The toxicity of the protein β-amyloid (βA) is correlated with the production of oxidative stress by nitric oxide (NO) production. The last meeting we show that this fraction increase the neural death into hippocampus (Limon et al.,Abs 842.5, SFN 2003). NO is a free radical that produce cellular damage and cellular death. The βA damage is present into the frontal cortex (CX) and hippocampus (Hp) in senile patients with Alzheimer’s Disease (AD). However is unclear about the effect on early stages. The aim of this investigation was evaluate the effect of 25-35 βA fraction on nitric oxide levels into CX and Hp of neonatal rats. Males and females Wistar rats of seven postnatal day (PD7), were used. We injected 1 µl of 25-35 β A fraction [100µM] previously incubated at 37°C x 24 hrs was by stereotaxic surgery into CX. The groups with four, eight and sixteen hours post-administration were sacrificed and measure the NO levels by the Griess reaction in CX and Hp. Four hours post-administration, we found that NO lev...