| Assay Method Information | |
| | Screen Quest Fluo-8 No Wash Calcium Assay |
| Description: | Extracellular binding of Bz-ATP to P2X7 receptor opens the channel and allows Ca2+ influx into the cells. This Ca2+ entry was measured in HEK-293 cells stably transfected with P2X7 receptor using Screen Quest Fluo-8 No Wash Calcium Assay Kit (AAt Bioquest, cat. 36316). Once inside the cell, the lipophilic blocking groups of Fluo-8 are cleaved by non-specific cell esterases, resulting in a negatively-charged fluorescent dye that stays inside cells. Its fluorescence increases upon binding to calcium. When HEK-293/P2X7 cells are stimulated with Bz-ATP, Ca2+ enters the cells and the fluorescence of Fluo-8 NW increases. The dye has an absorption spectrum compatible with excitation at 488 nm by argon laser sources and its emission wavelength is in the range of 515-575 nm.HEK-293 cells stably transfected with P2X7 receptor were seeded overnight in growth medium at 10,000 to 20,000 cells/well in 384-well plate. 24 hours later, the medium was removed and the cells were pre-loaded at RT for 1 hour with 20 μL/w of Fluo-8 NW. Then 10 μL/w of test compounds and reference antagonist A438079 at 3×-concentration were injected with the FLIPRTETRA and the kinetic response over a period of five minutes was monitored. A second injection of 15 μL/w of 3× reference activator (Bz-ATP at EC80) was performed with the FLIPRTETRA and the signal of the emitted fluorescence was recorded for additional three minutes. All the experiment was carried out in a Low Divalent Cation Assay Buffer (0.3 mM Ca2+ and 0 mM Mg2+). The effect of the test compounds was measured as percent inhibition vs the reference antagonist and IC50 values were calculated accordingly. |
| Affinity data for this assay | |
|---|---|
| If you find an error in this entry please send us an E-mail | |