Postnov D E, Ryazanova L S, Brazhe N A, Brazhe A R, Maximov G V, Mosekilde E, Sosnovtseva O V
Physics Department, Saratov State University, Saratov, 410026, Russia.
J Biol Phys. 2008 Aug;34(3-4):441-57. doi: 10.1007/s10867-008-9070-7. Epub 2008 May 20.
The paper describes a detailed mechanism-based model of a tripartite synapse consisting of P- and R-neurons together with a giant glial cell in the ganglia of the medical leech (Hirudo medicinalis), which is a useful object for experimental studies in situ. We describe the two main pathways of the glial cell activation: (1) via IP(3) production and Ca(2 +) release from the endoplasmic reticulum and (2) via increase of the extracellular potassium concentration, glia depolarization, and opening of voltage-dependent Ca(2 +) channels. We suggest that the second pathway is the more significant for establishing the positive feedback in glutamate release that is critical for the self-sustained activity of the postsynaptic neuron. This mechanism differs from the mechanisms of the astrocyte-neuron signaling previously reported.
该论文描述了一种基于机制的详细三方突触模型，该模型由医用水蛭（Hirudo medicinalis）神经节中的P神经元和R神经元以及一个巨大的神经胶质细胞组成，水蛭是原位实验研究的有用对象。我们描述了神经胶质细胞激活的两条主要途径：（1）通过肌醇三磷酸（IP(3)）的产生和内质网释放钙离子（Ca(2 +)）；（2）通过细胞外钾离子浓度的增加、神经胶质细胞去极化以及电压依赖性钙离子通道的开放。我们认为第二条途径对于在谷氨酸释放中建立正反馈更为重要，而这种正反馈对于突触后神经元的自持活动至关重要。该机制与先前报道的星形胶质细胞 - 神经元信号传导机制不同。
