Fig. 5: Mapping of Ca2+ sparks origins during β-adrenergic stimulation.
a, Correlative Ca2+ and RyR imaging in Ctl and ISO-treated cardiomyocytes, with spark locations marked with yellow crosses. b, Despite markedly increased spark frequency during ISO stimulation, the majority of Ca2+ sparks continued to be superimposed on RyR clusters (79% within 300 nm for Ctl, versus 83% in ISO). Data are presented as mean ± s.e.m. Differences between groups were tested with two-tailed linear mixed models with Tukey post hoc correction for multiple comparisons. *P < 0.05. P value for spark rate = 0.0291. For n values, see Source data. c,d, Representative DS Ca2+ sparks during Ctl (c) and ISO treatment (d) are illustrated with Ca2+-RyR mapping (left), with spark centroids indicated by red dots and localization uncertainty illustrated by surrounding white circles. Overall spark time courses are shown at the right. Both example sparks are single-release events. DS Ca2+ release (blue bars) was larger during ISO, resulting in larger amplitude Ca2+ sparks. The dashed line indicates the time point for the Ca2+-RyR overlay, and the duration of spark detection is shown in gray.
