Zezula J, Slany A, Sieghart W
Department of Biochemical Psychiatry, University Clinic for Psychiatry, Vienna, Austria.
Eur J Pharmacol. 1996 Apr 22;301(1-3):207-14. doi: 10.1016/0014-2999(96)00066-0.
The presence of allosteric binding sites on recombinant GABAA receptors formed after transfection of human embryonic kidney (HEK) 293 cells with alpha 1-, beta 3-, or gamma 2-subunits, or with various combinations of these subunits, was systematically investigated. From all possible subunit combinations, high affinity [3H]muscimol binding sites were induced in cells transfected with alpha 1 beta 3- or alpha 1 beta 3 gamma 2-subunits only. GABAA receptor associated [3H]flunitrazepam binding sites were induced in cells after transfection with alpha 1 gamma 2- or alpha 1 beta 3, gamma 2-subunits, and [35S]r-butylbicyclophosphorothionate (TBPS) binding sites were found in cells transfected with beta 3-, beta 3 gamma 2-, alpha 1 beta 3-, or alpha 1 beta 3 gamma 2-subunits. Binding of [35S]TBPS could be inhibited by pentobarbital, etazolate, (+)-etomidate, alphaxalone, propofol, chlormethiazole, and 4'-chlorodiazepam (Ro 5-4864) with a potency which differed in cells transfected with beta 3-, beta 3 gamma 2-, alpha 1 beta 3-, or alpha 1 beta 3 gamma 2-subunits. Results obtained indicate that receptors with different subunit composition actually can be formed in HEK cells and exhibit distinct pharmacological properties.
对人胚肾（HEK）293细胞转染α1-、β3-或γ2-亚基，或这些亚基的各种组合后形成的重组GABAA受体上变构结合位点的存在情况进行了系统研究。在所有可能的亚基组合中，仅转染α1β3-或α1β3γ2-亚基的细胞中诱导出高亲和力的[3H]蝇蕈醇结合位点。转染α1γ2-或α1β3γ2-亚基后，细胞中诱导出GABAA受体相关的[3H]氟硝西泮结合位点，而在转染β3-、β3γ2-、α1β3-或α1β3γ2-亚基的细胞中发现了[35S]r-丁基双环磷硫代酸酯（TBPS）结合位点。[35S]TBPS的结合可被戊巴比妥、乙唑酯、（+）-依托咪酯、阿法沙龙、丙泊酚、氯美噻唑和4'-氯地西泮（Ro 5-4864）抑制，其效力在转染β3-、β3γ2-、α1β3-或α1β3γ2-亚基的细胞中有所不同。所得结果表明，具有不同亚基组成的受体实际上可以在HEK细胞中形成，并表现出不同的药理学特性。
