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Activated stellate (Ito) cells possess voltage-activated calcium current
1Department of Gastroenterology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Biochimica Et Biophysica Acta
|April 21, 1999
Summary
Activated stellate cells, implicated in liver fibrosis, exhibit voltage-activated calcium currents. This study found L-type calcium currents appear in activated stellate (myofibroblast-like) cells during culture.
Area of Science:
- Hepatology
- Cell Biology
- Ion Channel Physiology
Background:
- Stellate (Ito) cells play a role in liver fibrosis and hepatic hemodynamics.
- Previous work indicated stellate cells possess voltage-activated Ca2+ current.
Purpose of the Study:
- To investigate the relationship between voltage-activated Ca2+ current and stellate cell activation.
- To determine when L-type Ca2+ currents emerge during stellate cell activation in vitro.
Main Methods:
- Whole-cell patch clamp technique was used to study voltage-activated Ca2+ currents in isolated rat stellate cells.
- Cell proliferation was assessed using BrdU incorporation.
- Cell activation was evaluated by alpha-smooth muscle actin expression and collagen type I mRNA levels.
Main Results:
- L-type voltage-activated Ca2+ current was detected in 12.5% and 69% of stellate cells at day 10 and 14 of culture, respectively.
- Stellate cell proliferation peaked by day 3-5 and decreased thereafter.
- Alpha-smooth muscle actin expression and collagen type I mRNA increased significantly after day 7 and day 10 of culture, respectively, indicating cell activation.
Conclusions:
- L-type voltage-activated Ca2+ current is a characteristic of activated stellate (myofibroblast-like) cells.
- The emergence of Ca2+ currents correlates with the activation state of stellate cells in culture.