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Glutamate Increases Glycogen Content and Reduces Glucose Utilization in Primary Astrocyte Culture
Author(s) -
Swanson Raymond A.,
Yu Albert C. H.,
Chan Pak H.,
Sharp Frank R.
Publication year - 1990
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1990.tb01898.x
Subject(s) - glutamate receptor , glycogen , incubation , astrocyte , glycogen synthase , endocrinology , kynurenic acid , medicine , biology , biochemistry , chemistry , receptor , central nervous system
The glycogen content of primary cultured astrocytes was approximately doubled by incubation with 1 m M L‐glutamate or L‐aspartate. Other amino acids and excitatory neurotransmitters were without effect. The increase in glycogen level was not blocked by the glutamate receptor antagonist kynurenic acid but was completely blocked by the glutamate uptake inhibitor threo ‐3‐hydroxy‐D,L‐aspartate and by removal of Na + from the medium. Incubation with radiolabeled glucose and glutamate revealed that the increased glycogen content was derived almost entirely from glucose. Glutamate at 1 m M was also found to cause a 53 ± 12% decrease in glucose utilization and a 112 ± 69% increase in glucose‐6‐phosphate levels. These results suggest that the glycogen content of astrocytes is linked to the rate of glucose utilization and that glucose utilization can, in turn, be affected by the availability of alternative metabolic substrates. These relationships suggest a mechanism by which brain glycogen accumulation occurs during decreased neuronal activity.