Gliotransmitter regulation of synaptic activity in astrocytic calcium dynamics model
Kursk State University, Department of Theoretical Physics, Radishcheva st., 33, 305000, Kursk, Russia1 pp. (accepted)
Spontaneous and induced by synaptic activity spatio-temporal patterns of calcium dynamics in astrocytes can segregate the space of the nervous tissue into areas with various conditions maintained that increase or decrease the efficiency of synapses due to localized release of gliotransmitters. It is assumed that understanding the pathways of regulation of nervous tissue excitation by these mechanisms may be of key importance for controlling the activity of the central nervous system.
The study is based on the model of calcium dynamics in astrocytes , which takes into account the spatially detailed morphology of astrocyte cells, the topology of their networks, calcium dynamics in astrocytes, the connection of astrocytes with neuronal axons. Based on the available experimental data, we extended this model by including an equation describing the gliotransmitter dynamics, taking into account that it depends on the morphological peculiarities of the site of the cell (i.e., it differs in leaflets, thick or thin processes and soma) and the current calcium profile. In addition, the concentration of gliotransmitter was determined to have a direct impact on the probability of glutamate release.
A numerical study of the model on a two-dimensional astrocyte template showed that:
– the gliotransmitter, on the one hand, has an important effect directly on calcium activity in astrocytes, on the other hand, it is able to regulate synaptic activity;
– the number of calcium events in the astrocyte cell depends on the local values of the gliotransmitter concentration;
– synaptic activity can be regulated by external injection of gliotransmitters.
As a part of further research, it is planned to study the effect of a gliotransmitter on synaptic activity in a refined model, in which the location of synapses in the cell will be as biophysically realistic as possible.
This study was supported by the Russian Science Foundation, grant 21-74-00095.
1. Verisokin, A. Yu., Verveyko, D. V., Postnov, D. E. & Brazhe, A. R. Modeling of Astrocyte Networks: Toward Realistic Topology and Dynamics. Front. Cell. Neurosci. 15, 645068 (2021).