Cerebrospinal fluid nitric oxide metabolites in painful diseases.

To elucidate the involvement of NO in pain transmission in humans, we measured NO metabolites (nitrite/nitrate) in the CSF of patients with painful diseases using an NO analyzer based on the Griess method. The nitrite/nitrate levels in patients with degenerative lumbar disease (DLD), but not those with fracture or appendicitis, were significantly higher than those in an age-matched control group. The duration of pain in the DLD group was much longer than that in the fracture or appendicitis group. The nitrite/nitrate levels in the middle-aged and elderly DLD patients depended on the duration of pain. These data probably suggest that the duration of pain is critical for the elevation in nitrite/nitrate levels.