Forskolin (adenylate cyclase activator) mimics the effects of PKA activation, while a membrane-permeable PKA peptide inhibitor (PKI-14-22 amide, myristoylated) reduces the effects of PKA without affecting CON myocytes. Five groups of myocytes isolated from the same heart were incubated for 4 h under the control conditions (CON), with 10 µM PKI (CON+PKI), with 10 µM forskolin, with 8CPT-cAMP (100 µM)/okadaic acid (100 nM) (PKA), and further 10 µM PKI (PKK+PKI). Myocytes were immunostained for Na_V1.5 and nCadherin, and subject to Airyscan imaging followed by quantification. (A) Representative merged Na_V1.5 and nCadherin views of myocytes corresponding to the groups in B. (B) Summary of Na_V1.5 enrichment at ICDs (nCad-positive areas) from the five groups listed along the abscissa. The dotted line at the y-axis 1 denotes no enrichment. Numbers in parentheses are those of myocytes quantified. Statistical analysis was one-way ANOVA on ranks, P < 0.05, followed by all-pairwise comparisons using Dunn’s method. Shown are P values <0.05 or >0.05 between specified groups.