| Nitric oxide reduces vagal baroreflex sensitivity in the late gestation fetus. | |
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MedLine Citation:
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PMID: 19391249 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Goals to understand the etiology of essential hypertension have proposed that this problem arises, in part, because of changes within brainstem circuits involved in arterial blood pressure (ABP) control. It has been suggested that nitric oxide (NO) exerts inhibitory influences on the integration of afferent discharge from the arterial baroreceptors. This study tested the hypothesis that the inhibitory influence of NO on the arterial baroreflex is present in fetal life. Fetal baroreflex sensitivity was calculated in fetal sheep, before and during the NO-clamp; a technique that permits NO synthase (NOS) blockade with l-NAME while maintaining basal cardiovascular function with sodium nitroprusside. Under halothane anesthesia, five fetal sheep at 0.8 gestation were instrumented with vascular catheters. Five days later, fetuses received a range of bolus doses of phenylephrine (5-75 microg I.A.) in randomized order either during saline or treatment with the NO clamp. Basal fetal ABP and heart rate before (50 +/- 4 mm Hg, 170 +/- 3 bpm) or during (51 +/- 4 mm Hg, 173 +/- 3 bpm) the NO-clamp were similar. The gradient of the pulse interval-ABP relationship was nearly doubled during NOS blockade (14.2 =/- 2.5 versus 7.8 +/- 1.6 ms/mm Hg). The data provide in vivo evidence that NO attenuates the sensitivity of the cardiac baroreflex during fetal life. |
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Authors:
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Avnesh S Thakor; Dino A Giussani |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Pediatric research Volume: 65 ISSN: 1530-0447 ISO Abbreviation: Pediatr. Res. Publication Date: 2009 Mar |
Date Detail:
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Created Date: 2009-04-23 Completed Date: 2009-06-16 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0100714 Medline TA: Pediatr Res Country: United States |
Other Details:
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Languages: eng Pagination: 269-73 Citation Subset: IM |
Affiliation:
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Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, United Kingdom. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Age Factors Animals Baroreflex / drug effects, physiology* Blood Chemical Analysis Blood Pressure / drug effects Fetus / physiology* NG-Nitroarginine Methyl Ester / pharmacology Nitric Oxide / metabolism* Nitric Oxide Synthase / antagonists & inhibitors Phenylephrine / administration & dosage, pharmacology Sheep Vagus Nerve / physiology |
| Chemical | |
Reg. No./Substance:
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10102-43-9/Nitric Oxide; 50903-99-6/NG-Nitroarginine Methyl Ester; 59-42-7/Phenylephrine; EC 1.14.13.39/Nitric Oxide Synthase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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