Abstracts

Rationale: The baboon represents a natural model for inherited generalized, photosensitive epilepsy. As part of a genetic study, cerebrospinal (CSF) monoamine metabolites were determined in a pedigreed colony of Papio h. anubis (PCA), cynocephalus and their hybrids (PCX). Our aim was to first identify any CSF differences within each gender for history of seizures and abnormal EEG (SZ+/EEG+) vs. asymptomatic (CTL) baboons. The analysis was then further broken down between genders. Methods: CSF samples were drawn from the cisterna magna 30 minutes after sedation with RAAK (rompun, acepromazine, atropine, ketamine). Homovanillic acid (HVA), 5-hydroxyindolacetic acid (5-HIAA), and 3-hydroxy-4-methoxyphenylglycol (MHPG) were assayed and analyzed using high-performance liquid chromatography. The CSF monoamine levels were compared within each gender for SZ+/EEG+ vs. CTL. The levels were further compared between genders for (1) the CTL baboons (2) those with interictal epileptiform discharges (IED) and (3) baboons SZ+/EEG+. Metabolite concentrations were compared between the two groups using Independent Samples Student t-tests. Results: An overall decreased trend in CSF monoamine metabolite levels was observed in the SZ+/EEG+ group for both genders, though no significant differences were observed. The decreased trend was most significant for HVA levels, followed by 5-HIAA. Significant differences were noted for MHPG in the CTL and IED+ group between genders, where the level in males was lower than females. Within each gender, the IED+ group had increased levels compared to the CTL group. Conclusions: Decreased CSF levels across all metabolite levels in the SZ+/EEG+ groups within both genders, though not significant, warrants further investigation into the mechanisms potentially responsible for this finding. The increased metabolites in the IED+ group compared to the CTL may represent an adaptive mechanism in baboons with controlled seizures. The lower levels in males in all groups (CTL, IED+, SZ+/EEG+), specifically MHPG, suggest a strong trend supporting epileptic males may be at a higher risk for Sudden Unexpected Death in Epilepsy (SUDEP) than epileptic females. Furthermore, low 5-HIAA levels in epileptic baboons have been previously reported as a potential association for a higher risk of SUDEP.