In Vivo Solid-Phase Microextraction for Sampling of Oxylipins in Brain of Awake, Moving Rats.

Oxylipins are key lipid mediators of important brain processes, including pain, sleep, oxidative stress, and inflammation. For the first time, an in-depth profile of up to 52 oxylipins can be obtained from the brains of awake moving animals using in vivo solid-phase microextraction (SPME) chemical biopsy tool in combination with liquid chromatography-high resolution mass spectrometry. Among these, 23 oxylipins are detectable in the majority of healthy wildtype samples. This new approach successfully eliminates the changes in oxylipin concentrations routinely observed during the analysis of post-mortem samples, allows time-course monitoring of their concentrations with high spatial resolution in specific brain regions of interest, and can be performed using the same experimental set-up as in vivo microdialysis (MD) thus providing a new and exciting tool in neuroscience and drug discovery.