Quantitative profiling of endocannabinoids and related N-acylethanolamines in human CSF using nano LC-MS/MS.

Endocannabinoids, a class of lipid messengers, have emerged as crucial regulators of synaptic communication in the central nervous system (CNS). Dysregulation of these compounds has been implicated in many brain disorders. Although some studies have identified and quantified a limited number of target compounds, a method that provides comprehensive quantitative information on endocannabinoids and related N-acylethanolamines (NAEs) in CSF is currently lacking as measurements are challenging due to low concentrations under normal physiological conditions. Here we developed and validated a high-throughput nano liquid chromatography-electrospray ionization mass spectrometry (nano LC-ESI-MS/MS) platform for the simultaneous quantification of endocannabinoids (anandamide (AEA), 2-arachidonoyl glycerol (2-AG)), ten related NAEs and eight additional putatively annotated NAEs in human CSF. Requiring only 200 μL of CSF our method has limits of detection from 0.28 to 61.2 pM with precisions of RSD <15% for most compounds. We applied our method to CSF from 45 healthy humans and demonstrated potential age and gender effects on concentrations of endocannabinoids and NAEs. Notably, our results show that docosahexaenoyl ethanolamide (DHEA) concentrations increase with age in males. Our method may offer new opportunities to gain insight into regulatory functions of endocannabinoids in the context of (ab)normal brain function.

Copyright © 2016, The American Society for Biochemistry and Molecular Biology.