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

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.