Hair cell activity in the presence of Qx28. (A–I) Five dpf WT larvae were preincubated in E3 water without (A and B) or with different Qx28 concentrations (C–I) for 1 hour and then cotreated with FM1-43 3 μM for 20 seconds. (J) The fluorescence incorporated per neuromast (red) was measured using ImageJ (NIH) and expressed as a percentage from control. The orbiter line (B) (52, 53) and fish preincubated with BAPTA were used as negative controls. Phalloidin counterstaining is shown in green. Results are expressed as mean ± SEM. Statistical analysis: 1-way ANOVA with correction for Dunnett’s multiple comparisons test. *P < 0.05, ****P < 0.0001 versus control. Number of neuromasts quantified: control = 33, orbiter = 8, BAPTA = 14, Qx28 1 nM = 12, Qx28 10 nM = 9, Qx28 100 nM = 30, Qx28 1 μM = 17, Qx28 10 μM and 50 μM = 10, Qx28 100 μM = 20. Scale bar: 7 μm. (K) Means ± SEM of the magnitude of microphonic responses from 6 dpf zebrafish in the presence of vehicle or Qx28 100 μM. Statistical analysis: Student’s 2-tailed t test. ****P < 0.0001 versus control. Measurements were obtained from 1 neuromast per fish from a total of 6 fish per condition. Top right: Microphonic potential traces of 6 dpf zebrafish in the presence of vehicle or Qx28 100 μM. The orbiter line was used as a negative control.
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