Expression of nitric oxide system in clinically evaluated cases of Alzheimer's disease.

The expression of neuronal nitric oxide (nNOS) and inducible nitric oxide (iNOS) as isoforms of the nitric oxide synthase (NOS) as well as nitrotyrosine as an end product of protein nitration was analyzed in sections of temporal cortex taken from postmortem brains of patients with Alzheimer's disease (AD). The patients were evaluated by the Clinical Dementia Rating scale (CDR0–CDR3) and studied in the Memory and Aging Project (MAP) of the Washington University Alzheimer Disease Research Center (ADCR). With the use of immunocytochemical procedures, neurons immunoreactive to nNOS were found to show large and small multipolar and pyramidal morphologies over the entire chronic AD evolution. The iNOS and nitrotyrosine immunoreactivities were also found in pyramidal-like cortical neurons and glial cells. Here, we speculate on the interaction among all specific neurodegenerative changes in AD and nitric oxide as an additional contribution to neuronal death in AD.