Regular and chaotic oscillations in astrocyte model with regulation of calcium release kinetics

The dynamics of an astrocyte model is investigated. The astrocytes represent a type of glial cells regulating oscillations of major signaling cells, e.g. neurons. Subserved by complex molecular mechanisms the astrocytes generate calcium auto-oscillations which, in turn, are associated with the release of neuroactive chemicals into extracellular space. At variance with classical astrocyte models the three-component model considered takes into account a regulation of calcium release due to nonlinear dynamics of inositol-1,4,5 trisphosphate (IP3). Stability of steady states, generation of regular and chaotic oscillations were analysed using bifurcation analysis. In particular, it was found that nonlinear IP3 relaxation dynamics can lead to appearance of complex modes in astrocyte dynamics including multistability and pulse oscillations of complex shape.