Figure 6. ORC-13661 blocks the hair cell’s mechanoelectrical transducer channel.

(A–C and E–G) Mechanoelectrical transducer (MET) currents measured from mid-coil outer hair cells in a 2-day-old culture prepared from a P2 mouse before, during, and after extracellular exposure to 0.3 μM (A–C) and 3 μM (E–G) ORC-13661. Currents were measured at membrane potentials ranging from –164 to +96 mV. A sinusoidal stimulus delivered to the fluid-jet (shown above each trace; driver voltage [DV]) resulted in the opening and closure of the MET channels. Currents are reduced during exposure to ORC-13661, predominantly at hyperpolarized potentials, and recover partially following reexposure to control solution. (D and H) Current-voltage relations measured from the cell exposed to 0.3 μM (D) and 3 μM (H) ORC-13661 before, during, and after ORC-13661 superfusion. These relations further reveal a greater reduction in current size at hyperpolarized potentials and partial recovery during washout. Cell capacitances were 8.4 pF (A–C) and 8.0 pF (E–G). Number of cells recorded from exposure to 0.3 μM n = 10 and 3 μM n = 5. All experiments were performed at room temperature (20°C–22°C).