Vayer P, Mandel P, Maitre M
J Neurochem. 1985 Sep;45(3):810-4. doi: 10.1111/j.1471-4159.1985.tb04065.x.
[3H]gamma-Hydroxybutyric acid [( 3H]GHB) at physiological concentration incubated with brain slices in Krebs-Ringer medium produced [3H]gamma-aminobutyric acid [( 3H]GABA). This compound was identified by its Rf values on thin-layer chromatograms and by analysis of the dansyl derivatives of the free amino acid fraction. No labelled glutamate could be detected. Brain slices incubated with labelled glutamate and nonradioactive GHB generated labelled 2-oxoglutarate, suggesting that gamma-aminobutyrate-2-oxoglutarate transaminase (GABA-T) is involved in catalyzing this reaction. Furthermore, specific inhibitors of GABA-T blocked the production of labelled GABA from labelled GHB and of labelled 2-oxoglutarate from labelled glutamate. Transformation of [3H]GHB into [3H]GABA was not inhibited by malonate, demonstrating that the succinate-linked pathway is not involved in the generation of GABA. The kinetic characteristics of the multienzyme system involved in GHB degradation studied in vitro are compatible with the production of GABA in vivo.
生理浓度的[3H]γ-羟基丁酸（[3H]GHB）与置于Krebs-Ringer培养基中的脑片一起孵育时会产生[3H]γ-氨基丁酸（[3H]GABA）。该化合物通过其在薄层色谱图上的比移值以及对游离氨基酸部分的丹磺酰衍生物的分析得以鉴定。未检测到标记的谷氨酸。用标记的谷氨酸和非放射性GHB孵育的脑片产生了标记的2-氧代戊二酸，这表明γ-氨基丁酸-2-氧代戊二酸转氨酶（GABA-T）参与催化该反应。此外，GABA-T的特异性抑制剂阻断了由标记的GHB产生标记的GABA以及由标记的谷氨酸产生标记的2-氧代戊二酸的过程。丙二酸不会抑制[3H]GHB向[3H]GABA的转化，这表明琥珀酸连接途径不参与GABA的生成。体外研究的参与GHB降解的多酶系统的动力学特征与体内GABA的产生情况相符。
