Cargando…
Ion Permeabilities in Mouse Sperm Reveal an External Trigger for SLO3-Dependent Hyperpolarization
Unlike most cells of the body which function in an ionic environment controlled within narrow limits, spermatozoa must function in a less controlled external environment. In order to better understand how sperm control their membrane potential in different ionic conditions, we measured mouse sperm m...
Autores principales: | , , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2013
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3618424/ https://www.ncbi.nlm.nih.gov/pubmed/23577126 http://dx.doi.org/10.1371/journal.pone.0060578 |
_version_ | 1782265418507878400 |
---|---|
author | Chávez, Julio C. de la Vega-Beltrán, José L. Escoffier, Jessica Visconti, Pablo E. Treviño, Claudia L. Darszon, Alberto Salkoff, Lawrence Santi, Celia M. |
author_facet | Chávez, Julio C. de la Vega-Beltrán, José L. Escoffier, Jessica Visconti, Pablo E. Treviño, Claudia L. Darszon, Alberto Salkoff, Lawrence Santi, Celia M. |
author_sort | Chávez, Julio C. |
collection | PubMed |
description | Unlike most cells of the body which function in an ionic environment controlled within narrow limits, spermatozoa must function in a less controlled external environment. In order to better understand how sperm control their membrane potential in different ionic conditions, we measured mouse sperm membrane potentials under a variety of conditions and at different external K(+) concentrations, both before and after capacitation. Experiments were undertaken using both wild-type, and mutant mouse sperm from the knock-out strain of the sperm-specific, pH-sensitive, SLO3 K(+) channel. Membrane voltage data were fit to the Goldman-Hodgkin-Katz equation. Our study revealed a significant membrane permeability to both K(+) and Cl(−) before capacitation, as well as Na(+). The permeability to both K(+) and Cl(−) has the effect of preventing large changes in membrane potential when the extracellular concentration of either ion is changed. Such a mechanism may protect against undesired shifts in membrane potential in changing ionic environments. We found that a significant portion of resting membrane potassium permeability in wild-type sperm was contributed by SLO3 K(+) channels. We also found that further activation of SLO3 channels was the essential mechanism producing membrane hyperpolarization under two separate conditions, 1) elevation of external pH prior to capacitation and 2) capacitating conditions. Both conditions produced a significant membrane hyperpolarization in wild-type which was absent in SLO3 mutant sperm. Hyperpolarization in both conditions may result from activation of SLO3 channels by raising intracellular pH; however, demonstrating that SLO3-dependent hyperpolarization is achieved by an alkaline environment alone shows that SLO3 channel activation might occur independently of other events associated with capacitation. For example sperm may undergo stages of membrane hyperpolarization when reaching alkaline regions of the female genital tract. Significantly, other events associated with sperm capacitation, occur in SLO3 mutant sperm and thus proceed independently of hyperpolarization. |
format | Online Article Text |
id | pubmed-3618424 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-36184242013-04-10 Ion Permeabilities in Mouse Sperm Reveal an External Trigger for SLO3-Dependent Hyperpolarization Chávez, Julio C. de la Vega-Beltrán, José L. Escoffier, Jessica Visconti, Pablo E. Treviño, Claudia L. Darszon, Alberto Salkoff, Lawrence Santi, Celia M. PLoS One Research Article Unlike most cells of the body which function in an ionic environment controlled within narrow limits, spermatozoa must function in a less controlled external environment. In order to better understand how sperm control their membrane potential in different ionic conditions, we measured mouse sperm membrane potentials under a variety of conditions and at different external K(+) concentrations, both before and after capacitation. Experiments were undertaken using both wild-type, and mutant mouse sperm from the knock-out strain of the sperm-specific, pH-sensitive, SLO3 K(+) channel. Membrane voltage data were fit to the Goldman-Hodgkin-Katz equation. Our study revealed a significant membrane permeability to both K(+) and Cl(−) before capacitation, as well as Na(+). The permeability to both K(+) and Cl(−) has the effect of preventing large changes in membrane potential when the extracellular concentration of either ion is changed. Such a mechanism may protect against undesired shifts in membrane potential in changing ionic environments. We found that a significant portion of resting membrane potassium permeability in wild-type sperm was contributed by SLO3 K(+) channels. We also found that further activation of SLO3 channels was the essential mechanism producing membrane hyperpolarization under two separate conditions, 1) elevation of external pH prior to capacitation and 2) capacitating conditions. Both conditions produced a significant membrane hyperpolarization in wild-type which was absent in SLO3 mutant sperm. Hyperpolarization in both conditions may result from activation of SLO3 channels by raising intracellular pH; however, demonstrating that SLO3-dependent hyperpolarization is achieved by an alkaline environment alone shows that SLO3 channel activation might occur independently of other events associated with capacitation. For example sperm may undergo stages of membrane hyperpolarization when reaching alkaline regions of the female genital tract. Significantly, other events associated with sperm capacitation, occur in SLO3 mutant sperm and thus proceed independently of hyperpolarization. Public Library of Science 2013-04-05 /pmc/articles/PMC3618424/ /pubmed/23577126 http://dx.doi.org/10.1371/journal.pone.0060578 Text en © 2013 Chávez et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Chávez, Julio C. de la Vega-Beltrán, José L. Escoffier, Jessica Visconti, Pablo E. Treviño, Claudia L. Darszon, Alberto Salkoff, Lawrence Santi, Celia M. Ion Permeabilities in Mouse Sperm Reveal an External Trigger for SLO3-Dependent Hyperpolarization |
title | Ion Permeabilities in Mouse Sperm Reveal an External Trigger for SLO3-Dependent Hyperpolarization |
title_full | Ion Permeabilities in Mouse Sperm Reveal an External Trigger for SLO3-Dependent Hyperpolarization |
title_fullStr | Ion Permeabilities in Mouse Sperm Reveal an External Trigger for SLO3-Dependent Hyperpolarization |
title_full_unstemmed | Ion Permeabilities in Mouse Sperm Reveal an External Trigger for SLO3-Dependent Hyperpolarization |
title_short | Ion Permeabilities in Mouse Sperm Reveal an External Trigger for SLO3-Dependent Hyperpolarization |
title_sort | ion permeabilities in mouse sperm reveal an external trigger for slo3-dependent hyperpolarization |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3618424/ https://www.ncbi.nlm.nih.gov/pubmed/23577126 http://dx.doi.org/10.1371/journal.pone.0060578 |
work_keys_str_mv | AT chavezjulioc ionpermeabilitiesinmousespermrevealanexternaltriggerforslo3dependenthyperpolarization AT delavegabeltranjosel ionpermeabilitiesinmousespermrevealanexternaltriggerforslo3dependenthyperpolarization AT escoffierjessica ionpermeabilitiesinmousespermrevealanexternaltriggerforslo3dependenthyperpolarization AT viscontipabloe ionpermeabilitiesinmousespermrevealanexternaltriggerforslo3dependenthyperpolarization AT trevinoclaudial ionpermeabilitiesinmousespermrevealanexternaltriggerforslo3dependenthyperpolarization AT darszonalberto ionpermeabilitiesinmousespermrevealanexternaltriggerforslo3dependenthyperpolarization AT salkofflawrence ionpermeabilitiesinmousespermrevealanexternaltriggerforslo3dependenthyperpolarization AT santiceliam ionpermeabilitiesinmousespermrevealanexternaltriggerforslo3dependenthyperpolarization |