Persistent depolarization and Glu uptake inhibition operate distinct osmoregulatory mechanisms in the mammalian brain

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Abstract

The ways of coupling neuronal with glial compartments in natural physiology was investigated in microdialysis experiments by monitoring extracellular concentration of amino acids in the brain of anaesthetized rats. We hypothesized that extracellular [Glu], [Gln] and [Tau] patterns would be state-dependent. This was tested by stimulation of N-methyl-D- aspartate (NMDA) receptors, by inhibition of Glu uptake or by local depolarization with a high-K+ dialysate, coupled with the addition of Co2+ to block Ca2+ influx. The results showed that (1) extracellular [Gln] was low whereas [Glu] and [Tau] were high during infusion of NMDA (0.5-1.0 mM) or high-K+ (80 mM) in the hippocampus and ventrobasal thalamus, (2) hippocampal extracellular [Glu], [Gln] and [Tau] were increased in response to the Glu uptake inhibitor, L-trans-pyrrolidine-2,4-dicarboxilic acid (tPDC, 0.5-3.0 mM), in a concentration-dependent manner, (3) high-K+-induced increase of extracellular [Glu] was partially blocked by the addition of 10 mM CoCl2 with the high-K+ dialysate in the hippocampus. Searching for main correlations between changes in [Glu], [Gln] and [Tau] by calculating partial correlations and with the use of factor analyses we found, the primary response of the mammalian brain to persistent depolarization is the neuronal uptake of [Gln] and release of [Tau] thereupon, acting independently of Glu changes. When glial and neuronal uptake of Glu is blocked, releases of Tau occur from neuronal as well as glial compartments accompanied by increases of [Gln] in the mammalian brain. (C) 2000 Elsevier Science Ltd.

Original languageEnglish
Pages (from-to)171-178
Number of pages8
JournalNeurochemistry International
Volume37
Issue number2-3
DOIs
Publication statusPublished - Aug 1 2000

Fingerprint

Neuroglia
Dialysis Solutions
Hippocampus
Brain
Microdialysis
N-Methylaspartate
N-Methyl-D-Aspartate Receptors
Thalamus
Statistical Factor Analysis
Amino Acids
Acids
pyrrolidine

Keywords

  • [Gln] and [Tau]
  • Co
  • Extracellular [Glu]
  • High- K
  • Hippocampus
  • L-trans-pyrrolidine-2,4-dicarboxilic acid
  • Microdialysis
  • N-methyl-D-aspartate
  • Rat brain
  • Ventrobasal thalamus

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Cellular and Molecular Neuroscience

Cite this

@article{04b458fc22604be4afb9879d429ede3c,
title = "Persistent depolarization and Glu uptake inhibition operate distinct osmoregulatory mechanisms in the mammalian brain",
abstract = "The ways of coupling neuronal with glial compartments in natural physiology was investigated in microdialysis experiments by monitoring extracellular concentration of amino acids in the brain of anaesthetized rats. We hypothesized that extracellular [Glu], [Gln] and [Tau] patterns would be state-dependent. This was tested by stimulation of N-methyl-D- aspartate (NMDA) receptors, by inhibition of Glu uptake or by local depolarization with a high-K+ dialysate, coupled with the addition of Co2+ to block Ca2+ influx. The results showed that (1) extracellular [Gln] was low whereas [Glu] and [Tau] were high during infusion of NMDA (0.5-1.0 mM) or high-K+ (80 mM) in the hippocampus and ventrobasal thalamus, (2) hippocampal extracellular [Glu], [Gln] and [Tau] were increased in response to the Glu uptake inhibitor, L-trans-pyrrolidine-2,4-dicarboxilic acid (tPDC, 0.5-3.0 mM), in a concentration-dependent manner, (3) high-K+-induced increase of extracellular [Glu] was partially blocked by the addition of 10 mM CoCl2 with the high-K+ dialysate in the hippocampus. Searching for main correlations between changes in [Glu], [Gln] and [Tau] by calculating partial correlations and with the use of factor analyses we found, the primary response of the mammalian brain to persistent depolarization is the neuronal uptake of [Gln] and release of [Tau] thereupon, acting independently of Glu changes. When glial and neuronal uptake of Glu is blocked, releases of Tau occur from neuronal as well as glial compartments accompanied by increases of [Gln] in the mammalian brain. (C) 2000 Elsevier Science Ltd.",
keywords = "[Gln] and [Tau], Co, Extracellular [Glu], High- K, Hippocampus, L-trans-pyrrolidine-2,4-dicarboxilic acid, Microdialysis, N-methyl-D-aspartate, Rat brain, Ventrobasal thalamus",
author = "K. K{\'e}kesi and N. Szil{\'a}gyi and G. Nyitrai and A. Dobolyi and Nina Skuban and J. Kardos",
year = "2000",
month = "8",
day = "1",
doi = "10.1016/S0197-0186(00)00020-6",
language = "English",
volume = "37",
pages = "171--178",
journal = "Neurochemistry International",
issn = "0197-0186",
publisher = "Elsevier Limited",
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TY - JOUR

T1 - Persistent depolarization and Glu uptake inhibition operate distinct osmoregulatory mechanisms in the mammalian brain

AU - Kékesi, K.

