A sensitive and practical RP-HPLC-FLD for determination of the low neuroactive amino acid levels in body fluids and its application in depression. (11th March 2016)

• Record Type: Journal Article
• Authors: Wu, Juan-Li; Yu, Si-Yang; Wu, Shi-Hua; Bao, Ai-Min
• Is Part Of: Neuroscience letters. Volume 616(2016)
• Page Start: 32
• Page End: 37
• Publication Date: 2016-03-11
• Subjects: CSF cerebrospinal fluid -- AAs amino acids -- HPLC high performance liquid chromatography -- FLD fluorescence detection -- OPA o-phthaldialdehyde -- MPA β-mercaptopropionic acid -- THF tetrahydrofuran -- TEA triethanolamine -- MDD major depressive disorder -- HClO4 perchloric acid; Amino acids -- HPLC -- Cerebrospinal fluid -- Plasma -- Major depressive disorder; Neurology -- Periodicals; Neurology -- Periodicals; Research -- Periodicals; Neurologie -- Périodiques; Neuroanatomie -- Périodiques; Neuropharmacologie -- Périodiques; Neurophysiologie -- Périodiques; Neurology; Periodicals; Electronic journals; 617.48
• DOI: 10.1016/j.neulet.2016.01.024
• Languages: English
• ISSNs: 0304-3940

Abstract

Graphical abstract: Highlights: Detection of amino acids in the cerebrospinal fluid is also of clinical importance. HPLC measurements of CSF amino acids (AAs) levels is challenging due to low levels. Improved protocol for HPLC detection for CSF-AAs measurement is presented. Improvement was achieved by modifying pH, derivatization and mobile phases. The improved protocol is applicable for detection of other neuroactive AAs. Abstract: Ion-exchange high performance liquid chromatography (HPLC) generally fails as a method to determine low levels of free amino acids (AAs) in body fluids. Here we present a modified reversed-phase HPLC (RP-HPLC) protocol for the determination of AAs in body fluids and its application in mood disorder patients. We improved a previous research protocol by modifying i) sample preparation, including deproteination, ii) derivitization, including derivating agent and condition, and iii) sample separation, which is mainly determined by the pH value, the components and the additives of the mobile phases. The combination of these modifications, together with fluorescence detection (FLD), allows sensitive and practical determination of free AA levels in body fluids of depressive patients. This protocol was validated by determining the postmortem cerebrospinal fluid (CSF) glutamic acid (Glu) and γ-aminobutyric acid (GABA) levels of 8 major depressive disorder (MDD) patients, 9 bipolar disorder (BD) patients, and 19 well-matched controls, while also testing the plasma and CSF AA levels of living MDD patients. CSF Glu and GABA levels were both significantly decreased in MDD but not in BD patients. The data indicate that this RP-HPLC-FLD protocol is applicable for detection of low levels of neuroactive AAs in body fluids, as well as for routine clinical applications.