Rapid electrical stimulation causes alterations in cardiac intercellular junction proteins of cardiomyocytes

The intercellular junctions contain two complexes, adhesion junctions (AJ) and connexin (Cx) gap junctions (GJs). GJs provide the pathway for intercellular current flow. AJs mediate normal mechanical coupling and play an important role in the stability of GJs. We investigated the effects of rapid electrical stimulation (RES) on cardiac intercellular junctions, especially β-catenin and Cx43 alterations. We also studied the effects of ANG II receptor blockade on intercellular junction remodeling. Neonatal rats were euthanized by decapitation, and cardiomyocytes were prepared, cultured, and subjected to RES. We used real-time PCR, western blot analysis, and immunohistochemical methods. Conduction properties were examined by an extracellular potential mapping system. Cx43 protein expression in cardiomyocytes was significantly increased after 60 min. β-Catenin expression in the total cell fraction was significantly increased after 30 min. The expression level of β-catenin in the nucleus, which functions as a T...