Fig. 3
Ca2+ current density is larger in complex calyces. a Example calyces are visualized in z-axis projection images. Representative traces show presynaptic Ca2+ currents (ICa2+) recorded from simple (black) and complex (red) calyces kept at −100 mV. ICa2+-s were tested by voltage steps between −90 and +50 mV with 10 mV increments (see schematic drawing). Average voltage-dependence curves of step ICa2+-s (mean ± SEM) are shown in simple and complex calyces. Amplitude-scaled version of simple calyx I–V curve (dashed black) overlaps with the complex one. b, c Bar graphs show the maximal step ICa2+ amplitude (ICa2+max), step ICa2+ density (ICa2+dens), and whole-cell capacitance (Cwhole-cell) of simple and complex calyces (step ICa2+ amplitude, simple, 1.33 ± 0.11 nA, n = 5/4, complex, 2.34 ± 0.20 nA, n = 8/7, t = 3.846, p = 0.003, df = 11, unpaired t-test [u.t.t]; step ICa2+ density, simple, 0.071 ± 0.0057 nA per pF, n = 5/4, complex, 0.106 ± 0.0087 nA per pF, n = 8/7, t = 2.974, p = 0.013, df = 11, u.t.t.; Cwhole-cell, simple, 18.8 ± 0.62 pF, n = 5/4, complex, 22.2 ± 0.83 pF, n = 8/7, t = 2.918, p = 0.014., df = 11, u.t.t.). Scatter-plots of individual experiments (right) were fitted with linear function (mean ± 95% confidence interval). R demonstrates correlation strength. Bar graphs summarize mean ± SEM (*p < 0.05, **p < 0.01). See Supplementary Figure 4. Scale bars: 5 μm (a)
