IonFlux - GABA Application

A wide variety of experiments and target screens can be performed on the IonFlux System. Here, an example is demonstrated to assay for modulators of the human GABA-A receptor, expressed in HEK293 cells from Millipore. This ligand-gated chloride channel is involved in CNS inhibition, thus constituting an important drug target in epilepsy, anxiety, and insomnia.
To perform screening assays, cell ensembles were exposed to EC20 concentrations of the native ligand GABA, in the presence of ascending concentrations of modulator substances that bind at the allosteric site on the receptor.
The plots show dose-response curves for two positive allosteric modulators in the benzodiazepine class, namely triazolam and diazepam, for which EC50 values of 3 nM and 0.5 μM were obtained.
The modulator-dependent shift in apparent GABA affinity was then determined by cumulatively applying different GABA concentrations in the presence of a fixed concentration of the modulator, in this case, 3 μM diazepam.
This type of experiment is enabled by the flow-through fluidic design available in the IonFlux instruments. The EC50 for GABA was shifted by about 1 μM to lower concentrations due to increased binding affinity in the presence of the modulator.

Category:

Science & Technology

Tags:

• ionflux
• gaba
• modulator
• EC50
• diazepam
• HEK293
• Millipore
• ligand
• gated
• chloride
• channel