Ion fluxes associated with excitatory amino acid transport

Jacques I. Wadiche; Susan G. Amara; Michael P. Kavanaugh

doi:10.1016/0896-6273(95)90159-0

Ion fluxes associated with excitatory amino acid transport

Jacques I. Wadiche
, Susan G. Amara
, Michael P. Kavanaugh

Division of Biological and Biomedical Sciences

Research output: Contribution to journal › Article › peer-review

478 Scopus citations

Abstract

Flux of substrate and charge mediated by three cloned excitatory amino acid transporters widely expressed in human brain were studied in voltage-clamped Xenopus oocytes. Superfusion of l-glutamate or d-aspartate resulted in currents due in part to electrogenic Na⁺ cotransport, which contributed 1 net positive charge per transport cycle. A significant additional component of the currents was due to activation of a reversible anion flux that was not thermodynamically coupled to amino acid transport. The selectivity sequence of this ligand-activated conductance was NO_3^- > I^- > Br^- > Cl^- > F^-. The results suggest that these proteins mediate both transporter- and channel-like modes of permeation, providing a potential mechanism for dampening cell excitability, in addition to removal of transmitter.

Original language	English
Pages (from-to)	721-728
Number of pages	8
Journal	Neuron
Volume	15
Issue number	3
DOIs	https://doi.org/10.1016/0896-6273(95)90159-0
State	Published - Sep 1995

Funding

We thank J. Arriza for providing EAAT plasmids and E, McCleskey, S. Eliasof, and B. Bean for discussion and comments. This work was supported by grant GM48709 from the National Institutes of Health.

Funder number
R01GM048709

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10.1016/0896-6273(95)90159-0

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title = "Ion fluxes associated with excitatory amino acid transport",

abstract = "Flux of substrate and charge mediated by three cloned excitatory amino acid transporters widely expressed in human brain were studied in voltage-clamped Xenopus oocytes. Superfusion of l-glutamate or d-aspartate resulted in currents due in part to electrogenic Na+ cotransport, which contributed 1 net positive charge per transport cycle. A significant additional component of the currents was due to activation of a reversible anion flux that was not thermodynamically coupled to amino acid transport. The selectivity sequence of this ligand-activated conductance was NO3- > I- > Br- > Cl- > F-. The results suggest that these proteins mediate both transporter- and channel-like modes of permeation, providing a potential mechanism for dampening cell excitability, in addition to removal of transmitter.",

author = "Wadiche, \{Jacques I.\} and Amara, \{Susan G.\} and Kavanaugh, \{Michael P.\}",

note = "Funding Information: We thank J. Arriza for providing EAAT plasmids and E, McCleskey, S. Eliasof, and B. Bean for discussion and comments. This work was supported by grant GM48709 from the National Institutes of Health.",

year = "1995",

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doi = "10.1016/0896-6273(95)90159-0",

language = "English",

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journal = "Neuron",

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T1 - Ion fluxes associated with excitatory amino acid transport

AU - Wadiche, Jacques I.

AU - Amara, Susan G.

AU - Kavanaugh, Michael P.

N1 - Funding Information: We thank J. Arriza for providing EAAT plasmids and E, McCleskey, S. Eliasof, and B. Bean for discussion and comments. This work was supported by grant GM48709 from the National Institutes of Health.

PY - 1995/9

Y1 - 1995/9

N2 - Flux of substrate and charge mediated by three cloned excitatory amino acid transporters widely expressed in human brain were studied in voltage-clamped Xenopus oocytes. Superfusion of l-glutamate or d-aspartate resulted in currents due in part to electrogenic Na+ cotransport, which contributed 1 net positive charge per transport cycle. A significant additional component of the currents was due to activation of a reversible anion flux that was not thermodynamically coupled to amino acid transport. The selectivity sequence of this ligand-activated conductance was NO3- > I- > Br- > Cl- > F-. The results suggest that these proteins mediate both transporter- and channel-like modes of permeation, providing a potential mechanism for dampening cell excitability, in addition to removal of transmitter.

AB - Flux of substrate and charge mediated by three cloned excitatory amino acid transporters widely expressed in human brain were studied in voltage-clamped Xenopus oocytes. Superfusion of l-glutamate or d-aspartate resulted in currents due in part to electrogenic Na+ cotransport, which contributed 1 net positive charge per transport cycle. A significant additional component of the currents was due to activation of a reversible anion flux that was not thermodynamically coupled to amino acid transport. The selectivity sequence of this ligand-activated conductance was NO3- > I- > Br- > Cl- > F-. The results suggest that these proteins mediate both transporter- and channel-like modes of permeation, providing a potential mechanism for dampening cell excitability, in addition to removal of transmitter.

UR - https://www.scopus.com/pages/publications/0029142729

U2 - 10.1016/0896-6273(95)90159-0

DO - 10.1016/0896-6273(95)90159-0

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AN - SCOPUS:0029142729

SN - 0896-6273

VL - 15

SP - 721

EP - 728

JO - Neuron

JF - Neuron

IS - 3

ER -

Ion fluxes associated with excitatory amino acid transport

Abstract

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