Calcium signaling during the early development of medaka and zebrafish.

The ex-utero fertilization and development of the optically clear embryos of teleost fish have long been favorites of developmental biologists. They have, therefore, provided considerable insight with regards to our understanding of embryonic pattern formation and the early development of vertebrates. These attributes have also been most helpful in the visualization of Ca(2+) signaling events that have been reported to accompany many of the fundamental steps and processes that constitute early embryonic development. These include egg activation; segregation of the cytoplasm from the yolk; cytokinesis; axis determination; cellular rearrangement and germ layer establishment; as well as the formation of the first tissue domains. The developing eggs and embryos of medaka (Oryzias latipes) and zebrafish (Danio rerio) have for many decades been a favorite choice of investigators attempting to visualize Ca(2+) signaling events. In this short review, we have attempted to catalog and present a comparative study of the developmental Ca(2+) signals recorded in these most amenable of vertebrate models.