Sasaki T
J Anat. 1984 Mar;138 ( Pt 2)(Pt 2):333-42.
In order to clarify the morphology and function of maturation ameloblasts, kitten tooth germs were examined using an ultrastructural tracer technique. Kitten maturation ameloblasts were divided into two cell types: a ruffle-ended type showing plasma membrane infoldings and invaginations at the distal cell surface and a smooth-ended type showing a non-invaginated, smooth distal cell surface. Both ameloblasts possessed two sets of junctional complexes at their proximal and distal ends. In either type of cell, intravenously injected horseradish peroxidase penetrated from the vascular region into the developing enamel surface through both the proximal and distal junctional complexes, although the tight junction compartment inhibited horseradish peroxidase permeation. Ruffle-ended ameloblasts further incorporated peroxidase from the distal cell surface into the cytoplasm by means of membrane invaginations and coated vesicles. Smooth-ended ameloblasts showed little intracellular peroxidase incorporation. These results show clearly that resorptive and non-resorptive maturation ameloblasts exist in kitten enamel organ and that the two cell types correspond to ruffle-ended and smooth-ended maturation ameloblasts in rat incisors.
为了阐明成熟成釉细胞的形态和功能，采用超微结构示踪技术对幼猫牙胚进行了研究。幼猫成熟成釉细胞分为两种细胞类型：一种是褶缘型，在细胞远端表面可见质膜内褶和内陷；另一种是平滑缘型，其远端细胞表面无内陷，较为平滑。两种成釉细胞在其近端和远端均有两组连接复合体。在任何一种细胞类型中，静脉注射的辣根过氧化物酶均可通过近端和远端连接复合体从血管区域渗透到正在发育的釉质表面，尽管紧密连接区会抑制辣根过氧化物酶的渗透。褶缘型成釉细胞还通过膜内陷和被膜小泡将远端细胞表面的过氧化物酶进一步摄入细胞质。平滑缘型成釉细胞几乎没有细胞内过氧化物酶的摄入。这些结果清楚地表明，幼猫釉器中存在吸收性和非吸收性成熟成釉细胞，且这两种细胞类型分别对应大鼠切牙中的褶缘型和平滑缘型成熟成釉细胞。
