Volume-dependent Glutamate Permeation Depends on Transmembrane Ionic Strength and Extracellular Cl−

Volume-dependent Glutamate Permeation Depends on Transmembrane Ionic Strength and Extracellular... Many mammalian cells regulate their volume by the osmotic movement of water directed by anion and cation flux. Ubiquitous volume-dependent anion currents permit cells to recover volume after swelling in response to a hypotonic environment. This study addressed competition between glutamate (Glu) and Cl− permeation in volume-activated anion currents in order to provide insight into the ionic requirements for volume regulation, volume-dependent anion channel activity and to the architecture of the channel pore. The effect of changing the intracellular molar fraction (MF) of Glu and Cl− on conductance and relative anion permeability was evaluated as a function of the extracellular permeant anion and/or the ionic strength. Relative permeability of Glu to Cl− was determined by measuring reversal potentials under defined ionic conditions. Under conditions with high (150 mM) or low (50 mM) ionic strength solutions on both sides of the membrane, Cl− was always more permeable than Glu. When a transmembrane ionic strength gradient (150 mM extracellular: 50 mM intracellular) was set to drive water into the cell, and in the presence of extracellular Cl−, Glu became up to 16-fold more permeable than Cl−. Replacement of extracellular Cl− with Glu abolished this effect. These results indicate that it is possible for Glu to move into the extracellular environment during volume-regulatory events and they support the emerging role of glutamate as a modulator of anion channel activity. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Volume-dependent Glutamate Permeation Depends on Transmembrane Ionic Strength and Extracellular Cl−

Loading next page...
 
/lp/springer_journal/volume-dependent-glutamate-permeation-depends-on-transmembrane-ionic-VarKbNCCoY
Publisher
Springer-Verlag
Copyright
Copyright © 2004 by Springer-Verlag New York Inc.
Subject
Philosophy
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-004-0653-3
Publisher site
See Article on Publisher Site

Abstract

Many mammalian cells regulate their volume by the osmotic movement of water directed by anion and cation flux. Ubiquitous volume-dependent anion currents permit cells to recover volume after swelling in response to a hypotonic environment. This study addressed competition between glutamate (Glu) and Cl− permeation in volume-activated anion currents in order to provide insight into the ionic requirements for volume regulation, volume-dependent anion channel activity and to the architecture of the channel pore. The effect of changing the intracellular molar fraction (MF) of Glu and Cl− on conductance and relative anion permeability was evaluated as a function of the extracellular permeant anion and/or the ionic strength. Relative permeability of Glu to Cl− was determined by measuring reversal potentials under defined ionic conditions. Under conditions with high (150 mM) or low (50 mM) ionic strength solutions on both sides of the membrane, Cl− was always more permeable than Glu. When a transmembrane ionic strength gradient (150 mM extracellular: 50 mM intracellular) was set to drive water into the cell, and in the presence of extracellular Cl−, Glu became up to 16-fold more permeable than Cl−. Replacement of extracellular Cl− with Glu abolished this effect. These results indicate that it is possible for Glu to move into the extracellular environment during volume-regulatory events and they support the emerging role of glutamate as a modulator of anion channel activity.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Jan 1, 2004

References

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