Altered Gamma-Aminobutyric Acid Metabolism Early in the Postirradiation Response of the Rat

The metabolism of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) was studied in rats subjected to 10,000 or 20,000 rads of pulsed mixed gamma-neutron radiation. Whole brain GABA levels were found to rise above control levels by 20 minutes following 10,000 rads and as early as one minute following 20,000 rads. L-glutamic acid decarboxylase activity was also observed to rise as early as one minute following either dose of radiation. The results are consistent with the hypothesis that GABA is involved in the etiology of the transient central nervous system disorders (apathy, disorientation, ataxia) observed in rats shortly after high doses of ionizing radiation.