Finite element model to study calcium distribution in oocytes involving voltage gated Ca2+ channel, ryanodine receptor and buffers

Abstract

Calcium is one of the most important signalling ions in cell biology performing numerous functions with high specificity. A calcium wave triggers life at fertilization but also can cause cell death. The means by which this single ion can be both highly specific and universal is believed to lie in its spatiotemporal dynamics mediated by ion channels, pumps, receptors and calcium buffers. During oocyte maturation the calcium signalling machinery undergoes differentiation which results in distinctly different calcium release patterns on all organizational scales from puffs to waves. The calcium concentration patterns required during different stages of oocyte maturation are still not completely known. Also the mechanisms involved in calcium dynamics in oocyte cell are still not well understood. In view of above a two dimensional model has been proposed to study calcium dynamics in an oocyte cell. The parameters such as buffers, ryanodine receptor and voltage gated calcium channel are incorporated in the model. Based on the biophysical conditions the initial and boundary conditions have been framed. The model is transformed into variational form and Ritz finite element method has been employed to obtain the solution. A program has been developed in MATLAB 7.10 for the entire problem and executed to obtain numerical results. The numerical results have been used to study the effect of buffers, RyR and VGCC on calcium distribution in oocyte. The results indicate that buffers can significantly decrease the calcium concentration and RyR & VGCC can significantly raise the calcium concentration level in the oocyte cell in order to initiate, sustain and terminate specific activities in the cell. The information generated from the model can be useful to biomedical scientists for clinical and biomedical applications.

Keywords: FEM; VGCC; Buffers; RyR; MATLAB; Reaction diffusion equation