ABSTRACT
Objective To explore the effects of subchronic arsenic exposure through drinking water on glutamate-glutamine cycle in the brain of mice. Methods The female Kunming mice were exposed to arsenite ( iAsⅢ ) by drinking water at the levels of 25, 50 and 100 mg/L respectively for 6 consecutive weeks. The blood and brain were taken, the concentration of inorganic arsenic (iAs), monomethylarsenic acid (MMA), dimethylarsenic acid (DMA) and the activity of glutamine synthetase (GS), phosphate activated glutaminase (PAG), superoxide dimutase (SOD) and the concentrations of glutamate (Glu), lipidperoxide(LPO) were determined. Results The concentrations of iAs, MMA and DMA in the blood and brains increased as the iAsⅢ concentrations in drinking water increased. The activity of GS, PAG and the concentrations of Glu in the arsenic exposed mice increased compared with the control. The activity of GS in 50 mg/L group, the activity of PAG in 25 and 50 mg/L groups, the concentration of Glu in 100 mg/L group showed a significant difference compared with the control. The activity of PAG in 25 mg/L group was significantly higher than that in 100 mg/L group. The activity of SOD in exposed groups was higher than that in the control, the concentration of LPO in exposed groups did not show a significant difference compared with the control. Conclusion Arsenic can enter the brain and organic arsenic is dominant both in the blood and brain, however, the composition of arsenic speciation is different in the blood and brain. DMA, as a main arsenide, distributed in the brain. Arsenic exposure can change the activity of GS and PAG which can influence the concentration of Glu. Moreover, arsenic exposure can increase the superoxide anion and make the activity of SOD increase compensatively.