Effects of dexamethasone and DHEA on the changes of glutamate and polyamine uptake in rat astrocytes by lipopolysaccharide and antimycin A

Sang-Hyun Choi, B. Lee, Kyung-Ho Shin, Bon Hong Min, Y. S. Chun, B. G. Chun

Research output: Contribution to journalArticle

Abstract

Interactions among dexamethasone, dehydroepiandrosterone (DHEA), lipopolysaccharide (LPS), and antimycin A on the glutamate uptake and the polyamine uptake were investigated in primary cultures of rat cerebral cortical astrocytes to examine the effects of dexamethasone and DHEA on the regulatory role of astrocytes in conditions of increased extracellular concentrations of glutamate or polyamines. 1. [3H]Glutamate uptake: LPS and antimycin A decreased V(max), but both drugs had little effect on K(m). Dexamethasone also decreased basal V(max) without any significant effect on K(m). And dexamethasone further decreased the antimycin A.-induced decrease of V(max). DHEA did not affect the kinetics of basal glutamate uptake and the change by LPS or antimycin A. 2. [14C]Putrescine uptake: LPS increased V(max), and antimycin A decreased V(max). They showed little effect on K(m). Dexamethasone decreased V(max) of basal uptake and further decreased the antimycin A-induced decrease of V(max), and also decreased V(max) to less than control in LPS-treated astrocytes. DHEA did not affect K(m) and the change of V(max) by LPS or antimycin A. 3. [14C]Spermine uptake: Antimycin A decreased V(max), and LPS might increase V(max). K(m) was little affected by the drugs. Dexamethasone decreased basal V(max) and might further decrease the antimycin A-induced decrease of V(max). And dexamethasone also decreased V(max) to less than control in LPS-treated astrocytes. DHEA might increase basal V(max) and V(max) of LPS-treated astrocytes. 4. V(max) of glutamate uptake by astrocytes was increased by putrescine (1000 μM and 2000 μM) and spermidine (200 μM, 500 μM and 2000 μM). Spermine, 200 μM (and 100 μM), also increased V(max), but a higher dose of 2000 μM decreased V(max). K(m) of glutamate uptake was not significantly changed by these polyamines, except that higher doses of spermine showed tendency to decrease K(m) of glutamate uptake. In astrocytes, dexamethasone inhibited the glutamate uptake and the polyamine uptake in normal or hypoxic conditions, and the polyamine uptake might be stimulated by LPS and DHEA. Polyamines could aid astrocytes to uptake glutamate.

Original languageEnglish
Pages (from-to)137-146
Number of pages10
JournalKorean Journal of Physiology and Pharmacology
Volume3
Issue number2
Publication statusPublished - 1999 Jan 1

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Antimycin A
Dehydroepiandrosterone
Polyamines
Astrocytes
Dexamethasone
Glutamic Acid
Lipopolysaccharides
Spermine
Putrescine
lipopolysaccharide A
Spermidine
Pharmaceutical Preparations

Keywords

  • Antimycin A
  • Astrocytes
  • Dehydroepiandrosterone
  • Dexamethasone
  • Glutamate uptake
  • Lipopolysaccharide
  • Putrescine uptake
  • Spermine uptake

ASJC Scopus subject areas

  • Physiology
  • Pharmacology

Cite this

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title = "Effects of dexamethasone and DHEA on the changes of glutamate and polyamine uptake in rat astrocytes by lipopolysaccharide and antimycin A",
abstract = "Interactions among dexamethasone, dehydroepiandrosterone (DHEA), lipopolysaccharide (LPS), and antimycin A on the glutamate uptake and the polyamine uptake were investigated in primary cultures of rat cerebral cortical astrocytes to examine the effects of dexamethasone and DHEA on the regulatory role of astrocytes in conditions of increased extracellular concentrations of glutamate or polyamines. 1. [3H]Glutamate uptake: LPS and antimycin A decreased V(max), but both drugs had little effect on K(m). Dexamethasone also decreased basal V(max) without any significant effect on K(m). And dexamethasone further decreased the antimycin A.-induced decrease of V(max). DHEA did not affect the kinetics of basal glutamate uptake and the change by LPS or antimycin A. 2. [14C]Putrescine uptake: LPS increased V(max), and antimycin A decreased V(max). They showed little effect on K(m). Dexamethasone decreased V(max) of basal uptake and further decreased the antimycin A-induced decrease of V(max), and also decreased V(max) to less than control in LPS-treated astrocytes. DHEA did not affect K(m) and the change of V(max) by LPS or antimycin A. 3. [14C]Spermine uptake: Antimycin A decreased V(max), and LPS might increase V(max). K(m) was little affected by the drugs. Dexamethasone decreased basal V(max) and might further decrease the antimycin A-induced decrease of V(max). And dexamethasone also decreased V(max) to less than control in LPS-treated astrocytes. DHEA might increase basal V(max) and V(max) of LPS-treated astrocytes. 4. V(max) of glutamate uptake by astrocytes was increased by putrescine (1000 μM and 2000 μM) and spermidine (200 μM, 500 μM and 2000 μM). Spermine, 200 μM (and 100 μM), also increased V(max), but a higher dose of 2000 μM decreased V(max). K(m) of glutamate uptake was not significantly changed by these polyamines, except that higher doses of spermine showed tendency to decrease K(m) of glutamate uptake. In astrocytes, dexamethasone inhibited the glutamate uptake and the polyamine uptake in normal or hypoxic conditions, and the polyamine uptake might be stimulated by LPS and DHEA. Polyamines could aid astrocytes to uptake glutamate.",
keywords = "Antimycin A, Astrocytes, Dehydroepiandrosterone, Dexamethasone, Glutamate uptake, Lipopolysaccharide, Putrescine uptake, Spermine uptake",
author = "Sang-Hyun Choi and B. Lee and Kyung-Ho Shin and Min, {Bon Hong} and Chun, {Y. S.} and Chun, {B. G.}",
year = "1999",
month = "1",
day = "1",
language = "English",
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pages = "137--146",
journal = "Korean Journal of Physiology and Pharmacology",
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TY - JOUR

T1 - Effects of dexamethasone and DHEA on the changes of glutamate and polyamine uptake in rat astrocytes by lipopolysaccharide and antimycin A

AU - Choi, Sang-Hyun

AU - Lee, B.

