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