Figure 4.

Overexpressing AKAP12 (A kinase anchoring protein 12) in adult primary cardiomyocytes significantly increases intracellular calcium post acute isoproterenol (ISO) treatment. A and H, Average tracings of [Ca²⁺]i represented by Fura-2 fluorescence ratio (340 nm/380 nm) from all primary adult cardiomyocytes isolated from male and female mice treated acutely with ISO. B through F, Quantification of [Ca²⁺]i and calcium kinetics among the AKAP12^OX and wild-type (WT) males; n=52 in WT and n=24 in AKAP12^OX. I through M, Quantification of [Ca²⁺]i and calcium kinetics among the AKAP12^OX and WT females; n=59 in WT and n=64 in AKAP12^OX. Comparison of paced cells parameters measured includes B and I, diastolic [Ca²⁺]i (F340/F380); C and J, systolic [Ca²⁺]i (F340/F380); D and K, [Ca²⁺]i change (%; E and L) time to 90% baseline (seconds); F and M, time to 90% peak (seconds). G and N, Scatter plot of systolic [Ca²⁺]i (F₃₄₀/F₃₈₀) and systolic sarcomere length (µm). N=4 in each group. All data represented as average mean±SEM of median values for each animal except A and H, which represents the mean±SEM. of all cells. Data were determined to have a parametric distribution by the Shapiro-Wilk test; α=0.005 and were analyzed using an unpaired 2-tailed Student t test. ‡‡ indicates that the isolation buffer contained Blebbistatin instead of BDM.