SECRETORY MECHANISMS IN THE SALIVARY GLANDS

唾液腺的分泌机制

基本信息

批准号：
2130485
负责人：
J. Ricardo Martinez
金额：
$ 18.48万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
1989
资助国家：
美国
起止时间：
1989-07-01 至 2000-02-29
项目状态：
已结题

项目摘要

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.

该项目的长期目标是阐明唾液腺细胞中的水和电解质分泌。这个分泌响应与涉及的信号转导途径有关膜磷酸肌醇的营业额，Ca2+的动员细胞内和细胞外隔室以及Ca2+的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和其他赠款期间该路径中的复杂功能链接，其中一些仅部分是部分目前理解，并且可能会或可能不会用所有刺激进行操作增强唾液液和电解质分泌。信号的某些元素此外，转导可能显示唾液细胞中的独特特征。我们的因此，新赠款期的一般目标是更大的探索详细说明唾液细胞信号传导中的这些功能关联。我们的具体目的是：1）进一步研究三个受体类型（胆碱能，α-肾上腺素和物质P受体和磷酸肌醇更新。这种耦合是通过GTP绑定而发生的许多细胞中的蛋白质，但几乎没有有关G蛋白的信息唾液细胞中的耦合。我们将使用免疫沉淀，竞争性放射素结合和生化方法以识别特定的G 与这些受体中的每一个相关的蛋白质，2）表征此外，CA2+存储的功能属性和Ca2+进入机制及其受每种类型影响的方式刺激。我们将使用光谱荧光，成像，同位素和X射线微探针分析技术以评估细胞Ca2+的变化激动剂的不存在和存在可以改变的物质动员内部或外部Ca2+，3）进一步探索 K和C1电导与可能的调节之间的功能联系因素，包括[Ca2+] I，G蛋白，蛋白激酶和CADP核糖。我们将使用成像，光谱荧光，同位素和X射线衍射测量k含量和跨膜通量变化的技术和C1暴露于各种激动剂和列出的物质后多于。我们建议在控制唾液中比较这些各种参数腺泡细胞A中的细胞中衍生出的大鼠用药物慢性治疗（RESERPINE，ATROPINE）修改受体功能，并显示在初步发现，信号通路中的下游元素。这些药物治疗导致液体的唾液分泌减少，很有用研究唾液功能障碍的模型及其可能与信号通路的元素变化。静脉内鼠的主要原因人类是用作受体拮抗剂的药物，我们的研究将有助于我们的理解或正常的唾液信号和它如何受到治疗剂的影响。