Calcium oscillations and waves in cells

Abstract

From beginning of the life to final moment of the life, Ca 2+ functions as an important signaling messenger. The intracellular Ca 2+ concentration, [Ca 2+] i, in resting cells is normally maintained at around 100 nM with a very steep ∼20,000 times concentration gradient of Ca 2+ between extracellular and intracellular compartments. Ca 2+ signals in the form of time-dependent changes in [Ca 2+] i appear as brief spikes that are organized into regenerative Ca 2+ waves. The release of Ca 2+ from internal stores plays a key role in regulating such Ca 2+ signals. Since global Ca 2+ oscillations arise from Ca 2+ waves initiated locally, it results in generation of stochastic Ca 2+ oscillations. In addition, the hierarchical organization of signaling structures translate the molecular fluctuations of single channels to the whole cell leading to formation of stochastic media. Several recent observations indicate that [Ca 2+] i changes are fluctuation driven as opposed to a typical deterministic intracellular reaction-diffusion system model. Elucidation of this signaling mechanism can provide detailed knowledge of relationship between cell signaling and cell physiology of living systems. © 2012 Springer Science+Business Media B.V.