Radioligand Binding Assay: human or rat P2X7-1321 N1 cells were collected and frozen @−80° C. On the day of the experiment, cell membrane preparations were made according to standard published methods. The total assay volume was 100 μl: 10 μl compound (10×)+(b) 40 μl tracer (2.5×)+50 μl membrane (2×). The tracer used for the assay was tritiated A-804598. The compound can be prepared as described in the literature. (Donnelly-Roberts, D. Neuropharmacology 2009, 56 (1), 223-229.) Compounds, tracer and membranes were incubated for 1 hour @ 4° C. The assay was terminated by filtration (GF/B filters pre-soaked with 0.3% PEI) and washed with washing buffer (Tris-HCl 50 mM).
FLIPR Assay: 1321 N1 cells expressing the recombinant human, rat or mouse P2X7 channel was cultured in HyQ DME/(HyClone/Dulbecco's Modified Eagle Medium) high glucose supplemented with 10% Fetal Bovine Serum (FBS) and appropriate selection marker. Cells were seeded at a density of 25000 cells/well (96-well clear bottom black walled plates) in 100 ul volume/well. On the day of the experiment, cell plates were washed with assay buffer, containing (in mM): 130 NaCl, 2 KCl, 1 CaCl2, 1 MgCl2, 10 HEPES, 5 glucose; pH 7.40 and 300 mOs. After the wash, cells were loaded with the Calcium-4 dye (Molecular Device) and incubated in the dark for 60 minutes. Test compounds were prepared at 250ÿ the test concentration in neat DMSO. Intermediate 96-well compound plates were prepared by transferring 1.2 uL of the compound into 300 uL of assay buffer. A further 3x dilution occurred when transferring 50 uL/well of the compound plate to 100 uL/well in the cell plate. Cells were incubate with test compounds and dye for 30 minutes. Calcium dye fluorescence was monitored in FLIPR as the cells were challenged by adding 50 uL/well of BzATP (final concentration is 250 uM BzATP (human and rat) or 600 (mouse)). The fluorescence change was measured 180 seconds after adding the agonist.
FLIPR Assay: 1321 N1 cells expressing the recombinant human, rat or mouse P2X7 channel was cultured in HyQ DME/(HyClone/Dulbecco's Modified Eagle Medium) high glucose supplemented with 10% Fetal Bovine Serum (FBS) and appropriate selection marker. Cells were seeded at a density of 25000 cells/well (96-well clear bottom black walled plates) in 100 ul volume/well. On the day of the experiment, cell plates were washed with assay buffer, containing (in mM): 130 NaCl, 2 KCl, 1 CaCl2, 1 MgCl2, 10 HEPES, 5 glucose; pH 7.40 and 300 mOs. After the wash, cells were loaded with the Calcium-4 dye (Molecular Device) and incubated in the dark for 60 minutes. Test compounds were prepared at 250ÿ the test concentration in neat DMSO. Intermediate 96-well compound plates were prepared by transferring 1.2 uL of the compound into 300 uL of assay buffer. A further 3x dilution occurred when transferring 50 uL/well of the compound plate to 100 uL/well in the cell plate. Cells were incubate with test compounds and dye for 30 minutes. Calcium dye fluorescence was monitored in FLIPR as the cells were challenged by adding 50 uL/well of BzATP (final concentration is 250 uM BzATP (human and rat) or 600 (mouse)). The fluorescence change was measured 180 seconds after adding the agonist.
Antagonist activity at recombinant rat P2X7 expressed in human 1321N1 cells assessed as inhibition of BzATP-induced calcium flux preincubated for 30 mins followed by BzATP addition measured over 180 secs by FLIPR assay
Antagonist activity at recombinant human P2X7 expressed in human 1321N1 cells assessed as inhibition of BzATP-induced calcium flux preincubated for 30 mins followed by BzATP addition measured over 180 secs by FLIPR assay