Assay Method Information

Assay Name:  Binding Assay
Description:  Human V1b receptor was transiently expressed in 293FT cells (Invitrogen). The cells were collected and then homogenated in a 15 mmol/L tris-hydrochloric acid buffer (pH 7.4 and containing 2 mmol/L magnesium chloride, 0.3 mmol/L ethylenediaminetetracetic acid, and 1 mmol/L glycol ether diaminetetraacetic acid). The resulting homogenate was centrifuged at 50,000xg at 4° C. for 20 minutes. The precipitate was resuspended in a 75 mmol/L tris-hydrochloric acid buffer (pH 7.4 and containing 12.5 mmol/L magnesium chloride, 0.3 mmol/L ethylenediaminetetracetic acid, 1 mmol/L glycol ether diaminetetraacetic acid, and 250 mmol/L sucrose) to give a crude membrane preparation, which was stored at 80° C. until the binding test was initiated. In the binding test, the crude membrane preparation was diluted with a 50 mmol/L tris-hydrochloric acid buffer (pH 7.4 and containing 10 mmol/L magnesium chloride and 0.1% bovine serum albumin) and mixed with each test compound and [3H]AVP (final concentration: 0.4 to 1 nmol/L), followed by incubation at room temperature for 60 minutes. The test compound was serially diluted with DMSO so that it would have final concentrations of 0.01 nmol/L to 1 umol/L at the time of mixing. After the incubation, the mixture was suction filtered through a GF/C filter that was preliminarily impregnated with 0.3% polyethyleneimine. The GF/C filter was dried and after adding a scintillator, the residual radioactivity on the filter was measured using TopCount (PerkinElmer Inc.). The radioactivity in the presence of unlabeled AVP at 10 mmol/L was defined as 0%, and the radioactivity in the absence of unlabeled AVP was defined as 100%. A dose-response curve was plotted from radio activities in the presence of a test compound at various concentrations, and the 50% inhibitory concentration (IC50 value) of the test compound was calculated. The IC50 values of the compounds of the present invention were in the range of 0.1 to 1000 nM.
Affinity data for this assay
 

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