SECRETORY MECHANISMS IN THE SALIVARY GLANDS

这个项目的长期目标是阐明 唾液腺泡细胞的水和电解质分泌。这个秘密 反应与信号转导途径有关，该信号转导途径涉及 膜磷脂的周转、钙离子的动员 胞内和胞外隔膜与钙离子激活 对分泌至关重要的单价离子通量(K，C1)。我们的研究 在当前的赠款期间和其他国家的赠款期间， 这一途径中的复杂功能连接，其中一些只是部分 目前已被理解，可能会也可能不会在所有刺激下运行 促进唾液和电解质的分泌。信号的某些元素 此外，转导可能在唾液细胞中显示出独特的特征。我们的 因此，新赠款期间的总体目标是在更大程度上探索 详细说明唾液细胞信号中的这些功能关联。我们的 具体目标是：1)进一步研究三者之间的耦合 受体类型(胆碱能、α-肾上腺素能和P物质受体 和磷脂酰肌醇周转率。这种耦合是通过GTP绑定实现的 许多细胞中的蛋白质，但关于G蛋白的信息很少 唾液细胞中的偶联。我们将使用免疫沉淀，竞争性的 放射配基结合和生化方法鉴定特异性G 与每一种受体相关的蛋白质，2)表征 进一步探讨了钙离子储存和钙离子进入的功能特性 机制以及它们受每种类型的 刺激。我们将使用荧光分光光度、成像、同位素和x射线。 微探针分析技术评价心肌细胞内钙离子的变化 没有和存在激动剂和可以改变 动员内部或外部钙离子，3)进一步探索 K和C1电导之间的功能联系和可能的调控 因子包括[Ca~(2+)]I、G蛋白、蛋白激酶和cADP核糖。 我们将使用成像、荧光光谱、同位素和x射线衍射。 测定钾含量和跨膜通量变化的技术 和C1在接触各种激动剂和所列物质之后 上面。我们建议在控制唾液中比较这些不同的参数。 慢性用药大鼠细胞内腺泡细胞 (利血平、阿托品)改变受体功能，S如 初步发现，信号通路中的下游元件。这些 药物治疗导致唾液分泌减少，是有用的。 唾液功能减退的研究模型及其可能的关系 改变了信号通路的元件。口干症的主要原因之一 人类使用药物作为受体拮抗剂和我们的研究 将有助于我们理解或正常的唾液信号和 治疗药物是如何影响它的。

The long-term objective of this project is to elucidate the mechanisms of water and electrolyte secretion in salivary acinar cells. This secretory response is associated with a signal transduction pathway that involves the turnover of membrane phosphoinositides, the mobilization of Ca2+ from intracellular and extracellular compartments and the activation by Ca2+ of monovalent ion fluxes (K, C1) that are critical for secretion. Our studies during the current grant period and those of others have demonstrated complex functional links in this pathway, some of which are only partially understood at present and may or may not operate with all stimuli that enhance salivary fluid and electrolyte secretion. Some elements of signal transduction may show, furthermore, unique features in salivary cells. Our general goal for the new grant period is, therefore, to explore in greater detail these functional associations in salivary cell signaling. Our specific aims are: 1) to investigate further the coupling between three types of receptors (cholinergic, alpha-adrenergic and substance P receptors and phosphoinositide turnover. This coupling occurs by GTP binding proteins in many cells but little information is available about G protein coupling in salivary cells. We will use immunoprecipitation, competitive radioligand binding and biochemical methods to identify the specific G proteins associated with each one of these receptors, 2) to characterize further the functional properties of Ca2+ storage sties and Ca2+ entry mechanisms and the manner in which they are affected by each type of stimulus. We will use spectrofluorimetric, imaging, isotopic and x-ray microprobe analysis techniques to evaluate changes in cell Ca2+ in the absence and presence of agonists and of substances that can modify the mobilization of internal or external Ca2+, 3) to explore further the functional link between K and C1 conductances and possible regulatory factors, including [Ca2+]i, G proteins, protein kinases and cADP ribose. We will use imaging, spectrofluorimetric, isotopic and x-ray diffraction techniques to measure changes in the content and transmembrane fluxes of K and C1 after exposure to the various agonists and of the substances listed above. We propose to compare these various parameters in control salivary acinar cells an in cells derived from rats treated chronically with drugs (reserpine, atropine) that modify receptor functions and, s shown in preliminary findings, downstream elements in the signaling pathway. These drug treatments cause reduced salivary secretion of fluid and are useful models for the study of salivary hypofunction and its possible relation to altered elements of the signaling pathway. A major cause of xerostomia in humans is the use of drugs acting as receptor antagonist and our studies would contribute to our understanding or normal salivary signaling and of how it may be affected by therapeutic agents.