Introduction: Skeletal myoblast(SMB) transplantation is a promising strategy for treating end-stage heart failure. Electrical and mechanical coupling is essential to synchronized contraction and coordinated function of transplanted SMBs. However the studies about induction of intercellular junction protein were very limited. We evaluated the influence of co-culture with cardiomyocytes/myocardial protein and oscillating pressure on the transdifferentiation of SMBs into cardiomyocytes and formation of intercellular gap junction. Subjects and Methods: SMBs were obtained from Fisher344 rat. Co-culture with cardiomyocytes or myocardial protein from F344 rat and application of oscillating pressure were introduced to induce transdifferentiation of SMBs. Differentiation status was evaluated with cardiac specific troponin-I/T(Tn-I/T), connexin 43(Cx43), N-cadherin(N-cad) by RT-PCR, immunocytochemistry, and western blot analysis. Responses to 棺-adrenergic stimulation on spontaneous beating myotubes were evaluated. Results: SMBs in single culture, cardiac specific Tn-I/T were not expressed and expression of Cx43 was decreased with differentiation into myotubes. Co-culture with cardiomyocytes or myocardial protein induced expression of Tn-I/T, and increased expression of Cx43 in SMBs. Application of oscillating pressure further augmented expression of Cx43 and N-cad. The enhanced Cx43 expression was regulated by 棺-catenin via non GSK-3棺 mediated pathway. When SMBs were co-cultured with cardiomyocytes, synchronous contractions of myotubes with adjacent cardiomyocytes were observed, additionally, 棺-adrenergic agonist significantly increased contraction rates of skeletal myotubes. It was not observed in single culture. Conclusion: Interaction with cardiomyocytes or myocardial protein had a critical effect on transdifferentiation of SMBs into cardiomyocytes and electrical coupling of myotubes with cardiomyocytes. Moreover, oscillating pressure augmented the increase of Cx43 expression in SMBs. These results showed that oscillating pressure and interaction with myocardial protein might play important roles to form electric and mechanical coupling between the transplanted SMBs and de novo cardiomyocytes in vivo.