Recently, functional interactions between neurons and astrocytes have been steadily clarified. In particular, the effects of presynaptic depolarization-induced suppression of excitation (DSE) through endocannabinoid (ECB) and endocannabinoids-mediated synaptic potentiation (eSP) by an astrocyte have been used as an evidence of global heterosynaptic modulation. However, the mechanism of occurrence of spatial modulation in a neural network remains unknown. Although the Ca2+ density in astrocytes is strongly related to eSP through ECB, the mechanism of the rise in the ECB receptor in Ca2+ remains unclear. Since Ca2+ is closely related to inositol-1,4,5-trisphosphate (IP3), it is believed that the released IP3 affects Ca2+ in astrocytes that receive ECB. Therefore, this study approximately showed the spatial distribution of DSE or eSP with astrocyte-neuron computational models, assuming that the IP3 caused by ECB is transmitted in an astrocyte. The results showed doughnut-shaped DSE, eSP, and DSE regions from the central ECB released points to the surroundings. They suggested that IP3 diffusion plays an important role in mediating this synaptic modulation.
Keywords: Astrocyte; Astrocyte–neurons model; Endocannabinoid; Inositol-1,4,5-trisphosphate.
© The Author(s), under exclusive licence to Springer Nature B.V. 2021.