Methylmercury-induced inhibition of regulatory volume decrease in astrocytes: Characterization of osmoregulator efflux and its reversal by amiloride

Michael Aschner, Domenico Vitarella, Jeffrey W. Allen, Dawn R. Conklin, Kelly S. Cowan

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Swelling of neonatal rat primary astrocyte cultures by hypotonic media leads to regulatory volume decrease (RVD) and the resumption of resting cell volume. RVD is associated with activation of conductive K+ and Cl- channels, allowing for the escape of KCl, as well as the release of osmoregulators, such as taurine and myoinositol. As we have previously shown [D. Vitarella, H.K. Kimelberg, M. Aschner, inhibition of RVD in swollen rat primary astrocyte cultures by methylmercury (MeHg) is due to increase amiloride-sensitive Na+ uptake, Brain Res. 732 (1996) 169-178.], MeHg, when added to hypotonic buffer inhibits RVD, primarily due to increased cellular permeability to Na+ via the Na+/H+ antiporter. The present study was, therefore, undertaken to assess the ability of cation-anion cotransport blockers to reverse the inhibitory effect of MeHg on RVD in swollen astrocytes, and to further characterize MeHg-induced changes in astrocytic osmoregulatory release processes. The studies demonstrate the following: (1) MeHg-induced inhibition of RVD is partially inhibited by the Na+/H+ antiporter blocker, amiloride, but not SITS (4-acetamido-4'- isothiocyanatostilbene-2,2'-disulfonic acid), DIDS (4,4'-diisothiocyano- 2,2'-stilbenedisulfonic acid), furosemide or bumetanide; (2) exposure of swollen astrocytes to MeHg is associated with specific effects on osmoregulatory release, leading to significant inhibition of taurine release and a significant increase in potassium and myoinositol release compared with release in hypotonic conditions.

Original languageEnglish (US)
Pages (from-to)133-142
Number of pages10
JournalBrain Research
Volume811
Issue number1-2
DOIs
StatePublished - Nov 16 1998
Externally publishedYes

Fingerprint

Amiloride
Astrocytes
4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
Sodium-Hydrogen Antiporter
Taurine
Inositol
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
Bumetanide
Furosemide
Cell Size
Anions
Culture Media
Cations
Permeability
Potassium
Buffers
Acids
Brain

Keywords

  • Amiloride
  • Astrocyte
  • Cell swelling
  • In vitro
  • Methylmercury
  • Myoinositol
  • Rat
  • Taurine

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Methylmercury-induced inhibition of regulatory volume decrease in astrocytes : Characterization of osmoregulator efflux and its reversal by amiloride. / Aschner, Michael; Vitarella, Domenico; Allen, Jeffrey W.; Conklin, Dawn R.; Cowan, Kelly S.

In: Brain Research, Vol. 811, No. 1-2, 16.11.1998, p. 133-142.

Research output: Contribution to journalArticle

Aschner, Michael ; Vitarella, Domenico ; Allen, Jeffrey W. ; Conklin, Dawn R. ; Cowan, Kelly S. / Methylmercury-induced inhibition of regulatory volume decrease in astrocytes : Characterization of osmoregulator efflux and its reversal by amiloride. In: Brain Research. 1998 ; Vol. 811, No. 1-2. pp. 133-142.
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