Fig. 3.

The transient Ca²⁺ current reappears during hair cell regeneration. (A) Traces of Ca²⁺ currents at different posttreatment days (PT7, PT25, and PT40) of regenerating hair cells after gentamicin-induced hair cell death at the basal portion of the basilar papilla. The current traces were elicited with 50-ms depolarizing voltage steps in 10-mV increments from a holding potential of −90 mV. Ca²⁺ currents underwent the most dramatic changes between ≈PT7 and PT40. There was the appearance of a transient current followed by a sustained current and, later, the disappearance of the transient component. (B) Mean peak current density ± SD. (PT7, n = 7; PT15, n = 9; PT25, n = 6; PT40, n = 7). (C) Histogram showing the magnitude of the peak current at different days after gentamicin treatment and the estimated transient current. (D) The current amplitude was larger and had pronounced inactivation from the holding potential of −90 mV (Left) than at −50 mV (Right). (E) Summary data of the holding potential-sensitive peak currents at different stages after gentamicin treatment.