Intercellular synchronization and fluctuations ofintracellular Ca2+ oscillation in spontaneously beatingcardiac myocytes in culture

摘要

Cultured cardiac myocytes from neonatal rats show spontaneous and cyclic contractions. The intracellular concentration of free Ca2+ also changes cyclically associated with the rhythmic contraction of myocytes (Ca2+ oscillation). In cultures at 4 days in vitro (4 DIV), the cyclic Ca2+oscillation was synchronized among myocytes in an aggregate as well as among myocytes without physical contact each other. This study aims at elucidating the mechanisms responsible for the intercellular synchronization and fluctuation of intracellular Ca2+ oscillation in cultured cardiacmyocytes. The present experimental and simulation studies suggested that the extracellular signaling pathway such as the ATP-purinoceptor system was involved in the intercellular synchronization of intracellular Ca2+ oscillation, and that the mechanical factor associated with rhythmic contraction contributed to the reduction in the fluctuation of intracellular Ca2+ oscillation, but did not affect the intercellular synchronization of Ca2+ oscillation in cultured cardiac myocytes.