Preferential block of the veratridine-induced, non-inactivating Na+ current by R56865 in single cardiac Purkinje cells.
Eur J Pharmacol
; 203(3): 371-8, 1991 Oct 22.
Article
em En
| MEDLINE
| ID: mdl-1663453
ABSTRACT
The effect of the cardioprotective agent R56865 on the veratridine (VTD)-modified sodium current was investigated in single rabbit cardiac Purkinje cells and ventricular myocytes. A steady, tetrodotoxin (TTX)-sensitive Na+ current (the non-inactivating Na+ current) was absent in most cells studied. In the presence of veratridine (15 x 10(-6) M) a non-inactivating Na+ current could be elicited at membrane potentials between -80 to +60 mV, with a maximum at about 0 mV. R56865 blocked this current effectively. The concentration for half maximal inhibition of the non-inactivating Na+ current was 2 x 10(-7) M. Blockade of this Na+ current by R56865 increased with depolarization. R56865 was much more effective in inhibiting the non-inactivating Na+ current than in inhibiting time-dependent Na+ currents elicited by short depolarizing pulses. The blocking effect of R56865 on the steady state influx of Na+ may contribute to cardioprotection in depolarized cells and in cells with modified Na+ channels as may occur during ischemia and reperfusion.
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Base de dados:
MEDLINE
Assunto principal:
Piperidinas
/
Células de Purkinje
/
Tiazóis
/
Veratridina
/
Canais de Sódio
Limite:
Animals
Idioma:
En
Revista:
Eur J Pharmacol
Ano de publicação:
1991
Tipo de documento:
Article
País de afiliação:
Bélgica