Effects of lanthanum on calcium-activated K^+ currents and its kinetics in MC3T3 cells  

作　　者：ZHANG LiPing1,2 & YANG Pin1 1Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education Institute of Molecular Science,Shanxi University,Taiyuan 030006,China 2College of Environment and Safety,Taiyuan University of Science and Technology,Taiyuan 030024,China 

出　　处：《Science China Chemistry》2010年第6期1281-1286,共6页中国科学（化学英文版）

基　　金：support from the Na-tional Natural Science Foundation of China (20637010);the Shanxi Provincial Natural Science Foundation for Youth (2007021010)

摘　　要：Using the whole cell patch-clamp technique,we studied the effects of La3+ on calcium-activated K+ currents and its kinetics of activation and inactivation in non-excitable MC3T3 cells.Our results showed that the calcium-activated outward K+ currents were promoted with increasing concentration of Ca2+ in the pipette solution and a voltage- and Ca2+-dependent manner.La3+ in the bath solution inhibited the currents in a concentration-dependent manner and the inhibition EC50 was 8.23 ± 1.45 μmol/L.At the concentration of 50 μmol/L,La3+ significantly changed the Vh of the activation curve and shifted the activation curve to more positive potentials,but shifted the inactivation curve to more negative potentials.It had no effect on the slope factor k of the activation and inactivation curves.Potassium currents inhibition could induce a series of physiological and molecular biological functions,presumably because of its ability to depolarize the plasma membrane and enhance cell excitability,resulting in increasing Ca2+ influx and cytoplast Ca2+ concentration.This process may be one of the molecular mechanisms by which La3+ affects the cell growth and function of MC3T3 cells.Using the whole cell patch-clamp technique,we studied the effects of La3+ on calcium-activated K+ currents and its kinetics of activation and inactivation in non-excitable MC3T3 cells.Our results showed that the calcium-activated outward K+ currents were promoted with increasing concentration of Ca2+ in the pipette solution and a voltage- and Ca2+-dependent manner.La3+ in the bath solution inhibited the currents in a concentration-dependent manner and the inhibition EC50 was 8.23 ± 1.45 μmol/L.At the concentration of 50 μmol/L,La3+ significantly changed the Vh of the activation curve and shifted the activation curve to more positive potentials,but shifted the inactivation curve to more negative potentials.It had no effect on the slope factor k of the activation and inactivation curves.Potassium currents inhibition could induce a series of physiological and molecular biological functions,presumably because of its ability to depolarize the plasma membrane and enhance cell excitability,resulting in increasing Ca2+ influx and cytoplast Ca2+ concentration.This process may be one of the molecular mechanisms by which La3+ affects the cell growth and function of MC3T3 cells.

关 键 词：MC3T3 cell POTASSIUM ion channel La3+ PATCH-CLAMP technique 

分 类 号：Q26[生物学—细胞生物学]