GABA concentrations in forebrain areas of suicide victims.

Concentrations of GABA and seven other amino acids, including the neurotransmitters or neuromodulators taurine, glycine, aspartate, and glutamate, were determined in postmortem brain samples from suicide victims and normal controls. The five brain areas (caudate nucleus, nucleus accumbens, frontal cortex, amygdala, and hypothalamus) contained very similar concentrations of the amino acids in both groups. The only significant difference between the groups was a low glutamine concentration in the hypothalamus of suicide victims. Even when the data were adjusted for differences in tryptophan concentration, a putative biochemical index for agonal and postmortem changes of brain tissue, no new differences emerged in the concentrations of neuroactive amino acids between suicide victims and control subjects.