(N21) Characterization of Endocannabinoids in the CSF and Serum of Dogs with Idiopathic Epilepsy

Abstract:

Background: Endocannabinoids have been implicated in the pathogenesis of seizures. Specifically, an endocannabinoid, anandamide (AEA), has been shown to be elevated in the CSF of dogs with idiopathic epilepsy (IE), compared to healthy dogs. This study aimed to evaluate AEA, 2-arachydonoylglycerol (2-AG), and three metabolites of AEA (prostamides) in the CSF and serum of dogs with poorly-controlled IE (PCIE), well-controlled IE (WCIE), and healthy controls (HC).

Objective: We hypothesized higher AEA and prostamides in PCIE compared to HC and WCIE dogs and that 2-AG would not be different between groups.

Animals: Banked samples from 47 dogs were included in this study. Epileptic dog samples were collected during routine workups. Healthy control samples were collected as part of other (unrelated) studies.

Methods: There were 47 banked CSF and 34 paired serum samples. Dogs were deemed PCIE with >2 seizures per month and WCIE with < 2 seizures per month. All samples were analyzed using liquid chromatography-mass spectrometry.

Results: Prostamides were below detectable limits in all samples. Serum AEA was higher in PCIE compared to other groups (p = 0.0007). There were no differences in 2-AG levels in any group. Serum AEA was lower in dogs with seizures ≤4 days from collection compared to those collected >4 days after the most recent seizure (p = 0.0392).

Conclusions: This supports previous research and suggests AEA has a role in IE that requires further analysis. Prostamide levels were below detectable limits in this study and may not be significant in IE.