Department of Neuroscience, Uppsala University, Uppsala, Sweden.
Department of Immunology, Genetic and Pathology, and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
Eur J Pharmacol. 2015 Feb 5;748:101-7. doi: 10.1016/j.ejphar.2014.12.001. Epub 2014 Dec 12.
GABAA receptors are pentameric chloride ion channels that are opened by GABA. We have screened a cell line derived from human glioblastoma, U3047MG, for expression of GABAA receptor subunit isoforms and formation of functional ion channels. We identified GABAA receptors subunit α2, α3, α5, β1, β2, β3, δ, γ3, π, and θ mRNAs in the U3047MG cell line. Whole-cell GABA-activated currents were recorded and the half-maximal concentration (EC₅₀) for the GABA-activated current was 36 μM. The currents were activated by THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) and enhanced by the benzodiazepine diazepam (1 μM) and the general anesthetics etomidate and propofol (50 μM). In line with the expressed GABAA receptors containing at least the α3β3θ subunits, the receptors were highly sensitive to etomidate (EC₅₀=55 nM). Immunocytochemistry identified expression of the α3 and β3 subunit proteins. Our results show that the GABAA receptors in the glial cell line are functional and are modulated by classical GABAA receptor drugs. We propose that the U3047MG cell line may be used as a model system to study GABAA receptors function and pharmacology in glial cells.
GABAA 受体是五聚体氯离子通道，被 GABA 激活。我们筛选了一种源自人胶质母细胞瘤的细胞系 U3047MG，以检测 GABAA 受体亚基亚型的表达和功能性离子通道的形成。我们在 U3047MG 细胞系中鉴定出 GABAA 受体亚基 α2、α3、α5、β1、β2、β3、δ、γ3、π 和 θ 的 mRNA。记录全细胞 GABA 激活电流，GABA 激活电流的半最大浓度 (EC₅₀) 为 36 μM。电流由 THIP（4,5,6,7-四氢异恶唑[5,4-c]吡啶-3-醇）激活，并被苯二氮䓬类药物地西泮（1 μM）和全身麻醉药依托咪酯和丙泊酚（50 μM）增强。与表达的至少包含 α3β3θ 亚基的 GABAA 受体一致，这些受体对依托咪酯高度敏感（EC₅₀=55 nM）。免疫细胞化学鉴定出 α3 和 β3 亚基蛋白的表达。我们的结果表明，神经胶质细胞系中的 GABAA 受体是功能性的，并受经典 GABAA 受体药物的调节。我们提出 U3047MG 细胞系可用于研究神经胶质细胞中 GABAA 受体功能和药理学的模型系统。
