Low lumbar CSF levels of homovanillic acid and 5-hydroxyindoleacetic acid in multiple system atrophy with autonomic failure.

Low lumbar CSF concentrations of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in patients with multiple system atrophy attended by autonomic failure (MSA) reflect decreased activity in central dopaminergic and serotonergic pathways. These neurochemical changes are consistent with the neuropathological involvement in MSA and distinguish such patients from those with pure autonomic failure who have normal CSF metabolite levels.