The electrogenic Na+/HCO3- cotransport modulates resting membrane potential and action potential duration in cat ventricular myocytes

Perforated whole-cell configuration of patch clamp was used to determine the contribution of the electrogenic Na+/ HCO3- cotransport (NBC) on the shape of the action potential in cat ventricular myocytes. Switching from Hepes to HCO3 - buffer at constant extracellular pH (pHo) hyperpolarized resting...

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Autores principales: Villa Abrille, María Celeste, Vila Petroff, Martín Gerardo, Aiello, Ernesto Alejandro
Formato: Articulo
Lenguaje:Inglés
Publicado: 2006
Materias:
Ciencias Médicas
cat ventricular myocytes
electrogenic Na+/HCO3− cotransport
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/83019
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-83019
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Médicas
cat ventricular myocytes
electrogenic Na+/HCO3− cotransport
spellingShingle Ciencias Médicas
cat ventricular myocytes
electrogenic Na+/HCO3− cotransport
Villa Abrille, María Celeste
Vila Petroff, Martín Gerardo
Aiello, Ernesto Alejandro
The electrogenic Na+/HCO3- cotransport modulates resting membrane potential and action potential duration in cat ventricular myocytes
topic_facet Ciencias Médicas
cat ventricular myocytes
electrogenic Na+/HCO3− cotransport
description Perforated whole-cell configuration of patch clamp was used to determine the contribution of the electrogenic Na+/ HCO3- cotransport (NBC) on the shape of the action potential in cat ventricular myocytes. Switching from Hepes to HCO3 - buffer at constant extracellular pH (pHo) hyperpolarized resting membrane potential (RMP) by 2.67 ± 0.42 mV (n = 9, P < 0.05). The duration of action potential measured at 50% of repolarization time (APD50) was 35.8 ± 6.8% shorter in the presence of HCO3- than in its absence (n =9, P < 0.05). The anion blocker SITS prevented and reversed the HCO3--induced hyperpolarization and shortening of APD. In addition, no HCO3-induced hyperpolarization and APD shortening was observed in the absence of extracellular Na+. Quasi-steady-state currents were evoked by 8 s duration voltage-clamped ramps ranging from -130 to +30 mV. A novel component of SITS-sensitive current was observed in the presence of HCO3-. The HCO3--sensitive current reversed at -87 ± 5 mV (n =7), a value close to the expected reversal potential of an electrogenic Na+/HCO3- cotransport with a HCO3-: Na+ stoichiometry ratio of 2: 1. The above results allow us to conclude that the cardiac electrogenic Na+/HCO3- cotransport has a relevant influence on RMP and APD of cat ventricular cells.
format Articulo
Articulo
author Villa Abrille, María Celeste
Vila Petroff, Martín Gerardo
Aiello, Ernesto Alejandro
author_facet Villa Abrille, María Celeste
Vila Petroff, Martín Gerardo
Aiello, Ernesto Alejandro
author_sort Villa Abrille, María Celeste
title The electrogenic Na+/HCO3- cotransport modulates resting membrane potential and action potential duration in cat ventricular myocytes
title_short The electrogenic Na+/HCO3- cotransport modulates resting membrane potential and action potential duration in cat ventricular myocytes
title_full The electrogenic Na+/HCO3- cotransport modulates resting membrane potential and action potential duration in cat ventricular myocytes
title_fullStr The electrogenic Na+/HCO3- cotransport modulates resting membrane potential and action potential duration in cat ventricular myocytes
title_full_unstemmed The electrogenic Na+/HCO3- cotransport modulates resting membrane potential and action potential duration in cat ventricular myocytes
title_sort electrogenic na+/hco3- cotransport modulates resting membrane potential and action potential duration in cat ventricular myocytes
publishDate 2006
url http://sedici.unlp.edu.ar/handle/10915/83019
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bdutipo_str Repositorios
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