Fig. 2: Golgi-delimited cAMP generation promotes faster ventricular relaxation in zebrafish.
From: Cardiac contraction and relaxation are regulated by distinct subcellular cAMP pools
a, Illustration of the mounting position of the zebrafish to image the heart and diagram of the zebrafish heart. b, Representative image of a live zebrafish heart (left), demonstrating ventricular contraction and relaxation (right). Fluctuations in the fluorescence of the heart during contraction and relaxation over time are measured. The time between fluorescence maxima to minima is the time of relaxation (1), and the subsequent fluorescence minima to maxima portion of the graph is measured as the time of contraction (2). n = 38, 6 biological replicates. Sale bar, 50 μm. A, atrium; V, ventricle. c, Changes in heart contraction. d, Relaxation time relative to baseline in Golgi-bPAC-expressing zebrafish. Basal images of the zebrafish hearts were acquired for 1,500 frames. The transgenic Golgi-bPAC zebrafish were exposed to 4.2 μW cm−2 blue light and imaged after 1, 3 and 5 min stimulation. The quantified data are represented as mean ± s.e.m. The P values were calculated by one-way ANOVA. n = 38 zebrafish, 6 biological replicates. e–g, Comparisons of rates of contraction and relaxation at 1, 3 and 5 min after 4.2 μW cm−2 blue light illumination. The differences between faster contraction versus relaxation time over baseline are quantified and presented here as floating bars indicating minimum and maximum with line at median with P values presented. Data were analyzed by two-tailed t-test. n = 38 zebrafish, 6 biological replicates.
