Paradoxical mineralocorticoid receptor activation and left ventricular diastolic dysfunction under high oxidative stress conditions.
J Hypertens
; 26(7): 1453-62, 2008 Jul.
Article
en En
| MEDLINE
| ID: mdl-18551023
ABSTRACT
BACKGROUND:
Salt status plays a pivotal role in angiotensin-II-induced organ damage by regulating reactive oxygen species status, and it is reported that reactive oxygen species activate mineralocorticoid receptors.METHOD:
To clarify the role of reactive oxygen species-related mineralocorticoid receptor activation in angiotensin-II-induced cardiac dysfunction, we examined the effect of the following salt status; an MR antagonist, eplerenone; and an antioxidant, tempol in angiotensin-II-loaded Sprague-Dawley rats.RESULTS:
Angiotensin-II/salt-loading elevated blood pressure, and neither eplerenone nor tempol antagonized the rise in blood pressure significantly. Left ventricular diastolic function was monitored by measuring peak velocity of a mitral early inflow (E), the ratio of mitral early inflow to atrial contraction related flow (E/A), deceleration time of mitral early inflow and -dP/dt, the time constant (T), and filling pressure (left ventricular end-diastolic pressure) by echocardiography or cardiac catheterization. Despite the suppressed serum aldosterone, left ventricular diastolic function was deteriorated with angiotensin II/high salt, but not affected by angiotensin II/low salt. However, angiotensin-II/salt-induced cardiac dysfunction was restored by eplerenone and tempol. Nicotinamide adenine dinucleotide phosphateoxidase-derived superoxide formation was greater in the hearts of the angiotensin II/high-salt rats than of the angiotensin II/low-salt rats. The expression of the Na(+) -H(+) exchanger isoform 1, a target of mineralocorticoid receptor activation, was significantly increased in the angiotensin II/high-salt group. Both tempol and eplerenone inhibited the angiotensin-II/salt-induced upregulation of Na(+) -H(+) exchanger isoform 1.CONCLUSION:
These findings demonstrate that mineralocorticoid receptor activation by oxidative stress can cause left ventricular diastolic dysfunction in a rat model of mild hypertension.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Vasoconstrictores
/
Angiotensina II
/
Receptores de Mineralocorticoides
/
Disfunción Ventricular Izquierda
/
Estrés Oxidativo
Tipo de estudio:
Etiology_studies
/
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
J Hypertens
Año:
2008
Tipo del documento:
Article
País de afiliación:
Japón