IONIC REGULATION OF SPERM BEHAVIOR

建议的研究将调查基本的生化机制，通过 精子调节其细胞内pH(Phi)以及通过什么生化作用 对受精很重要的过程受pH的调节。机制： 将被研究的PHI调节包括运行的Na+：H+交换 在细胞膜和呼吸酸的产生上 线粒体。细胞内pH对控制两种原生菌有重要意义 哺乳动物和无脊椎动物精子的准备过程 受精：代谢活动和顶体反应。世界上的精子 将海胆、紫海胆作为一个简单的模型系统。 实验将确定Na+：H+交换是否紧密耦合 需要能量，如果它是可逆的，如果它对Na+是选择性的。这个 线粒体的贡献将通过抑制来评估 呼吸和操纵phi。PHI监管的两个目标领域 来扩展我们对离子过程的理解 调节精子生化。首先，Phi之间的关系， 细胞内钙离子和环核苷酸将被检测，因为后者 两个细胞内信使也随着精子代谢的变化而发生变化 激活或顶体反应。此外，Na+：K+ATPase活性 将作为PHI和相关变化的函数进行研究。的功能 这种酶对细胞Na+的调节是必不可少的，因此对 Na+：H+交换。Na+：H+ATPase活性也维持正常细胞 K+梯度和膜电位在诱导后均崩塌 顶体反应。对这些离子的机理的理解 这些改变将提供有关精子功能的特定生物学知识 并与可能制定的避孕策略或 精子活力的保存。

Research proposed will investigate basic biochemical mechanisms by which sperm regulate their intracellular pH (pHi) and by which biochemical processes important to fertilization are regulated by pH. Mechanisms of pHi regulation to be investigated include a Na+:H+ exchange which operates at the cell plasma membrane and respiratory acid production by the mitochondria. Intracellular pH is important to the control of two primary processes which prepare both mammalian and invertebrate sperm for fertilization: metabolic activity and the acrosome reaction. Sperm of the sea urchin, S. purpuratus will be used as a simple model system. Experiments will determine if the Na+:H+ exchange is tightly coupled and requires energy, if it is reversible, and if it is selective for Na+. The contribution of the mitochondria will be evaluated by inhibiting respiration and manipulating pHi. Two target areas for regulation by pHi will be explored to extend our understanding of how ionic processes regulate sperm biochemistry. First, relationships between pHi, intracellular Ca++ and cyclic nucleotides will be examined since the latter two intracellular messengers also undergo changes with sperm metabolic activation or the acrosome reaction. Additionally, Na+:K+ ATPase activity will be studied as a function of pHi and related changes. The functions of this enzyme are essential to regulation of cell Na+ and therefore to the Na+:H+ exchange. Na+:H+ ATPase activity also maintains the normal cellular K+ gradient and membrane potential which both collapse upon induction of the acrosome reaction. Understanding of the mechanisms of these ionic alterations will provide specific biological knowledge about sperm function and is relevant to possible development of contraceptive strategies or preservation of sperm viability.