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Importance of Glutamine for γ‐Aminobutyric Acid Synthesis in Rat Neostriatum In Vivo
Author(s) -
Paulsen R. E.,
Odden E.,
Fonnum F.
Publication year - 1988
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.1471-4159.1988.tb03099.x
Subject(s) - glutamine , in vivo , glutamine synthetase , biochemistry , citric acid cycle , tricarboxylic acid , aminobutyric acid , aminooxyacetic acid , chemistry , amino acid , biology , metabolism , enzyme , receptor , microbiology and biotechnology
This work was carried out to evaluate the importance of glial cells in providing precursors for the in vivo synthesis of γ‐aminobutyric acid (GABA). Fluorocitrate, which selectively inhibits the tricarboxylic acid cycle in glial cells, was administered locally in rat neostriatum. Inhibition of the glial cell tricarboxylic acid cycle led to a decrease both in glutamine level and in γ‐vinyl GABA (GVG)‐induced GABA accumulation, an observation indicating reduced GABA synthesis. The role of glutamine, which is synthesized in glial cells as a precursor for GABA, was further investigated by inhibition of glutamine synthetase with intrastriatally administered methionine sulfoximine. In this case, the glutamine level was reduced to near zero values, and the GVG‐induced GABA accumulation was only half that of normal. The results show that glutamine is an important precursor for GABA synthesis, but it cannot be the sole precursor because it was not possible to depress the GVG‐induced GABA accumulation completely.