Protection of zinc on hippocampal nitric oxide synthase in lead-exposed rats

To investigate the relationship between the effects of lead on long term potentiation(LTP) in hippocampus and changes of nitric oxide synthase(NOS) in subfields of hippocampus, and the antagonistic role of zinc.Y-maze test was applied to study the effects of lead on learning and memory ability in rats; NADPH-d histochemistry and nNOS immunohischemistry were used to investigate the activity and protein expression of NOS in different hippocampal subfields in lead-exposed rat.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 neuronal nitric oxide synthase(nNOS) positive neurons in CA_1 and dentate gyrus of lead-exposed rats were significantly decreased(P0.05), but no significant changes in CA_3; no difference was found between the control and lead-zinc groups in CA_1, CA_3 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.