| Mammalian prestin is a weak Cl- / HCO3- electrogenic antiporter. | |
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MedLine Citation:
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PMID: 22890707 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The lateral membrane of mammalian cochlear outer hair cells contains prestin, a protein which can act as a fast voltage-driven actuator responsible for electromotility and enhanced sensitivity to sound. The protein belongs to the SLC26 family of transporters whose members are characterised as able to exchange halides for SO42- or HCO3- yet previous analysis of mammalian prestin have suggested that such exchange functions were minimal. Here anion transport is investigated both in guinea pig outer hair cells (OHCs) and in an expression system where we employ a sensitive intracellular pH (pHi) probe, pHluorin, to report HCO3- transport and to monitor the small pHi changes observable in the cells. In the presence of extracellular HCO3-, pHi recovered from an acid load 4 times faster in prestin-transfected cells. The acceleration required a chloride gradient established by reducing extracellular chloride to 2mM. Similar results were also shown using BCECF as an alternative pHi sensor, but with recovery only found in those cells expressing prestin. Simultaneous electrophysiological recording of the transfected cells during bicarbonate exposure produced a shift in the reversal potential to more negative potentials, consistent with electrogenic transport. These data therefore suggest that prestin can act as a weak HCO3-/ Cl- antiporter and it is proposed that, in addition to participating in wide band cochlear sound amplification, prestin may also be involved in the slow time scale (>10s) phenomena where changes in cell stiffness and internal pressure have been implicated. The results show the importance of considering the effects of the endogenous bicarbonate buffering system in evaluating the function of prestin in cochlear outer hair cells. |
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Authors:
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Pavel Mistrrik; Nicolas Daudet; Karin Morandell; Jonathan F Ashmore |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-8-13 |
Journal Detail:
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Title: The Journal of physiology Volume: - ISSN: 1469-7793 ISO Abbreviation: J. Physiol. (Lond.) Publication Date: 2012 Aug |
Date Detail:
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Created Date: 2012-8-14 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0266262 Medline TA: J Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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University College London. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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