Abstract
1. The use of molecular biology in combination with electrophysiology in the HEK-293 cell line has given fascinating insights into neuronal ion channel function. Nevertheless, to fully understand the properties of channels exogenously expressed in these cells, a detailed evaluation of endogenous channels is indispensable.
2. Previous studies have shown the expression of endogenous voltage-gated K+, Ca2+, and Cl− channels and this predicts that changes in membrane potential will cause intramembrane charge movement, though this gating charge translocation remain undefined. Here, we confirm this prediction by performing patch-clamp experiments to record ionic and gating currents. Our data show that HEK-293 cells express at least two types of K+-selective endogenous channels which sustain the majority of the ionic current, and exclude a significant contribution from Ca2+ and Cl− channels to the whole-cell current.
3. Gating currents were unambiguously resolved after ionic current blockade enabling this first report of intramembrane charge movement in HEK-293 cells arising entirely from endogenous K+ channel activity, and providing valuable information concerning the activation mechanism of voltage-gated K+ channels in these cells.
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Avila, G., Sandoval, A. & Felix, R. Intramembrane Charge Movement Associated with Endogenous K+ Channel Activity in HEK-293 Cells. Cell Mol Neurobiol 24, 317–330 (2004). https://doi.org/10.1023/B:CEMN.0000022765.52109.26
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DOI: https://doi.org/10.1023/B:CEMN.0000022765.52109.26