Heterogeneous composition of voltage-dependent K⁺ currents in hepatic stellate cells

Purpose: Hepatic stellate cells (HSC) are a type of pericyte with varying characteristics according to their location. However, the electrophysiological properties of HSC are not completely understood. Therefore, this study investigated the difference in the voltage-dependent K⁺ currents in HSC. Materials and Methods: The voltage-dependent K⁺ currents in rat HSC were evaluated using the whole cell configuration of the patch-clamp technique. Results: Four different types of vottage-dependent K⁺ currents in HSC were identified based on the outward and inward K⁺ currents. Type D had the dominant delayed rectifier K⁺ current, and type A had the dominant transient outward K⁺ current. Type I had an inwardly rectifying K⁺ current, whereas the non-type I did not. TFA (5 mM) and 4-AP (2 mM) suppressed the outward K⁺ currents differentially in type D and. A. Changing the holding potential from - 80 to - 40 mV reduced the amplitude of the transient outward K⁺ currents in type A. The inwardly rectifying K⁺ currents either declined markedly or were sustained in type I during the hyperpolarizing step pulses from - 120 to - 150 mV. Conclusion: There are four different configurations of voltage-dependent K⁺ currents expressed in cultured HSC. These results are expected to provide information that will help determine the properties of the K⁺ currents in HSC as well as the different type HSC populations.