Ca2+-current-voltage relationships evoked by incremental 15 ms step depolarizations from -87 mV to +58 mV revealed a ~25% reduction of ICa in 1/3 DKO and TKO mice. (A') Due to the perinatal lethality of TKO mice, detailed electrophysiological characterization of TKO IHCs had to be performed on organotypically-cultured organs of Corti after 7 days in vitro (DIV). C57BL/6J (Wt) and 1/3-DKO served as controls. Please note that all recordings from cultured IHCs were performed at [Ca2+]e of 10 mM to maximize IHC exocytic performance. (A") Quantification and statistical analysis of individual maximum ICa amplitudes (Imax) of the respective genotypes revealed a significant reduction in Imax in both endophilin mutant genotypes. (*p = 0.046, one-way ANOVA with post-hoc Tukey's). 