Characteristics of potassium and calcium currents of hepatic stellate cells (Ito) in rat

Keon Il Lee, In Deok Kong, Soon Koo Baik, Hyun Soo Kim, Dong Ki Lee, Sang Ok Kwon, Boe Gwun Chun

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Abstract

Hepatic stellate cells (HSCs) are known to play a role in the pathogenesis of the increased intrahepatic vascular resistance found in chronic liver diseases. The aim of this study was to evaluate the K+ and Ca2+ currents in cultured HSCs from rat liver, through the patch-clamp technique. Most cells were positive for desmin immunostain after isolation and in α-smooth muscle actin immunostain after 10 - 14 days of culturing. Outward and inward rectifying K+ currents were confirmed. Two different types of K+ currents were distinguished: one with the inward rectifying current and the other without. The outward K+ currents consisted of at least four components: tetraethylammonium (TEA -sensitive current, 4-aminopyridine (4-AP)-sensitive current, pimozide-sensitive current and three blocker-resistant current. The peaks of the outward K+ currents evoked by a depolarizing pulse were decreased to 32.0 ± 3.0, 62.8 ± 3.7 and 32.8 ± 3.5% by 5 mM TEA, 2 mM 4-AP and 15 μM pimozide, respectively. Moreover, the combined application of three blockers caused 86.6 ± 4.8% suppression. The inward currents evoked hyperpolarizing pulses were inwardly rectifying and almost blocked by Ba2+. Elevation of external K+ increased the inward current amplitude and positively shifted its reversal potential. Voltage-dependent Ca2+ currents which were completely abolished by Cd2+ and nimodipine were detected in 14 day cultured HSCs. In this study, the cultured HSCs were found to express outward K+ current composed of multiple pharmacological components, Ba2+-sensitive inward rectifying K+ current and L-type Ca2+ current.

Original languageEnglish
Pages (from-to)649-660
Number of pages12
JournalYonsei medical journal
Volume45
Issue number4
DOIs
Publication statusPublished - 2004 Aug 31

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All Science Journal Classification (ASJC) codes

  • Medicine(all)

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