IONIC MEDIATORS & METAREGULATIONS IN SPERM CAPACITATION

离子介体

基本信息

批准号：
3322966
负责人：
Donner F Babcock
金额：
$ 17.75万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
1986
资助国家：
美国
起止时间：
1986-08-01 至 1994-02-28
项目状态：
已结题

项目摘要

The long range goals of this project are to elucidate the metaregulatory mechanisms that maintain the resting internal ionic mileau of sperm and alter it in response to those instructive signals that coordinate sperm capacitation (the obligatory, terminal maturational sequence that prepares sperm for fertilization). The more complete understanding of the processes that control crucial cellular functions in sperm, gained from these studies, will allow more selective and effective intervention in the palliative sense required for some clinical infertility and the preventative sense required for sperm-directed antifertility measures. The specific aims of this project are: to determine the mechanisms that function in maintaining resting internal. [Ca++] and pH in sperm (with particular attention to anion [Cl-] and cation [Ca++,K+] channels and to Na+/H+ and Na+/Ca++exchange activities); to depict the temporal and spatial relationships of the elevations of pHi and Cai associated with the zona-induced acrosome reaction; to describe the ion channels, exchangers or pumps operating in these agonist-induced ionic alterations; to delineate the electrophysiological characteristics of sperm membrane ion channels; to define the role of GTP binding regulatory proteins (G proteins) in these processes; to demonstrate the function of a peptide component of seminal plasma that possibly modulates these actions of G proteins. Some powerful new tools are available for achievement of these goals. A variety of fluorescent probes now provide continous, sensitive and specific means for determination and monitoring of intracellular pH, [Ca++],[Cl-] and [Na+] and membrane potential of intact sperm. Video fluorescence imaging allows examinations of individual cells and of changes within localized subcellular compartments. Electrical recordings from mixed proteolipid membranes provide direct measure of single channel conductances and determination of the ion selectivity, voltage dependence, of individual ion channels (or exchangers) and the actions of their modulatory effectors. By a coordinated application of these biophysical and biochemical methods we will more completely describe the bases of homeostasis and metaregulatory control in experiments that identify and systematically examine requirements for operation of molecular components and by examination of their responses to a physiological agonist of mammalian sperm exocytosis and a peptide component of sperm with putative modulatory effector activity.

该项目的长期目标是阐明元监管维持精子静息内部离子环境的机制改变它以响应那些协调精子的指导信号获能（必须的、终末成熟序列，准备精子用于受精）。对流程有更全面的了解控制精子中关键的细胞功能，从这些中获得研究，将允许更有选择性和有效的干预某些临床不孕症所需的姑息治疗和针对精子的抗生育措施所需的预防意识。这该项目的具体目标是：确定机制维持内部休息的功能。精子中的 [Ca++] 和 pH（特别注意阴离子 [Cl-] 和阳离子 [Ca++,K+] 通道并进行 Na+/H+ 和 Na+/Ca++ 交换活动）；到描述 pHi 和 pHi 海拔高度的时间和空间关系 Cai 与透明带诱导的顶体反应有关；描述离子在这些激动剂诱导的离子中运行的通道、交换器或泵变更；描绘精子的电生理特征膜离子通道；定义 GTP 结合监管的作用这些过程中的蛋白质（G蛋白）；演示a的功能精浆的肽成分可能调节这些作用 G蛋白。一些强大的新工具可用于实现这些目标。各种荧光探针现在提供连续、用于测定和监测的敏感且具体的方法细胞内 pH、[Ca++]、[Cl-] 和 [Na+] 以及完整膜电位精子。视频荧光成像可以检查单个细胞以及局部亚细胞区室内的变化。电气混合蛋白脂质膜的记录提供了直接测量单通道电导和离子选择性的测定，电压依赖性，各个离子通道（或交换器）和它们的调节效应器的作用。通过协调应用我们将更完整地描述这些生物物理和生化方法实验中稳态和元调节控制的基础识别并系统地检查分子操作的要求成分并通过检查它们对生理激动剂的反应哺乳动物精子胞吐作用和精子的肽成分假定的调节效应子活性。