Abstract: Objective To explore the effect of methyl tertiar y-bitul ether(M T BT)on nNOS and neurotransmitter Glu of brain tissues of fetal mice during gestation.Methods 40 healthy and pregnant K M mice were distributed in five groups randomly.The MT BE exposed doses were 800,400,100,25 and 0 mg/(kg·bw)by gavage from the 0 d to the end of gestation,once perday.The immunohisto-chemical method(SABC method)was used to check the expression of nN OS and neurotr ansmitter Gluin the brain tissues of the fetal mice.Results The expression of then N OS and neurotransmitter Gluin the cerebral cortex,hippocampus and cerebellum of the fetal mice was dereased when the exposed dose was 400 mg/kg·bwand the data showed a dose-effect relationship.Conclusion MTBE can decreased the content and activities of nNOS and neurotransmitter Gluin the braintissue of the fetal mice.