(A–C) Representative images of hair-cell stereocilia (conjugated phalloidin, gray) and FM1-43FX fluorescence intensity of the corresponding neuromast in representative control (A) or mechanically overstimulated fish immediately (B, B’) or 4 hr (C) following exposure. Yellow arrows in (B’) indicate phalloidin labeling that appeared tapered. (D) Average relative FM1-43FX fluorescence intensity measurements in control and exposed neuromasts over 4 hr of recovery. FM1-43FX uptake was significantly reduced in exposed neuromasts immediately following mechanical overstimulation but appear to completely recover by 4 hr (Tukey’s multiple comparisons test ****p < 0.0001 (0h), p = 0.0579 (1 h), p = 0.8387 (2h), p = 0.8387 (4h)). Dashed lines indicate FM1-43FX fluorescence intensity measurements in exposed neuromasts parsed into ‘normal’ and ‘disrupted’ morphologies. (E) Average stereocilia length of centrally localized hair bundles in control and exposed neuromasts. Dashed lines indicate measurements in exposed neuromasts parsed into ‘normal’ and ‘disrupted’ morphologies. Error Bars = SD (F) Relative FM1-43FX fluorescence in both ‘normal’ and ‘disrupted’ exposed neuromasts was significantly reduced immediately following exposure but recovered over time (Tukey’s multiple comparisons test ****p < 0.0001, *p = 0.0328 (0h); ****p < 0.0001, **p = 0.0098 (1h); **p = 0.0025 control vs. dis, **p = 0.0089 normal vs. dis (2 h)). Each point represents an individual neuromast. Nearly all observed exposed neuromasts appeared morphologically normal following 4 hr; note only one neuromast data point in the disrupted category of the 4 hr recovery graph. Data were obtained from 26 to 32 neuromasts per condition over three trials.
