Methylmercury-induced alterations in excitatory amino acid transport in rat primary astrocyte cultures

Michael Aschner, Y. L. Du, M. Gannon, H. K. Kimelberg

Research output: Contribution to journalArticle

78 Citations (Scopus)

Abstract

To determine whether methylmercury (MeHg) has the potential to interfere with homeostatic functions in neonatal rat cortical primary astrocyte cultures, the effects of MeHg on the uptake and efflux of both l-glutamate and d-aspartate were examined. Uptake of both of these excitatory amino acids (EAAs) was significantly (P < 0.05) reduced in the presence of MeHg concentrations as low as 10-5 M. Efflux of both glutamate and aspartate from preloaded astrocytes was also increased by MeHg in a dose- and time-dependent fashion. Since in our earlier studies we had found that MeHg causes dose-dependent astrocytic swelling, which could have been the mechanism of the increased efflux, we examined whether blockage of conductive ion fluxes, which have been implicated in astrocytic swelling, could reverse the MeHg-induced increase in l-glutamate and d-aspartate efflux. Three compounds which inhibit the hypotonic-media-induced efflux of EAA, 4-acetamido-4′-isothiocyanatostilbene-2,2′-disulfonic acid (SITS), L-644,711 (a derivative of ethacrynic acid) and furosemide were tested at their maximal concentrations for their ability to reverse MeHg-induced EAA efflux. Only furosemide (5 mM) could sustain the reversal for the entire 120 min duration of the efflux measurement. Since hypotonic-media swelling-induced release of EAAs is inhibited by these anion inhibitors (in the following rank order: L-644,711 > SITS > furosemide), we conclude that different mechanisms account for EAA release from primary astrocyte cultures during MeHg exposure as compared to hypotonic media-induced efflux.

Original languageEnglish (US)
Pages (from-to)181-186
Number of pages6
JournalBrain Research
Volume602
Issue number2
DOIs
StatePublished - Feb 5 1993
Externally publishedYes

Fingerprint

Excitatory Amino Acids
Astrocytes
4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
Furosemide
Aspartic Acid
Glutamic Acid

Keywords

  • Astrocyte
  • d-Aspartate
  • l-Glutamate
  • Methylmercury
  • Transport

ASJC Scopus subject areas

  • Developmental Biology
  • Molecular Biology
  • Clinical Neurology
  • Neuroscience(all)

Cite this

Methylmercury-induced alterations in excitatory amino acid transport in rat primary astrocyte cultures. / Aschner, Michael; Du, Y. L.; Gannon, M.; Kimelberg, H. K.

In: Brain Research, Vol. 602, No. 2, 05.02.1993, p. 181-186.

Research output: Contribution to journalArticle

Aschner, Michael ; Du, Y. L. ; Gannon, M. ; Kimelberg, H. K. / Methylmercury-induced alterations in excitatory amino acid transport in rat primary astrocyte cultures. In: Brain Research. 1993 ; Vol. 602, No. 2. pp. 181-186.
@article{05fcabd256b34a65be5cd44f2386695b,
title = "Methylmercury-induced alterations in excitatory amino acid transport in rat primary astrocyte cultures",
abstract = "To determine whether methylmercury (MeHg) has the potential to interfere with homeostatic functions in neonatal rat cortical primary astrocyte cultures, the effects of MeHg on the uptake and efflux of both l-glutamate and d-aspartate were examined. Uptake of both of these excitatory amino acids (EAAs) was significantly (P < 0.05) reduced in the presence of MeHg concentrations as low as 10-5 M. Efflux of both glutamate and aspartate from preloaded astrocytes was also increased by MeHg in a dose- and time-dependent fashion. Since in our earlier studies we had found that MeHg causes dose-dependent astrocytic swelling, which could have been the mechanism of the increased efflux, we examined whether blockage of conductive ion fluxes, which have been implicated in astrocytic swelling, could reverse the MeHg-induced increase in l-glutamate and d-aspartate efflux. Three compounds which inhibit the hypotonic-media-induced efflux of EAA, 4-acetamido-4′-isothiocyanatostilbene-2,2′-disulfonic acid (SITS), L-644,711 (a derivative of ethacrynic acid) and furosemide were tested at their maximal concentrations for their ability to reverse MeHg-induced EAA efflux. Only furosemide (5 mM) could sustain the reversal for the entire 120 min duration of the efflux measurement. Since hypotonic-media swelling-induced release of EAAs is inhibited by these anion inhibitors (in the following rank order: L-644,711 > SITS > furosemide), we conclude that different mechanisms account for EAA release from primary astrocyte cultures during MeHg exposure as compared to hypotonic media-induced efflux.",
keywords = "Astrocyte, d-Aspartate, l-Glutamate, Methylmercury, Transport",
author = "Michael Aschner and Du, {Y. L.} and M. Gannon and Kimelberg, {H. K.}",
year = "1993",
month = "2",
day = "5",
doi = "10.1016/0006-8993(93)90680-L",
language = "English (US)",
volume = "602",
pages = "181--186",
journal = "Brain Research",
issn = "0006-8993",
publisher = "Elsevier",
number = "2",

