| Assay Method Information | |
| | human P2X7 channel assay by automated patch-clamp |
| Description: | In order to directly monitor the block of P2X7 channel, an electrophysiological assay was developed and implemented on the QPatch16X automated electrophysiology instrument.HEK-293 cells expressing the P2X7 channels were cultured in modified EMEM.72 hours before experiment, 5 million cells were seeded onto T225 flasks. Just before the experiment cells were washed twice, detached from the flask with trypsin-EDTA, re-suspended in the suspension solution and placed on the QPatch 16x.The compounds (20 mM in a 100% DMSO) stored at −20° C. were prepared the day of the experiment (a first dilution 1:20 in 100% DMSO to prepare a 1 mM stock solution, then a 1 microM solution in external solution+a serial dilution 1:10).The standard whole-cell voltage clamp experiments were performed at room temperature. For these experiments the multihole technology was used and the data were sampled at 2 KHz.The intracellular solution contained (mM) 135 CsF, 10 NaCl, 1 EGTA, 10 HEPES, (pH 7.2 with CsOH) whereas the extracellular contained (mM) 145 NaCl, 4 KCl, 0.5 MgCl2, 1 CaCl2, 10 HEPES, 10 Glc (pH 7.4 with NaOH).After establishment of the seal and the passage in the whole cell configuration, the cells were held at −80 mV. The P2XR7 current was evoked by applying 100 microM of BzATP alone (4 times) and then in the presence increasing concentrations of the compound under investigation (1, 10, 100 and 1000 nM).The pre-incubation periods 5 to 8 contain increasing concentrations of the compound of interest (1, 10, 100 and 1000 nM), as illustrated in FIGURE.The maximal inward current evoked by BzATP in absence or presence of increasing concentrations of the compounds under investigation was measured and normalized. The potential modulatory effect was measured as % of control and as IC50 determined fitting the dose-response curves data with the following equation:Y=100/(1+10^((Log IC50-X)*HillSlope))where:X: log of concentrationY: normalized response, 100% down to 0%, decreasing as X increases.LogIC50: same log units as XHillSlope: slope factor or HS, unitless. |
| Affinity data for this assay | |
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