Crozet N
INRA, Unité de biologie de la fécondation, Jouy-en-Josas.
Contracept Fertil Sex. 1994 May;22(5):328-30.
The acrosome reaction that occurs after sperm capacitation, is an exocytotic event induced by a Ca++ influx. It plays an essential role during fertilization, by making spermatozoa able of penetrating the zona and capable of fusing with the egg plasma membrane. Zona pellucida is the natural inducer of the acrosome reaction. Binding of the sperm receptor to ZP3, a zona glycoprotein acting as ligand, triggers the molecular events leading to acrosomal exocytosis. G-proteins may be involved in the signal-transduction pathway during the acrosome reaction. Other known inducers of the human acrosome reaction include follicular fluid, progesterone and the calcium ionophore A23187. Progesterone acts through a receptor on the sperm plasma membrane, while the ionophore promotes non-physiological sperm Ca++ uptake. Several cytochemical procedures have been proposed for evaluating the acrosome reaction: the acrosomal status can be observed after staining or after labeling with lectins or antibodies. These methods both attempt to evaluate sperm viability and to distinguish degenerative acrosomal loss.
精子获能后发生的顶体反应是由钙离子内流诱导的胞吐事件。它在受精过程中起着至关重要的作用，使精子能够穿透透明带并与卵质膜融合。透明带是顶体反应的天然诱导剂。精子受体与作为配体的透明带糖蛋白ZP3结合，触发导致顶体胞吐的分子事件。G蛋白可能参与顶体反应期间的信号转导途径。其他已知的人类顶体反应诱导剂包括卵泡液、孕酮和钙离子载体A23187。孕酮通过精子质膜上的受体起作用，而离子载体促进非生理性的精子钙离子摄取。已经提出了几种细胞化学方法来评估顶体反应：染色后或用凝集素或抗体标记后可以观察顶体状态。这些方法都试图评估精子活力并区分退行性顶体丢失。
