Negative Inotropic Effects of Class I Antiarrhythmics on Guinea Pig Ventricular Myocardium: Correlation with L-Type Ca2+ Channel Blockade.
Biol Pharm Bull
; 46(1): 133-137, 2023.
Article
em En
| MEDLINE
| ID: mdl-36596522
ABSTRACT
The negative inotropic effects of nine Vaughan Williams class I antiarrhythmic drugs were examined in guinea pig ventricular tissue preparations. The drugs decreased the contractile force of papillary muscles with different potencies the potency order was propafenone > aprindine > cibenzoline > flecainide > ranolazine > disopyramide > pilsicainide > mexiletine > GS-458967. The potency of drugs correlated with the reported IC50 values to block the L-type Ca2+ channel rather than the Na+ channel. The effects of drugs were roughly the same when examined under a high extracellular K+ solution, which inactivates the Na+ channel. Furthermore, the attenuation of the extracellular Ca2+-induced positive inotropy was strong with propafenone, moderate with cibenzoline, and weak with pilsicainide. These results indicate that the negative inotropic effects of class I antiarrhythmic drugs can be largely explained by their blockade of the L-type Ca2+ channel.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Propafenona
/
Antiarrítmicos
Limite:
Animals
Idioma:
En
Revista:
Biol Pharm Bull
Assunto da revista:
BIOQUIMICA
/
FARMACOLOGIA
Ano de publicação:
2023
Tipo de documento:
Article