Abstract: ObjectiveTo explore the acute toxic mechanism of methyl tertiary butyl ether(MTBE)by detecting the Fos protein expression,the activity of Na⁺,K⁺-ATPase,Ca²⁺-ATPase and the structure changes of nerve cell and neuroglia in the cerebral cortex Methods 66 adult SD rats were randomly divided into control and experimental groups.The MTBE exposure dose was 0,700,1 050,1 400 mg/(kg·bw)and the control group with the same doses of normal saline njected into abdominal cavity.The immunohistochemical method(SABC method)was used to detect the Fos protein in the cerebral cortex.The spectrophotometric method was used to measure the activity change of the Na⁺,K⁺-ATPase,Ca²⁺-ATPase in the cerebral cortex.The patholog ical study(Nissl staining)and immunohistochemical method(GFAP)were performed with optical microscope to observe histopathological changes in nerve cell and neuroglia cell of the cerebral cortex.ResultsThe expression of the Fos protein in cerebral cortex was increased when ex posed to MTBE 700,1 050,1400 mg/(kg·bw).The expression of the Fos protein in cerebral cortex was changed in different time(0.5,1.0,2.0,4.0,8.0 h)afterexposed to MTBE 1.050 mg(kg·bw)2 The expression of the Fos began to increase in 0.5 h and reached the peak at 1.0 h,and then reduced in 2.0h,recovred to normal level in 8.0 h.The activity of Na⁺,K⁺-ATPase,Ca²⁺ATPase in cerebral cortex decreased dramatically in 1.0 h compared with the contro l(P<0.05).The activity of Na⁺,K⁺-ATPase,Ca²⁺-ATPase recovered to nor mal level(P>0.05)in 8.0 h.The structure change was not observed obviously in the nerve cell and the neurog lia.ConclusionThe acute toxic effect of MTBE can be resulted in the cerebrum.MTBE can reduce the activity of the Na⁺,K⁺-ATPase,Ca²⁺-ATPase,affect the energy metabolism of the nerve cell following the inhibitory action of cerebrum.The structure changes of the nerve cell and the neuro glia are not observed obviously when MTBE has an acute toxic effect on cerebr um.