Agonist activity at recombinant GABAA receptor subunit alpha-2 expressed in CHO cells at 3 uM by sensitive fluorometric read-out assay relative to midazolam
Agonist activity at recombinant GABAA receptor subunit alpha-2 expressed in CHO cells at 1 uM by sensitive fluorometric read-out assay relative to midazolam
Radioligand Competition Binding Assay: The affinity of the test compounds was determined by radioligand competition binding assay, using the known compound [3H]Ro-15-1788 (Flumazenil) (Perkin Elmer, 85.4 Ci/mmol) and the human recombinant GABA A receptor containing the alpha2, beta2, and gamma3 subunits.Membranes were prepared from HEK cells expressing hGABA A alpha2beta2- gamma3 receptor, and validated to ascertain protein concentration, receptor expression and to determine the Kd of the flumazenil as well as the Ki of a standard set of compounds before being used to test new compounds.The assay was carried out in 96 well plates; testing compounds using a 10 point semi-log dilution range from 19 uM top concentration. 100 ul of radioligand and 100 ul of membrane in 50 mM Tris-HCI and 0.05% F127 with 1 ul of test compound was incubated for 2 hours to allow the reaction to achieve equilibrium, and then harvested onto filter plates, dried and counted on a TopCount NXT. The data was analysed, and the Ki values were presented.
Negative allosteric modulation of recombinant human GABA-A alpha2 expressed in HEK293 cells assessed as reduction in GABA-induced current at 1 uM relative to control
Positive allosteric modulation of recombinant human GABA-A alpha2 expressed in HEK293 cells assessed as reduction in GABA-induced current at 1 uM relative to control
Binding affinity to human recombinant GABAA alpha2 receptor assessed as inhibition constant incubated for 1 hrs by liquid scintillation counting analysis