Hostname: page-component-848d4c4894-x24gv Total loading time: 0 Render date: 2024-05-31T23:58:46.128Z Has data issue: false hasContentIssue false

Non-specific currents at fertilisation in sea urchin oocytes

Published online by Cambridge University Press:  15 January 2010

Maria Laura De Simone
Affiliation:
Stazione Zoologica and Università ‘Federico II’, Naples, Italy
Lucia Grumetto
Affiliation:
Stazione Zoologica and Università ‘Federico II’, Naples, Italy
Elisabetta Tosti
Affiliation:
Stazione Zoologica and Università ‘Federico II’, Naples, Italy
Martin Wilding
Affiliation:
Stazione Zoologica and Università ‘Federico II’, Naples, Italy
Brian Dale*
Affiliation:
Stazione Zoologica and Università ‘Federico II’, Naples, Italy
*
Brian Dale, Stazione Zoologica, Villa Comunale, 1, 80121 Naples, Italy. Telephone: +39-81-583-3233. Fax: +39-81-583-3260. e-mail: bdale@alpha.szn.it.

Summary

Using the whole-cell voltage-clamp technique to clamp sea urchin oocytes we show that the fertilising spermatozoon triggers an inward current of −521 ± 56.7 pA (n = 8) at activation. Simultaneously, the plasma membrane depolarises and the conductance increases from 23.4 ± 1.4 to 40.6 ± 1.2 nS (n = 8). The I/V curve for the peak activation current is linear and the current reverses between 0 and + 20 mV, suggesting a non-specific ion current. Since injection of inositol triphosphate induced an inward current of −1062 ± 314 pA (n = 4), and the current was inhibited by preloading oocytes with the calcium chelator BAPTA, the non-specific activation current in sea urchin appears to be calcium dependent.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Chambers, E.L. (1989). Fertilization in voltage clamped sea urchin eggs. In Mechanisms of Egg Activation, ed. Nuccitelli, R., Cherr, G. & Clark, W.H.. New York: Plenum Press.Google Scholar
Dale, B. (1983). Fertilization in Animals. London: Edward Arnold.Google Scholar
Dale, B. (1987). Fertilization channels in ascidian eggs are not activated by calcium. Exp. Cell Res. 172, 474–80.Google Scholar
Dale, B. & De Felice, L.J. (1984). Sperm activated channels in ascidian oocytes. Dev. Biol. 101, 235–9.CrossRefGoogle ScholarPubMed
Dale, B. & De Felice, L.J. (1990). Soluble sperm factors, electrical events and egg activation. In Mechanism of Fertilization, ed. Dale, B.. NATO ASI series vol. H45. Berlin: Springer.Google Scholar
Dale, B., De Felice, L.J. & Taglietti, V. (1978). Membrane noise and conductance increase during single spermatozoonegg interactions. Nature 275, 217–19.CrossRefGoogle ScholarPubMed
Dale, B., Fortunato, A., Monfrecola, V. & Tosti, E. (1996). A soluble sperm factor gates Ca2+-activated channels in human oocytes. J. Assist. Repród. Genet. 13, 573–7.CrossRefGoogle Scholar
David, C., Halliwell, J. & Whitaker, M. (1988). Some properties of the membrane currents underlying the fertilization potential in sea urchin eggs. J. Physiol. (lond.) 402, 139–54.Google Scholar
De Felice, L.J. & Kell, M.J. (1987). Sperm-activated currents in ascidian oocytes. Dev. Biol. 119, 123–8.CrossRefGoogle ScholarPubMed
Gianaroli, L., Tosti, E., Magli, M.C., Iaccarino, M., Ferraretti, A.P. & Dale, B. (1994). Fertilization current in the human oocyte. Mol. Repród. Dev. 38, 209–14.Google Scholar
Kline, D. & Nuccitelli, R. (1985). The wave of activation current in the Xenopus egg. Dev. Biol. 111, 471–87.Google Scholar
McCulloh, D.H. & Chambers, E.L. (1992). Fusion of membranes during fertilization, J. Gen. Physiol. 99, 137–75.CrossRefGoogle ScholarPubMed
Miyazaki, S. (1993). Fertilization potential and calcium transient in mammalian eggs. Dev. Growth Differ. 30, 603–10.Google Scholar
Miyazaki, S. & Igusa, Y. (1981). Fertilization potential in golden hamster eggs consists of recurring hyperpolarization. Nature 290, 706–7.CrossRefGoogle Scholar
Pecorella, C., Tosti, E., Kyozuka, K. & Dale, B. (1993). Activation current, sperm entry and surface contractions in ascidian eggs. Zygote 1, 113–19.CrossRefGoogle ScholarPubMed
Peters, R. & Richter, H.P. (1981). Translational diffusion in the plasma membrane of sea urchin eggs. Dev. Biol. 86, 285–93.Google Scholar
Whitaker, M.J. & Steinhardt, R.A. (1982). Ionic regulation of egg activation. Q. Rev. Biophys. 15, 593666.Google Scholar
Whitaker, M.J. & Irvine, R.F. (1984). Inositol 1,4,5-trisphosphate microinjection activates sea urchin eggs. Nature 312, 636–9.CrossRefGoogle Scholar