Effect Of Subchronic Exposure To Arsenic On Levels Of Monoamine Neurotransmitters In Cerebrum And Cerebellum Of Mice

Objective: To study effects of subchronic exposure to arsenic on levels of monoamine neurotransmitters in cerebrum and cerebellum of mice as to provide the evidence of molecular target for exploring mechanism of As neurotoxicity.Methods: 70 mice were divided into 7 groups with 10 for each, Group 1 received drinking distilled water alone (control). Group 2, 3 and 4 received 1 ppm , 2 ppm and 4 ppm As2O3. Group 5 and 6 received both 4 mg/L As2O3 and 150 mg/kg taurine or 45 mg/kg Vit C (as interfering groups), respectively, Group 7 received 4 ppm As2O3 for 30days, arsenic trioxide of other groups was given through drinking water for 60 days and taurine or Vit C was poured into stomach twice a week. On the 30th or 60th day after As exposure, mice were decapitated and their brains were removed, then the monoamine neurotransimitters norepinephrine (NE), dopamine (DA), serotonin (5-HT)of cerebrum and cerebellum were measured by HPLC with fluorescence detector as describerd elsewhere. Data were presented as mean±standard deviation (SD). All data were analyzed with SPSS11.0 for windows. Difference in mean values between groups was tested with the one-way ANOVA. p values less than 0.05 or 0.01 were considered significant.Results: There were significant differences in concentration of NE, DA, 5-HT between three experimental groups and control group in cerebrum and cerebellum (P<0.05); There were no changes in 5-HT levels after As2O3 treatment in 2 ppm and 4 ppm groups between 1 ppm group in cerebrum and there were no changes in DA levels after arsenic treatment in 2 ppm and 4 ppm groups compared to 1 ppm group in cerebellum. A significant change was observed in NE, DA levels in 2 ppm and 4 ppm groups compared to 1 ppm group (P<0.05) and a significant change was observed in NE, 5-HT levels in 2 ppm and 4 ppm groups compared to 1 ppm group (P<0.05) ;the concentrations of monoamine neurotransmitter in the experimental groups increased in a time-dependent manner in cerebrum and cerebellum of mice exposed to 4 ppm As2O3 for 0 days, 30days and 60days; there were significant differences in concentration of NE, DA, 5-HT between 4 ppm, 4 ppm+VitC, 4 ppm+Taurine groups and control group in cerebrum and cerebellum (P<0.05); there were almost no significant differences among the 4 ppm, 4 ppm+VitC, 4 ppm+ Taurine groups.Conclusion: Subchronic low-dose exposure to arsenic decrease the content of NE, DA, 5-HT in cerebrum and cerebellum of mice. The decrease of NE,DA and 5-HT may be one mechanism of the toxicity of arsenic on the neurobehavior of mice. The reduction of monoamine neurotransmitters induced by As was mitigated by the coadministration of taurine or Vit C;...