Bleakman D, Ballyk B A, Schoepp D D, Palmer A J, Bath C P, Sharpe E F, Woolley M L, Bufton H R, Kamboj R K, Tarnawa I, Lodge D
Eli Lilly and Co., Lilly Research Centre, Windlesham, Surrey, U.K.
Neuropharmacology. 1996;35(12):1689-702. doi: 10.1016/s0028-3908(96)00156-6.
The activity and selectivity of the glutamate receptor antagonists belonging to the 2,3-benzodiazepine class of compounds have been examined at recombinant human non-NMDA glutamate receptors expressed in HEK293 cells and on native rat NMDA and non-NMDA receptors in vitro. The racemic 2,3-benzodiazepines GYKI52466, LY293606 (GYKI53405) and LY300168 (GYKI53655) inhibited AMPA (10 microM)-mediated responses in recombinant human GluR1 receptors expressed in HEK293 cells with approximate IC50 values of 18 microM, 24 microM and 6 microM, respectively and AMPA (10 microM) responses in recombinant human GluR4 expressing HEK293 cells with approximate IC50 values of 22 microM, 28 microM and 5 microM, respectively. GYKI 52466, LY293606 and LY300168 were non-competitive antagonists of AMPA receptor-mediated responses in acutely isolated rat cerebellar Purkinje neurons with approximate IC50 values of 10 microM, 8 microM and 1.5 microM, respectively. The activity of racemic compounds LY293606 and LY300168 was established to reside in the (-) isomer of each compound. At a concentration of 100 microM, GYKI52466, LY293606 and LY300168 produced < 30% inhibition of kainate-activated currents evoked in HEK293 cells expressing either human homomeric GluR5 or GluR6 receptors or heteromeric GluR6+KA2 kainate receptors. The activity of the 2,3-benzodiazepines at 100 microM was weak at kainate receptors, but was stereoselective. Similar levels of inhibition were observed for kainate-induced currents in dorsal root ganglion neurons. Intact tissue preparations were also used to examine the stereoselective actions of the 2,3-benzodiazepines. In the cortical wedge preparation, the active isomer of LY300168, LY303070, produced a non-competitive antagonism of AMPA-evoked depolarizations with smaller changes in depolarizations induced by kainate and no effect on NMDA-dependent depolarizations. LY303070 was also effective in preventing 30 microM AMPA-induced depolarizations in isolated spinal cord dorsal roots with an approximate IC50 value of 1 microM. Synaptic transmission in the hemisected spinal cord preparation was stereoselectively antagonized by the active isomers of LY300168 and LY293606. In summary, these results indicate that 2,3-benzodiazepines are potent, selective and stereospecific antagonists of the AMPA subtype of the non-NMDA glutamate receptor.
已在体外对人胚肾293（HEK293）细胞中表达的重组人非NMDA谷氨酸受体以及天然大鼠NMDA和非NMDA受体上，检测了属于2,3 - 苯并二氮杂䓬类化合物的谷氨酸受体拮抗剂的活性和选择性。外消旋的2,3 - 苯并二氮杂䓬类化合物GYKI52466、LY293606（GYKI53405）和LY300168（GYKI53655）抑制HEK293细胞中表达的重组人GluR1受体对AMPA（10微摩尔）介导的反应，其半数抑制浓度（IC50）值分别约为18微摩尔、24微摩尔和6微摩尔，对HEK293细胞中表达的重组人GluR4受体对AMPA（10微摩尔）的反应的IC50值分别约为22微摩尔、28微摩尔和5微摩尔。GYKI 52466、LY293606和LY300168是急性分离的大鼠小脑浦肯野神经元中AMPA受体介导反应的非竞争性拮抗剂，其IC50值分别约为10微摩尔、8微摩尔和1.5微摩尔。已确定外消旋化合物LY293606和LY300168的活性存在于每种化合物的（ - ）异构体中。在100微摩尔浓度下，GYKI52466、LY293606和LY300168对表达人同源GluR5或GluR6受体或异源GluR6 + KA2海人藻酸受体的HEK293细胞中由海人藻酸激活的电流的抑制率<30%。2,3 - 苯并二氮杂䓬类化合物在100微摩尔时对海人藻酸受体的活性较弱，但具有立体选择性。在背根神经节神经元中，海人藻酸诱导的电流也观察到类似水平的抑制。完整组织标本也用于检测2,3 - 苯并二氮杂䓬类化合物的立体选择性作用。在皮质楔形标本中，LY300168的活性异构体LY303070对AMPA诱发的去极化产生非竞争性拮抗作用，对海人藻酸诱导的去极化变化较小，对NMDA依赖性去极化无影响。LY303070在分离的脊髓背根中预防30微摩尔AMPA诱导的去极化也有效，IC50值约为1微摩尔。LY300168和LY293606的活性异构体对脊髓半切标本中的突触传递有立体选择性拮抗作用。总之，这些结果表明2,3 - 苯并二氮杂䓬类化合物是强力、选择性和立体特异性的非NMDA谷氨酸受体AMPA亚型拮抗剂。
