Fléchon J E
Am J Anat. 1985 Nov;174(3):239-48. doi: 10.1002/aja.1001740306.
The mammalian acrosome reaction is an exocytotic process that can be analyzed by the technique of freeze-fracture; only sperm cells capacitated in vitro or treated to elicit the acrosome reaction in vitro have been studied, and all pictures published are from material fixed before freezing. All the authors point out the appearance of particle-free areas in the plasma membrane of the acrosomal region during capacitation and before any fusion. This is interpreted as an increase in membrane fluidity as suggested by studies on membrane lipid composition in guinea-pig sperm. We have recently described the induced acrosome reaction in ram spermatozoa. Fusion starts at the limit of the anterior and equatorial segments and progresses forward in the anterior segment along ramified paths, resulting in a fenestration gradient of the acrosomal cap. Fusion propagation may be controlled by fluidity increase in the plasma membrane of the anterior segment, and it is probably inhibited in the equatorial segment by the ordered structure of the acrosomal membrane.
哺乳动物的顶体反应是一种胞吐过程，可通过冷冻断裂技术进行分析；此前仅对体外获能或经处理以在体外引发顶体反应的精子细胞进行过研究，且所有已发表的图片均来自冷冻前固定的材料。所有作者都指出，在获能过程中以及任何融合发生之前，顶体区域质膜上会出现无颗粒区域。如对豚鼠精子膜脂质组成的研究所表明的，这被解释为膜流动性的增加。我们最近描述了在公羊精子中诱导的顶体反应。融合始于前段和赤道段的交界处，并在前段沿分支路径向前推进，导致顶体帽出现窗孔梯度。融合的传播可能受前段质膜流动性增加的控制，而在赤道段可能因顶体膜的有序结构而受到抑制。
