ABSTRACT
<p><b>AIM</b>To investigate the causative role of nitric oxide synthase (NOS) and nitric oxide (NO) in neurotoxicity of beta-amyloid (Abeta) and the pathogenesis of Alzheimer's disease (AD).</p><p><b>METHODS</b>Using behavioral and neuropathological methods, we observed the effects of Abeta(1-40) injection into hippocampi on rats learning and memory in Y maze and on the neuropathology in hippocampi. The intervention by intraperitoneal administration of aminoguanidine (AG), a selective inducible NOS (iNOS) inhibitor, and 7-nitroindazole (7-NI), a selective neuronal NOS (nNOS) inhibitor, in the neurotoxicity of Abeta(1-40) was studied then.</p><p><b>RESULTS</b>The capability of acquisition and retrieval in Y maze and local neurons in hippocampus of the rats were impaired significantly after Abeta(1-40) injection. Intraperitoneal administration of AG, but not 7-NI, could prevent the damages caused by Abeta(1-40) injection above-mentioned.</p><p><b>CONCLUSION</b>iNOS/NO participates in the mechanisms of Abeta-induced neurotoxicity and may play an important role in the pathogenesis of AD.</p>