Effects of ytterbium on outward K~+ currents in NIH3T3 cell

Using the whole cell patch-clamp technique, we observed the outward K+ currents and studied for the first time the effects of Yb3+ on the currents and kinetics of activation and inactivation in non-excitable NIH3T3 cell. Our results show that the outward K+ currents were promoted with increasing concentration of Ca2+ in pipette solution and saturated at the concentration of 100 μmol/L Ca2+. Yb3+ in bath solution inhibited the currents in a concentration-dependent manner. At the concentration of 1 μmol/L, Yb3+ significantly changed the Vh of activation curve and shifted the activation curve to more negative potentials, but with no effect on its slope factor k. Meanwhile, it had no effect on the inactivation curve. Potassium currents inhibition can 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 mo- lecular mechanisms to affect cell division and proliferation of Yb3+ on NIH3T3 cells.