Electrotonic suppression of early afterdepolarizations in the neonatal rat ventricular myocyte monolayer.
J Physiol
; 591(21): 5357-64, 2013 Nov 01.
Article
em En
| MEDLINE
| ID: mdl-24018945
ABSTRACT
Pathologies that result in early afterdepolarizations (EADs) are a known trigger for tachyarrhythmias, but the conditions that cause surrounding tissue to conduct or suppress EADs are poorly understood. Here we introduce a cell culture model of EAD propagation consisting of monolayers of cultured neonatal rat ventricular myocytes treated with anthopleurin-A (AP-A). AP-A-treated monolayers display a cycle length dependent prolongation of action potential duration (245 ms untreated, vs. 610 ms at 1 Hz and 1200 ms at 0.5 Hz for AP-A-treated monolayers). In contrast, isolated single cells treated with AP-A develop prominent irregular oscillations with a frequency of 2.5 Hz, and a variable prolongation of the action potential duration of up to several seconds. To investigate whether electrotonic interactions between coupled cells modulates EAD formation, cell connectivity was reduced by RNA silencing gap junction Cx43. In contrast to well-connected monolayers, gap junction silenced monolayers display bradycardia-dependent plateau oscillations consistent with EADs. Further, simulations of a cell displaying EADs electrically connected to a cell with normal action potentials show a coupling strength-dependent suppression of EADs consistent with the experimental results. These results suggest that electrotonic effects may play a critical role in EAD-mediated arrhythmogenesis.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Potenciais de Ação
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Conexina 43
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Miócitos Cardíacos
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Ventrículos do Coração
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Potenciais da Membrana
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Physiol
Ano de publicação:
2013
Tipo de documento:
Article