Development of a LC-ESI-MRM method for the absolute quantification of orexin A in the CSF of individual mice

Abstract

Sleep-wakefulness is disrupted in most neurological and psychiatric disorders. Although clinical data implicate orexin (hypocretin), a crucial sleep/wake regulatory neuropeptide, in such disorders, limited sample volumes effectively prevent quantification of cerebrospinal fluid (CSF) levels of orexin A in mouse models of brain disorders. Current enzyme- and radio-immunoassays for orexin A generally require 50–100 µL CSF, whereas typical CSF sample volumes from mice are ~5–10 µL/mouse. We therefore aimed to develop and validate a liquid chromatography (LC) targeted mass spectrometry (MS) method for the absolute quantification of orexin A in the CSF of individual mice. LC coupled to tandem MS ..