CHEMBL3705645

Radioligand Binding Assay: HEK293 cells stably expressing human CB2 receptors were grown until a confluent monolayer was formed. Briefly, the cells were harvested and homogenized in TE buffer (50 mM Tris-HCl, 1 mM MgCl2, and 1 mM EDTA) using a polytron for 2X10 second bursts in the presence of protease inhibitors, followed by centrifugation at 45,000 ug for 20 minutes. The final membrane pellet was re-homogenized in storage buffer (50 mM Tris-HCl, 1 mM MgCl2, and 1 mM EDTA and 10% sucrose) and frozen at -78 C. until used. Saturation binding reactions were initiated by the addition of membrane preparation (protein concentration of 5 ug/well for human CB2) into wells of a deep well plate containing [3H]CP 55,940 (120 Ci/mmol, a nonselective CB agonist commercially available from Tocris) in assay buffer (50 mM Tris, 2.5 mM EDTA, 5 mM MgCl2, and 0.5 mg/mL fatty acid free BSA, pH 7.4). After 90 min incubation at 30 C., binding reaction was terminated by the addition of 300 uL/well of cold assay buffer.