Mechanical regulation of cardiac myofibrillar structure

D. G. Simpson, W. W. Sharp, T. K. Borg, R. L. Price, A. M. Samarel, L. Terracio

Research output: Contribution to journalArticlepeer-review


The excitation-contraction coupling cycle (ECC) consists of a complex cascade of electrochemical and mechanical events; however, the relative contributions of these different processes in the regulation of cardiac myofibrillar structure are not well understood. There is extensive evidence to suggest that the mechanical aspects of the ECC play a crucial role in controlling the availability of contractile proteins for myofibrillar assembly. To examine if these physical forces might also serve to stabilize the structure of preexisting myofibrils, beating and nonbeating cultures of neonatal cardiac myocytes (NCM) were subjected to a 5% static stretch. Contractile arrest was achieved by treating NCM with 12 μM nifedipine, which resulted in immediate and sustained contractile arrest and initiated the evolution of marked myofibrillar abnormalities within 24 hours. As judged by scanning confocal and transmission electron microscopic examination, an external load appears to partially stabilize myofibrillar structure in nonbeating NCM. These results suggest that the maintenance of myofibrillar structure may be highly dependent upon the mechanical aspects of ECC.

Original languageEnglish (US)
Pages (from-to)131-140
Number of pages10
JournalAnnals of the New York Academy of Sciences
StatePublished - 1995

ASJC Scopus subject areas

  • General Neuroscience
  • General Biochemistry, Genetics and Molecular Biology
  • History and Philosophy of Science


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