AU - Shin, Kyung-Ho

AU - Min, Bon Hong

AU - Chun, Y. S.

AU - Chun, B. G.

PY - 1999/1/1

Y1 - 1999/1/1

N2 - Interactions among dexamethasone, dehydroepiandrosterone (DHEA), lipopolysaccharide (LPS), and antimycin A on the glutamate uptake and the polyamine uptake were investigated in primary cultures of rat cerebral cortical astrocytes to examine the effects of dexamethasone and DHEA on the regulatory role of astrocytes in conditions of increased extracellular concentrations of glutamate or polyamines. 1. [3H]Glutamate uptake: LPS and antimycin A decreased V(max), but both drugs had little effect on K(m). Dexamethasone also decreased basal V(max) without any significant effect on K(m). And dexamethasone further decreased the antimycin A.-induced decrease of V(max). DHEA did not affect the kinetics of basal glutamate uptake and the change by LPS or antimycin A. 2. [14C]Putrescine uptake: LPS increased V(max), and antimycin A decreased V(max). They showed little effect on K(m). Dexamethasone decreased V(max) of basal uptake and further decreased the antimycin A-induced decrease of V(max), and also decreased V(max) to less than control in LPS-treated astrocytes. DHEA did not affect K(m) and the change of V(max) by LPS or antimycin A. 3. [14C]Spermine uptake: Antimycin A decreased V(max), and LPS might increase V(max). K(m) was little affected by the drugs. Dexamethasone decreased basal V(max) and might further decrease the antimycin A-induced decrease of V(max). And dexamethasone also decreased V(max) to less than control in LPS-treated astrocytes. DHEA might increase basal V(max) and V(max) of LPS-treated astrocytes. 4. V(max) of glutamate uptake by astrocytes was increased by putrescine (1000 μM and 2000 μM) and spermidine (200 μM, 500 μM and 2000 μM). Spermine, 200 μM (and 100 μM), also increased V(max), but a higher dose of 2000 μM decreased V(max). K(m) of glutamate uptake was not significantly changed by these polyamines, except that higher doses of spermine showed tendency to decrease K(m) of glutamate uptake. In astrocytes, dexamethasone inhibited the glutamate uptake and the polyamine uptake in normal or hypoxic conditions, and the polyamine uptake might be stimulated by LPS and DHEA. Polyamines could aid astrocytes to uptake glutamate.

AB - Interactions among dexamethasone, dehydroepiandrosterone (DHEA), lipopolysaccharide (LPS), and antimycin A on the glutamate uptake and the polyamine uptake were investigated in primary cultures of rat cerebral cortical astrocytes to examine the effects of dexamethasone and DHEA on the regulatory role of astrocytes in conditions of increased extracellular concentrations of glutamate or polyamines. 1. [3H]Glutamate uptake: LPS and antimycin A decreased V(max), but both drugs had little effect on K(m). Dexamethasone also decreased basal V(max) without any significant effect on K(m). And dexamethasone further decreased the antimycin A.-induced decrease of V(max). DHEA did not affect the kinetics of basal glutamate uptake and the change by LPS or antimycin A. 2. [14C]Putrescine uptake: LPS increased V(max), and antimycin A decreased V(max). They showed little effect on K(m). Dexamethasone decreased V(max) of basal uptake and further decreased the antimycin A-induced decrease of V(max), and also decreased V(max) to less than control in LPS-treated astrocytes. DHEA did not affect K(m) and the change of V(max) by LPS or antimycin A. 3. [14C]Spermine uptake: Antimycin A decreased V(max), and LPS might increase V(max). K(m) was little affected by the drugs. Dexamethasone decreased basal V(max) and might further decrease the antimycin A-induced decrease of V(max). And dexamethasone also decreased V(max) to less than control in LPS-treated astrocytes. DHEA might increase basal V(max) and V(max) of LPS-treated astrocytes. 4. V(max) of glutamate uptake by astrocytes was increased by putrescine (1000 μM and 2000 μM) and spermidine (200 μM, 500 μM and 2000 μM). Spermine, 200 μM (and 100 μM), also increased V(max), but a higher dose of 2000 μM decreased V(max). K(m) of glutamate uptake was not significantly changed by these polyamines, except that higher doses of spermine showed tendency to decrease K(m) of glutamate uptake. In astrocytes, dexamethasone inhibited the glutamate uptake and the polyamine uptake in normal or hypoxic conditions, and the polyamine uptake might be stimulated by LPS and DHEA. Polyamines could aid astrocytes to uptake glutamate.

KW - Antimycin A

KW - Astrocytes

KW - Dehydroepiandrosterone

KW - Dexamethasone

KW - Glutamate uptake

KW - Lipopolysaccharide

KW - Putrescine uptake

KW - Spermine uptake

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M3 - Article

AN - SCOPUS:0033040828

VL - 3

SP - 137

EP - 146

JO - Korean Journal of Physiology and Pharmacology

JF - Korean Journal of Physiology and Pharmacology

SN - 1226-4512

IS - 2

ER -