Changes in free amino acid contents of rat brain induced by exposure to methyl bromide

Rats were exposed to methyl bromide (MB) for 24 h at 10-120 ppm or for 3 weeks at 1-10 ppm. Changes in free amino acid contents of rat midbrain were measured by high-performance liquid chromatography (HPLC). MB increased glutamine and aspartic acid contents dose-dependently by short-and long-term exposure. Alanine content was markedly increased by long-term exposure to 10 ppm MB. Glycine was dose-dependently increased, except at 120 ppm. The harmful effect of MB on the central nervous system is discussed in relation to the changes in amino acid metabolism.