Department of Biomedical Sciences, Cornell University, Ithaca, New York, USA.
Biol Reprod. 2010 Oct;83(4):507-13. doi: 10.1095/biolreprod.109.083113. Epub 2010 May 12.
Hyperactivation, a motility pattern of mammalian sperm in the oviduct, is essential to fertilization. Hyperactivation helps sperm to swim effectively through oviductal mucus, to escape from the sperm reservoir, and to penetrate the cumulus matrix and zona pellucida of the oocyte. There is some evidence that mammalian sperm can undergo chemotaxis; however, the relationship of chemotaxis to hyperactivation is unknown. Ca(2+) signaling is involved in hyperactivation and implicated in chemotaxis as well. In vivo, sperm hyperactivate in the lower oviduct, far from the cumulus-oocyte complex and possibly beyond the influence of chemotactic gradients emanating from the oocyte or cumulus. Thus, sperm are likely to be hyperactivated before sensing chemotactic gradients. Chemotactic signals might modulate hyperactivation to direct sperm toward oocytes as they reach a region of influence. Ca(2+)-directed modulation of hyperactivation is a potential mechanism of this process.
超激活是哺乳动物精子在输卵管中的一种运动模式，对受精至关重要。超激活有助于精子有效地穿过输卵管黏液，从精子库中逃脱，并穿透卵母细胞的卵丘基质和透明带。有证据表明哺乳动物精子可以进行趋化性；然而，趋化性与超激活的关系尚不清楚。钙离子信号参与超激活，并与趋化性有关。在体内，精子在下输卵管中发生超激活，远离卵丘-卵母细胞复合物，可能超出了来自卵母细胞或卵丘的趋化梯度的影响。因此，精子在感知趋化梯度之前可能已经超激活。趋化信号可能调节超激活，将精子引导向卵母细胞，因为它们到达影响区域。钙离子指导的超激活调节是这个过程的一个潜在机制。
