Assessment of cerebrospinal fluid levels of dopamine metabolites by gas chromatography

The acid metabolites of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were determined in lumbar cerebrospinal fluid (CSF) by a new procedure. After gas Chromatographic separation, the pentafluoropropionyl 2,2,3,3,3-pentafluoro-1-propionyl esters of DOPAC and HVA were analyzed by electron capture detection. Normal HVA levels were quantitated in as little as 0.1 ml CSF. No significant amounts of DOPAC (< 1 ng/ml) were found in any of the drug-free samples analyzed. Levels of DOPAC increased only marginally in the CSF of patients receiving acute or chronic doses of lDopa. Baseline HVA levels ranged from 4.5-50 ng/ml with a mean value of 23 ng/ml. These studies demonstrate that HVA is the major dopamine metabolite in human CSF.