title: Microdialysis of melatonin in the confluens sinuum of the rat following quantification by gas chromatography-mass spectrometry in the negative chemical ion mode.
abstract: In this study, an original surgical implantation technique in the confluens sinuum via the superior sagittal vein was developed to quantify melatonin secretion by the pineal gland. Melatonin (CAS 73-31-4) was determined using gas chromatography couples to negative ion chemical ionisation mass spectrometry following liquid extraction and derivatisation by penta-fluoropropionic acid anhydride (PFPA). The minimum detectable amount was 40 fg per injection, corresponding to 1 pg.ml-1 in dialysate. The assay was linear in the range 20-1000 pg.ml-1. This method was suitable for routine melatonin determination in dialysats of peripheral and central circulation with coefficients of variation of 11.2 and 24.6%, respectively for within and between analyses. Profiles of melatonin concentration were obtained (n = 3 rats) over a 2-day experimentation with a slowly diminution of the filtration capacity of the probe during the second day. The nocturnal concentrations of melatonin in the confluens sinuum dialysat ranged from 1003.9 to 2345 pg.ml-1 in the dialysat, indicating wide interindividual variations in the melatonin levels.
authors.affiliation: Laboratoire de Cinétique des Xénobiotiques, Faculté des Sciences Pharmaceutiques, Toulouse, France.
authors.forename: H
authors.initials: H
authors.lastname: Boudra
authors.forename: S
authors.initials: S
authors.lastname: Saivin
authors.forename: P
authors.initials: P
authors.lastname: Delagrange
authors.forename: M F
authors.initials: MF
authors.lastname: Malmary
authors.forename: P
authors.initials: P
authors.lastname: Genissel
authors.forename: G
authors.initials: G
authors.lastname: Houin
mesh_terms: D000818:Animals; D002138:Calibration; D002940:Circadian Rhythm / Q000502:physiology; D004388:Dura Mater / Q000737:chemistry* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D008550:Melatonin / Q000032:analysis* / Q000378:metabolism; D017551:Microdialysis; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results
chemical_list: D008550:Melatonin