The Journal of Cell Biology, Vol 82, 426-440, Copyright © 1979 by The Rockefeller University Press

ARTICLES

Electrically mediated fast polyspermy block in eggs of the marine worm, Urechis caupo

M Gould-Somero, LA Jaffe and LZ Holland

Previous work has established that the polyspermy block in Urechis acts at the level of sperm-egg membrane fusion. (J. Exp. Zool. 196:105). Present results indicate that during the first 5--10 min after insemination the block is mediated by a positive shift in membrane potential (the fertilization potential) elicited by the penetrating sperm, since holding the membrane potential of the unfertilized egg positive by passing current reduces the probability of sperm entry, while progressively reducing the amplitude of the fertilization potential by decreasing external Na+ progressively enhances multiple sperm penetrations. Also, a normal fertilization potential is correlated with a polyspermy block even under conditions (pH 7) in which eggs do not develop. We have investigated the mechanism of the electrical polyspermy block by quantifying the relationship between sperm incorporation, membrane potential and ion fluxes. Results indicate that the polyspermy block is mediated by the electrial change per se and not by the associated fluxes of Na+, Ca++, and H+.
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This article has been cited by other articles:

• TAKAHASHI, K., OKAMURA, Y. (1998). Ion Channels and Early Development of Neural Cells. Physiol. Rev. 78: 307-337 [Abstract] [Full Text]  
• Kupitz, Y, Atlas, D (1993). A putative ATP-activated Na+ channel involved in sperm-induced fertilization. Science 261: 484-486 [Abstract]  
• Gould, M, Stephano, J. (1987). Electrical responses of eggs to acrosomal protein similar to those induced by sperm. Science 235: 1654-1656 [Abstract]  

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