Effect of osmolality and anion channel inhibitors on myo-inositol efflux in cultured astrocytes

Russell E. Isaacks, Alexander S. Bender, Chang Y. Kim, You Fong Shi, Michael D Norenberg

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Recent studies have shown that swelling-activated myo-inositol efflux from rat C6 glioma cells is mediated by a single transport mechanism and most likely by a volume-sensitive anion channel. In those studies, cells were acclimated in hypertonic medium and then swollen by returning the cells to isotonic medium. In the present study, myo-inositol efflux was determined in primary cultures of astrocytes by first incubating the cells in isotonic radiolabelled medium for 2 hr and then placing the cells in either unlabelled isotonic, hypertonic, or hypotonic medium and measuring release with time. Computer analyses of efflux data indicated a two-component system of myo- inositol efflux. The rate constants for the initial fast component for isotonic and hypotonic cells were 0.0398 ± 0.005 and 0.0631 ± 0.0288 min- 1, respectively. The efflux rates of the slow component, while quite small, were severalfold greater with increasing hypotonic media as compared to the cells in isotonic medium. Several anion membrane transport inhibitors were tested to explore the swelling activated efflux mechanism of myo-inositol. Furosemide (0.5 mM), 1,9 dideoxyforskolin (0.1 mM), NPPB (0.1 mM), niflumic acid (0.5 mM), and SITS (0.5 mM) blocked the fast component of myo-inositol efflux by 17, 49, 55, 75, and 93%, respectively. Our results suggest that the fast component of myo-inositol efflux in primary cultures of astrocytes is mediated by anion transporters or channels and that myo-inositol flux contributes to cell volume regulation in cultures of primary astrocytes.

Original languageEnglish
Pages (from-to)866-871
Number of pages6
JournalJournal of Neuroscience Research
Volume57
Issue number6
DOIs
StatePublished - Sep 15 1999

Fingerprint

Inositol
Astrocytes
Osmolar Concentration
Anions
4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
Niflumic Acid
Furosemide
Cell Size
Glioma
Membranes

Keywords

  • Anion channel inhibitors
  • Anion channels
  • Astrocytes
  • Hyposmolality
  • Myo-inositol efflux

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Effect of osmolality and anion channel inhibitors on myo-inositol efflux in cultured astrocytes. / Isaacks, Russell E.; Bender, Alexander S.; Kim, Chang Y.; Shi, You Fong; Norenberg, Michael D.

In: Journal of Neuroscience Research, Vol. 57, No. 6, 15.09.1999, p. 866-871.

Research output: Contribution to journalArticle

Isaacks, Russell E. ; Bender, Alexander S. ; Kim, Chang Y. ; Shi, You Fong ; Norenberg, Michael D. / Effect of osmolality and anion channel inhibitors on myo-inositol efflux in cultured astrocytes. In: Journal of Neuroscience Research. 1999 ; Vol. 57, No. 6. pp. 866-871.
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