Fig. 1.
Current–voltage (I–V) relation recorded in an inner hair cell (IHC) afferent dendrite. Current responses to voltage steps in the absence (A) and the presence (B) of 1 μM tetrodotoxin (TTX). Voltage step protocol (inset in A): 200 ms voltage steps from −104 to −4 mV in 10 mV increments, from a holding potential of −84 mV. A: rapidly activating and inactivating sodium currents that sometimes escaped the voltage clamp (expanded trace shown in inset) were blocked by 1 μM TTX (B). C: current responses at 20 ms (solid circle) and 200 ms (open triangle) into the voltage steps after leak subtraction. A slowly activating inward current (i.e., a hyperpolarization-activated current [Ih]) was found at voltage steps to −94 mV or more negative potentials. Fast activating outward currents (within 5 ms) were activated at −64 mV and more positive voltages.