Fig. 4.

Nicotine-evoked postsynaptic currents in young inner hair cells. A: the effect of hair cell membrane potential (indicated in mV above each recording) on nicotine-evoked currents. Average waveforms aligned by rise time. The majority of current flows through calcium-activated potassium channels and so reverses around the potassium equilibrium potential of −80 mV. At −64 mV, the current is biphasic due to sequential flux through the hair cell’s nAChR and calcium-activated potassium channels. B: nicotine-evoked currents before (black) and in the presence of strychnine (red; 10 µM applied in the bath), a potent antagonist of α9-containing nAChRs. C: nicotine-evoked currents before (black) and in the presence of tetrodotoxin (red; 1 µM applied in the bath). Vertical gray-shaded bars indicate 500-ms puff of 1 mM nicotine.