Characteristics of Potassium and Calcium Currents of Hepatic Stellate Cells (Ito) in Rat.
10.3349/ymj.2004.45.4.649
- Author:
Keon Il LEE
1
;
In Deok KONG
;
Soon Koo BAIK
;
Hyun Soo KIM
;
Dong Ki LEE
;
Sang Ok KWON
;
Boe Gwun CHUN
Author Information
1. Department of Physiology, Wonju College of Medicine, Yonsei University, Wonju, Korea.
- Publication Type:Original Article
- Keywords:
Hepatic stellate cells;
outward K+ currents;
inward K+ currents;
L-type Ca2+ current
- MeSH:
Animals;
Calcium/*metabolism;
Calcium Channel Blockers/pharmacology;
Calcium Channels, L-Type/*physiology;
Cells, Cultured;
Hepatocytes/cytology/*physiology;
Immunohistochemistry;
Male;
Membrane Potentials/drug effects/physiology;
Patch-Clamp Techniques;
Potassium/*metabolism;
Potassium Channel Blockers/pharmacology;
Potassium Channels, Voltage-Gated/*physiology;
Rats;
Rats, Sprague-Dawley
- From:Yonsei Medical Journal
2004;45(4):649-660
- CountryRepublic of Korea
- Language:English
-
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 alpha-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 15microM 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+ currents composed of multiple pharmacological components, Ba2+-sensitive inward rectifying K+ current and L-type Ca2+ current.
