Biogenic amine disturbances in cerebrospinal fluid in parkinsonism and unipolar depression: use of the probenecid method.

Probenecid was administered to 7 unipolar depressed patients, 7 parkinsonians and 7 extrapyramidal patients with senile dementia matched for age and sex. Before and after the administration of probenecid, the levels of 5-hydroxindoleacetic acid (5HIAA) and homovanillic acid (HVA) were determined in the cerebrospinal fluid (CSF) of all patients in order to study the central turnover rate of serotonin and dopamine. Unipolar depressed patients showed a significantly lower increase in CSF 5HIAA levels after probenecid than parkinsonians. Patients with parkinsonism had a reduced increment of CSF HVA levels following probenecid administration when compared to unipolar depressed and extrapyramidal patients with senile dementia. The authors conclude that the biochemical study of CSF biogenic amines using the probenecid method can be used as a highly sensitive biological screening test for diagnosing Parkinson and depressive syndromes among an aging population of retarded, tremoring, rigid and hypokinetic patients.