Defects in T-tubular electrical activity underlie local alterations of calcium release in heart failure.
Proc Natl Acad Sci U S A
; 111(42): 15196-201, 2014 Oct 21.
Article
en En
| MEDLINE
| ID: mdl-25288764
ABSTRACT
Action potentials (APs), via the transverse axial tubular system (TATS), synchronously trigger uniform Ca(2+) release throughout the cardiomyocyte. In heart failure (HF), TATS structural remodeling occurs, leading to asynchronous Ca(2+) release across the myocyte and contributing to contractile dysfunction. In cardiomyocytes from failing rat hearts, we previously documented the presence of TATS elements which failed to propagate AP and displayed spontaneous electrical activity; the consequence for Ca(2+) release remained, however, unsolved. Here, we develop an imaging method to simultaneously assess TATS electrical activity and local Ca(2+) release. In HF cardiomyocytes, sites where T-tubules fail to conduct AP show a slower and reduced local Ca(2+) transient compared with regions with electrically coupled elements. It is concluded that TATS electrical remodeling is a major determinant of altered kinetics, amplitude, and homogeneity of Ca(2+) release in HF. Moreover, spontaneous depolarization events occurring in failing T-tubules can trigger local Ca(2+) release, resulting in Ca(2+) sparks. The occurrence of tubule-driven depolarizations and Ca(2+) sparks may contribute to the arrhythmic burden in heart failure.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Calcio
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Células Musculares
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Miocitos Cardíacos
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Insuficiencia Cardíaca
Límite:
Animals
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2014
Tipo del documento:
Article