Oja S S, Kontro P
Department of Biomedical Sciences, University of Tampere, Finland.
Neurochem Res. 1988 Oct;13(10):923-8. doi: 10.1007/BF00970763.
The release of [3H]gamma-aminobutyric acid (GABA) and its radioactive metabolites from slices of the cerebral cortex, cerebellum, striatum and brain stem of developing and adult mice was studied. The slices were incubated and superfused in the absence and presence of the GABA aminotransferase (GABA-T) inhibitor aminooxyacetic acid (AOAA). Exposure to 100 microM AOAA totally inhibited GABA-T and all radioactivity released from slices was in authentic GABA. In studies on developing brain the 10-microM concentration was also effective enough, except in cerebellar slices. In the absence of AOAA the major part of radioactivity spontaneously released from slices of adult cerebral cortex and cerebellum was tritiated water and still about one third part in the presence of 10 microM AOAA. Potassium stimulation induced only the release of radioactive GABA but not labeled metabolites in both presence and absence of AOAA. AOAA reduced the stimulation-induced release of GABA. It is recommended that the use of GABA-T inhibitors should be discontinued in release experiments. Then labeled GABA must be separated in the effluents from its radioactive breakdown products.
研究了发育中和成年小鼠大脑皮层、小脑、纹状体及脑干切片中[3H]γ-氨基丁酸（GABA）及其放射性代谢产物的释放情况。将切片在不存在和存在γ-氨基丁酸转氨酶（GABA-T）抑制剂氨氧基乙酸（AOAA）的情况下进行孵育和灌流。暴露于100微摩尔AOAA可完全抑制GABA-T，切片释放的所有放射性物质均为真实的GABA。在发育中大脑的研究中，10微摩尔的浓度也足够有效，但小脑切片除外。在不存在AOAA的情况下，成年大脑皮层和小脑切片自发释放的大部分放射性物质是氚化水，在存在10微摩尔AOAA的情况下仍约占三分之一。在存在和不存在AOAA的情况下，钾刺激仅诱导放射性GABA的释放，而不诱导标记代谢产物的释放。AOAA减少了刺激诱导的GABA释放。建议在释放实验中停止使用GABA-T抑制剂。然后必须将标记的GABA与其放射性分解产物在流出物中分离。
