The Contribution of Changes of Intracelluar Potassium Ion Concentration to the Kinetics of Voltage-Dependent Potassium Current

Abstract

Voltage-dependent potassium channels (Kv channels) mediate the voltage-dependent potassium ionic current, contribute to the generation of the action potential and to the regulation of neuronal excitability. To date, a large number of studies of these ion channels have been carried out using the patch-clamp method in the whole-cell configuration. It is generally assumed that during the implementation of this method intracellular ion concentrations remain approximately constant due to the relatively rapid exchange of the content between the cytoplasm and the patch pipette. However, this assumption may be incorrect if the flow of ions through the membrane is large. It was demonstrated in this study that the large outward currents of potassium ions can lead to a decrease in their intracellular concentration even during the whole-cell patch-clamp recording. This phenomenon can accelerate the decay of the recorded voltage-dependent potassium currents and may consequently lead to the overestimation of the inactivation rate of voltage-dependent potassium channels.