Endocytosis was assessed by determining the decrease in Cm during 20 s post-depolarization in perforated patch recordings from both Wt, 1/2-DKO and 1/3-DKO IHCs. The two kinetic components are presented as average ∆Cm recordings after (A) 20 ms (Wt n = 12/ N = 8; 1/2-DKO n = 13/ N = 7; 1/3-DKO n = 13/ N = 10) and (B) 200 ms (Wt n = 12/ N = 8; 1/2-DKO n = 13/ N = 6; 1/3-DKO n = 14/ N = 10) depolarization stimuli. 