Abstract | OBJECTIVE: Several studies suggest the importance of the interaction between the renin angiotensin and sympathetic nervous systems in blood pressure control, especially in clinical situations such as the metabolic syndrome. Previously, we have demonstrated changes in noradrenergic hypothalamic control of blood pressure in an animal model of insulin resistance and hypertension. The aim of the present study was to evaluate the effects of the interaction between the noradrenergic and angiotensinergic systems on hypothalamic blood pressure regulation in fructose hypertensive rats. METHODS: RESULTS: Meanwhile irbesartan perfusion did not modify neither mean arterial pressure (MAP) nor heart rate or noradrenaline hypothalamic levels in the C group, its highest dose diminished MAP (DeltaMAP: F: - 16.3+/-1 mm Hg, p<0.05) and noradrenaline levels (% of basal levels: 58+/-7%, p<0.05) in the F group, without affecting heart rate. Intrahypothalamic perfusion of metoprolol diminished MAP only in the F group (DeltaMAP: F: -12.1+/-1.1 mm Hg, p<0.05), but did not modify heart rate in both groups. On the other hand, it diminished noradrenaline hypothalamic levels in C (% of basal levels: 53+/-6%, p<0.05) but not in the F group. The pressor response to angiotensin II microinjection was increased in F rats (DeltaMAP: F: 13.3+/-1.5 mm Hg vs. C: 6.9+/-1.8 mm Hg; p<0.05). Previous administration of metoprolol markedly abolished this increment. CONCLUSIONS:
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Authors | Marcos A Mayer, Christian Höcht, Mariela Gironacci, Javier A W Opezzo, Carlos A Taira, Belisario E Fernández, Ana M Puyó |
Journal | Regulatory peptides
(Regul Pept)
Vol. 146
Issue 1-3
Pg. 38-45
(Feb 07 2008)
ISSN: 0167-0115 [Print] Netherlands |
PMID | 17822786
(Publication Type: Journal Article)
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Chemical References |
- Antihypertensive Agents
- Biphenyl Compounds
- Receptors, Adrenergic
- Receptors, Angiotensin
- Tetrazoles
- Fructose
- Metoprolol
- Irbesartan
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Topics |
- Animals
- Antihypertensive Agents
(pharmacology)
- Biphenyl Compounds
(pharmacology)
- Fructose
(pharmacology)
- Hypertension
(chemically induced)
- Hypothalamus
(drug effects, physiology)
- Insulin Resistance
- Irbesartan
- Male
- Metoprolol
(pharmacology)
- Models, Animal
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic
(drug effects)
- Receptors, Angiotensin
(drug effects)
- Tetrazoles
(pharmacology)
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