Radioligand Binding Assay: HEK293 cells stably expressing rat 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 2x 10 second bursts in the presence of protease inhibitors, followed by centrifugation at 45,000x g 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 20 ug/well for rat 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 45 min incubation at 30u C., binding reaction was terminated by the addition of 300 ul/well of cold assay buffer.
Radioligand Binding Assays: The CB1 and CB2 radioligand binding assays described herein are utilized to ascertain the selectivity of compounds of the present application for binding to CB2 relative to CB1 receptors.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 210 second bursts in the presence of protease inhibitors, followed by centrifugation at 45,000xg 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.
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.
Agonist activity at rat CB2 receptor expressed in CHOK1 cells assessed as inhibition of forskolin-induced cAMP production treated 15 mins before forskolin challenge measured after 1 hr by HTRF assay
Agonist activity at rat CB2 receptor expressed in CHOK1 cells assessed as inhibition of forskolin-induced cAMP production treated 15 mins before forskolin challenge measured after 1 hr by HTRF assay relative to control
Displacement of [3H]-CP55940 from recombinant rat CB2 receptor expressed in CHOK1 cells assessed as residual binding level at 50 nM by radiometric assay relative to control
Displacement of [3H]-CP55940 from recombinant rat CB2 receptor expressed in CHOK1 cells assessed as residual binding level at 500 nM by radiometric assay relative to control
Displacement of [3H]-CP55940 from recombinant rat CB2 receptor expressed in CHOK1 cells assessed as residual binding level at 1000 nM by radiometric assay relative to control