Role of Phosphoinositide Hydrolysis in Astrocyte Volume Regulation

A. S. Bender, J. T. Neary, M. D. Norenberg

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


Astrocytes exposed to hypoosmotic stress swell and subsequently reduce their size to almost their original volume, a phenomenon called regulatory volume decrease (RVD). We found that during hypoosmotic swelling there was a twofold increase in phosphatidylinositol (PI) hydrolysis. This increase was inhibited by the phospholipase C inhibitor, U-73122 (10 μM). Inhibition of PI hydrolysis resulted in blockage of RVD. We also examined whether agents that stimulate PI hydrolysis would enhance RVD. These agents significantly accelerated RVD. The rank order of potency was endothelin (20 nM) ≥ norepinephrine (100 μM) > endothelin-3 (7 n/M) > thrombin (1 U/ml) ≥ ATP (500 μM) > bradykinin (20 μM) ≥ carbachol (500 μM), as indicated by RVD rate constants. The extent of PI hydrolysis induced by these agents at the beginning of RVD exhibited a logarithmic relationship with the magnitude of RVD enhancement. Also, there was a linear relationship between the rate of PI hydrolysis and RVD rate constants. Our results suggest that stimulated PI hydrolysis is involved in the regulation of cell volume in astrocytes.

Original languageEnglish (US)
Pages (from-to)1506-1514
Number of pages9
JournalJournal of neurochemistry
Issue number4
StatePublished - Oct 1993


  • Astrocytes
  • Cell volume
  • Inositol phosphates
  • Intracellular free Ca
  • Phosphatidylinositol hydrolysis agonists
  • Regulatory volume decrease

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience


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