Recovery of sensitivity after a 90% bleach of the visual pigment. (A) Changes in log sensitivity after pigment bleaching plotted as a function of time. Sensitivity before pigment bleaching (upward filled triangle) is plotted (mean ± SEM). A 90% bleach is given at time 0 s. Recovery of sensitivity began at much later times than for the 50% bleach shown in Fig. 2 due to the longer period of dark current suppression for the 90% bleach. Recovery of sensitivity at the base of the outer segment commenced with a time constant of ∼150 s but could not be accurately fit at the tip of the outer segment. (B) Suction electrode–only recording configuration for the experiment. On the bottom, responses to saturating flashes at selected time points during recovery in A are shown. (C) Dim flash responses in the dark-adapted cell after dialysis (gray) and at steady state after pigment bleaching (black) indicating the response speeding characteristic of bleaching adaptation.