Conversion of Ca oscillation into propagative electrical signals by Ca-activated ion channels and connexin as a reconstituted Ca clock model for the pacemaker activity.

Conversion of intracellular Ca signals to electrical activity results in multiple and differing physiological impacts depending on cell types. In some organs such as gastrointestinal and urinary systems, spontaneous Ca oscillation in pacermaker cells can function essentially as a Ca clock mechanism, which has been originally found in pacemaking in sinoatrial node cell of the heart. The conversion of discrete Ca clock events to spontaneous electrical activity is an essential step for the initiation and propagation of pacemaker activity through the multicellular organs resulting in synchronized physiological functions.