EFFECT OF LEAD ON NOS IN CENTRAL NERVOUS SYSTEM OF RATS.

Changes of the NOS activity and the expression of NOS protein in central nervous systems of rats,which were subacutely intoxicated with oral exposure to lead acetate for 30 days,were observed with improved NADPH techniques and immunohistochemistry to study neurotoxic mechanism of lead.The rats were divided into five groups.Three groups were exposed to 1 0g/L、5 0g/L and 20 0g/L of lead acetate in drinking water,respectively.Positive control was 1 0g/L aspartic acid.Negative control was tap water.Results showed that the activity of NOS enzyme were dramatically suppressed in both hippocampus and cerebellum,but the expression of iNOS protein were higher than those in controls with immunohistochemical method.It revealed that lead could restrain NOS at the enzyme activity level,which probably is one of important molecular mechanism of the damage in learning and memory functions.