MECHANISM OF NA+-DEPENDENT METABOLITE TRANSPORT

NA依赖性代谢物转运机制

• 批准号: 3225381
• 负责人: GEORGE A KIMMICH
• 金额: $ 15.35万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-03-01 至 1992-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3225381
• 关键词: Aves; adenosine triphosphate; aminoacid transport; bioenergetics; carbohydrate sequence; carbohydrate transport; chick embryo; electrophysiology; gastrointestinal epithelium; ion transport; mathematical model; membrane model; membrane permeability; membrane potentials; nonelectrolyte transport; radiotracer; tissue /cell culture

This proposal is aimed at the development of new methodology for rapid noninvasive measurement of cellular membrane potentials and use of these methods to characterize the Delta Psi dependence of a variety of plasma membrane related transport events. Isolated intestinal epithelial cells prepared from chickens will continue to be the primary model experimental system. The work described falls in three broad categories: 1) establishment of the relationship between unidirectional influx of tetraphenylphosphonium (TPP+) and Delta Psi for use as a calibration curve in defining unknown membrane potentials, 2) a systematic study of the quantitative relationship between Delta Psi and Na+-dependent sugar or amino acid transport processes, and 3) identification of the cellular "signals" and mode of action of those agents which are important in allowing intestinal tissue to convert from its normal absorptive functional state for salt and water to a secretory state resulting in the symptoms of diarrhea. The Delta Psi-sugar transport relationships will be used to discriminate between transport models involving Delta Psi-dependent translocation vs. Delta Psi-dependent Na+ binding events as a means of evaluating a "Na+-well" conceptual model which has not yet been tested experimentally. The possibility that Na+-dependent transport systems can be used as intrinsic sensors for noninvasive quantitative measurement of membrane potentials will also be evaluated. Finally, the methods established will be applied to a characterization of the specific ion flux pathways altered in activity by Ca++, cAMP, and certain hormones or drugs with particular emphasis on correlating changes in cellular transport activity with concomitant changes in the appropriate "signal" molecule or ion. The endeavor offers an opportunity for providing some of the first mechanistic insight to the quantitative role which membrane potentials play in driving Na+-dependent transport systems as well as insight to the mechanisms by which the intestinal epithelium converts from absorptive to secretory activity for salt and water and the regulation of the ion transport pathways involved. This insight carries significant clinical ramifications because of the enormous impact diarrheal diseases have as world-wide health problems.

该提案旨在开发新的方法来快速 细胞膜电位的无创测量及其应用 表征各种等离子体的 Delta Psi 依赖性的方法 膜相关的转运事件。 分离的肠上皮细胞 由鸡制备的仍将是主要的实验模型 系统。 所描述的工作分为三大类：1) 建立单向流入之间的关系 四苯基磷 (TPP+) 和 Delta Psi 用作校准曲线 在定义未知的膜电位时，2）对 Delta Psi 与 Na+ 依赖性糖之间的定量关系或 氨基酸转运过程，以及 3) 细胞鉴定 那些重要的“信号”和作用方式 允许肠道组织从其正常的吸收功能转变 盐和水进入分泌状态，导致以下症状 腹泻。 Delta Psi-糖运输关系将用于 区分涉及 Delta Psi 相关的传输模型 易位与 Delta Psi 依赖的 Na+ 结合事件作为一种手段 评估尚未经过测试的“Na+-well”概念模型 实验性地。 Na+ 依赖性运输系统的可能性 用作内部传感器，用于无创定量测量 膜电位也将被评估。 最后，方法 建立的将应用于特定离子通量的表征 Ca++、cAMP 和某些激素或药物改变活性的途径 特别强调细胞运输的相关变化 活性伴随适当“信号”分子的变化或 离子。 这项努力提供了一个机会，提供一些第一批 对膜电位所起的定量作用的机制洞察 驱动 Na+ 依赖的运输系统以及对 肠上皮从吸收性转变为吸收性的机制 盐和水的分泌活性以及离子的调节 涉及的运输途径。 这一见解具有重要的临床意义 由于腹泻疾病的巨大影响而产生的后果 世界范围的健康问题。