PHYSIOLOGY AND IMMUNOHISTOCHEMISTRY OF DENTAL PULP

了解成牙本质细胞的生理特性是一个重要的 朝着了解细胞机制的方向迈进一步 牙髓中的代谢和转导过程。现在是间接证据 提示这种过程是通过跨膜的改变来调节的。 成牙本质细胞膜中离子通道的电导。其中最多的 这些离子途径的关键是那些控制钙周转的途径。 钙调节对成牙本质细胞尤其重要，因为 细胞内和细胞外钙水平都可能在 牙本质的形成，这些细胞可能直接参与运输 钙到矿化基质。除了成矿作用外， 成牙本质细胞离子通道也可能参与体感， 调节静水压力的变化和/或渗透压的变化 由于机械或水动力扰动而产生的坡度。初级阶段 拟议研究的目的是检查离子机制。 这些细胞对与以下因素相关的反应的基础 牙髓中牙本质的发生和体感转导。在这些 研究I将使用膜片钳记录技术来监测单个 成牙本质细胞膜中的通道电流和全细胞电流 完整哺乳动物成牙本质细胞的体外和原位制备。在……里面 初步研究发现了一种L型钙通道以及 一种阳离子传导机械敏感(“拉伸激活”)通道 这些细胞。拟议的研究将朝着量化的方向发展 对这些和其他电导率的分析，并将包括一项检查 牙本质营养因子、神经源性因子和炎症因子的作用 与牙髓的生理或病理生理反应有关。 在初步研究中，L还发现了神经样非成牙本质细胞 外植体来源的牙髓细胞培养中的卫星细胞。具体来说， 培养的牙髓细胞含有电压门控的钠电导 运动学特性类似于神经胶质细胞或雪旺细胞、神经元 卫星细胞存在于外周和中枢神经系统中。 此外，牙髓细胞对通常标记的抗体有反应。 神经系统中的再生细胞以及发育中的牙髓细胞 在牙齿上。因此，这些培养物可能代表了损伤、恢复、 和/或牙髓中非成牙本质细胞的成熟。在紧张中 系统中，有人认为这种卫星细胞可能有助于 邻近初级传入的敏感化，通过改变 钠电流的密度、分布或动力学性质。因此， 拟议研究的第二个目标是确定 牙髓细胞钠电流可能在牙科疾病中具有类似的功能作用 纸浆，通过监测其生理和动力学性质，以及 下层钠离子通道的分布和密度 牙髓细胞培养的成熟。在这些实验中，培养物将被 用已知可诱导分化的药物治疗，例如生长因子， 地塞米松，或称DMSO，以及与 用抗钠单抗进行免疫组织化学研究 频道本身。

Understanding the physiological properties of odontoblasts is an important step towards understanding the cellular mechanisms that account for metabolic and transductive processes in dental pulp. Indirect evidence now suggests that such processes are mediated by alterations in transmembrane conductances via ion channels in the odontoblast membrane. Among the most critical of these ionic pathways are those that govern calcium turnover. Calcium regulation is especially important for odontoblast cells, since both intra- and extracellular calcium levels may fluctuate during dentinogenesis, and these cells may be directly involved in transporting calcium to the mineralizing matrix. In addition to mineralogenesis, odontoblast ion channels may also be involved in somatosensation, mediating changes in hydrostatic pressure and/or changes in the osmotic gradient produced by mechanical or hydrodynamic perturbation. The primary objective of the proposed research is to examine the ionic mechanisms underlying the response of these cells to factors associated with dentinogenesis and somatosensory transduction in dental pulp. In these studies I will use patch-clamp recording techniques to monitor single- channel and whole-cell current in the odontoblast membrane using both in vitro and in situ preparations of intact mammalian odontoblast cells. In preliminary studies I have identified an L-type calcium channel as well as a cation-conducting mechanosensitive ("stretch-activated") channel in these cells. The proposed studies will be directed towards a quantitative analysis of these and other conductances, and will include an examination of the effects of dentinotrophic, neurogenic, and inflammatory factors linked to physiological or pathophysiological responses in dental pulp. In preliminary studies l have also identified neural-like non-odontoblast satellite cells in explant-derived pulp cell cultures. Specifically, cultured pulp cells contained a voltage-gated sodium conductance with kinetic properties similar to those of glial or Schwann cells, neuronal satellite cells found in both the peripheral and central nervous systems. In addition, pulp cells were reactive to antibodies that typically label regenerating cells in the nervous system, as well as developing pulp cells in teeth. Thus, these cultures may represent a model for injury, recovery, and/or maturation of non-odontoblast cells in dental pulp. In the nervous system, it has been suggested that such satellite cells may contribute to sensitization of adjacent primary afferents, by alterations in the density, distribution or kinetic properties of it's sodium current. Thus, a second objective of the proposed research is to determine whether the pulp cell sodium current may have a similar functional role in dental pulp, by monitoring its physiological and kinetic properties, and the distribution and density of the underlying sodium channels during maturation of pulp cell cultures. In these experiments, cultures will be treated with agents known to induce differentiation, e.g., growth factors, dexamethasone, or DMSO, and patch-clamp recordings made in parallel with immunohistochemical studies using a monoclonal antibody to the sodium channel itself.