Biochemical aids in the diagnosis of Parkinson's disease.

Degeneration of dopamine (DA) containing neurons in the basal ganglia of Parkinsonian patients causes a reduction in cerebrospinal fluid (CSF) concentrations of the principal metabolite of dopamine, homovanillic acid (HVA). Not only are steady state HVA levels depressed, but there is substantial diminution in the rate of HVA accumulation in CSF during the oral administration of probenecid, a drug which inhibits HVA transport from the spinal fluid compartment. Two methods for the measurement of HVA in human CSF, employing fluorometry or gas liquid chromatography-mass spectroscopy, are described and the results compared in patients with Parkinsonism as well as other central nervous system disorders.