Effect of metabolic stress on the release of glutamic acid and GABA in the brain tissue of Mongolian hamsters
Buczek, M.; Harrington, J.F.; Lust, W.D.; Assaf, H.M.; Ratcheson, R.A.
Neurologia i Neurochirurgia Polska Suppl 1: 251-257
1992
ISSN/ISBN: 0028-3843 PMID: 1357567 Document Number: 399483
The concentrations of glutamic acid and GABA were determined in the brain tissue in gerbils under conditions simulating "metabolic stress", that is ischaemia, aglycaemia and anoxia. The material for the determinations was taken from fragments of the hippocampus incubated under these conditions in artificial cerebrospinal fluid, and the concentrations of these neurotransmitters were determined by histochemical methods in vitro. The release of glutamic acid and GABA into the extracellular space increased with longer duration of the incubation in a linear fashion in all experimental groups and was most pronounced in ischaemia. In case of calcium absence in the extracellular space inhibition was observed of the release of these neurotransmitters which suggested an important role of bivalent cations in the regulation of the studied process, especially under control conditions. During anoxia and ischaemia a considerable part of the release of glutamic acid and GABA seems to be calcium-independent which may suggest presence of additional sources of release of the amino acid neurotransmitters, apart from their release from the direct pool. It is possible that these sources are activated during metabolic stress involving nerve cells.