In vitro changes in gamma-aminobutyric acid output from the cerebral cortex induced by inhibitors of gamma-aminobutyric acid uptake and metabolism.
The effects of inhibitors of gamma-aminobutyric acid (GABA) metabolism or uptake on GABA output from the cerebral cortex was studied by means of a collecting cup placed on the exposed cortex of rats anaesthetized with urethane. GABA was identified and quantified by a mass-fragmentographic method. Ethanolamine-O-sulphate (10(-2) M) applied directly on the cerebral cortex caused a long-lasting twofold increase in GABA output, whereas DL-2,4-diaminobutyric acid (5 X 10(-3) M) caused a sevenfold increase and beta-alanine was active. The results indicate that glial uptake has little effect on GABA inactivation in the cerebral cortex. The inhibition of neuronal uptake seems a more effective tool to increase GABA concentration in the synaptic cleft, and consequently also in GABA output, than the inhibition of GABA metabolism.
D000613:Aminobutyrates / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D004983:Ethanolamines / Q000494:pharmacology*; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D009457:Neuroglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000613:Aminobutyrates; D004983:Ethanolamines; C005959:2,4-diaminobutyric acid; D005680:gamma-Aminobutyric Acid; C020619:ethanolamine O-sulfate