The baboon represents a natural model for genetic generalized epilepsy and 
sudden unexpected death in epilepsy (SUDEP). In this retrospective study, 
cerebrospinal fluid (CSF) monoamine metabolites and scalp electroencephalography 
(EEG) were evaluated in 263 baboons of a pedigreed colony. CSF monoamine 
abnormalities have been linked to reduced seizure thresholds, behavioral 
abnormalities and SUDEP in various animal models of epilepsy. The levels of 
3-hydroxy-4-methoxyphenylglycol, 5-hydroxyindolacetic acid and homovanillic acid 
in CSF samples drawn from the cisterna magna were analyzed using 
high-performance liquid chromatography. These levels were compared between 
baboons with seizures (SZ), craniofacial trauma (CFT) and asymptomatic, control 
(CTL) baboons, between baboons with abnormal and normal EEG studies. We 
hypothesized that the CSF levels of major monoaminergic metabolites (i.e., 
dopamine, serotonin and norepinephrine) associate with the baboons' 
electroclinical status and thus can be used as clinical biomarkers applicable to 
seizures/epilepsy. However, despite apparent differences in metabolite levels 
between the groups, usually lower in SZ and CFT baboons and in baboons with 
abnormal EEG studies, we did not find any statistically significant differences 
using a logistic regression analysis. Significant correlations between the 
metabolite levels, especially between 5-HIAA and HVA, were preserved in all 
electroclinical groups. While we were not able to demonstrate significant 
differences in monoamine metabolites in relation to seizures or EEG markers of 
epilepsy, we cannot exclude the monoaminergic system as a potential source of 
pathogenesis in epilepsy and SUDEP. A prospective study evaluating serial CSF 
monoamine levels in baboons with recently witnessed seizures, and evaluation of 
abnormal expression and function of monoaminergic receptors and transporters 
within epilepsy-related brain regions, may impact the electroclinical status.