Liver failure can lead to generalized hyperammonemia, which is thought to be the underlying cause of hepatic
encephalopathy. This neuropsychiatric syndrome is accompanied by functional changes of astrocytes. These glial cells
enter ammonia-induced self-amplifying cycle characterized by brain oedema, oxidative and osmotic stress that causes
modification of proteins and RNA. Consequently, protein expression and function are affected, including that of
glutamine synthetase and plasmalemmal glutamate transporters, leading to glutamate excitotoxicity; Ca2+-dependent
exocytotic glutamate release from astrocytes contributes to this extracellular glutamate overload.
Keywords: Astrocytes, exocytosis, glutamate release, hepatic encephalopathy.
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