Sites of origin in the central nervous system of monoamine metabolites measured in human cerebrospinal fluid.

The concentrations of homovanillic acid (HVA) and 5-hydroxyindole-acetic acid (5-HIAA) were measured in five cases with partial or complete block of CSF circulation, at various levels. Determinations were made in both a lumbar and a cisternal, or `mixed', sample obtained during pneumoencephalography. Most of the HVA appears to enter the ventricular system at the lateral ventricles, whereas much of the 5-HIAA in CSF originates in lower neuronal structures, including the spinal cord. The spinal contribution to the 5-HIAA content of lumbar CSF is of the order of 23-37%.