BQ⁺ alters both open- and closed-time distributions of Cx50 hemichannels. (A) Representative open- and closed-time distributions at −70 mV in the absence (control) and the presence of 500 µM BQ⁺ plotted on a logarithmic abscissa. Lines are single-exponential fits to the histograms. (B) Concentration dependence of mean open (left) and mean closed (right) times.