Figure 7.

Ca²⁺ spark data obtained using xySpark. Accumulated data were obtained using xySpark to analyze confocal image stacks obtained from rat ventricular myocytes loaded with fluo-4. (A) Mean data showing the total number of detected events, amplitude, width, and duration (t_1/2) at ε = 3, 3.4, 3.8, or 4.2. Also given are histograms of spark amplitude (B), FWHM (C), and the half time (t_1/2) of the descending phase (D) at ε = 3, 3.4, 3.8, or 4.2. For clarity, curves (B and D: Poisson; C: Gaussian) are fitted only to data obtained at ε = 3.8 (dashed line). ^∗∗p < 0.05, n = 11, n.s.d. indicates no significant difference. Also shown are original (E) and mean (F) data from a second group of cells, showing the effect of 200 nM ISO on spark frequency. ^∗∗∗p < 0.01, n = 10. To see this figure in color, go online.