Changes in inward rectifier K+ channels in hepatic stellate cells during primary culture.
OBJECTIVE
This study examined the expression and function of inward rectifier K(+) channels in cultured rat hepatic stellate cells (HSC).


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Lee
Dong Hyeon
DH
Department of Physiology, College of Medicine, Pochon CHA University, Seongnam, Gyeonggi-do, Korea.
Kong
In Deok
ID
Lee
Joong-Woo
JW
Park
Kyu-Sang
KS
D000818:Animals; D001464:Barium / Q000494:pharmacology; D015153:Blotting, Western; D002478:Cells, Cultured; D004594:Electrophysiology; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
D024661:Potassium Channels, Inwardly Rectifying; D001464:Barium; D011188:Potassium