ABSTRACT
Objective To observe the adverse effect of methylmercury on the cortex and cerebellum respectively as well as to approach the antagonisms of dextromethorphan(DM) and riluzole to the mercury-induced neurotoxicity.Methods Twenty-eight Wistar rats were randomly divided into 4 groups by weight,7 in each.The first group was the control group and the second group was methylmercuric chloride(MMC) group.The third and fourth groups were DM and riluzole group respectively.Both of the former groups were subcutaneously injected with saline.The third and fourth groups were subcutaneously injected with 13.5 ?mol/kg DM and 21.35 ?mol/kg respectively every other day.Two hours later,the animals in the control group were intraperitoneally given the injection of saline.From the second to fourth groups were injected with 12.0 ?mol/kg MMC.The administration of MMC above was given five times a week(from Monday to Friday),for 4 weeks as well as the administration of DM and riluzole every other day before injected with MMC(on Monday,Wednesday and Friday).Twenty-four hours after the last injection,7 rats in each group were sacrificed.The contents of Hg,Ca2+-ATPase in the cerebellum were determined.Results In MMC group,the contents of Hg,Glu and the content of Gln were decreased,the activities of SDH,Na+-K+-ATPase and Ca2+-ATPase were decreased compared with the control group.Compared with MMC group,in DM and riluzole groups,the contents of Hg,Glu decreased,the content of Gln increased,moreover,the activities of SDH,Na+-K+-ATPase and glutamate(Glu),glutamine(Gln) in the rat cortex and the activities of SDH,Na+-K+-AT Pase and Ca2+-AT Pase increased significantly.Conclusion "Glu-Gln Cycle" can be destroyed by MMC,DM and liluzole present some antagonistic effects on MMC-indused neurotoxicity in rats.
ABSTRACT
Objective To determine the antagonism of dizocilpine maleate(MK-801) and taurine to glutamate metabolism disturbance induced by methylmercury(MeHg) in cerebrum.Methods Forty Wistar rats were randomly divided into five groups.The first group was the control group,the second one was low dose MeHg-exposed group and the third was high dose MeHg-exposed group,these three groups were given physiological saline respectively.The fourth group was subcutaneously injected with 0.3 ?mol/kg of MK-801 and the five group was subcutaneously injected with 1 mmol/kg of taurine.Two hours later,the control group was intraperitoneally given physiological saline,the second group was intraperitoneally given 4 ?mol/kg of methylmercury chloride,the third,fourth and five groups were given 12 ?mol/kg of methylmercury chloride.The administration above was given five times a week for 4 weeks.The contents of mercury and Glu and Gln and the activities of GS and PAG in pallium were determined.Results Compared with the control group,the activities of PAG and the contents of mercury and Glu in MeHg-exposed groups increased significantly,the activities of GS and the contents of Gln decreased significantly.Compared with high dose MeHg group,in MK-801 and taurine treated groups,no significant differences were seen in the contents of mercury,and the contents of Glu,the activities of PAG were decreased significantly,the contents of Gln and the activities of GS were increased significantly.Conclusion Methylmercury can disorder glutamate metabolism in cerebrum of rats,and MK-801 and taurine can effectively counteract the adverse effects of methylmercury.