Factors underlying the variable inotropic effect of ouabain on isolated rat atria. Changes in contractile frequency and adrenergic mechanisms
The effects of concentrations of ouabain on the isometric developed tension (IDT) of isolated left auricles driven at 0·4, 0·8 and 3·3 Hz, were explored. With 0·4 or 0·8 Hz, increasing concentrations of ouabain (3·4 or 6·8 times 10−6; 1·0; 3·4 or 6·8 times 10−6M) elicited a decreasing enhancement of...
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1979
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223573_v31_n1_p545_GIMENO http://hdl.handle.net/20.500.12110/paper_00223573_v31_n1_p545_GIMENO |
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paper:paper_00223573_v31_n1_p545_GIMENO2023-06-08T14:50:02Z Factors underlying the variable inotropic effect of ouabain on isolated rat atria. Changes in contractile frequency and adrenergic mechanisms 3',4' dihydroxy 2 methylpropiophenone adrenergic receptor cocaine ouabain reserpine sotalol tyramine 3',4' dihydroxy o methylpropiophenone animal experiment catecholamine depletion drug response drug screening drug sensitivity heart heart atrium heart atrium contraction heart contraction in vitro study isometric tension rat Animal Catecholamines Cocaine Drug Interactions Heart Rate In Vitro Male Myocardial Contraction Ouabain Rats Reserpine Sotalol Sympathetic Nervous System Tyramine The effects of concentrations of ouabain on the isometric developed tension (IDT) of isolated left auricles driven at 0·4, 0·8 and 3·3 Hz, were explored. With 0·4 or 0·8 Hz, increasing concentrations of ouabain (3·4 or 6·8 times 10−6; 1·0; 3·4 or 6·8 times 10−6M) elicited a decreasing enhancement of atrial contractile peak tension, whereas with 3·3 Hz the effect was augmented with concentration. Ouabain (3·4 times 10−6 M) enhanced comparably the IDT at all the driving rates, but at higher concentrations the effect varied with the frequency. The positive inotropic action of ouabain at 3·4 times 10−6 M on preparations driven at faster frequencies was antagonized by Sotalol (MJ‐1999) and also after catecholamine depletion by in vivo reserpinization followed by addition of tyramine in vitro. Cocaine or U‐0521 significantly enhanced the positive inotropic effect of ouabain (3·4 times 10−5 M) in atria stimulated at low rates. On the contrary, Sotalol, cocaine, U‐0521 or catecholamine depletion did not alter the positive inotropic influence of ouabain at 3·4 times 10−6 M at any of the frequencies used. It is suggested that ouabain influenced contractile peak tension of rat isolated atria through two mechanisms: one, seen after higher concentrations, which appeared to be associated with adrenergic factors and dependent on the frequency of stimulation; the other, observable with the lower concentrations, which did not appear to have a direct relationship with adrenergic processes and which was independent of the frequency of stimulation. 1979 Royal Pharmaceutical Society of Great Britain 1979 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223573_v31_n1_p545_GIMENO http://hdl.handle.net/20.500.12110/paper_00223573_v31_n1_p545_GIMENO |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
3',4' dihydroxy 2 methylpropiophenone adrenergic receptor cocaine ouabain reserpine sotalol tyramine 3',4' dihydroxy o methylpropiophenone animal experiment catecholamine depletion drug response drug screening drug sensitivity heart heart atrium heart atrium contraction heart contraction in vitro study isometric tension rat Animal Catecholamines Cocaine Drug Interactions Heart Rate In Vitro Male Myocardial Contraction Ouabain Rats Reserpine Sotalol Sympathetic Nervous System Tyramine |
| spellingShingle |
3',4' dihydroxy 2 methylpropiophenone adrenergic receptor cocaine ouabain reserpine sotalol tyramine 3',4' dihydroxy o methylpropiophenone animal experiment catecholamine depletion drug response drug screening drug sensitivity heart heart atrium heart atrium contraction heart contraction in vitro study isometric tension rat Animal Catecholamines Cocaine Drug Interactions Heart Rate In Vitro Male Myocardial Contraction Ouabain Rats Reserpine Sotalol Sympathetic Nervous System Tyramine Factors underlying the variable inotropic effect of ouabain on isolated rat atria. Changes in contractile frequency and adrenergic mechanisms |
| topic_facet |
3',4' dihydroxy 2 methylpropiophenone adrenergic receptor cocaine ouabain reserpine sotalol tyramine 3',4' dihydroxy o methylpropiophenone animal experiment catecholamine depletion drug response drug screening drug sensitivity heart heart atrium heart atrium contraction heart contraction in vitro study isometric tension rat Animal Catecholamines Cocaine Drug Interactions Heart Rate In Vitro Male Myocardial Contraction Ouabain Rats Reserpine Sotalol Sympathetic Nervous System Tyramine |
| description |
The effects of concentrations of ouabain on the isometric developed tension (IDT) of isolated left auricles driven at 0·4, 0·8 and 3·3 Hz, were explored. With 0·4 or 0·8 Hz, increasing concentrations of ouabain (3·4 or 6·8 times 10−6; 1·0; 3·4 or 6·8 times 10−6M) elicited a decreasing enhancement of atrial contractile peak tension, whereas with 3·3 Hz the effect was augmented with concentration. Ouabain (3·4 times 10−6 M) enhanced comparably the IDT at all the driving rates, but at higher concentrations the effect varied with the frequency. The positive inotropic action of ouabain at 3·4 times 10−6 M on preparations driven at faster frequencies was antagonized by Sotalol (MJ‐1999) and also after catecholamine depletion by in vivo reserpinization followed by addition of tyramine in vitro. Cocaine or U‐0521 significantly enhanced the positive inotropic effect of ouabain (3·4 times 10−5 M) in atria stimulated at low rates. On the contrary, Sotalol, cocaine, U‐0521 or catecholamine depletion did not alter the positive inotropic influence of ouabain at 3·4 times 10−6 M at any of the frequencies used. It is suggested that ouabain influenced contractile peak tension of rat isolated atria through two mechanisms: one, seen after higher concentrations, which appeared to be associated with adrenergic factors and dependent on the frequency of stimulation; the other, observable with the lower concentrations, which did not appear to have a direct relationship with adrenergic processes and which was independent of the frequency of stimulation. 1979 Royal Pharmaceutical Society of Great Britain |
| title |
Factors underlying the variable inotropic effect of ouabain on isolated rat atria. Changes in contractile frequency and adrenergic mechanisms |
| title_short |
Factors underlying the variable inotropic effect of ouabain on isolated rat atria. Changes in contractile frequency and adrenergic mechanisms |
| title_full |
Factors underlying the variable inotropic effect of ouabain on isolated rat atria. Changes in contractile frequency and adrenergic mechanisms |
| title_fullStr |
Factors underlying the variable inotropic effect of ouabain on isolated rat atria. Changes in contractile frequency and adrenergic mechanisms |
| title_full_unstemmed |
Factors underlying the variable inotropic effect of ouabain on isolated rat atria. Changes in contractile frequency and adrenergic mechanisms |
| title_sort |
factors underlying the variable inotropic effect of ouabain on isolated rat atria. changes in contractile frequency and adrenergic mechanisms |
| publishDate |
1979 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223573_v31_n1_p545_GIMENO http://hdl.handle.net/20.500.12110/paper_00223573_v31_n1_p545_GIMENO |
| _version_ |
1768546147312336896 |