Gamma-aminobutyric acid (GABA), a four-carbon non-protein amino acid, is a significant component of the free amino acid pool in most prokaryotic and eukaryotic organisms. In plants, stress initiates a signal-transduction pathway, in which increased cytosolic Ca2+ activates Ca2+/calmodulin-dependent glutamate decarboxylase activity and GABA synthesis. Elevated H+ and substrate levels can also st...

Levels of gamma-aminobutyric acid (GABA) in cerebrospinal fluid (CSF) were measured by radioreceptor assay (RRA) in 25 normal controls and in 121 patients with various central nervous system disorders. CSF-GABA levels could be measured down to 5 pmoles/ml reliably by this assay. In normal controls, the mean (+/- SEM) GABA level in CSF was 127 +/- 5.2 pmoles/ml. There was no correlation between ...

Background Whilst robust preclinical and postmortem evidence suggests that altered GABAergic function is central to the development of psychosis, little is known about whether it is altered in subjects at ultra-high risk of psychosis, or its relationship to prodromal symptoms. Methods Twenty-one antipsychotic naïve ultra-high risk individuals and 20 healthy volunteers underwent proton magneti...

The antagonists of gamma-aminobutyric acid, bicuculline and picrotoxin, were found to narrow the receptive field profile of the large field horizontal cell (L1HC) in the turtle retina when added to the perfusion medium in micromolar concentrations. The coupling resistance between neighboring L1HCs was increased by bicuculline or picrotoxin. Under control conditions, the dye Lucifer yellow injec...

Enzymatic analyses of Bacillus thuringiensis extracts suggest that a modified Krebs tricarboxylic acid cycle (without alpha-ketoglutarate dehydrogenase) can operate during sporulation in conjunction with the glyoxylic acid cycle and the gamma-aminobutyric acid pathway.