Figure 5. Increasing the extracellular concentration of Ca²⁺ or ACh reverts the block of I_K(ACh) by gentamicin.

A, example of sequential current traces evoked by 300 μM ACh alone (ACh300) or with 50 μM GM (ACh300GM50). The carrier solution was either standard (1.26 mM Ca²⁺) or supplemented with 10 mM CaCl₂ as indicated. Recording traces are separated by 1 min intervals. B, example of sequential current traces evoked by 100 μM ACh (ACh100) and by increasing concentrations of ACh (100, 300 and 500 μM) supplemented with 50 μM GM (ACh100GM50, ACh300GM50 and ACh500GM50). Recording traces are separated by 1 min intervals. A and B are from two different OHCs voltage clamped at -40 mV and dialysed with internal solution 1. Drugs were applied to both cells using the U-tubing system described in Methods, thus explaining the longer delay of the responses.