Assay Method Information

Assay Name:  Measurement of A2a Binding Affinity Using Radioligand Binding
Description:  148 μL (5 μg/mL) membranes (Perkin Elmer, Cat. No. RBHA2aM400UA) and 2 μL compounds of the invention to be tested (test compound) were transferred to individual wells of a 96-well polypropylene assay plate and incubated for 15 to 30 minutes at room temperature. [3H] SCH58261 ((7-(2-phenylethyl)-5-amino-2-(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine)) was diluted in assay buffer (50 mM Tris pH 7.4, 10 mM MgCl2, 0.005% Tween20) to a concentration of 4 nM and 50 μL transferred to each well of the assay plate. To define total and non-specific binding, wells containing 1% DMSO and 1 μM ZM241385 (Tocris Bioscience, Cat. No. 1036) respectively, were also included. The assay plate was incubated at room temperature for 60 minutes with agitation. Using a FilterMate Harvester (Perkin Elmer), the contents of the assay plate were filtered through a UniFilter-96 PEI coated plate (Perkin Elmer Cat. No. 6005274 or 6005277). Filtering was achieved by aspirating the contents of the assay plate for 5 seconds, then washing and aspirating the contents three times with ice-cooled wash buffer (50 mM Tris-HCl pH 7.4, 150 mM NaCl) and allowing the vacuum manifold to dry the plate for 30 seconds. The filter plate was incubated for at least 1 hour at 55° C., and allowed to dry. The bottom of the filter plate was sealed with backing tape. 40 μL Ultima Gold (Perkin Elmer, Cat. No. 6013329) was added to each well of the filter plate and the top of the plate was sealed with TopSeal-A PLUS clear plate seal (Perkin Elmer, Cat. No. 6050185). The plate was incubated for at least 20 minutes, and then the amount of radioactivity remaining in each well was determined using a TopCount (Perkin Elmer) scintillation counter. After normalization to total and non-specific binding, the percent effect at each compound concentration was calculated. The plot of percent effect versus the log of compound concentration was analyzed electronically using a 4-parameter logistic fit based on the Levenberg-Marquardt algorithm to generate IC50 values.
Affinity data for this assay
 

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