Vestibular Dark Cells Contain an H+/Monocarboxylate− Cotransporter in Their Apical and Basolateral Membrane

Vestibular Dark Cells Contain an H+/Monocarboxylate− Cotransporter in Their Apical and... The transport of lactate and pyruvate across membranes of vestibular dark cells (VDC) may be important under aerobic, ischemic or hypoxic conditions. This study addresses the questions whether VDC from the gerbil contain an H+/monocarboxylate− cotransporter (MCT) and in which membrane, apical or basolateral, MCT is located. Uptake of monocarboxylates into VDC was monitored in functional studies by measuring the cytosolic pH (pH i ) and by measuring the pH-sensitive equivalent short circuit current (I sc ). Subtypes of the functionally identified MCT which are present in vestibular labyrinth tissues were identified as transcripts by cloning and sequencing of reverse-transcriptase polymerase chain reaction (RT-PCR) products. Monocarboxylates but not dicarboxylates induced a transient acidification of pH i which was inhibited by 5 mmα-cyano-4-hydroxycinnamate (CHC) but not by 1 μm DIDS or 500 μm pCMBS. The initial rate of acidification induced by monocarboxylates was dose-dependent in the range between 1 and 20 mm. K m values were for pyruvate 1.3, acetate 3.7, l-lactate 3.8 and d-lactate 7.3 mm. Both apical and basolateral application of monocarboxylates caused a transient increase of I sc which was sensitive to 5 mm CHC. RT-PCR revealed the presence of transcripts for the MCT subtypes MCT1 and MCT2. The identity of transcripts was confirmed by sequence analysis. These observations suggest that VDC contain an MCT in their apical and basolateral membrane and that the vestibular labyrinth contains transcripts for the subtypes MCT1 and MCT2. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Vestibular Dark Cells Contain an H+/Monocarboxylate− Cotransporter in Their Apical and Basolateral Membrane

Loading next page...
 
/lp/springer_journal/vestibular-dark-cells-contain-an-h-monocarboxylate-cotransporter-in-b9sivoL1Gl
Publisher
Springer-Verlag
Copyright
Copyright © Inc. by 1998 Springer-Verlag New York
Subject
Life Sciences; Biochemistry, general; Human Physiology
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s002329900368
Publisher site
See Article on Publisher Site

Abstract

The transport of lactate and pyruvate across membranes of vestibular dark cells (VDC) may be important under aerobic, ischemic or hypoxic conditions. This study addresses the questions whether VDC from the gerbil contain an H+/monocarboxylate− cotransporter (MCT) and in which membrane, apical or basolateral, MCT is located. Uptake of monocarboxylates into VDC was monitored in functional studies by measuring the cytosolic pH (pH i ) and by measuring the pH-sensitive equivalent short circuit current (I sc ). Subtypes of the functionally identified MCT which are present in vestibular labyrinth tissues were identified as transcripts by cloning and sequencing of reverse-transcriptase polymerase chain reaction (RT-PCR) products. Monocarboxylates but not dicarboxylates induced a transient acidification of pH i which was inhibited by 5 mmα-cyano-4-hydroxycinnamate (CHC) but not by 1 μm DIDS or 500 μm pCMBS. The initial rate of acidification induced by monocarboxylates was dose-dependent in the range between 1 and 20 mm. K m values were for pyruvate 1.3, acetate 3.7, l-lactate 3.8 and d-lactate 7.3 mm. Both apical and basolateral application of monocarboxylates caused a transient increase of I sc which was sensitive to 5 mm CHC. RT-PCR revealed the presence of transcripts for the MCT subtypes MCT1 and MCT2. The identity of transcripts was confirmed by sequence analysis. These observations suggest that VDC contain an MCT in their apical and basolateral membrane and that the vestibular labyrinth contains transcripts for the subtypes MCT1 and MCT2.

Journal

The Journal of Membrane BiologySpringer Journals

Published: May 1, 1998

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off