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Updated: May 10, 2026
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Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
La corriente de Cl(-) activada por calcio contribuye al retraso de las despolarizaciones posteriores en los miocitos
A O Verkerk1, M W Veldkamp, L N Bouman
1Department of Physiology, Academic Medical Center, University of Amsterdam, The Netherlands. a.o.verkerk@amc.uva.nl
Circulation
|June 7, 2000
Resumen
La corriente transitoria hacia adentro (I(ti)) en las células cardíacas involucra corrientes de intercambio de cloruro (Cl-) y sodio-calcio (Na+-Ca2+). El bloqueo del componente de Cl-corriente puede ayudar a prevenir las arritmias al reducir las despolarizaciones posteriores retardadas (DAD).
Área de la Ciencia:
- Electrofisiología Cardíaca Electrofisiología cardíaca.
- Fisiología del canal iónico Fisiología del canal iónico
- Farmacología Cardiovascular Farmacología Cardiovascular
Sus antecedentes:
- La corriente transitoria hacia adentro (TI) subyace a las despolarizaciones posteriores tardías (DADs), un factor clave en las arritmias cardíacas.
- Los mecanismos iónicos de I(ti) difieren entre los miocitos ventriculares y las fibras de Purkinje, con estudios previos que implican el intercambio Na+-Ca2+, las corrientes Cl- y las corrientes catiónicas no selectivas.
Objetivo del estudio:
- Para dilucidar la base iónica de I ((ti) en ovejas Purkinje y miocitos ventriculares.
- Para investigar el potencial antiarrítmico de bloquear el componente Cl- corriente de I(ti).
Principales métodos:
- La electrofisiología de la pinza de parche de células enteras se empleó en ovejas aisladas Purkinje y miocitos ventriculares.
- I(ti) fue inducida usando despolarizaciones repetitivas en presencia de norepinefrina.
- Se evaluaron los efectos del bloqueador de aniones 4,4'-diisothiocyanatostilbene-2,2'-ácido disulfónico (DIDS) y el bloqueo del intercambio de Na+-Ca2+.
Principales resultados:
- Ti) exhibió corriente hacia adentro con potenciales negativos y corriente hacia afuera con potenciales positivos en ambos tipos de células.
- DIDS bloqueó por completo el componente externo e inhibió ligeramente el componente interno de I ((ti).
- El componente I ((ti) sensible a DIDS se estaba rectificando externamente, consistente con una corriente Cl-, mientras que el componente insensible a DIDS fue abolido por el bloqueo de intercambio Na+-Ca2+.
Conclusiones:
- I(ti) tanto en los miocitos de Purkinje como en los miocitos ventriculares está mediada por dos mecanismos iónicos distintos: una corriente de Cl- y una corriente de intercambio Na+-Ca2+.
- El bloqueo del componente de corriente Cl de I(ti) redujo significativamente la amplitud DAD y desencadenó la actividad, lo que sugiere posibles beneficios antiarrítmicos.
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