Anti-phase calcium oscillations in astrocytes via inositol (1,4,5)-trisphosphate regeneration

Observations in cultured mouse astrocytes suggest anti-phase synchronization of cytosolic calcium concentrations in nearest neighbor cells that are coupled through gap junctions. A mathematical model is used to investigate physiologic conditions under which diffusion of the second messenger inositol (1, 4, 5)-trisphosphate (IP3) through gap junctions can facilitate synchronized anti-phase Ca2+ oscillations. Our model predicts anti-phase oscillations in both cytosolic calcium and IP3 concentrations if (a) the gap junction permeability is within a window of values and (b) IP3 is regenerated in the astrocytes via, e.g. phospholipase C-delta. This result sheds new light on the current dispute on the mechanism of intercellular calcium signaling. It provides indirect evidence for a partially regenerative mechanism as the model excludes anti-phase synchrony in the absence Of IP3 regeneration. (C) 2005 Elsevier Ltd. All rights reserved.