Suppression of ammonia-induced swelling by aspartate but not by ornithine in primary cultures of rat astrocytes

Chinta R K Murthy, Michael D Norenberg

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Cerebral edema with a rise in intracranial pressure is the hallmark of fulminant hepatic failure (FHF) and acute hyperammonemic (HA) states and is characterized by a poor survival rate. Astrocytes are the cells in brain which are swollen in these conditions. Several hypotheses have been proposed to explain the mechanism of cerebral edema in FHF and treatment strategies have evolved based on these putative mechanisms. Treatment with a mixture of ornithine and aspartate has been proven to be clinically beneficial as it reduces edema and improves the neurological status. It has been suggested that these two amino acids generate the glutamate required for the synthesis of glutamine and that they also enhance urea synthesis in surviving hepatocytes in FHF and HA. Presently, we report that of these two amino acids, only aspartate is effective in suppressing ammonia-induced swelling in primary cultures of astrocytes, while ornithine is ineffective. These results are discussed in relation to the metabolism of aspartate and ornithine in astrocytes, with an emphasis on glutamine synthesis and the malate-aspartate shuttle (MAS). We propose that the ability of aspartate to generate glutamate in the cytosol for glutamine synthesis and oxaloacetate in mitochondria to support the citric acid cycle play a role in its ability to reduce ammonia-induced swelling in astrocytes.

Original languageEnglish
Pages (from-to)171-176
Number of pages6
JournalNeurochemistry International
Volume41
Issue number2-3
DOIs
StatePublished - May 27 2002

Fingerprint

Ammonia
Astrocytes
Acute Liver Failure
Glutamine
Aspartic Acid
Brain Edema
Glutamic Acid
Amino Acids
Oxaloacetic Acid
Ornithine
Citric Acid Cycle
Intracranial Pressure
Cytosol
Urea
Hepatocytes
Edema
Mitochondria
ornithylaspartate
Brain

Keywords

  • Ammonia
  • Aspartate
  • Astrocyte swelling
  • Astrocytes
  • Brain edema
  • Glutamine
  • Malate-aspartate shuttle
  • Ornithine

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Cellular and Molecular Neuroscience

Cite this

Suppression of ammonia-induced swelling by aspartate but not by ornithine in primary cultures of rat astrocytes. / Murthy, Chinta R K; Norenberg, Michael D.

In: Neurochemistry International, Vol. 41, No. 2-3, 27.05.2002, p. 171-176.

Research output: Contribution to journalArticle

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