title: Determination of gamma-aminobutyric acid levels in human cerebrospinal fluid using Pseudomonas.
abstract: The principle objective was to demonstrate the efficacy of a bacterial, radioligand, competitive binding method in determining gamma-aminobutyric acid (GABA) levels in human cerebrospinal fluid (CSF). In a double blind study, CSF GABA concentrations were measured by the bacterial method using a mutant of Pseudomonas fluorescens and by a standard radioligand competitive binding assay using rat brain membranes. Linear regression analysis demonstrated a highly significant correlation (r = 0.84; P < 0.001) between the two methods. In an ancillary study, a similar correlation (r = 0.90; P < 0.001) was found between the bacterial method and HPLC, another standard procedure in determining CSF GABA levels. Furthermore, the mean CSF GABA measurements found with the bacterial method were in agreement with those reported in the literature using the brain membrane method or HPLC. The bacterial method was highly reproducible and reliable with a detection to 5 nM GABA. It was specific for GABA and was not affected by other naturally occurring compounds which are found in higher concentrations in CSF than GABA or which were suspected to interfere with the neurotransmitter in a binding assay. The bacterial radioligand method was shown to be an accurate, sensitive, and rapid assay for CSF GABA.
authors.affiliation: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Evansville 47712, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Nicholson-Guthrie
authors.forename: G D
authors.initials: GD
authors.lastname: Guthrie
authors.forename: E C
authors.initials: EC
authors.lastname: Daly
authors.forename: C S
authors.initials: CS
authors.lastname: Shuck
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000648:ultrastructure; D002021:Buffers; D002555:Cerebrospinal Fluid / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004311:Double-Blind Method; D006801:Humans; D016014:Linear Models; D008297:Male; D008566:Membranes / Q000378:metabolism; D008875:Middle Aged; D011551:Pseudomonas fluorescens / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011869:Radioligand Assay / Q000379:methods*; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D005680:gamma-Aminobutyric Acid / Q000134:cerebrospinal fluid*
chemical_list: D002021:Buffers; D005680:gamma-Aminobutyric Acid