Extracellular and intracellular Mg 2+ play various physiological roles. Normally, the concentration of negative ions in cells is higher than that of cations. The positive Mg 2+ as a counterion interacts with negatively charged molecules such as RNA, DNA, ROS and ATP. Mg 2+ is thus involved in DNA/RNA stabilization, regulation of enzyme activities, regulation of ion channel function and protection of the cell from oxidative stress. Thus, a disturbance in the level of Mg 2+ can affect these functions and contribute to pathological conditions. Intracellular Mg 2+ is important for the regulation of various reactions involved in protein synthesis, energy metabolism and signal transduction, while participating in intracellular signaling by promoting protein kinase. Mg 2+ protects cells from free radicals due to its ability to scavenge ROS.

Intracellular Mg 2+ participates in maintaining genome stability, as a cofactor in DNA repair enzymes and as a competitive inhibitor of DNA-damaging agents. Extracellular Mg 2+ participates in the regulation of ion channels, especially the NMDA receptor, the important one in maintaining normal neuronal functions.

Nerve cells communicate through electrical and chemical signals, and Mg 2+ controls the strength of the channel protein at the electrical synapse. In addition, Mg 2+ influx is triggered in the neuron at the time of activity by chemical synapses, making it important for the regulation of electrical and chemical neuronal communication. Thus, Mg 2+ plays a role in synaptic plasticity and the creation of a neuronal network.


SOURCE: Biometals 2021