Objective:To investigate the changes of nitric oxide(NO)content and nitric ox-ide syn thase(NOS)activity in the serum of patients with brain tumor and the both antioxide properties and cerebral protective effect of propofol in vivo during the operation.Method:Twenty patients sched-uled for brain tumor resection were divided randomly into propofol group and control(isoflurance)group.Forty blood donors were as normal control.Results:Both NO content and NOS activity were signifi-cantly in creased before the ...