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| Farah,V.M.A.; Moreira,E.D.; Ushizima,M.; Cestari,I.A.; Irigoyen,M.C.; Krieger,E.M.. |
| 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%), 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% and ~65%, respectively)... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Baroreflex sensitivity; Losartan; Angiotensin II; Renal hypertension. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000001200014 |
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| Farah,V.M.A.; Moreira,E.D.; Pires,M.D.; Irigoyen,M.C.C.; Krieger,E.M.. |
| Baroreflex sensitivity was studied in the same group of conscious rats using vasoactive drugs (phenylephrine and sodium nitroprusside) administered by three different approaches: 1) bolus injection, 2) steady-state (blood pressure (BP) changes produced in steps), 3) ramp infusion (30 s, brief infusion). The heart rate (HR) responses were evaluated by the mean index (mean ratio of all HR changes and mean arterial pressure (MAP) changes), by linear regression and by the logistic method (maximum gain of the sigmoid curve by a logistic function). The experiments were performed on three consecutive days. Basal MAP and resting HR were similar on all days of the study. Bradycardic responses evaluated by the mean index (-1.5 ± 0.2, -2.1 ± 0.2 and -1.6 ± 0.2... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Baroreflex; Baroreceptor; Bradycardia; Tachycardia. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999000300018 |
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| Fernandes,T.L.; Piratello,A.C.; Farah,V.; Fiorino,P.; Moreira,E.D.; Irigoyen,M.C.; Krieger,E.M.. |
| We determined the sympathetic and parasympathetic control of heart rate (HR) and the sensitivity of the cardiopulmonary receptors after selective carotid and aortic denervation. We also investigated the participation of the autonomic nervous system in the Bezold-Jarish reflex after selective removal of aortic and carotid baroreceptors. Male Wistar rats (220-270 g) were divided into three groups: control (CG, N = 8), aortic denervation (AG, N = 5) and carotid denervation (CAG, N = 9). AG animals presented increased arterial pressure (12%) and HR (11%) compared with CG, while CAG animals presented a reduction in arterial pressure (16%) and unchanged HR compared with CG. The sequential blockade of autonomic effects by atropine and propranolol indicated a... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Carotid denervation; Aortic denervation; Bezold-Jarish reflex. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010000700011 |
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