Effect of ammonia on calcium homeostasis in primary astrocyte cultures

J. T. Neary, C. Woodson, J. Blicharska, L. O.B. Norenberg, M. D. Norenberg

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Calcium influx, accumulation and efflux were studied in primary cultures of rat astrocytes treated with ammonium chloride. Treatment of the cells for 3 days with 10 mM NH4Cl resulted in a 35% reduction in 45Ca influx. The decrease in calcium influx was dose-dependent between 2 and 10 mM NH4Cl. Short-term (30 min) exposure to ammonia had no effect on calcium influx. Calcium accumulation, as measured by 20-min exposure to 45Ca, decreased after treating cultures with 10 mM NH4Cl for one or 3 days; a greater effect was observed after the 3-day treatment. Studies with lanthanum, an inhibitor of calcium transport, indicated that the effect of ammonia was not due to non-specific leakage of calcium. Calcium efflux was not affected by exposure of the cultures to ammonium chloride. Purinergic-evoked calcium influx and mobilization was not altered by ammonia. While the mechanism(s) of calcium homeostasis affected by long-term hyperammonemia remain to be defined, these results suggest that reduced astrocytic calcium may be related to the pathogenesis of ammonia-related disorders such as hepatic encephalography.

Original languageEnglish (US)
Pages (from-to)231-235
Number of pages5
JournalBrain research
Volume524
Issue number2
DOIs
StatePublished - Aug 6 1990

Keywords

  • Ammonia
  • Astrocyte
  • Calcium flux
  • Hepatic encephalopathy

ASJC Scopus subject areas

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

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