SECRETORY MECHANISMS IN THE SALIVARY GLANDS

唾液腺的分泌机制

• 批准号: 3223085
• 负责人: J. Ricardo Martinez
• 金额: $ 16.62万
• 依托单位: LOVELACE RESPIRATORY RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 1993-08-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3223085
• 关键词: acinar cell; adenosinetriphosphatase; calcium; chlorine; cyclic AMP; cyclic GMP; forskolin; furosemide; ion transport; ionophores; laboratory rat; macromolecule; membrane transport proteins; nitroferricyanide; ouabain; potassium; radionuclides; salivary glands; secretion; sodium; tritium

The long-term, overall objective of this project is to elucidate the mechanisms underlying the secretion of saliva and of its two major fractions, the water/electrolyte and macromolecular fractions. The more immediate goal of the studies described in this proposal is to characterize the ion transport systems which are involved in the formation of the fluid/electrolyte fraction of primary or precursor saliva by acinar cells. The proposed studies are based on previous evidence indicating that salivary fluid originates primarily in these cells and that its secretion is inhibited by ouabain and by furosemide. A model of the ionic mechanism of salivary fluid secretion is proposed, involving, as a first step, a Na-coupled, furosemide-sensitive Cl-entry into the cells, which is driven by the Na gradient generated by an ouabain-sensitive Na, K pump. We propose to use, therefore, dispersed acini isolated from the rat submandibular gland to investigate the presence and activation of these two transport systems. The specific aims are to measure: 1) furosemide-sensitive fluxes of Na-22 and Cl-36. Both isotope exchange and net fluxes will be measured before and after exposure to cholinergic and adrenergic agents. The effects of ouabain, of changes in the ionic composition (Na, C1, K, Ca) of the incubation medium, of the Ca++ ionophore A23187, of exogenous derivatives of cAMP and cGMP and of substances which alter cell nucleotide content (such as forskolin and Na nitroprusside) will also be investigated. 2) The rate of binding of H-3 ouabain. The time required for half maximal and maximal binding, association, dissociation and equilibrium dissociation (KD) constants and density of binding sites (Bmax) will be measured under the same experimental conditions indicated for isotope fluxes. 3) Ouabain-sensitive Rb-86 uptake. Rates of uptake will be measured in the same experimental conditions as H-3-ouabain binding. The results of these studies should provide more direct evidence for the presence and activation of two ion transport systems involved in the secretion of fluid and electrolytes by salivary acinar cells and contribute to our understanding of the mechanisms of saliva formation.

该项目的长期总体目标是阐明 唾液及其两个主要的分泌的机制 馏分，水/电解质和大分子分数。 更多 该提案中描述的研究的直接目标是表征 与形成有关的离子运输系统 腺泡细胞对原代或前体唾液的流体/电解质分数。 拟议的研究基于以前的证据，表明 唾液流体主要起源于这些细胞，其分泌 乌巴因和速尿会抑制。 离子机制的模型 提出了唾液液分泌的，涉及第一步 NA耦合，对速尿敏感的Cl-进入细胞，该细胞是驱动的 由瓦巴因敏感的Na，K泵产生的Na梯度。 我们 因此，建议使用从大鼠中分离出的acini 下颌腺研究这两个的存在和激活 运输系统。 具体目的是衡量：1） Na-22和Cl-36的速尿敏感通量。 同位素交换和 净通量将在暴露于胆碱能之前和之后测量 肾上腺素能剂。 乌巴因的影响，离子变化 Ca ++离子载体的孵育培养基的组成（Na，C1，K，Ca） A23187，cAMP和CGMP的外源衍生物以及物质的物质 改变细胞核苷酸含量（例如福斯科林和NA硝普雷塞德）将会 也可以调查。 2）H-3 ouabain的结合速率。 时间 最大和最大结合，关联，解离需要 和平衡分离（KD）常数和结合位点的密度 （BMAX）将在相同的实验条件下进行测量 对于同位素通量。 3）对瓦巴因敏感的RB-86吸收。 吸收率 将在与H-3-ouabain相同的实验条件下测量 结合。 这些研究的结果应提供更直接的证据 为了存在和激活两个参与的离子传输系统 唾液腺泡细胞和电解质的分泌 有助于我们对唾液形成机制的理解。