ABSTRACT
Chick embryos have been used widely as model systems for studies in experimental embryology and teratology. Especially early chick embryos are very useful for studies of neural tube defects. We made a try to figure out the effect of Ca++ on neurulation using Ca++ antagonist and Ca++ free media in early chick embryo, which is stage 8 by Hamburger & Hamilton classification. After 6~9 hours incubation in media treated with verapamil and media without Ca++, we observed the effects of these agents by LM and EM. All of 12 embryos incubated in Ca++ free media showed that neural tube was diffusely opened along the whole axis and other deformity was not found. The chick embryos cultured in medium treated with verapamil revealed various abnormalities in dose related manner. The case of arrest of the growth was also observed, which was not found Ca++ free media group. On scanning electron microscopic examination, the surface of neuroepithelium was flattened in embryos cultured in Ca++ free media.