Reduction in asymmetrical dimethylarginine, an endogenous nitric oxide synthase inhibitor, in the cerebrospinal fluid during aging and in patients with Alzheimer's disease

To investigate the significance of nitric oxide (NO) -mediated neuron death in aging and Alzheimer's disease (AD), the concentration of asymmetrical d imethylarginine (ADMA), an endogenous NO synthase inhibitor, in the cerebro spinal fluid was determined in neurologically normal controls and patients with AD. The ADMA concentration significantly decreased with age, whereas t he arginine concentration was unaltered. In patients with AD, the ADMA conc entration was significantly decreased, compared with controls of a similar age (-48%, P = 0.0001), and it significantly decreased with decreasing cogn itive functions (r(s) = 0.58, P < 0.05), whereas the arginine concentration did not change. These findings suggest that ADMA may play an important rol e in regulating NO synthesis in brain aging and AD. (C) 2001 Elsevier Scien ce Ireland Ltd. All rights reserved.