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. 2016 Mar 16;43(8):1062–1074. doi: 10.1111/ejn.13209

Figure 2.

Figure 2

9‐AC block requires negative charge and appears independent of the integrity of the cytoskeleton. (A–C) Capacitances of three voltage‐clamped OHCs. Labelling conventions are as in Fig. 1A. (A) Extracellular application of 500 μm 9‐AM, an electrically neutral analog of 9‐AC. There is no detectable effect on cell capacitance, meaning that the negative charge of 9‐AC is mandatory for 9‐AC block. (B) Application of 500 μm 9‐AC to an OHC treated extracellularly with diamide. NLC is reversibly reduced; fit parameters are given in Table 3. (C) Application of 500 μm 9‐AC to an OHC treated intracellularly and extracellularly with latrunculin A. NLC is reversibly reduced; fit parameters are given in Table 4. (D) The relative reduction in Q max in response to extracellular application of 500 μm 9‐AC, DMSO or 500 μm 9‐AM. Labelling on the abscissa has the following meaning. Control, extracellular application of 500 μm 9‐AC to control OHCs (n = 11). DMSO, extracellular application of DMSO to control OHCs (n = 6). 9‐AM, extracellular application of 500 μm 9‐AM to control OHCs (n = 6). Diam, diamide‐treated OHCs (n = 5) with extracellular application of 500 μm 9‐AC. Latr, latrunculin‐treated OHCs (n = 7) with extracellular application of 500 μm 9‐AC. There is no significant difference for relative Q max reductions for cells treated with diamide or latrunculin A compared with untreated cells, indicating that the cytoskeleton is not a primary target of 9‐AC. Relative reductions for DMSO and 9‐AM applications are not significantly different from zero and there was also no effect on the other capacitance‐defining parameters; that is, neither DMSO nor 9‐AM had a detectable effect on NLC.