Fig. 1.

Upon acute β–AR stimulation (isoproterenol), PKD1 cKO cardiomyocytes exhibited smaller Ca²⁺ transient (CaT) amplitudes and slower kinetics compared to WT littermates. A, Experimental protocol for Ca²⁺ imaging. B, Representative confocal images and C, representative traces of intracellular Ca²⁺ transients (CaT) in both WT and PKD1 cKO Fluo-4 AM loaded myocytes at baseline and after 5-min incubation with 100 nM isoproterenol (ISO). D, CaT amplitude increase after ISO treatment was lower in the PKD1 cKO, along with slower CaT decay tau. No significant changes in CaT time to peak in both genotypes. Data points represent cells (WT, n = 12; KO, n = 12) and numbers on the bars the mice (WT, N = 6; KO, N = 5). Data are presented as mean ± SEM. Two-way ANOVA, followed by Tukey’s multiple comparisons test. Differences were considered statistically significant if P < 0.05.