Fig. 1.

Current and voltage responses from IHCs of Pcdh15 mutant mice. a, b Potassium currents recorded from IHCs of control Pcdh15^+/av3j (a) and littermate mutant Pcdh15^av3j/av3j mice (b) using 10 mV depolarizing voltage steps from –84 mV to the various test potentials shown by some of the traces. The adult-type currents (I_K,f and I_K,n) were only present in IHCs from control Pcdh15^+/av3j mice (a). IHCs from Pcdh15^av3j/av3j mice retained the currents characteristic of immature cells (b_, I_K and I_K1). The absence of the rapidly activating I_K,f in Pcdh15 ^av3j/av3j IHCs is also evident when comparing the activation time course of the total outward currents on an expanded time scale (see insets). a, b are representative recordings from 10 (3 mice) and 12 (3 mice) IHCs, respectively. c, d Voltage responses elicited by applying depolarizing current injections to control, Pcdh15^+/av3j c and mutant, Pcdh15^av3j/av3j d IHCs from their resting membrane potentials. Depolarizing current injections caused slow APs in the Pcdh15^avj3/av3j mutant IHC. c, d are representative recordings from 8 (3 mice) and 15 (3 mice) IHCs, respectively. Recordings were performed near body temperature