Interaction between Ca(2+) channel blockers and isoproterenol on L-type Ca(2+) current in canine ventricular cardiomyocytes.
Acta Physiol (Oxf)
; 206(1): 42-50, 2012 Sep.
Article
em En
| MEDLINE
| ID: mdl-22520840
ABSTRACT
AIM:
The aim of this work was to study antagonistic interactions between the effects of various types of Ca(2+) channel blockers and isoproterenol on the amplitude of L-type Ca(2+) current in canine ventricular cells.METHODS:
Whole-cell version of the patch clamp technique was used to study the effect of isoproterenol on Ca(2+) current in the absence and presence of Ca(2+) channel-blocking agents, including nifedipine, nisoldipine, diltiazem, verapamil, CoCl(2) and MnCl(2) .RESULTS:
Five micromolar Nifedipine, 1 µM nisoldipine, 10 µM diltiazem, 5 µM verapamil, 3 mM CoCl(2) and 5 mM MnCl(2) evoked uniformly a 90-95% blockade of Ca(2+) current in the absence of isoproterenol. Isoproterenol (100 nM) alone increased the amplitude of Ca(2+) current from 6.8 ± 1.3 to 23.7 ± 2.2 pA/pF in a reversible manner. Isoproterenol caused a marked enhancement of Ca(2+) current even in the presence of nifedipine, nisoldipine, diltiazem and verapamil, but not in the presence of CoCl(2) or MnCl(2) .CONCLUSION:
The results indicate that the action of isoproterenol is different in the presence of organic and inorganic Ca(2+) channel blockers. CoCl(2) and MnCl(2) were able to fully prevent the effect of isoproterenol on Ca(2+) current, while the organic Ca(2+) channel blockers failed to do so. This has to be born in mind when the effects of organic Ca(2+) channel blockers are evaluated either experimentally or clinically under conditions of increased sympathetic tone.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Bloqueadores dos Canais de Cálcio
/
Canais de Cálcio Tipo L
/
Miócitos Cardíacos
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Ventrículos do Coração
/
Isoproterenol
Limite:
Animals
Idioma:
En
Revista:
Acta Physiol (Oxf)
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Hungria