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.

该项目的远距离目标是阐明元调节维持精子和精子内部离子米的机制根据那些协调精子的指导性信号来改变它电容（强制性的终末成熟序列精子用于受精）。对流程的更完整的理解控制精子中至关重要的细胞功能，从中获得研究将使对某些临床不孕症和精子指导的抗毒性措施所需的预防性意义。这该项目的具体目的是：确定机制在维护内部静止的功能。精子中的[Ca ++]和pH（特别注意阴离子[Cl-]和阳离子 [Ca ++，K+]通道以及Na+/H+和Na+/Ca ++交换活动）；到描述PHI高程的时间和空间关系 CAI与Zona引起的Adrosom反应相关；描述离子在这些激动剂引起的离子中运行的通道，交换器或泵改变；描述精子的电生理特征膜离子通道；定义GTP结合调节的作用在这些过程中的蛋白质（G蛋白）；演示一个功能精确等离子体的肽成分，可能调节这些动作 G蛋白。一些强大的新工具可用于实现这些目标。现在各种荧光探针提供连续的，确定和监测的敏感和特定手段细胞内pH，[Ca ++]，[Cl-]和[Na+]以及完整的膜电位精子。视频荧光成像允许检查单个细胞以及局部亚细胞室内的变化。电气混合蛋白脂质膜的记录提供了直接衡量的单个通道电导和离子选择性的确定电压依赖性，单个离子通道（或交换器）和其调节效应子的作用。通过协调的应用这些生物物理和生化方法我们将更加完整地描述在实验中的体内平衡和元调节控制的基础识别并系统地检查分子运行的要求组件和通过检查其对生理激动剂的反应哺乳动物的精子胞吐作用和精子的肽成分推定的调节效应子活性。