Characteristics of potassium and calcium currents of hepatic stellate cells (ito) in rat.
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 15 micro M 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.
Lee
Keon Il
KI
Department of Physiology, Wonju College of Medicine, Yonsei University 162 Ilsan-dong, Wonju 220-701, Korea.
Kong
In Deok
ID
Baik
Soon Koo
SK
Kim
Hyun Soo
HS
Lee
Dong Ki
DK
Kwon
Sang Ok
SO
Chun
Boe Gwun
BG
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000502:physiology*; D002478:Cells, Cultured; D022781:Hepatocytes / Q000166:cytology / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D024642:Potassium Channels, Voltage-Gated / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D026902:Potassium Channel Blockers; D024642:Potassium Channels, Voltage-Gated; D011188:Potassium; D002118:Calcium