Abstract
Microiontophoretic application of both, the octapeptide angiotensin II (Ang II) and its N-terminal heptapeptide angiotensin-(1-7), [Ang-(1-7)], has been shown to increase the firing rate of rat hypothalamic paraventricular neurones. In the present microiontophoretic study, the effect of the angiotensin analogue [7-D-Ala]-Ang-(1-7) on Ang II- and Ang-(1-7)-induced firing rate increase of paraventricular neurones has been tested. While the response to Ang II was unchanged, the response to Ang-(1-7) was effectively blocked by [7-D-Ala]-Ang-(1-7). The results indicate that the Ang-(1-7)-induced excitation of paraventricular neurones may be mediated by a distinct Ang-(1-7)-receptor and that [7-D-Ala]-Ang-(1-7) is a selective antagonist of this receptor.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Action Potentials / drug effects
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Angiotensin I
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Angiotensin II / analogs & derivatives*
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Angiotensin II / antagonists & inhibitors*
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Angiotensin II / metabolism
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Angiotensin II / pharmacology
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Angiotensin Receptor Antagonists*
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Animals
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Male
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Neurons / drug effects*
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Neurons / physiology
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Paraventricular Hypothalamic Nucleus / cytology
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Paraventricular Hypothalamic Nucleus / drug effects*
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Paraventricular Hypothalamic Nucleus / physiology
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Peptide Fragments / antagonists & inhibitors*
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Peptide Fragments / metabolism
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Peptide Fragments / pharmacology*
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Rats
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Rats, Sprague-Dawley
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Receptors, Angiotensin / metabolism
Substances
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7-Ala-angiotensin (1-7)
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Angiotensin Receptor Antagonists
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Peptide Fragments
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Receptors, Angiotensin
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Angiotensin II
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Angiotensin I
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angiotensin I (1-7)