Premium
KINETICS OF IN VIVO CONVERSION OF γ‐[ 3 H]AMINOBUTYRIC ACID TO γ‐[ 3 H]HYDROXYBUTYRIC ACID BY RAT BRAIN 1, 2
Author(s) -
Gold B. I.,
Roth R. H.
Publication year - 1977
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1977.tb10670.x
Subject(s) - chemistry , aminooxyacetic acid , in vivo , ethanol , gamma aminobutyric acid , convulsant , kinetics , stereochemistry , biochemistry , enzyme , biology , receptor , microbiology and biotechnology , physics , quantum mechanics
— The appearance of γ‐[ 3 H]hydroxybutyric acid ([ 3 H]GHB) in rat brain at various times after the intraventricular administration of [ 3 H]GABA was determined. Radioactivity recovered as [ 3 H]GHB was maximal 30 s after [ 3 H]GABA administration and declined exponentially thereafter. From a linear transformation of the disappearance with time of [ 3 H]GHB formed from [ 3 H]GABA, the fractional rate of disappearance and turnover time of GHB were calculated. Administration of amino‐oxyacetic acid (50 mg/kg i.p.) 1 h before [ 3 H]GABA, reduced [ 3 H]GHB formation, measured 4 min after [ 3 H]GABA, to 28% of that found in control animals. This strongly suggests that GABA‐transaminase catalyzes at least one step in the conversion pathway. [ 3 H]GHB recoverable 4 min after [ 3 H]GABA was unchanged when animals were pretreated with pyrazole (1.25–5.0 mmol/kg), diphenyl‐hydantoin (25 and 75 mg/kg), phenobarbital (7.5–60 mg/kg), ethanol (1.25–5.0 g/kg), or morphine (2.5–10 mg/kg). Significantly more [ 3 H]GHB could be recovered at several time points from animals which had been pretreated with 50 mg/kg i.p. of the convulsant 3‐mercaptopropionic acid.