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 IP3 production and Ca2 + release from the endoplasmic reticulum and (2) via increase of the extracellular potassium concentration, glia depolarization, and opening of voltage-dependent Ca2 + 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.

中文翻译：

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巨胶质细胞：基于机制建模的新见解

该论文描述了一种基于详细机制的三方突触模型，该模型由 P 和 R 神经元以及医学水蛭 (Hirudomedicineis) 神经节中的巨大神经胶质细胞组成，这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个主要途径：（1）通过内质网的 IP3 产生和 Ca2+ 释放；（2）通过增加细胞外钾浓度、神经胶质细胞去极化和电压依赖性 Ca2+ 通道的开放. 我们认为第二种途径对于在谷氨酸释放中建立正反馈更为重要，这对突触后神经元的自我维持活动至关重要。这种机制不同于先前报道的星形胶质细胞-神经元信号传导机制。