THE NITRIC-OXIDE SYNTHASE EXPRESSION OF RAT CORTICAL AND HIPPOCAMPAL-NEURONS CHANGES AFTER EARLY LEAD EXPOSURE

The effect of lead exposure in nitric oxide synthase containing neuron s (nNOS) within rat cortex and hippocampus was studied. Lead administr ation (1 g% lead acetate in drinking water) was commenced prior to mat ing and continued until 30 postnatal (PN) days. Immunohistochemical st udies using antibody to nNOS showed, after lead treatment at PN21-PN30 , a reduction in neuronal size and optical density (OD) of nNOS+ cells . In both regions, non-pyramidal immunoreactive neurons exhibited smal ler soma size and less developed dendrites. A significant difference i n cell areas and OD of lead exposed versus control rats and no variati on in the number of nNOS+ neurons was seen. Morphological modification s after early lead exposure,induced nNOS reduction in NOS expressing n eurons thereby interfering in NO synthesis. (C) 1997 Elsevier Science Ireland Ltd.