Intracellular calcium concentration

Intracellular calcium concentration ([Ca²⁺]i) refers to the concentration of free Ca²⁺ ions inside a cell, typically maintained at low nanomolar levels under resting conditions. Calcium ions serve as a universal second messenger, regulating processes such as muscle contraction, neurotransmitter release, energy metabolism, cell proliferation, apoptosis, and gene expression. Intracellular Ca²⁺ levels are controlled by tightly coordinated uptake, release, and buffering systems involving the plasma membrane, endoplasmic/sarcoplasmic reticulum, mitochondria, and various calcium channels, pumps, exchangers, and binding proteins. Dysregulation of calcium homeostasis contributes to numerous diseases, but intracellular calcium itself is a state, not a single molecular therapeutic target. Drugs modulate calcium signaling primarily by acting on these channels or transporters, not the calcium ions directly.

Other names

cytosolic calciumintracellular Ca²⁺intracellular Ca²⁺ concentration[Ca²⁺]i

Modulation of calcium influx or efflux (blocking or enhancing channels, transporters, pumps); Inhibition/stimulation of calcium release from stores (e.g., ryanodine or IP₃ receptor ligands); Stabilization or destabilization of calcium-binding proteins