Histochemical and Immunohistochemical Studies on the Mechanisms of Calcium Regulation by Dental and Periodontal Hard Tissue-Forming Cells (1993)

点击翻译按钮获取中文摘要

In order to elucidate the mechanisms whereby cells of the dental and periodontal mineralized tissue-forming cells regulate calcium, our research group introduced a new method to reveal possible Ca-binding sites in cell layrs by vascularly perfusing animals with a high Ca-containing solution followed by anhydrous tissue processing for light and electron microscopy and X-ray microanalysis. With this method we found granular precipitates of Ca-phosphate to occur exclusively in the ameloblasts at the stage of matrix formation, and the smooth-ended maturation ameloblasts (SA). A complete absence of such precipitate in bone-related cells was also noted.In the second research term, we examined whether or not the peculiar phenomenon is specific for continuously growing teeth or is an essential one for mammalian amelogenesis. In the molar tooth germs of high-Ca perfused young rats, we observed similar mineral deposits in the ameloblast layr as those in the incisors. The inhibition of two types of Ca-binding proteins having been assumed to be related to cellular Ca-transport, and known to be contained in the cytoplasm of ameloblasts, did not make any changes in mineral deposits in the ameloblast layr.The presence of putative Ca-binding sites that appear to bind with excessively high concentration of calcium entering in the cytoplasm has been shown to be a common feature of the amelogenesis at least in rat teech, implicated its relation to the yet unknown mechamism of calcium regulation by the ameloblasts.We would like to further elaborate the biological significance of peculiar mineral deposits in Ca-loaded ameloblasts in future studies.