Open AccessValidation of a Medium-Throughput Electrophysiological Assay for KCNQ2/3 Channel Enhancers Using IonWorks HT
Author(s) -
Flora Jow,
Ru Shen,
Pranab K. Chanda,
Eugene Tseng,
Howard Zhang,
Jeffrey D. Kennedy,
John Dunlop,
Mark R. Bowlby
Publication year - 2007
Publication title -
slas discovery
Language(s) - English
Resource type - Journals
eISSN - 2472-5560
pISSN - 2472-5552
DOI - 10.1177/1087057107307448
Subject(s) - electrophysiology , enhancer , patch clamp , clone (java method) , depolarization , chemistry , chromatography , biology , biophysics , microbiology and biotechnology , biochemistry , gene , neuroscience , gene expression
Enhancers of KCNQ channels are known to be effective in chronic pain models. To discover novel enhancers of KCNQ channels, the authors developed a medium-throughput electrophysiological assay by using the IonWorks platform. Screening of 20 CHO-K1 clones stably expressing KCNQ2/3 was performed on the IonWorks HT until the best clone (judged from seal rate, current level, and stability) was obtained. The KCNQ2/3 current amplitude in the cells was found to increase from 60 +/- 15 pA to 473 +/- 80 pA (at -10 mV), and the expression rate was increased by 56% when the cells were incubated at 27 degrees C overnight. The clone used for compound screening had a seal rate of greater than 90% and an overall success rate of greater than 70%. The voltage step protocol (hold cells at -80 mV and depolarize to -10 mV for 1 s) was designed to provide moderate current but still allow for pharmacological current enhancement. EC(50)s were generated from 8-point concentration-response curves with a control compound on each plate using compounds that were also tested with conventional patch clamp. The authors found that there was a very good correlation (R(2) > 0.9) between the 2 assays, thus demonstrating the highly predictive nature of the IonWorks assay.