Analysis of intact glucuronides and sulfates of serotonin, dopamine, and their phase I metabolites in rat brain microdialysates by liquid chromatography - tandem mass spectrometry

Päivi Uutela, Ruut Reinilä, Kirsi Harju, Petteri Piepponen, Raimo A Ketola, Risto Kostiainen

    Research output: Contribution to journalArticleScientificpeer-review

    Abstract

    "A method for the analysis of intact glucuronides and sulfates of common neurotransmitters serotonin (5-HT) and dopamine (DA) as well as of 5-hydroxy-3-indoleacetic acid (5-HIAA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in rat brain microdialysates by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. Enzyme-assisted synthesis using rat liver microsomes as a biocatalyst was employed for the production of 5-HT-, 5-HIAA-, DOPAC-, and HVA-glucuronides for reference compounds. The sulfate conjugates were synthesized either chemically or enzymatically using a rat liver S9 fraction. The LC-MS/MS method was validated by determining the limit,; of detection and quantitation, linearity, and repeatability for the quantitative analysis of 5-HT and DA and their glucuronides, as well as of 5-HLAA, DOPAC, and HVA and their sulfate-conjugates. In this study, 5-HT-glucuronide was for the first time detected in rat brain. The concentration of 5-HT-glucuronide (1.0-1.7 nM) was up to 2.5 times higher than that of free 5-HT (0.4-2.1 nM) in rat brain microdialysates, whereas the concentration of DA-glucuronide (1.0-1.4 nM) was at the same level or lower than the free DA (1.2-2.4 nM). The acidic metabolites of neurotransmitters, 5-HLAA, HVA, and DOPAC, were found in free and sulfated form, whereas their glucuronidation was not observed."
    Original languageEnglish
    JournalAnalytical Chemistry
    Volume81
    Issue number20
    Pages (from-to)8417-8425
    Number of pages9
    ISSN0003-2700
    DOIs
    Publication statusPublished - 2009
    MoE publication typeA1 Journal article-refereed

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