Warshawsky H, Josephsen K
Anat Rec. 1981 May;200(1):1-10. doi: 10.1002/ar.1092000102.
Odontoblasts are cells with single cytoplasmic processes that grow longer as more dentin is elaborated. Ameloblasts also have single processes and it has been postulated that they too grow longer as more enamel is made. Support for this hypothesis was obtained using rat incisors to investigate the behavior of substances labeled with 3H-proline and 3H-fucose. A comparison was made between odontoblasts, which have processes known to grow and remain within the dentin, and the ameloblasts whose Tomes' processes are hypothesized to grow and leave remnants in the completed enamel. With 3H-proline, the odontoblast bodies are labeled at the early time intervals. They synthesize and secrete a layer of intensely labeled predentin, which by 1 and 2 days is converted to mineralized dentin. Matrix deposited after the main pulse is weakly labeled. Odontoblast processes are never labeled in dentin formed prior to injection. With 3H-fucose, the cell bodies are labeled at the early intervals and the newly formed glycoproteins are deposited into the predentin. Almost immediately, these are progressively added to the dentin at the calcification front. With time a gradient of labeling extends from the unlabeled dentin toward the odontoblast bodies. Unlike the behavior of labeled proteins, by 1 and 2 days labeled glycoproteins appear along the entire length of the odontoblast processes. In the enamel, no Tomes' processes are present during maturation. With 3H-proline, reactions are adjacent to the cells and diffuse toward, but do not reach the dentino-enamel junction by 1 and 2 days. With 3H-fucose, reactions appear over the enamel near the cells. By 1 and 2 days no diffusive pattern is seen, but grains are concentrated near the dentino-enamel junction, in a region containing holes known to be the beginning of Tomes' processes. Since odontoblast glycoproteins migrate along odontoblast processes, it was postulated that cytoplasmic remnants were present in enamel along which ameloblast glycoproteins could also migrate to reach the holes at the dentino-enamel junction.
成牙本质细胞是具有单个细胞质突起的细胞，随着更多牙本质的形成，这些突起会变得更长。成釉细胞也有单个突起，据推测，随着更多釉质的形成，它们也会变得更长。通过使用大鼠切牙来研究用³H-脯氨酸和³H-岩藻糖标记的物质的行为，获得了对这一假设的支持。对成牙本质细胞（其突起已知会生长并保留在牙本质内）和成釉细胞（其托姆斯突被假设会生长并在完成的釉质中留下残余物）进行了比较。使用³H-脯氨酸时，在早期时间间隔内成牙本质细胞体被标记。它们合成并分泌一层标记强烈的前期牙本质，到第1天和第2天时，前期牙本质会转化为矿化牙本质。主脉冲后沉积的基质标记较弱。在注射前形成的牙本质中，成牙本质细胞突起从未被标记。使用³H-岩藻糖时，细胞体在早期被标记，新形成的糖蛋白沉积到前期牙本质中。几乎立即，这些糖蛋白在钙化前沿逐渐添加到牙本质中。随着时间的推移，标记梯度从未标记的牙本质向成牙本质细胞体延伸。与标记蛋白质的行为不同，到第1天和第2天时，标记的糖蛋白出现在成牙本质细胞突起的整个长度上。在釉质成熟过程中不存在托姆斯突。使用³H-脯氨酸时，反应与细胞相邻并向牙本质-釉质界扩散，但到第1天和第2天时未到达牙本质-釉质界。使用³H-岩藻糖时，反应出现在细胞附近的釉质上。到第1天和第2天时，没有观察到扩散模式，但颗粒集中在牙本质-釉质界附近的一个区域，该区域含有已知是托姆斯突起始部位的小孔。由于成牙本质细胞糖蛋白沿着成牙本质细胞突起迁移，因此推测釉质中存在细胞质残余物，成釉细胞糖蛋白也可以沿着这些残余物迁移以到达牙本质-釉质界的小孔。
