A low calcium condition; important roles of ionized calcium in biology

Calcium is the most widely distributed and inevitably important bivalent ion which has an intimate relation both to functions and structures in living organisms. However, studies on the structural and functional alterations induced under a low calcium condition have been ignored. In the last two decades, to clarify the role of ionized calcium in biology, the morpho-functional alterations in various organs and tissues under a low calcium condition provoked by calcium chelating drugs have been examined. In this paper, the range of results obtained through our experiments will be reviewed and the almost miraculous roles of the calcium ion in biology will be discussed. Most of the presented results offer just the beginning of a new era of the research in this field, therefore further continuous studies can be expected.