title: A transient rise in intracellular Ca2+ is a precursor reaction to the zona pellucida-induced acrosome reaction in mouse sperm and is blocked by the induced acrosome reaction inhibitor 3-quinuclidinyl benzilate.
abstract: The acrosome reaction induced by the zona pellucida in mouse sperm has been shown to proceed in two stages experimentally distinguishable by the fluorescent probe chlortetracycline. Entry into the first stage of sperm bound to isolated, structurally intact zonae pellucidae is blocked by the compound 3-quinuclidinyl benzilate. In this study, we show, utilizing the fluorescent Ca2+ indicator fluo-3, that the first stage of the zona-induced acrosome reaction is characterized by an increase in intracellular Ca2+, followed by a decrease as the acrosome reaction proceeds. This calcium transient is completely suppressed by 3-quinuclidinyl benzilate. We conclude that the Ca2+ transient is induced by the zona pellucida and is required for the zona-induced acrosome reaction. Blockage of this sperm intracellular Ca2+ transient provides a mechanism for the inhibitory action of 3-quinuclidinyl benzilate on the zona-induced acrosome reaction in mouse sperm.
authors.affiliation: Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia.
authors.forename: B T
authors.initials: BT
authors.lastname: Storey
authors.forename: C L
authors.initials: CL
authors.lastname: Hourani
authors.forename: J B
authors.initials: JB
authors.lastname: Kim
mesh_terms: D000177:Acrosome / Q000502:physiology*; D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004527:Egg Proteins; D005089:Exocytosis; D005260:Female; D005456:Fluorescent Dyes / Q000378:metabolism; D016257:Fura-2 / Q000378:metabolism; D006575:Heterocyclic Compounds, 3-Ring; D007424:Intracellular Fluid / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000502:physiology*; D051379:Mice; D008856:Microscopy, Fluorescence; D011813:Quinuclidinyl Benzilate / Q000494:pharmacology*; D011956:Receptors, Cell Surface; D015398:Signal Transduction; D013084:Sperm-Ovum Interactions / Q000187:drug effects*; D014966:Xanthenes / Q000378:metabolism; D015044:Zona Pellucida / Q000502:physiology*; D000072216:Zona Pellucida Glycoproteins
chemical_list: D000814:Aniline Compounds; D004527:Egg Proteins; D005456:Fluorescent Dyes; D006575:Heterocyclic Compounds, 3-Ring; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D014966:Xanthenes; D000072216:Zona Pellucida Glycoproteins; C068483:rhod-2; C059715:Fluo-3; D011813:Quinuclidinyl Benzilate; D002118:Calcium; D016257:Fura-2