Figure 1. Properties of Ca2+ sparks and corresponding Ca2+ blinks. Figure 1. Properties of Ca2+ sparks and corresponding Ca2+ blinks. A, Two examples (left and right) of simultaneously measured Ca2+ sparks and Ca2+ blinks recorded from different release sites. Top, Normalized (F/F0) line scan images of Rhod-2 fluorescence and corresponding profiles of Ca2+ sparks obtained by averaging fluorescence from the 1-μm-wide regions marked by red boxes. Bottom, Normalized line scan images of Fluo-5N fluorescence and corresponding profiles of Ca2+ blinks obtained by averaging fluorescence from the regions marked by green boxes. Blink profiles were fitted by exponential functions to the rising and decay phase, respectively (dashed blue line). B, a, Average time-to-peak (TTP) of sparks and time-to-nadir (TTN) of blinks. b, Average time constants of spark decay and blink recovery. c, Relationship between the time constants of spark decay and blink recovery. d, Average FDHM of sparks and blinks. C, Left, Fluo-5N signal during Ca2+ blink and complete depletion of the SR after the application of 10 mmol/L caffeine. Right, Distribution and mean±SD of [Ca2+]SR at the nadir of blinks ([Ca2+]SR, nadir). Histogram was fitted with a single Gaussian function (red line). Zima A V et al. Circulation Research 2008;103:e105-e115 Copyright © American Heart Association