Osmotic regulation of myo-inositol uptake in primary astrocyte cultures

Russell E. Isaacks, Alexander S. Bender, Chang Y. Kim, Nicole M. Prieto, Michael D. Norenberg

Research output: Contribution to journalArticle

100 Scopus citations

Abstract

Uptake of myo-inositol by astrocytes in hypertonic medium (440 mosm/kg H2O) was increased near 3-fold after incubation for 24 hours, which continued for 72 hours, as compared with the uptake by cells cultured in isotonic medium (38 nmoles/mg protein). myo-Inositol uptake by astrocytes cultured in hypotonic medium (180 mosm/kg H2O) for periods up to 72 hours was reduced by 74% to 8 to 10 nmoles/mg protein. Astrocytes incubated in either hypotonic or hypertonic medium for 24 hours and then placed in isotonic medium reversed the initial down- or up-regulation of uptake. Activation of chronic RVD and RVI correlates with regulation of myo-inositol uptake. A 30 to 40 mosm/kg H2O deviation from physiological osmolality can influence myo-inositol homeostasis. The intracellular content of myo-inositol in astrocytes in isotonic medium was 25.6 ± 1.3 μg/mg protein (28 mM). This level of myo-inositol is sufficient for this compound to function as an osmoregulator in primary astrocytes and it is likely to contribute to the maintenance of brain volume.

Original languageEnglish (US)
Pages (from-to)331-338
Number of pages8
JournalNeurochemical Research
Volume19
Issue number3
DOIs
StatePublished - Mar 1 1994

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Keywords

  • Astrocytes
  • cell volume regulation
  • myo-inositol content
  • myo-inositol uptake
  • osmotic regulation

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry

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