Two-dimensional compartmental simulation of calcium dynamics in neurons

Various cellular organelles, namely, cytosol, endoplasmic reticulum (ER), mitochondria (Mito), and mitochondria-associated membrane (MAM) intricately coordinate intracellular neuronal calcium ([Ca2+]) dynamics to control cellular functions and uphold homeostasis. The neuron cell is a composite non-homogeneous media. The reported one-dimensional models are unable to provide insights into the [Ca2+] regulation interactions between these organelles in neurons. Therefore, a two-dimensional compartmental framework is proposed to explore the calcium signaling in different organelles namely cytosol, ER, mitochondria, and MAM in neurons. These organelles are non-uniformly distributed with different reaction–diffusion processes. The system of reaction–diffusion equations is utilized to depict the changes in calcium concentrations throughout various cellular organelles. Numerical outcomes were acquired using the finite element simulation combined with the Crank–Nicholson approach. Different cellular mechanisms like IP3-receptor (IP3R), voltage-gate calcium channel (VGCC), sarcoendoplasmic reticulum calcium ATPase (SERCA) pump, mitochondrial calcium uniporter, mitochondrial sodium–calcium exchanger, and source influx have been incorporated into the present framework. The impacts of variations in the processes across the cellular medium due to various organelles have been deciphered with the help of simulation results. The proposed model provides better insights into the non-uniform distributed processes on calcium signaling within ER, mitochondria, cytosol, and MAMs. The present findings can be beneficial for biomedical experts in developing therapeutic protocols.