Stimulation of Myocardial Na+-Independent Cl−-HCO3− Exchanger by Angiotensin II Is Mediated by Endogenous Endothelin
Experiments were performed in isolated cat papillary muscles loaded with the pH-sensitive dye 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein in the esterified form to study the effect of endothelin-1 (ET-1) on the activity of the Na<sup>+</sup>-independent Cl<sup>−</sup>-H...
| Autores principales: | , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2000
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/132989 |
| Aporte de: |
| id |
I19-R120-10915-132989 |
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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 |
Medicina papillary muscles anion exchanger activity |
| spellingShingle |
Medicina papillary muscles anion exchanger activity Camilión de Hurtado, María Cristina Álvarez, Bernardo Víctor Ennis, Irene Lucía Cingolani, Horacio Eugenio Stimulation of Myocardial Na+-Independent Cl−-HCO3− Exchanger by Angiotensin II Is Mediated by Endogenous Endothelin |
| topic_facet |
Medicina papillary muscles anion exchanger activity |
| description |
Experiments were performed in isolated cat papillary muscles loaded with the pH-sensitive dye 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein in the esterified form to study the effect of endothelin-1 (ET-1) on the activity of the Na<sup>+</sup>-independent Cl<sup>−</sup>-HCO<sub>3</sub><sup>−</sup> exchanger. Exposure to ET-1 (10 nmol/L) raised pH<sub>i</sub> by 0.13±0.03 U (<i>P</i><0.05) in papillary muscles superfused with nominally HCO<sub>3</sub><sup>−</sup>-free solution, whereas no significant change was detected under CO<sub>2</sub>/HCO<sub>3</sub><sup>−</sup>-buffered medium. However, if ET-1 was applied to muscles pretreated with the anion exchanger inhibitor 4-acetamido-4′-isothiocyanato-stilbene-2,2′-disulfonic acid, pH<sub>i</sub> increased by 0.09±0.02 U (<i>P</i><0.05) in the presence of CO<sub>2</sub>/HCO<sub>3</sub><sup>−</sup> buffer. The rate of pH<sub>i</sub> recovery from trimethylamine hydrochloride–induced intracellular alkaline load was enhanced so that net HCO<sub>3</sub> efflux increased about three times in the presence of ET-1 (2.74±0.25 versus 9.66±1.29 mmol · L<sup>−1</sup> · min<sup>−1</sup> at pH<sub>i</sub> 7.55, <i>P</i><0.05). This effect was canceled by previous exposure to either 50 nmol/L PD 142,893 (nonselective endothelin receptor blocker) or 300 nmol/L BQ 123 (selective blocker of ET<sub>A</sub> receptors). BQ 123 also abolished angiotensin II–induced activation of the Na<sup>+</sup> independent Cl<sup>−</sup>-HCO<sub>3</sub><sup>−</sup> exchanger. These results show that ET-1 increases the activity of the Na<sup>+</sup>-independent Cl<sup>−</sup>-HCO<sub>3</sub><sup>−</sup> exchanger in cardiac tissue through the ET<sub>A</sub> receptors. Furthermore, our data suggest that the previously described angiotensin II–induced stimulation of the anion exchanger activity is mediated by endogenous ET-1. |
| format |
Articulo Articulo |
| author |
Camilión de Hurtado, María Cristina Álvarez, Bernardo Víctor Ennis, Irene Lucía Cingolani, Horacio Eugenio |
| author_facet |
Camilión de Hurtado, María Cristina Álvarez, Bernardo Víctor Ennis, Irene Lucía Cingolani, Horacio Eugenio |
| author_sort |
Camilión de Hurtado, María Cristina |
| title |
Stimulation of Myocardial Na+-Independent Cl−-HCO3− Exchanger by Angiotensin II Is Mediated by Endogenous Endothelin |
| title_short |
Stimulation of Myocardial Na+-Independent Cl−-HCO3− Exchanger by Angiotensin II Is Mediated by Endogenous Endothelin |
| title_full |
Stimulation of Myocardial Na+-Independent Cl−-HCO3− Exchanger by Angiotensin II Is Mediated by Endogenous Endothelin |
| title_fullStr |
Stimulation of Myocardial Na+-Independent Cl−-HCO3− Exchanger by Angiotensin II Is Mediated by Endogenous Endothelin |
| title_full_unstemmed |
Stimulation of Myocardial Na+-Independent Cl−-HCO3− Exchanger by Angiotensin II Is Mediated by Endogenous Endothelin |
| title_sort |
stimulation of myocardial na+-independent cl−-hco3− exchanger by angiotensin ii is mediated by endogenous endothelin |
| publishDate |
2000 |
| url |
http://sedici.unlp.edu.ar/handle/10915/132989 |
| work_keys_str_mv |
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Repositorios |
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