Membrane hyperpolarization during human sperm capacitation
| Autor: | Celia M. Santi, Oscar Sánchez-Carranza, Alberto Darszon, Claudia L. Treviño, A. Solís-López, Paulina Torres-Rodríguez, Ignacio López-González |
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| Rok vydání: | 2014 |
| Předmět: |
Male
Embryology BK channel Acrosome reaction CHO Cells Biology Membrane Potentials Mice Cricetulus Capacitation Genetics medicine Animals Humans Large-Conductance Calcium-Activated Potassium Channels Large-Conductance Calcium-Activated Potassium Channel alpha Subunits Molecular Biology Membrane potential Acrosome Reaction Cell Membrane Obstetrics and Gynecology Clofilium Articles Cell Biology Membrane hyperpolarization Hyperpolarization (biology) Spermatozoa Sperm Cell biology Reproductive Medicine Potassium Channels Voltage-Gated biology.protein Calcium Sperm Capacitation Developmental Biology medicine.drug |
| Zdroj: | MHR: Basic science of reproductive medicine. 20:619-629 |
| ISSN: | 1460-2407 1360-9947 |
| Popis: | Sperm capacitation is a complex and indispensable physiological process that spermatozoa must undergo in order to acquire fer- tilization capability. Spermatozoa from several mammalian species, including mice, exhibit a capacitation-associated plasma membrane hyperpo- larization, which is necessary for the acrosome reaction to occur. Despite its importance, this hyperpolarization event has not been adequately examined in human sperm. In this report we used flow cytometry to show that a subpopulation of human sperm indeed undergo a plasma mem- brane hyperpolarization upon in vitro capacitation. This hyperpolarization correlated with two other well-characterized capacitation parameters, namely an increase in intracellular pH and Ca 2+ concentration, measured also by flow cytometry. We found that sperm membrane hyperpolar- ization was completely abolished in the presence of a high external K + concentration (60 mM), indicating the participation of K + channels. In order to identify, which of the potential K + channels were involved in this hyperpolarization, we used different K + channel inhibitors including charybdotoxin, slotoxin and iberiotoxin (which target Slo1) and clofilium (a more specific blocker for Slo3). All these K + channel antagonists inhibited membrane hyperpolarization to a similar extent, suggesting that both members of the Slo family may potentially participate. Two very recent papers recorded K + currents in human sperm electrophysiologically, with some contradictory results. In the present work, we show through immunoblotting that Slo3 channels are present in the human sperm membrane. In addition, we found that human Slo3 channels expressed in CHO cells were sensitive to clofilium (50 mM). Considered altogether, our data indicate that Slo1 and Slo3 could share the prepon- derant role in the capacitation-associated hyperpolarization of human sperm in contrast to what has been previously reported for mouse sperm, where Slo3 channels are the main contributors to the hyperpolarization event. |
| Databáze: | OpenAIRE |
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