Abstract
In this study we explored the possibility that angiotensin-(1-7) (Ang-(1-7)) is involved in the control of blood pressure at the rostral ventrolateral medulla (RVLM) by determining the effect of angiotensin antagonists (DuP 753 and A-779) and the effect of the angiotensin converting enzyme inhibitor, ramiprilat on the pressor action produced by angiotensin I (Ang I). The pressor effect produced by bilateral microinjection of Ang I into the RVLM of anesthetized rats was not significantly altered by DuP 753 or by the ACE inhibitor ramiprilat. Conversely, the Ang-(1-7) antagonist, A-779, reduced significantly the pressor effect produced by Ang I. These data suggest that in our experimental condition Ang I was preferentially converted to Ang-(1-7) at RVLM, or that Ang I and/or one of its fragments acts through a receptor blocked by A-779.
MeSH terms
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Angiotensin I / administration & dosage
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Angiotensin I / pharmacology*
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Angiotensin I / physiology
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Angiotensin II / analogs & derivatives
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Angiotensin II / pharmacology
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Angiotensin II / physiology
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Angiotensin Receptor Antagonists
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Angiotensin-Converting Enzyme Inhibitors / pharmacology
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Animals
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Biphenyl Compounds / pharmacology
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Blood Pressure / drug effects*
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Blood Pressure / physiology
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Imidazoles / pharmacology
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Losartan
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Male
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Medulla Oblongata / drug effects*
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Medulla Oblongata / physiology*
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Microinjections
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Peptide Fragments / pharmacology
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Peptide Fragments / physiology
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Ramipril / analogs & derivatives
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Ramipril / pharmacology
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Rats
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Rats, Wistar
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Receptors, Angiotensin / physiology
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Tetrazoles / pharmacology
Substances
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7-Ala-angiotensin (1-7)
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Angiotensin Receptor Antagonists
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Angiotensin-Converting Enzyme Inhibitors
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Biphenyl Compounds
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Imidazoles
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Peptide Fragments
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Receptors, Angiotensin
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Tetrazoles
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Angiotensin II
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ramiprilat
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Angiotensin I
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angiotensin I (1-7)
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Losartan
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Ramipril