PROTECTION OF ZINC ON HIPPOCAMPAL NITRIC OXIDE SYNTHASE IN LEAD-EXPOSED RAT

Objective: To investigate the relationship between the effects of lead on LTP in hippocampus and changes of NOS in subfields of hippocampus, and the antagonistic role of zinc. Methods: Y-maze test was applied to study the effects of lead on learning and memory ability in rats; NADPH-d histochemistry and nNOS immunohistochemistry were used to investigate the postischemic changes of nitric oxide synthase(NOS) in different hippocampal subfields in lead-exposed rat. Results: Compared with the control and lead-zinc group, the learning and memory ability of lead-exposed rats was significantly decreased (P0.05); the number of NOS positive neurons and nNOS positive neurons in CA1 and dentate gyrus of lead-exposed rats were significantly decreased (P0.05), but no significant changes in CA3; no difference was found between the control and lead-zinc groups in CA1, CA3 and dentate gyrus. Conclusion: Lead may damage the learning-memory ability of the rats; the effects of lead on LTP in hippocampus might be related to the changes of NOS in different subfields of hippocampus in lead-exposed rats; zinc might play an important role in preventing lead-induced damages.