SPERM-EGG INTERACTION: EXCITATION-ACTIVATION COUPLING

受精包括两个阶段：(1)激发(转导 从精子到卵子的信号)，以及(2)激活(爆炸性释放 钙离子和三磷酸肌醇水平的升高)，这触发了 发育的开始。引起激励的步骤和联系在一起的步骤 激发到激活是未知的。长期目标是 确定精子诱导兴奋的机制和 在脑电活动中兴奋与激活的耦合。以下将是 确定：(1)。Na+、K+、H+和Ca+离子在多大程度上 负责激励和激活过程中的膜电流。 系统离子取代引起的反转电势的移动 电生理监测将使我们能够确定 每个离子的相对渗透率。(2)。Na+，K+，H+， 钙离子影响激发和/或激发的耦合。 激活。激励、激活和电压依赖关系的变化 由系统性离子替代引起的精子进入将使我们能够精确定位 特别影响这些事件的离子。(3)。不管是不是 精子-卵子融合事件发生在激活甚至激发之前。膜 核聚变可以使兴奋性分子从 精子到卵子的细胞质。将使用三种方法，即， 荧光标记在配子之间的转移；膜片钳 电容测量和连续切片的电子显微镜 改进方法。(4)精子表面配体-卵子受体 相互作用有助于激发卵子。Bindin，这个物种 特定的精子-卵子黏附蛋白以及其他精子成分 将检查它们是否有能力引起相同的电导变化 在激发过程中观察到的。拟议的研究最终可能提供 设计新避孕药的基本信息或 了解某些类型的不孕症。这项研究是定向的 为了了解是什么导致静止的细胞经历激活， 细胞分裂和生长，因此可能与癌症的发生有关。一个 电生理学(膜电位、电阻和 电容测量、电流和电压钳位分析以及贴片 夹持技术)、图像处理方法、微注射和电子 将使用显微镜。

Fertilization involves two phases: (1) excitation (transduction of a signal from the sperm to the egg), and (2) activation (explosive release of Ca2+ and elevation of inositol triphosphate levels), which triggers the onset of development. The steps causing excitation and those which link excitation to activation are not known. Long term objectives are to determine the mechanism underlying sperm-induced excitation and the coupling of excitation to activation in the egg. The following will be determined: (1). the extent to which Na+, K+, H+ and Ca 2+ ions are responsible for the membrane currents during excitation and activation. Shifts of the reversal potentials caused by systematic ion substitutions and monitored electrophysiologically will allow us to determine the relative permeability for each ion. (2). the extent to which Na+, K+, H+, Ca 2+ ions affect excitation and/or the coupling of excitation to activation. Shifts in the voltage dependence of excitation, activation and sperm entry caused by systematic ion substitution will allow us to pinpoint ions which specifically affect these events. (3). Whether or not the sperm-egg fusion event precedes activation or even excitation. Membrane fusion may permit the diffusion of an excitatory molecule from the cytoplasm of the sperm to the egg. Three methods, will be used, namely, transfer of fluorescent markers between the gametes; patch clamp capacitance measurements; and electron microscopy of serial sections using improved methods. (4) Whether or not a sperm surface ligand-egg receptor interaction contributes to excitation of the egg. Bindin, the species specific, sperm-egg adhesive protein, as well as other sperm components will be examined for their ability to cause the same conductance changes as observed during excitation. The proposed research could ultimately provide information basic to the design of new contraceptive agents or to the understanding of certain types of infertility. The research is directed toward understanding what causes a quiescent cell to undergo activation, cell division and growth, and thus may be related to carcinogenesis. A combination of electrophysiology (membrane potential, resistance, and capacitance measurements, current and voltage clamp analysis, and patch clamp techniques), image processing methods, microinjection, and electron microscopy will be used.