Interaction between calcium and slow channel blocking drugs on atrial rate

The relationship between extracellular calcium concentration and the chronotropic effect of prenylamine, verapamil and nifedipine was studied in isolated spontaneously beating rat atria. The three slow channel blocking drugs produced a concentration-dependent decrease in atrial rate, though with dif...

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Autores principales: Camilión de Hurtado, María Cristina, Cingolani, Horacio Eugenio
Formato: Articulo
Lenguaje:Inglés
Publicado: 1983
Materias:
Medicina
Calcium
Slow channel blockers
Atrial rate
Verapamil
Nifedipine
Prenylamine
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/138733
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-138733
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Medicina
Calcium
Slow channel blockers
Atrial rate
Verapamil
Nifedipine
Prenylamine
spellingShingle Medicina
Calcium
Slow channel blockers
Atrial rate
Verapamil
Nifedipine
Prenylamine
Camilión de Hurtado, María Cristina
Cingolani, Horacio Eugenio
Interaction between calcium and slow channel blocking drugs on atrial rate
topic_facet Medicina
Calcium
Slow channel blockers
Atrial rate
Verapamil
Nifedipine
Prenylamine
description The relationship between extracellular calcium concentration and the chronotropic effect of prenylamine, verapamil and nifedipine was studied in isolated spontaneously beating rat atria. The three slow channel blocking drugs produced a concentration-dependent decrease in atrial rate, though with different relative potencies. The order of potency for decreasing atrial rate, independently of the calcium level (1.0, 3.0, 6.0 or 9.0 mmol/l) was: verapamil > nifedipine > prenylamine. Increasing calcium from 1.0 to 6.0 and 9.0 mmol/l increased atrial rate from 251±beats·min−1 to 265±6 beats·min−1 and 285±9 beats·min−1 (mean±1 standard error) respectively (P<0.05). Despite their positive chronotropic effect high calcium levels failed to reverse the negative chronotropic effect of the slow channel blockers. Furthermore, the negative chronotropic effect of both verapamil and nifedipine was enhanced at high calcium levles. Raising calcium from 1.0 to 6.0 mmol/l in the presence of verapamil (1×10−7 mol/l) or nifedipine (3×10−7 mol/l) increased 2-fold the negative chronotropic effect of the calcium channel blockers. In addition, the concentration-effect curves for verapamil and nifedipine shifted to the left by 0.50±0.14 and 0.50±0.16 log units, respectively, when calcium increased from 1.0 to 6.0 mmol/l.
format Articulo
Articulo
author Camilión de Hurtado, María Cristina
Cingolani, Horacio Eugenio
author_facet Camilión de Hurtado, María Cristina
Cingolani, Horacio Eugenio
author_sort Camilión de Hurtado, María Cristina
title Interaction between calcium and slow channel blocking drugs on atrial rate
title_short Interaction between calcium and slow channel blocking drugs on atrial rate
title_full Interaction between calcium and slow channel blocking drugs on atrial rate
title_fullStr Interaction between calcium and slow channel blocking drugs on atrial rate
title_full_unstemmed Interaction between calcium and slow channel blocking drugs on atrial rate
title_sort interaction between calcium and slow channel blocking drugs on atrial rate
publishDate 1983
url http://sedici.unlp.edu.ar/handle/10915/138733
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bdutipo_str Repositorios
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