Abstract Astrocytes display a highly complex, spongiform morphology, with their fine terminal processes SAM-E (leaflets) exercising dynamic degrees of synaptic coverage, from touching and surrounding the synapse to being retracted from the synaptic region.In this paper, a computational model is used to reveal the effect of the astrocyte-synapse spatial relationship on ionic homeostasis.Specifically, our model predicts that varying degrees of astrocyte leaflet coverage influences concentrations of K+, Na+ and Ca2+, and results show that leaflet motility strongly influences Ca2+ uptake, as well as glutamate and K+ to a lesser extent.Furthermore, this paper highlights that an astrocytic leaflet that is in proximity to the synaptic cleft loses the ability to Crescent Bag form a Ca2+ microdomain, whereas when the leaflet is remote from the synaptic cleft, a Ca2+ microdomain can form.
This may have implications for Ca2+-dependent leaflet motility.