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. 2018 Jan 12;7:e30241. doi: 10.7554/eLife.30241

Figure 6. Capacitance responses recorded from RIBEYE knockout mice show little difference between phenotypes.

Figure 6.

Example records of Cm responses (top), showing two release components and Ca2+ currents (below) recorded from a WT (blue) (A) and a KO (red) mouse (B) in response to 1 s depolarizations from −84 mV to −49 and −44 mV. The dashed line indicates pre-stimulus baseline Cm. The black solid line indicates the first linear component of release, and the cyan line the second superlinear component. (C) Summary plot of first and second component magnitudes. No statistical difference was found between groups. For the linear component, n = 15 for WT and 15 for KO, p=0.23. For the second superlinear component, n = 17 for both groups and p=0.38. Filled stars indicate mean for this and all subsequent figures. (D) Summary plot of first and second component rates obtained by linear fits to data points, as indicated by lines in (A,B). No statistical difference was found between groups where, n = 16 for WT and 13 for KO, with p=0.266. For the second component rate, n = 17 for both groups, with p=0.085. (E) A population histogram for the voltage at which the superlinear response is first observed. Fits to Gaussian distributions show no change in the mean value but an increase in the width of the plot for the KO. (F) Example of delay in onset of capacitance change with small depolarizations for a KO cell. Plots of Cm verses voltage responses measured at 0.1 (G), 0.5 s (H) 1 s (I) or 3 s (J) show a significant difference for release at 0.1 s and −44 mV (p=0.03), error bars represent SEM. Fitting the relationships with simple exponential functions reveals differences in the shapes of the curves but not in maximum release for the 0.1 and 0.5 plots, whereas there are no differences in curve shapes for the 1 and 3 s time points. N provided in figure for each group. (K) Shows that time to release is significantly longer for KO compared to WT for depolarizations eliciting less than 50% of the maximal calcium current; n = 32 for WT and 26 for KO, p=0.0012.