Modulation of I_h voltage dependence by cAMP. (A) Representative I_h traces from WT SGNs (P4, apex) in control (left) and after bath application of 200 µM 8-Br-cAMP (right). Recordings were made in two different cells from the same SGN explant tissue. Currents were evoked using the same voltage-clamp protocol shown in Fig. 2. (B) Mean voltage-dependent G_h activation curve from P3–4 SGNs. 200 µM 8-Br-cAMP was used. Data were fitted by a Boltzmann function. Note the shift in V_1/2 toward depolarized potentials with 8-Br-cAMP. Error bars equal ±1 SD.