title: Giant glial cell: new insight through mechanism-based modeling.
abstract: 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.
authors: Physics Department, Saratov State University, Saratov, 410026, Russia. postnov@chaos.ssu.runnet.ru
authors: D E
authors: DE
authors: Postnov
authors: L S
authors: LS
authors: Ryazanova
authors: N A
authors: NA
authors: Brazhe
authors: A R
authors: AR
authors: Brazhe
authors: G V
authors: GV
authors: Maximov
authors: E
authors: E
authors: Mosekilde
authors: O V
authors: OV
authors: Sosnovtseva