Recording ten-fold larger I Kr conductances with automated patch clamping using equimolar Cs + solutions.

Autor:	Bloothooft M; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands., Verbruggen B; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands., Seibertz F; Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany.; DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.; Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany.; Nanion Technologies GmbH, Munich, Germany., van der Heyden MAG; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands., Voigt N; Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany.; DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.; Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany., de Boer TP; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands.
Jazyk:	angličtina
Zdroj:	Frontiers in physiology [Front Physiol] 2024 Jan 24; Vol. 15, pp. 1298340. Date of Electronic Publication: 2024 Jan 24 (Print Publication: 2024).
DOI:	10.3389/fphys.2024.1298340
Abstrakt:	Background: The rapid delayed rectifier potassium current (I Kr ) is important for cardiac repolarization and is most often involved in drug-induced arrhythmias. However, accurately measuring this current can be challenging in human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes because of its small current density. Interestingly, the ion channel conducting I Kr , hERG channel, is not only permeable to K + ions but also to Cs + ions when present in equimolar concentrations inside and outside of the cell. Methods: In this study, I hERG was measured from Chinese hamster ovary (CHO)-hERG cells and hiPSC-CM using either Cs + or K + as the charge carrier. Equimolar Cs + has been used in the literature in manual patch-clamp experiments, and here, we apply this approach using automated patch-clamp systems. Four different (pre)clinical drugs were tested to compare their effects on Cs + - and K + -based currents. Results: Using equimolar Cs + solutions gave rise to approximately ten-fold larger hERG conductances. Comparison of Cs + - and K + -mediated currents upon application of dofetilide, desipramine, moxifloxacin, or LUF7244 revealed many similarities in inhibition or activation properties of the drugs studied. Using equimolar Cs + solutions gave rise to approximately ten-fold larger hERG conductances. In hiPSC-CM, the Cs + -based conductance is larger compared to the known K + -based conductance, and the Cs + hERG conductance can be inhibited similarly to the K + -based conductance. Conclusion: Using equimolar Cs + instead of K + for I hERG measurements in an automated patch-clamp system gives rise to a new method by which, for example, quick scans can be performed on effects of drugs on hERG currents. This application is specifically relevant when such experiments are performed using cells which express small I Kr current densities in combination with small membrane capacitances. Competing Interests: Author FS was employed by Nanion Technologies GmbH. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision. (Copyright © 2024 Bloothooft, Verbruggen, Seibertz, Heyden, Voigt and de Boer.)
Databáze:	MEDLINE
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