Age-related regulation of excitation-contraction coupling in XXXX heart.

@entity1433 @entity35 @entity48744 @entity8452 @entity141
Hearts from subjects with different ages have different @entity141 signaling. Release of @entity141 from intracellular stores in response to an action potential initiates cardiac contraction. Both depolarization-stimulated and spontaneous @entity141 releases, @entity141 transients and @entity141 sparks, demonstrate the main events of excitation-contraction coupling (ECC). Global increase in free @entity141 concentration ([ @entity141 ]( i )) consists of summation of @entity141 release events in cardiomyocytes. Since the @entity141 flux induced by @entity141 sparks reports a summation of @entity8452 -sensitive @entity141 release channels ( @entity48744 s)'s behavior in a spark cluster, evaluation of the properties of @entity141 sparks and @entity141 transients may provide insight into the role of @entity48744 s on altered heart function between 3-month-old (young adult) and 6-month-old (mature adult) @entity35 . Basal [ @entity141 ]( i ) and @entity141 sparks frequency were significantly higher in mature adult @entity35 compared to those of young adults. Moreover, amplitudes of @entity141 sparks and @entity141 transients were significantly smaller in mature adults than those of young adults with longer time courses. A smaller L-type @entity141 current density and decreased SR @entity141 load was observed in mature adult @entity35 . In addition, @entity48744 s were markedly hyperphosphorylated, and phosphorylation levels of PKA and CaMKII were higher in heart from mature adults compared to those of young adults, whereas their SERCA protein levels were similar. Our data demonstrate that hearts from @entity35 with different ages have different @entity141 signaling including hyperphosphorylation of @entity48744 s and higher basal [ @entity141 ]( i ) together with increased oxidized protein- @entity1433 in mature adult @entity35 compared to those of young adults, which play important roles in ECC. Finally, we report that ECC efficiency changes with age during maturation, partially related with an increased cellular oxidation level leading to reduced free protein- @entity1433 in cardiomyocytes.
