Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Multiple activation currents can be evoked in Xenopus laevis eggs when cortical granule exocytosis is inhibited by weak bases.
Charbonneau M
,
Webb DJ
.
???displayArticle.abstract???
The fertilization potential in Xenopus eggs under normal circumstances is considered to be a unique event. It is associated with a concomitantly occurring cortical granule exocytosis. If eggs were exposed to weak bases, exocytosis was inhibited but the fertilization potential could still be evoked. After recovery from this first transient increase in membrane conductance, a second could be elicited by a further stimulus. A fertilization potential could be triggered either before or after the egg had undergone an electrically induced activation potential. This suggests that sperm receptors and sperm activated ionic channels in the egg membrane remain functional following the conductance change, at least when the exocytotic event was prevented. A transient conductance increase could only be induced by NH4+ (pH 9.0) in unactivated eggs that had not undergone cortical granule exocytosis. Tremendous variation was noticed between successive activation currents elicited in the same egg. Under voltage-clamp at 0 mV holding potential, the current often changed from inward to outward. Although cortical granule exocytosis may only play a minor role in the transient conductance change triggered at fertilization, it may well be involved in subsequent modifications of membrane conductance.
Charbonneau,
Fertilization of amphibian eggs: a comparison of electrical responses between anurans and urodeles.
1983, Pubmed
Charbonneau,
Fertilization of amphibian eggs: a comparison of electrical responses between anurans and urodeles.
1983,
Pubmed
Dale,
Maturation and fertilization of the sea urchin oocyte: an electrophysiological study.
1981,
Pubmed
Dale,
Electrical response to fertilization in ascidian oocytes.
1983,
Pubmed
Elinson,
Site of sperm entry and a cortical contraction associated with egg activation in the frog Rana pipiens.
1975,
Pubmed
Gilkey,
Roles of calcium and pH in activation of eggs of the medaka fish, Oryzias latipes.
1983,
Pubmed
Gould-Somero,
Electrically mediated fast polyspermy block in eggs of the marine worm, Urechis caupo.
1979,
Pubmed
Grey,
Formation and structure of the fertilization envelope in Xenopus laevis.
1974,
Pubmed
,
Xenbase
Hagiwara,
Electrical properties of egg cell membranes.
1979,
Pubmed
,
Xenbase
Holland,
Electrophysiological response to insemination in oocytes of Urechis caupo.
1981,
Pubmed
Hutter,
The pH sensitivity of the chloride conductance of frog skeletal muscle.
1967,
Pubmed
Jaffe,
The time course of cortical vesicle fusion in sea urchin eggs observed as membrane capacitance changes.
1978,
Pubmed
Jaffe,
Fertilization-induced ionic conductances in eggs of the frog, Rana pipiens.
1985,
Pubmed
Miyazaki,
Fast polyspermy block and activation potential. Correlated changes during oocyte maturation of a starfish.
1979,
Pubmed
Nuccitelli,
The electrical changes accompanying fertilization and cortical vesicle secretion in the medaka egg.
1980,
Pubmed
Peres,
The effective membrane capacity of Xenopus eggs: its relations with membrane conductance and cortical granule exocytosis.
1985,
Pubmed
,
Xenbase
Poenie,
Changes of free calcium levels with stages of the cell division cycle.
,
Pubmed
Rink,
Free calcium in Xenopus embryos measured with ion-selective microelectrodes.
1980,
Pubmed
,
Xenbase
Schlichter,
Electrical responses of immature and mature Rana pipiens oocytes to sperm and other activating stimuli.
1981,
Pubmed
Shen,
Intracellular pH controls the development of new potassium conductance after fertilization of the sea urchin egg.
1980,
Pubmed
Webb,
Direct measurement of intracellular pH changes in Xenopus eggs at fertilization and cleavage.
1981,
Pubmed
,
Xenbase
Webb,
Fertilization potential and electrical properties of the Xenopus laevis egg.
1985,
Pubmed
,
Xenbase
Webb,
A comparative study of the membrane potential from before fertilization through early cleavage in two frogs, Rana pipiens and Xenopus laevis.
1985,
Pubmed
,
Xenbase
Winkler,
Mechanism of action of NH4Cl and other weak bases in the activation of sea urchin eggs.
1978,
Pubmed
de Laat,
Intracellular ionic distribution, cell membrane permeability and membrane potential of the Xenopus egg during first cleavage.
1974,
Pubmed
,
Xenbase
