THE EFFECT OF ARSENIC TRIOXIDE ON BRAIN MONOAMINE METABOLISM AND LOCOMOTOR-ACTIVITY OF MICE

The arsenic trioxide (AsT) content, and monoamine levels in the cerebral cortex, hippocampus, hypothalamus and corpus striatum were determined in mice administrated AsT (3 and 10 mg/kg) for 14 days. The vertical and horizontal motor activity was also examined. The AsT content in discrete brain areas differed but was clearly dose-dependent. Metabolites of norepinephrine and dopamine increased in the cerebral cortex, hippocampus and hypothalamus and decreased in the corpus striatum in AsT-treated mice. Metabolites of 5-hydroxytryptamine increased in all the discrete brain areas. The vertical and horizontal motor activity was increased by AsT at 3 mg/kg and decreased by AsT at 10 mg/kg. These results show that AsT modifies CNS metabolism and function at low doses. AsT penetrates the blood-brain barrier to cause these effects.