Amine metabolism in the human brain: Further evaluation of the probenecid test

Abstract

Summary Probenecid inhibits the release of 5-hydroxyindoleacetic acid (5-HIAA, a 5-hydroxytryptamine metabolite) and homovanillic acid (HVA, a dopamine metabolite) from the cerebrospinal fluid (CSF). The relation between probenecid levels in blood and lumbar CSF, after intravenous and oral loading of the drug, was studied. The correlation between the increase in acid levels (HVA and 5-HIAA) and the concentration of probenecid in human lumbar CSF has been determined. A method was described for determination of HVA, 5-HIAA and probenecid in 4 ml lumbar CSF. No correlation between levels of probenecid in plasma and CSF was found. A significant correlation exists between CSF levels of probenecid and the increase of HVA and 5-HIAA in lumbar CSF of patients with various psychiatric abnormalities. These findings indicate that the determination of probenecid in lumbar CSF is of importance in the study of the possible correlation between probenecid induced changes in amine metabolites in CSF and metabolism of amines in the human brain.