SPERM-EGG INTERACTION--EXCITATION-ACTIVATION COUPLING

受精包括两个阶段：（1）兴奋（一个信号的传导）， 从精子到卵子的信号），和（2）激活（爆炸性释放 Ca 2+和三磷酸肌醇水平升高），这会触发 发展的开始。 引起兴奋的步骤和那些连接 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， 兴奋与激活的耦合。 以下人员 确定：（1）. Na+、K+、H+和Ca 2+离子在体内的分布程度 负责兴奋和激活期间的膜电流。 系统离子置换引起的反转电位漂移 和电生理监测将使我们能够确定 每个离子的相对渗透率。 （二）、 Na+，K+，H+， Ca 2+离子影响激发和/或激发与 activation. 在电压依赖性的激发，激活和 系统性离子置换导致的精子进入将使我们能够确定 这些离子会对这些事件产生特殊影响。 （三）、大是大非面前是否 精子-卵子融合事件先于激活或甚至激发。膜 融合可以允许兴奋性分子从细胞中扩散， 精子的细胞质到卵子。将使用三种方法，即， 荧光标记在配子间的转移;膜片钳 电容测量;和电子显微镜的连续切片， 改进方法。 (4)精子表面配体-卵子受体 相互作用有助于卵的激发。Bindin，物种 特异性精卵粘附蛋白以及其它精子成分 将检查它们引起相同电导变化的能力， 在激发过程中观察到。 拟议的研究最终可以提供 设计新的避孕药或 了解某些类型的不孕症。 该研究旨在 为了理解是什么导致静止细胞经历激活， 细胞分裂和生长，因此可能与致癌作用有关。 一 电生理学（膜电位、电阻和 电容测量、电流钳和电压钳分析以及贴片 钳位技术）、图像处理方法、显微注射和电子显微镜。 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.