Activity Changes of Brain Enzymes in Rats Exposed to Different Qualities of Ionizing Radiation
ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD
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The effect of different qualities of ionizing radiation on the activity of brain enzymes involved in the metabolism of neurotransmitters in specific regions of the brain of rats was investigated. Groups of Sprague-Dawley adult male rats were exposed to approximately 20,000 rads of radiation either rich in neutrons or rich in gamma rays from the AFRRI-TRIGA reactor, in the form of a square wave approximately 90 seconds long. It was found that, when the animals were exposed to radiation rich in neutrons, monoamine oxidase activity was pronouncedly decreased in all brain areas studied. In contrast, a very marked increase in the activity of this enzyme was observed when the animals received the same dose of radiation rich in gamma rays. Minor changes were observed in the activities of choline acetyl transferase and RNA polymerase. Acetylcholinesterase activity did not change appreciably.