Cell-cycle-dependent changes in membrane potential of L-929 cells caused by the effect of hydrogen peroxide.

The changes in membrane potential of L-929 fibroblasts caused by H2O2 (10-50 microM) at different phases of the cell cycle were investigated. The membrane potential of cells in G0, early G1, and G2/M responded to H2O2 by hyperpolarizing, while cells in late G1/S responded by depolarizing. Quinidine (50 microM), a blocker of Ca2+-dependent K+ conductance, inhibited the hyperpolarization response of L-929 cells to H2O2 in all cases.