Description

A critical bottleneck in the drug discovery pathway for compounds improve biochemical synthesis and channel function of CF mutations has been the electrophysiological evaluation of compounds. Until recently, only two electrophysiological methods have been available: Ussing chamber short circuit measurements and patch clamp technique. Both assays are low throughput, time consuming and tedious. We developed a high throughput, simple electrophysiological functional assay that can be used to evaluate and discover CFTR modulators. A change in ion channel activity is expected to alter conductance (Gm) of the cell membrane to the permeant ion. Thus, an increase in CFTR activity is expected to increase Gm for chloride and thus transepithelial conductance (GT) for anions. As measurements of 24 epithelia are simultaneously performed the conductance assay provides a substantial improvement in throughput.

The transepithelial potential is recorded with voltage electrodes and a programmable differential amplifier.
To record the transepithelial resistance we send a 1 Hz sine wave current through the membrane. High accuracy of the RT measurements is obtained with Fourier/cross-correlation techniques. Twisted pair flat cables are used to connect MTECC to the electrode manifold. Several software packages are available: (1) manual mode, where electrodes are moved by the operator and (2) robot mode where electrode position is controlled by a Yamaha robot. Data are stored on disk in ASCII format, which enables import in MS Excel.

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