ImmunoーElectronmicroscopy of the Formation and Resorption of the Basement Membrane in the Tooth Enamel Organ

点击翻译按钮获取中文摘要

This study demonstrates ultrastructural localization of laminin, typeーIV collagen and acid phosphatase (ACPase) in the rat and monkey tooth enamel organs.Immunostaining for laminin and type-IV collagen was observed in the basement membranes of the inner enamel epithelium and differentiating ameloblasts. Reaction products occurred frequently in the rough endoplasmic reticulum of inner enamel epithelium cells. In differentiating ameloblasts, plasmaーmembrane undulation in the distal end caused deep, irregular invaginations. Various numbers of coated pits accompanied the invaginated plasma membrane. Reaction products occurred in both invaginations and coated pits. Reaction of ACPase was demonstrated in distalーcytoplasmic granules in differentiating ameloblasts. Sometimes the granules were very close to the invaginated plasma membranes. These results indicate that the basement membrane is produced by inner enamel epithelium cells and absorbed by differentiating ameloblasts.Intense laminin reaction occurred in both the internal and the external basal lamina. Laminin reaction products were observed within the rough endoplasmic reticulum of junctional epithelium cells and in minute invaginations formed at their distal plasma membranes adjacent to the basal lamina. Small spherical bodies occurring in the invaginations also reacted positively to laminin. No typeーIV collagen reaction products were seen in the internal basal lamina. The external basal lamina showed reaction to typeーIV collagen. These results indicate that the internal basal lamina contains laminin but no typeーIV collagen and that junctional epithelium cells synthesize laminin.