Calcium signalling in astrocytes and modulation of neural activity

Dynamics of a minimal neural model consisting of an astrocyte, a neuron, and an interneuron

“…The model describing calcium dynamics adopted in this paper is that of Di Garbo et al [36]. In this model, the calcium fluxes through the membrane are the following: (1) a leakage Ca 2+ influx described by the rate ν LM ; (2) a capacitive calcium entry (CCE) of rate ν CCE ; (3) an extrusion across the plasma membrane described by the rate ν OUT ; (4) an influx of Ca 2+ mediated by the P2X ionotropic ATP receptor with rate ν ATP(P2X) .…”

“…In general, two main experimental models of channel opening have been proposed: one is based on the hypothesis of a small diffusible messenger released from the depleted ER [40] and the second suggests a direct or indirect physical contact between ER proteins and the plasma membrane [41]. In the model used here, this calcium entry pathway is modeled as a nonlinear function of C ER : The adopted values of the constants k CCE and H CCE were chosen to mimic, at best, the experimental features of the calcium response of an astrocyte in the presence of extracellular ATP [36]. Astrocytes express a wide variety of neurotransmitter receptors that, when activated by appropriate agonists, evoke a large repertory of responses, including [Ca 2+ ] i increase and release of gliotransmitters like glutamate and ATP [11-14, 34, 35, 42].…”

“…In Di Garbo et al [36], it was shown that the above model is capable of describing, both qualitatively and quantitatively, the experimental results reported in [10]. In particular, it was shown that the model is able to reproduce the ATP-evoked biphasic calcium response (the transient and the sustained phase) in the astrocyte: the transient phase corresponds to the release of calcium from the ER store, while the sustained part is mainly determined by the influx of extracellular calcium mediated by the P2X purinoreceptors.…”

“…In particular, it was shown that the model is able to reproduce the ATP-evoked biphasic calcium response (the transient and the sustained phase) in the astrocyte: the transient phase corresponds to the release of calcium from the ER store, while the sustained part is mainly determined by the influx of extracellular calcium mediated by the P2X purinoreceptors. Additional details on this specific topic can be found in Di Garbo et al [36].…”

Two dimensional finite element estimation of calcium ions in presence fo NCX and Buffers in Astrocytes

“…Brajesh Kumar Jha and Amrita Jha exchanger etc [1,2,4,8,14,16,20]. In present study calcium buffering and NCX is taken into consideration to study the effect of them on free Ca 2+ concentration.…”