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In investigating ion channel pharmacology, the manual patch clamp is still considered the gold standard for data quality, notwithstanding the major drawbacks of low throughput and the need for skilled operators. The automated patch clamp platform CytoPatch™ Instrument overcomes these restrictions. Its modular fully automated design makes it possible to obtain scalable throughput without the need for well-trained operators. Its chip design and perfusion system reproduces the manual patch technique, thus ensuring optimal data quality. Further, the use of stably transfected frozen cells, usable immediately after thawing, eliminates the cell quality impairment and low success rates associated with a running cell culture and renders screening costs accurately calculable. To demonstrate the applicability of this platform, 18 blinded compounds were assessed for their impact on the cardiac human Ether-à-go-go related gene K(+) channel. The IC(50) values obtained by the CytoPatch Instrument using the frozen human embryonic kidney 293 cells showed a high correlation (R(2)=0.928) with those obtained from manual patch clamp recordings with human embryonic kidney 293 cells from a running cell culture. Moreover, this correlation extended to sticky compounds such as terfenadine or astemizole. In conclusion, the CytoPatch Instrument operated with frozen cells ready to use directly after thawing provides the same high data quality known from the manual voltage clamp and has the added benefit of enhanced throughput for use in ion channel screening and safety assessment.

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pA/pF, n¼8, p>0.001, respectively at -90 mV) indicating a strong dominant negative effect of the mutant. The outward component of IK1 measured at -50 mV was also markedly reduced with the heterozygous expression vs. WT (0.5255.5 pA/pF vs. 23.456.7 pA/pF, n¼8, p>0.001, respectively). Conclusion: We report a novel KCNJ2 mutation associated with classical phenotypic features of Andersen-Tawil syndrome and CPVT mimicry. The R260P mutation produced a strong dominant negative effect leading to marked suppression of the inward rectifier potassium current.

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