title: Quantitative mass spectrometry imaging of small-molecule neurotransmitters in rat brain tissue sections using nanospray desorption electrospray ionization.
abstract: Small molecule neurotransmitters are essential for the function of the nervous system, and neurotransmitter imbalances are often connected to neurological disorders. The ability to quantify such imbalances is important to provide insights into the biochemical mechanisms underlying the disorder. This proof-of-principle study presents online quantification of small molecule neurotransmitters, specifically acetylcholine, γ-aminobutyric acid (GABA) and glutamate, in rat brain tissue sections using nanospray desorption electrospray ionization (nano-DESI) mass spectrometry imaging. By incorporating deuterated internal standards in the nano-DESI solvent we show identification, accurate mapping, and quantification of these small neurotransmitters in rat brain tissue without introducing any additional sample preparation steps. We find that GABA is about twice as abundant in the medial septum-diagonal band complex (MSDB) as in the cortex, while glutamate is about twice as abundant in the cortex as compared to the MSDB. The study shows that nano-DESI is well suited for imaging of small molecule neurotransmitters in health and disease.
authors: Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden. Ingela.Lanekoff@kemi.uu.se.
authors: Hilde-Marléne
authors: HM
authors: Bergman
authors: Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden. Ingela.Lanekoff@kemi.uu.se.
authors: Erik
authors: E
authors: Lundin
authors: Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.
authors: Malin
authors: M
authors: Andersson
authors: Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden. Ingela.Lanekoff@kemi.uu.se.
authors: Ingela
authors: I
authors: Lanekoff
mesh_terms: D000109:Acetylcholine / Q000032:analysis; D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging*; D001923:Brain Chemistry; D005260:Female; D018698:Glutamic Acid / Q000032:analysis; D018377:Neurotransmitter Agents / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards; D021241:Spectrometry, Mass, Electrospray Ionization; D005680:gamma-Aminobutyric Acid / Q000032:analysis
chemical_list: D018377:Neurotransmitter Agents; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D000109:Acetylcholine