ION TRANSPORT THROUGH THE MATURATION STAGE ENAMEL ORGAN

到目前为止，在所研究的哺乳动物物种中，已经确定有 成釉细胞成熟过程中成釉细胞的两种类型 釉质形成阶段：皱折端(R-A)和光滑端(S-A)。 这些不同类型的细胞的功能还没有 下定决心。来自我们实验室和其他组织的报告表明 顺序调节的细胞类型可能涉及各种离子 运输活动。我们最近报道了一些方法，通过这些方法 不同细胞类型、~(45)Ca摄取模式之间的关系 可以建立牙釉质的染色特性。 这些方法和其他方法将被应用于努力获得对 R-A和S-A成釉细胞的功能 离子传输活动。 建议的具体目标如下：(1)进行镧 大鼠对钙离子通透性测定的灌流研究 R-A和S-A成釉细胞之间的胞外通道；2) 确定成熟期牛牙釉质器官的结构 特别注意鉴定成釉细胞类型； (3)牛牙釉质在R-A和S-A谱带下的溶解度研究 将不同浓度的酸或EDTA应用于成釉细胞 釉质表面，并在解剖下观察结果 显微镜和扫描电子显微镜；(4)为了测定氮， 牛门牙表面釉质中氟、磷的含量 在R-A和S-A成釉细胞序列带下的质子研究 活化分析；及(5)化验牙釉质样本 R-A和S-A成釉细胞磷、蛋白质和磷的交替条带 用化学法测定氟化物含量；并测定釉原蛋白 以及此类样品的釉质含量。 研究结果应该提供哪些假说可以作为依据的信息 解释这两种细胞类型的功能和涉及的机制 这样的功能。对这些假设的系统测试将在#年进行。 后续研究。

In the mammalian species studied to date, it is established that there are two general types of ameloblasts in the enamel organ during the maturation stage of enamel formation: ruffled-ended (R-A) and smooth-ended (S-A). The functions of these respective types of cells have not have been determined. Reports from our laboratories and from other groups suggest that the sequentially modulating cell types may be involved in various ion transport activities. We have recently reported on methods by which the relationship between the respective cell types, 45Ca uptake patterns in the enamel, and staining characteristics of the enamel can be established. These methods and others will be applied in an effort to gain insight into the functions of the R-A and S-A ameloblasts, particularly with regard to ion transport activities. The proposed specific aims are as follows: (1) to conduct lanthanum perfusion studies on the rat to determine the permeability to calcium of the extracellular channels between the R-A and the S-A ameloblasts; 2) to define the structure of the maturation stage bovine enamel organ, with particular attention directed to identification of ameloblast cell types; (3) to study the solubility of cow enamel under the bands of R-A and S-A ameloblasts by application of various concentrations of acid or EDTA to the enamel surface, and observation of the result under the dissecting microscope and the scanning electron microscope; (4) to assay the nitrogen, fluorine, and phosphorus content of the surface enamel of bovine incisors under the sequential bands of R-A and S-A ameloblasts using proton activation analysis; and (5) to assay enamel samples taken from under the alternating bands of R-A and S-A ameloblasts for phosphorus, protein, and fluoride content using chemical methods; and to determine the amelogenin and enamelin content of such samples. The findings should provide information on which hypotheses can be based to explain the functions of the two cell types and the mechanisms involved in such functions. Systematic testing of such hypotheses would be pursued in subsequent studies.