Determination of dimethylarginine levels in rats using HILIC‐MS/MS: An in vivo microdialysis study

Abstract

Nitric oxide (NO) is one of the most important mediators and neurotransmitters and its levels change under pathological conditions. NO production may be regulated by endogenous nitric oxide synthase (NOS) inhibitors, in particular asymmetric dimethylarginine (ADMA). Most of the interest is focused on ADMA, since this compound is present in plasma and urine and accumulation of ADMA has been described in many disease states but little is known about cerebrospinal fluid (CSF) concentrations of this compound and of its structural isomer symmetric dimethylarginine (SDMA). To determine the levels of methylarginines, we here present a new hydrophilic interaction chromatography (HILIC)-MS/MS method for the precise determination of these substances in CSF from microdialysis samples of rat prefrontal cortex (PFC). The method requires only minimal sample preparation and features isotope-labelled internal standards.

Intracerebral Administration of S-Adenosylhomocysteine or S-Adenosylmethionine Attenuates the Increases in the Cortical Extracellular Levels of Dimethylarginines Without Affecting cGMP Level in Rats with Acute Liver Failure

“…Separation was started with setting up MRM transitions that were highly specific for each compound. Using transitions 203.15 > 46.11 (collision energy 14) for ADMA and 203.15 > 172.17 (collision energy 12) for SDMA, we saw no crosstalk between signals of both compounds as it was previously reported in literature (Martens-Lobenhoffer et al 2012; Zotti et al 2008). …”

Cerebrovascular reactivity and cerebral perfusion of rats with acute liver failure: role of L‐glutamine and asymmetric dimethylarginine in L‐arginine‐induced response

“…Using transitions 203.15 > 46.11 (collision energy 14) for ADMA we saw no crosstalk between signals of both compounds in accordance with previous reports (Zotti et al . ; Martens‐Lobenhoffer and Bode‐Böger ). Monitored transmission for ADMA‐D6 (IS) was 209.19 > 164.19 (collision energy 15).…”

Recent advances in application of hydrophilic interaction chromatography for quantitative bioanalysis

“…An added value with HILIC in the light that biomarkers can be chemically unstable is that a simple protein precipitation procedure followed by direction injection is feasible for sample preparation. There have been many reports in the literature using this approach for quantitation of biomarkers such as dimethylarginine 100–102, ornithione 103, GABA (γ‐aminobutyric acid) 104, acetylcholine 105, methylalonic acid 89, and so on. Orthogonal sample preparation and chromatographic separation such as RP‐SPE‐HILIC and mixed‐mode SPE‐HILIC have also been employed to achieve extensive sample cleanup in quantitation of melamine 106, nucleosides 107, S ‐adenosylmethionine 58, glutathione 108, etc .…”