Membrane potential, pH and the activation of surf clam oocytes

Wiley - Tập 3 Số 3 - Trang 299-304 - 1980
Toren Finkel1, Don P. Wolf1
1Division of Reproductive Biology, Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia, and The Marine Biological Laboratory Woods Hole, Massachusetts

Tóm tắt

AbstractUnfertilized oocytes of the surf clam, Spisula solidissima, have resting membrane potentials of −18 ± 7 mV (n = 20). Within five seconds of sperm addition, an electrophysiologically detectable response was apparent, which was characterized by a rapid and prolonged depolarrization depolarization followed four to five minutes post‐insemination by the beginning of the beginning of a steady hyperpolarization to approximatelv −70 mV. This final hyperpolarization was completed within ten minutes of sperm addition. The initial rapid depolarization following insemination may result from a transient increase in sodium conductance, and it may be crucial in preventing polyspermy, since the degree of polyspermy in Spisula oocytes was sensitive to external sodium ion concentrations. Evidence was obtained that changes in intracellular pH are essential for oocvte activation. Using germinal vesical breakdown (GVB) as a marker for activation, it was shown that agents that raise intracellular pH (ammonia and procaine) induced GVB, whereas agents that lower intracellular pH pH (Na‐acetate or Na‐propionate seawater) inhibited GVB.

Từ khóa


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Thông tin xuất bản

Wiley

Tập 3 Số 3

299-304

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