Figure 7. Lack of vesicular zinc does not alter the relationship between stimulus strength and Ca²⁺ release.

A, Ca²⁺ signals triggered by 8, 12, 16 and 20 synaptic stimulations (at 100 Hz) and visualized using a pseudo line scan along apical dendrite (continuous red line, left). Corresponding Ca²⁺ traces and electrophysiological responses are shown at the bottom. Ca²⁺ signals were averaged within the area of the hot spot indicated by dashed red lines.Ba, plot showing correlation between integrated Ca²⁺ signals, normalized with the respect to maximum value and the number of synaptic stimuli. Data from an individual cell are shown. Note that in both ZnT3 wild-type and KO mice, linear correlation was observed between the number of stimuli and the amplitude of the Ca² waves, unlike the data obtained from rats (Fig. 6).Bb, summary plot indicating that Ca²⁺ signals evoked by different number of synaptic stimuli were not significantly different in ZnT3 KO mice (n = 14) when compared to wild-type animals (n = 9).