Acute AT1 receptor blockade does not improve the depressed baroreflex in rats with chronic renal hypertension
Braz. j. med. biol. res
;
33(12): 1491-6, Dec. 2000. graf
Artigo
em Inglês
| LILACS
| ID: lil-274894
ABSTRACT
To assess the role of angiotensin II in the sensitivity of the baroreflex control of heart rate (HR) in normotensive rats (N = 6) and chronically hypertensive rats (1K1C, 2 months, N = 7), reflex changes of HR were evaluated before and after (15 min) the administration of a selective angiotensin II receptor antagonist (losartan, 10 mg/kg, iv). Baseline values of mean arterial pressure (MAP) were higher in hypertensive rats (195 ± 6 mmHg) than in normotensive rats (110 ± 2 mmHg). Losartan administration promoted a decrease in MAP only in hypertensive rats (16 percent), with no changes in HR. During the control period, the sensitivity of the bradycardic and tachycardic responses to acute MAP changes were depressed in hypertensive rats (~70 percent and ~65 percent, respectively) and remained unchanged after losartan administration. Plasma renin activity was similar in the two groups. The present study demonstrates that acute blockade of AT1 receptors with losartan lowers the MAP in chronic renal hypertensive rats without reversal of baroreflex hyposensitivity, suggesting that the impairment of baroreflex control of HR is not dependent on an increased angiotensin II level
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Angiotensina II
/
Barorreflexo
/
Losartan
/
Frequência Cardíaca
/
Hipertensão Renal
/
Anti-Hipertensivos
Limite:
Animais
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
2000
Tipo de documento:
Artigo
País de afiliação:
Brasil
Instituição/País de afiliação:
Universidade de São Paulo/BR
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