Lusitropic effects of α- and β-adrenergic stimulation in amphibian heart
The effects ofl 3 and ct-adrenergic stimulation in amphibian superfused hearts and ventricular strips were studied. Superfusion with 3 • 10 .8 M isoproterenol produced a positive inotropic effect, as detected by a 92 + 24% increase in the maximal rate of contraction (+T) and a positive lusitropic ef...
| Autores principales: | , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
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1994
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/146933 |
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I19-R120-10915-146933 |
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| record_format |
dspace |
| institution |
Universidad Nacional de La Plata |
| institution_str |
I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Médicas amphibian myocardial relaxation α and β-adrenergic stimulation Ca2+ myofibrillar sensitivity protein phosphorylation |
| spellingShingle |
Ciencias Médicas amphibian myocardial relaxation α and β-adrenergic stimulation Ca2+ myofibrillar sensitivity protein phosphorylation Vila Petroff, Martín Gerardo Mundiña-Weilenmann, Cecilia Vittone, Leticia Beatriz Chiappe de Cingolani, Gladys Ethel Mattiazzi, Alicia Ramona Lusitropic effects of α- and β-adrenergic stimulation in amphibian heart |
| topic_facet |
Ciencias Médicas amphibian myocardial relaxation α and β-adrenergic stimulation Ca2+ myofibrillar sensitivity protein phosphorylation |
| description |
The effects ofl 3 and ct-adrenergic stimulation in amphibian superfused hearts and ventricular strips were studied. Superfusion with 3 • 10 .8 M isoproterenol produced a positive inotropic effect, as detected by a 92 + 24% increase in the maximal rate of contraction (+T) and a positive lusitropic effect characterized by a decrease in both the ratio +'F/-i" (23 + 5%) and the half relaxation time (tt/2) (19 + 4%). The mechanical behavior induced by the [3-agonist was associated with an increase in the intracellular cAMP levels from control values of 173 + 19 to 329 + 28 nmol/mg wet tissue. Hearts superfused with 32p in the presence of isoproterenol showed a significant increase in Tn 1 phosphorylation (from 151 + 13 to 240 + 44 pmo132p/mg MF protein) without consistent changes in phosphorylation of C-protein. In sarcoplasmic reticulum membrane vesicles, no phospholamban phosphorylation was detected either by [3-adrenergic stimulation of superfused hearts or when phosphorylation conditions were optimized by direct treatment of the vesicles with cAMP-dependent protein kinase (PKA) and [y 32p] ATE The effect ofct-adrenergic stimulation on ventricular strips was studied at 30 and 22~ At 30~ the effects of 10 5 to 104M phenylephrine on myocardial contraction and relaxation were diminished to non significant levels by addition of propranolol. At 22~ blockage with propranolol left a remanent positive inotropic effect (10% of the total effect ofphenylephrine) and changed the phenylephrine-induced positive lusitropic effect into a negative lusitropic action. These propranolol-resistant effects were abolished by prazosin. Our results suggest that in amphibian heart, both the inotropic and lusitropic responses to catecholamines are mainly due to a [3-adrenergic stimulation which predominates over the ct-adrenergic response. Phospholamban phosphorylation seems not to be involved in mediating the positive lusitropic effect of [3-adrenergic agents whereas phosphorylation oftroponin I may play a critical role. (Mol Cell Biochem 141: 87-95, 1994). |
| format |
Articulo Articulo |
| author |
Vila Petroff, Martín Gerardo Mundiña-Weilenmann, Cecilia Vittone, Leticia Beatriz Chiappe de Cingolani, Gladys Ethel Mattiazzi, Alicia Ramona |
| author_facet |
Vila Petroff, Martín Gerardo Mundiña-Weilenmann, Cecilia Vittone, Leticia Beatriz Chiappe de Cingolani, Gladys Ethel Mattiazzi, Alicia Ramona |
| author_sort |
Vila Petroff, Martín Gerardo |
| title |
Lusitropic effects of α- and β-adrenergic stimulation in amphibian heart |
| title_short |
Lusitropic effects of α- and β-adrenergic stimulation in amphibian heart |
| title_full |
Lusitropic effects of α- and β-adrenergic stimulation in amphibian heart |
| title_fullStr |
Lusitropic effects of α- and β-adrenergic stimulation in amphibian heart |
| title_full_unstemmed |
Lusitropic effects of α- and β-adrenergic stimulation in amphibian heart |
| title_sort |
lusitropic effects of α- and β-adrenergic stimulation in amphibian heart |
| publishDate |
1994 |
| url |
http://sedici.unlp.edu.ar/handle/10915/146933 |
| work_keys_str_mv |
AT vilapetroffmartingerardo lusitropiceffectsofaandbadrenergicstimulationinamphibianheart AT mundinaweilenmanncecilia lusitropiceffectsofaandbadrenergicstimulationinamphibianheart AT vittoneleticiabeatriz lusitropiceffectsofaandbadrenergicstimulationinamphibianheart AT chiappedecingolanigladysethel lusitropiceffectsofaandbadrenergicstimulationinamphibianheart AT mattiazzialiciaramona lusitropiceffectsofaandbadrenergicstimulationinamphibianheart |
| bdutipo_str |
Repositorios |
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1764820460608946178 |