| ANP potentiates nonarterial baroreflex bradycardia: evidence from sinoaortic denervation in rats. | |
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MedLine Citation:
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PMID: 12132649 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Previous findings indicate that atrial natriuretic peptide (ANP) enhances the reflex bradycardia arising from stimulation of cardiac mechanoreceptors and chemoreceptors, but not that from arterial baroreceptors. The present study tests this proposal by examining the effect of ANP on these reflexes in six chronically sinoaortic-denervated (SAD), and eight sham-operated (sham), conscious rats. Arterial baroreceptor-heart rate (HR) reflex function was examined by constructing full-range steady-state blood pressure (BP)-HR curves using alternating doses of pressor (methoxamine, 2-100 microg/kg) and depressor (nitroprusside, 1-50 microg/kg) agents. Nonarterial baroreceptor reflex function was assessed by the 'ramp' bradycardic response to the rapid BP rise after i.v. methoxamine (100 microg/kg bolus dose). The cardiopulmonary chemoreflex was evoked by i.v. injections of serotonin (1-20 microg/kg). These three tests were performed on each rat during infusions, in random order, of rat ANP (150 ng/kg/min i.v.) and saline vehicle. The ability of ANP to significantly enhance ramp reflex bradycardia was not diminished in SAD compared with sham rats (+54 +/- 12% vs. +42 +/- 15%, respectively). ANP also significantly enhanced cardiopulmonary chemoreflex bradycardia in both groups (+60 +/- 15% in SAD, +40 +/- 8% in sham). Neither the normal steady-state BP-HR response in sham rats nor the small residual response in SAD rats was enhanced by ANP (-1 +/- 7% in sham, -11 +/- 8% in SAD). We conclude that ANP enhances reflex bradycardias of nonarterial, probably cardiac mechanoreceptor, origin. |
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Authors:
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Colleen J Thomas; Andrew M Allen; Robin M McAllen; Robyn L Woods |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Autonomic neuroscience : basic & clinical Volume: 97 ISSN: 1566-0702 ISO Abbreviation: Auton Neurosci Publication Date: 2002 May |
Date Detail:
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Created Date: 2002-07-22 Completed Date: 2003-01-13 Revised Date: 2009-08-12 |
Medline Journal Info:
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Nlm Unique ID: 100909359 Medline TA: Auton Neurosci Country: Netherlands |
Other Details:
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Languages: eng Pagination: 89-98 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Atrial Natriuretic Factor / pharmacology* Baroreflex / drug effects* Blood Pressure / drug effects Bradycardia / chemically induced, physiopathology* Denervation Drug Synergism Heart Rate / drug effects Male Methoxamine / pharmacology Nitroprusside / pharmacology Rats Rats, Wistar Sinoatrial Node / innervation Sympathomimetics / pharmacology Vasodilator Agents / pharmacology |
| Chemical | |
Reg. No./Substance:
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0/Sympathomimetics; 0/Vasodilator Agents; 15078-28-1/Nitroprusside; 390-28-3/Methoxamine; 85637-73-6/Atrial Natriuretic Factor |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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