Siebler M, Köller H, Stichel C C, Müller H W, Freund H J
Department of Neurology, University of Düsseldorf, Germany.
Synapse. 1993 Jul;14(3):206-13. doi: 10.1002/syn.890140304.
As a model for an integrated neuronal network based on the concept of modular units, we have investigated the occurrence of spontaneous activity and the formation of synaptic circuits in primary cultures of dissociated hippocampal neurons from the embryonic rat. Sodium-dependent action potentials (APs) could be elicited after 1 day in vitro (DIV), whereas spontaneous postsynaptic potentials (PSPs), "miniature" PSPs and APs appeared after 3-6 DIV. The number of cells with spontaneous APs and the rate of APs increased during development of the neuritic network. In addition to a stochastic spike interval distribution, pyramid-shaped neurons could be identified after 10-12 DIV, which fired preferentially at interspike intervals between 20-120 ms and 190-400 ms. This distinctive bimodal interspike interval pattern was sensitive to GABA-A antagonists. Simultaneous recordings of pairs of neurons demonstrated recurrent inhibitory, GABA-ergic synaptic circuits. In addition, a subpopulation of GABAergic neurons could be visualized by immunocytochemistry. These results are discussed in relation to the hypothesis that spontaneous firing of connected neurons is network-driven, based on synaptic "noise" and patterned by recurrent inhibition.
作为基于模块化单元概念的整合神经网络模型，我们研究了来自胚胎大鼠的解离海马神经元原代培养物中自发活动的发生以及突触回路的形成。体外培养1天后（DIV）可诱发钠依赖性动作电位（AP），而自发突触后电位（PSP）、“微小”PSP和AP在3 - 6 DIV后出现。在神经突网络发育过程中，具有自发AP的细胞数量和AP频率增加。除了随机的峰间隔分布外，10 - 12 DIV后可识别出金字塔形神经元，其优先在20 - 120毫秒和190 - 400毫秒的峰间隔放电。这种独特的双峰峰间隔模式对GABA - A拮抗剂敏感。成对神经元的同步记录显示了反复抑制性的、GABA能突触回路。此外，通过免疫细胞化学可观察到GABA能神经元亚群。基于突触“噪声”且由反复抑制形成模式，将这些结果与相连神经元的自发放电是网络驱动的这一假设相关联进行了讨论。
