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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

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