Interaction between isoproterenol and dihydropyridines in heart cells.
The negative inotropic potencies (IC50) of the calcium channel blockers nicardipine (12 +/- 2 nM) and nifedipine (9 +/- 2 nM) measured in cultured chick embryo ventricular cells were not significantly different. Exposure of the cells to isoproterenol potentiated the negative inotropic effect of low concentrations of nicardipine (10(-9)-10(-8) M) and decreased the effect of higher concentrations (10(-7) M). In contrast, isoproterenol shifted the entire dose-response curve for nifedipine to the right. These results provide evidence that activation of beta-adrenoceptors modulates the negative inotropic effect of nifedipine and nicardipine differently.
Briand
V
V
Laboratoire de Pharmacologie Cardiovasculaire et Unité INSERM U228, Paris, France.
Laurent
S
S
Schmitt
H
H
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D004095:Dihydropyridines / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000166:cytology; D009529:Nicardipine / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D013997:Time Factors
D004095:Dihydropyridines; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009529:Nicardipine; D009543:Nifedipine; D007545:Isoproterenol