Tetrahydrobiopterin (BH_4) is an essential cofactor for biosynthesis of monoamine neurotransmitters including dopamine and serotonin. Here, we report the levels of pteridines, i.e. BH_4, dihydrobiopterin, biopterin, dihydroneopterin, neopterin, in the cerebrospinal fluids (CSF) of patients with neurological diseases including sporadic Parkinson's disease (sPD), frontotemporal dementia (FTD), multiple system atrophy (MSA), and meningitis. Each pteridine was directly measured by a post-column oxidation method. Determination of reduced form of pteridines by a post-column oxidation method in biological fluids, including CSF, serum, and urine, would be useful to monitor the level of oxidative stress in vivo.
