Giant Glial Cell: New Insight Through Mechanism-Based Modeling

• Published in: Journal of biological physics Vol. 34; no. 3-4; pp. 441 - 457
• Main Authors: Postnov, D. E, Ryazanova, L. S, Brazhe, N. A, Brazhe, A. R, Maximov, G. V, Mosekilde, E, Sosnovtseva, O. V
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.08.2008; Springer Netherlands; Springer Nature B.V
• Subjects: Biochemistry; Biological and Medical Physics; Biophysics; Cellular biology; Complex Fluids and Microfluidics; Complex Systems; Glia; Hirudinea; Hirudo medicinalis; Neuron; Neurons; Neurosciences; Original Paper; Physics; Physics and Astronomy; Soft and Granular Matter; Tripartite synapse; Neuron; Glia; Modeling; Tripartite synapse
• ISSN: 0092-0606; 1573-0689
• DOI: 10.1007/s10867-008-9070-7

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.