Figure 2.

The A-current and its effects on the voltage response. A-C, The 4-AP-sensitive A-current found in short and intermediate hair cells was elicited by depolarizing the cell to -3 mV from holding potentials of -83 mV. This current was blocked partially by 30 μm AA and its nonmetabolic analog ETYA and blocked almost completely by 10 mm 4-AP. D, A transient voltage response was elicited when hair cells were depolarized in current clamp from their resting potential (I = 0). The addition of 20μm AA increased the amplitude of this response and prevented repolarization of the cell. E, F, Hair cells held at more negative membrane potentials and superfused with either 20 μm AA or 10 mm 4-AP showed an increase in the amplitude and duration of this transient voltage response. The results in A are from a different cell than those in E and F, which are from the same cell. The A-current response in B and C was isolated as outlined in Materials and Methods.