Cx43 hemichannels are involved in APD prolongation in WT and S3A isolated cardiomyocytes. (A) Representative AP traces of WT and S3A isolated cardiomyocytes. Cells were stimulated with 1 µM Iso (green) in the absence or presence of Cx43 blockers contained inside the pipette: Gap19 (232 ng/μl) and Cx43 CT antibody (abCx43; 2.5 ng/μl). (B) Quantification of APD observed in A. P = 0.0001 WT vs. WT + Iso; P = 0.0001 WT + Iso vs. WT + Iso + abCx43, P = 0.0001 WT + Iso vs. S3A + Iso, P = 0.0001 S3A + Iso vs. S3A + Iso + Gap19 and S3A + Iso + abCx43. Comparisons between groups were made using nested-ANOVA. The number in parentheses indicates biological replicate. We analyzed three to five cells per mouse.