Figure 7.

At around the onset of hearing, short-term synaptic facilitation during high-frequency stimulation is abolished by blocking Ca²⁺-activated BK channels. A, Representative averaged traces of 10 individual synaptic responses in P11–P13 OHCs on a 10 Hz (left) or 80 Hz (right) 10-pulse train stimulation protocol in the absence (top) or the presence (bottom) of 200 nm IbTx. For clarification purposes, artifacts were removed and bars over traces indicate the corresponding stimulation pattern. B, The S, P, and the eIPSC average A were computed for every pulse during 10-shock trains at frequencies of 10 Hz (left) and 80 Hz (right). The normalized mean values for these parameters at the two stimulation frequencies are plotted against the pulse number protocol in the absence (top) or the presence (bottom) of 200 nm IbTx. 10 Hz: n = 4 for Ctrl and n = 4 for 200 nm IbTx; 80 Hz: n = 6 for Ctrl and n = 6 for 200 nm IbTx. See Table 4 for quantification.