Determination of p-hydroxyphenylacetic acid in cerebrospinal fluid by high-performance liquid chromatography with electrochemical detection.

Using reversed-phase high-performance liquid chromatography and electrochemical detection with a rapid one-step purification on a Sephadex G-10 column, we have developed a sensitive technique to measure p-hydroxyphenylacetic acid, the oxidatively deaminated metabolite of p-tyramine. The metabolite was measured in cerebrospinal fluid with high recovery and precision. Concentrations of p-hydroxyphenylacetic acid ranged from 4.2 to 17.0 ng/ml with a mean value of 7.8 ng/ml +/- 1.1 SEM in lumbar cerebrospinal fluid of 11 control patients. In a preliminary analysis, the concentrations in schizophrenic patients were significantly lower than those in controls. Since p-hydroxyphenylacetic acid in cerebrospinal fluid seems to be derived from the brain, this finding may indicate a decrease in brain formation. The present method should be useful in clinical investigations to clarify a functional role of p-tyramine in the brain.