Effects of exposure to amitraz on noradrenaline, serotonin and dopamine levels in brain regions of 30 and 60 days old male rats

The effects of amitraz oral exposure (20, 50 and 80 mg/kg bw, 5 days) on brain region monoamine levels of male rats at 30 and 60 days of age were examined. The amitraz-treated rats at the oral doses of 20 and 50 mg/kg bw had no visible injury, i.e., any clinical signs of dysfunction observed in any of the animals. However, rats treated with amitraz at the highest dose (80 mg/kg bw, 5 days) showed a slight motor incoordination after 1-2 h of treatment. These signs were reversible approximately at 6 h after dose. After the last dose of amitraz, NE, DA and 5-HT and its metabolites levels were determined in the brain regions hypothalamus, midbrain, prefrontal cortex, striatum and hippocampus by HPLC. Amitraz caused changes in the NE, DA and 5-HT and their metabolite levels in a brain regional-, dose- and age-related manner. In the brain regions studied, amitraz induced a statistically significant increase in 5-HT. NE and DA content with age interaction, but the NE increases in prefrontal cortex and hippocampus was without age interaction. Moreover, in the brain regions studied, amitraz induced a statistically significant decrease in the metabolite 5-HIAA, MHPG, DOPAC and HVA levels displaying an age interaction, excepting the SHIM decrease in midbrain and the DOPAC decrease in hypothalamus and striatum which were without age interaction. Furthermore, amitraz evoked a statistically significant decrease in 5-HT, NE and DA turnover in the brain regions studied. The present findings indicate that amitraz significantly altered CNS monoaminergic neurotransmitters in a brain regional-, dose- and age-related manner. (c) 2013 Elsevier Ireland Ltd. All rights reserved.