Glutamine Synthetase - Biological Function

Biological Function

GS is present predominantly in the brain, kidneys, and liver. GS in the brain participates in the metabolic regulation of glutamate, the detoxification of brain ammonia, the assimilation of ammonia, recyclization of neurotransmitters, and termination of neurotransmitter signals. GS, in the brain, is found primarily is astrocytes. Astrocytes protect neurons against excitotoxicity by taking up excess ammonia and glutamate. In hyperammonemic environments (high levels of ammonia), astroglial swelling occurs. Different perspectives have approached the problem of astroglial swelling. One study shows that morphological changes occur that increase GS expression in glutamatergic areas or other adaptations that alleviates high levels of glutamate and ammonia. Another perspective is that astrocyte swelling is due to glutamine accumulation. To prevent increased levels of cortical glutamate and cortical water content, a study has been conducted to prevent GS activity in rats by the use of MSO.