AU - Szilágyi, N.

AU - Nyitrai, G.

AU - Dobolyi, A.

AU - Skuban, Nina

AU - Kardos, J.

PY - 2000/8/1

Y1 - 2000/8/1

N2 - The ways of coupling neuronal with glial compartments in natural physiology was investigated in microdialysis experiments by monitoring extracellular concentration of amino acids in the brain of anaesthetized rats. We hypothesized that extracellular [Glu], [Gln] and [Tau] patterns would be state-dependent. This was tested by stimulation of N-methyl-D- aspartate (NMDA) receptors, by inhibition of Glu uptake or by local depolarization with a high-K+ dialysate, coupled with the addition of Co2+ to block Ca2+ influx. The results showed that (1) extracellular [Gln] was low whereas [Glu] and [Tau] were high during infusion of NMDA (0.5-1.0 mM) or high-K+ (80 mM) in the hippocampus and ventrobasal thalamus, (2) hippocampal extracellular [Glu], [Gln] and [Tau] were increased in response to the Glu uptake inhibitor, L-trans-pyrrolidine-2,4-dicarboxilic acid (tPDC, 0.5-3.0 mM), in a concentration-dependent manner, (3) high-K+-induced increase of extracellular [Glu] was partially blocked by the addition of 10 mM CoCl2 with the high-K+ dialysate in the hippocampus. Searching for main correlations between changes in [Glu], [Gln] and [Tau] by calculating partial correlations and with the use of factor analyses we found, the primary response of the mammalian brain to persistent depolarization is the neuronal uptake of [Gln] and release of [Tau] thereupon, acting independently of Glu changes. When glial and neuronal uptake of Glu is blocked, releases of Tau occur from neuronal as well as glial compartments accompanied by increases of [Gln] in the mammalian brain. (C) 2000 Elsevier Science Ltd.

AB - The ways of coupling neuronal with glial compartments in natural physiology was investigated in microdialysis experiments by monitoring extracellular concentration of amino acids in the brain of anaesthetized rats. We hypothesized that extracellular [Glu], [Gln] and [Tau] patterns would be state-dependent. This was tested by stimulation of N-methyl-D- aspartate (NMDA) receptors, by inhibition of Glu uptake or by local depolarization with a high-K+ dialysate, coupled with the addition of Co2+ to block Ca2+ influx. The results showed that (1) extracellular [Gln] was low whereas [Glu] and [Tau] were high during infusion of NMDA (0.5-1.0 mM) or high-K+ (80 mM) in the hippocampus and ventrobasal thalamus, (2) hippocampal extracellular [Glu], [Gln] and [Tau] were increased in response to the Glu uptake inhibitor, L-trans-pyrrolidine-2,4-dicarboxilic acid (tPDC, 0.5-3.0 mM), in a concentration-dependent manner, (3) high-K+-induced increase of extracellular [Glu] was partially blocked by the addition of 10 mM CoCl2 with the high-K+ dialysate in the hippocampus. Searching for main correlations between changes in [Glu], [Gln] and [Tau] by calculating partial correlations and with the use of factor analyses we found, the primary response of the mammalian brain to persistent depolarization is the neuronal uptake of [Gln] and release of [Tau] thereupon, acting independently of Glu changes. When glial and neuronal uptake of Glu is blocked, releases of Tau occur from neuronal as well as glial compartments accompanied by increases of [Gln] in the mammalian brain. (C) 2000 Elsevier Science Ltd.

KW - [Gln] and [Tau]

KW - Co

KW - Extracellular [Glu]

KW - High- K

KW - Hippocampus

KW - L-trans-pyrrolidine-2,4-dicarboxilic acid

KW - Microdialysis

KW - N-methyl-D-aspartate

KW - Rat brain

KW - Ventrobasal thalamus

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U2 - 10.1016/S0197-0186(00)00020-6

DO - 10.1016/S0197-0186(00)00020-6

M3 - Article

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AN - SCOPUS:17744410260

VL - 37

SP - 171

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JO - Neurochemistry International

JF - Neurochemistry International

SN - 0197-0186

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