Study On Neurotoxicity Of Coumaphos,Profenofos And Paclobutrazol Involving Neurotransmitters

Coumaphos,profenofos and paclobutrazol are widely used worldwide.However,their toxicities have been not comprehensively evaluated on organisms,such as neurotoxicity.Neurotransmitters play critical roles in signal transmission.The change in concentration of neurotransmitters and their metabolites can indicate the influence of pollutants on nervous system.This study investigated the effects of coumaphos,profenofos and paclobutrazol on cholinergic,dopaminergic,noradrenergic and serotoninergic neurotransmission system in mice.Besides,integrated biomarker response(IBR)was also employed to evaluate neurotoxicity of these pesticides.The main results were listed as follows:Exposure to coumaphos resulted in decsrease of serotonin(5-HT)and its metabolite 5-hydroxyindole-3-acetic acid(5-HIAA),but increase of the turnover(5-HIAA/5-HT).The concentrations of NE(norepinephrine)were observed to decrease,while the concentrations of MNE(normetanephrine)and turnover(MNE/NE)increased.Besides,the concentrations of ACh(acetylcholine)and DA(dopamine)increased in the serum.There were no obvious effects on 5-HT and NE in the mice exposed to profenofos.But,the concentrations of their metabolites and turnover were found to significantly decrease.Meanwhile,the concentrations of DA and ACh increased.Paclobutrazol exposure reduced the concentrations of 5-HT,5-HIAA and turnover(5-HIAA/5-HT)and elevated the concentrations of NE,DA and ACh.Moreover,the concentrations of MNE and turnover(MNE/NE)decreased.The IBR results indicated that the neurotransmitters in mice were activated at the beginning of exposure to coumaphos,recoveried in the middle stage of exposure,and activated again at the end of exposure.Profenofos activated the neurotransmitters at the first week of exposure.However,the changes in neurotransmitters were not observed in the following two weeks.At the end of four-week exposure,the IBR values decreased in males.The effects of paclobutrazol was similar to those of profenofos with a little difference.The neurotransmitters were observed to be inhibited in both females and males exposed to profenofos.The neurotoxicity order was determined for the three pesticides as:paclobutrazol>coumaphos>profenofos.The difference of toxicity in sex was:males>females.Coumaphos,profenofos and paclobutrazol showed adverse effects on various neurotransmission systems in mice with different patterns.The results in the present study provide new insights for the neurotoxicity of these pesticides.