}

TY - JOUR

T1 - Methylmercury-induced alterations in excitatory amino acid transport in rat primary astrocyte cultures

AU - Aschner, Michael

AU - Du, Y. L.

AU - Gannon, M.

AU - Kimelberg, H. K.

PY - 1993/2/5

Y1 - 1993/2/5

N2 - To determine whether methylmercury (MeHg) has the potential to interfere with homeostatic functions in neonatal rat cortical primary astrocyte cultures, the effects of MeHg on the uptake and efflux of both l-glutamate and d-aspartate were examined. Uptake of both of these excitatory amino acids (EAAs) was significantly (P < 0.05) reduced in the presence of MeHg concentrations as low as 10-5 M. Efflux of both glutamate and aspartate from preloaded astrocytes was also increased by MeHg in a dose- and time-dependent fashion. Since in our earlier studies we had found that MeHg causes dose-dependent astrocytic swelling, which could have been the mechanism of the increased efflux, we examined whether blockage of conductive ion fluxes, which have been implicated in astrocytic swelling, could reverse the MeHg-induced increase in l-glutamate and d-aspartate efflux. Three compounds which inhibit the hypotonic-media-induced efflux of EAA, 4-acetamido-4′-isothiocyanatostilbene-2,2′-disulfonic acid (SITS), L-644,711 (a derivative of ethacrynic acid) and furosemide were tested at their maximal concentrations for their ability to reverse MeHg-induced EAA efflux. Only furosemide (5 mM) could sustain the reversal for the entire 120 min duration of the efflux measurement. Since hypotonic-media swelling-induced release of EAAs is inhibited by these anion inhibitors (in the following rank order: L-644,711 > SITS > furosemide), we conclude that different mechanisms account for EAA release from primary astrocyte cultures during MeHg exposure as compared to hypotonic media-induced efflux.

AB - To determine whether methylmercury (MeHg) has the potential to interfere with homeostatic functions in neonatal rat cortical primary astrocyte cultures, the effects of MeHg on the uptake and efflux of both l-glutamate and d-aspartate were examined. Uptake of both of these excitatory amino acids (EAAs) was significantly (P < 0.05) reduced in the presence of MeHg concentrations as low as 10-5 M. Efflux of both glutamate and aspartate from preloaded astrocytes was also increased by MeHg in a dose- and time-dependent fashion. Since in our earlier studies we had found that MeHg causes dose-dependent astrocytic swelling, which could have been the mechanism of the increased efflux, we examined whether blockage of conductive ion fluxes, which have been implicated in astrocytic swelling, could reverse the MeHg-induced increase in l-glutamate and d-aspartate efflux. Three compounds which inhibit the hypotonic-media-induced efflux of EAA, 4-acetamido-4′-isothiocyanatostilbene-2,2′-disulfonic acid (SITS), L-644,711 (a derivative of ethacrynic acid) and furosemide were tested at their maximal concentrations for their ability to reverse MeHg-induced EAA efflux. Only furosemide (5 mM) could sustain the reversal for the entire 120 min duration of the efflux measurement. Since hypotonic-media swelling-induced release of EAAs is inhibited by these anion inhibitors (in the following rank order: L-644,711 > SITS > furosemide), we conclude that different mechanisms account for EAA release from primary astrocyte cultures during MeHg exposure as compared to hypotonic media-induced efflux.

KW - Astrocyte

KW - d-Aspartate

KW - l-Glutamate

KW - Methylmercury

KW - Transport

UR - http://www.scopus.com/inward/record.url?scp=0027480552&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027480552&partnerID=8YFLogxK

U2 - 10.1016/0006-8993(93)90680-L

DO - 10.1016/0006-8993(93)90680-L

M3 - Article

C2 - 8095428

AN - SCOPUS:0027480552

VL - 602

SP - 181

EP - 186

JO - Brain Research

JF - Brain Research

SN - 0006-8993

IS - 2

ER -