes but occurred less frequently and had somewhat slower kinetics than perisomatic events generated near the stratum pyramidale. In records from multiple sites in the CA3 stratum pyramidale, we distinguished inhibitory fields that seemed to be initiated by interneurones with spatially distinct axonal arborisations.
格利克菲尔德和同事（2009 年）提出单个海马中间神经元在单突触潜伏期产生场电位。我们在大鼠海马切片 CA3 区的同时细胞内和多个细胞外记录中研究了这一观察结果。我们证实中间神经元在单突触潜伏期诱发场电位。锥体细胞引发双突触抑制场电位，但不会引发可检测的单突触兴奋性场。我们证实抑制性场具有 GABA 能性质，并表明它们在低外 Cl(-) 下被抑制，表明它们起源于突触后部位。在 CA3 区的金字塔层中，超过 800 微米的距离的多个部位检测到由单个中间神经元产生的场电位。我们使用细胞外电极阵列检查在与 CA3 金字塔层正交或沿其方向的部位记录的自发抑制场的幅度分布。空间分布的抑制场事件的聚类分析使我们能够将终止于不同躯体-树突轴区域的中间神经元产生的事件分开。在树突部位产生的事件具有相似的幅度，但发生的频率较低，动力学稍慢于在靠近金字塔层部位产生的体周事件。在 CA3 金字塔层的多个部位的记录中，我们区分了似乎由具有空间上不同轴突分支的中间神经元引发的抑制场。
