Yonsei Medical Journal 2008-06-30

Changes in inward rectifier K+ channels in hepatic stellate cells during primary culture.

Dong Hyeon Lee, In Deok Kong, Joong-Woo Lee, Kyu-Sang Park

Index: Yonsei Med. J. 49(3) , 459-71, (2008)

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Abstract

This study examined the expression and function of inward rectifier K(+) channels in cultured rat hepatic stellate cells (HSC).The expression of inward rectifier K(+) channels was measured using real-time RT-PCR, and electrophysiological properties were determined using the gramicidin-perforated patch-clamp technique.The dominant inward rectifier K(+) channel subtypes were K(ir)2.1 and K(ir)6.1. These dominant K(+) channel subtypes decreased significantly during the primary culture throughout activation process. HSC can be classified into two subgroups: one with an inward-rectifying K(+) current (type 1) and the other without (type 2). The inward current was blocked by Ba(2+) (100 microM) and enhanced by high K(+) (140 mM), more prominently in type 1 HSC. There was a correlation between the amplitude of the Ba(2+)-sensitive current and the membrane potential. In addition, Ba(2+) (300 microM) depolarized the membrane potential. After the culture period, the amplitude of the inward current decreased and the membrane potential became depolarized.HSC express inward rectifier K(+) channels, which physiologically regulate membrane potential and decrease during the activation process. These results will potentially help determine properties of the inward rectifier K(+) channels in HSC as well as their roles in the activation process.