| Influence of age on arterial baroreflex inhibition of sympathetic nerve activity in healthy adult humans. | |
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MedLine Citation:
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PMID: 9815084 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Resting levels of muscle sympathetic nerve activity (MSNA) increase markedly with age in healthy adult humans. An age-related reduction in arterial baroreflex inhibition of MSNA could contribute to these elevations. To test this hypothesis, we measured MSNA using peroneal microneurography in young (age, 25 +/- 1 yr; n = 8) and older (69 +/- 1 yr; n = 7) healthy normotensive men before (baseline control) and during graded constant infusion of phenylephrine hydrochloride (0.5-2.0 microgram . kg-1. min-1) that produced a sustained approximately 10-mmHg increase in arterial blood pressure. Central venous pressure was controlled at baseline levels (+/-1 mmHg) using lower body negative pressure. Resting MSNA was approximately 95% higher in the older compared with the young subjects (43 +/- 5 vs. 22 +/- 3 bursts/min; P < 0.05). However, arterial baroreflex MSNA inhibitory responsiveness was similar in the older compared with the young subjects (254 +/- 112 vs. 259 +/- 40 arbitrary integration units/mmHg, respectively), although the percent reduction in MSNA was smaller in the older men (8.9 +/- 0.7 vs. 5.2 +/- 1.1%/mmHg), due to their elevated baseline levels. The reflex increase in the R-R interval was not different in the two groups (13 +/- 10 vs. 16 +/- 7 ms/mmHg). In summary, our findings suggest that arterial baroreflex inhibition of MSNA is preserved with age in healthy normotensive adult humans. As such, this mechanism does not appear to contribute to the age-related rise in tonic MSNA. |
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Authors:
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K P Davy; H Tanaka; E A Andros; J G Gerber; D R Seals |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The American journal of physiology Volume: 275 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1998 Nov |
Date Detail:
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Created Date: 1998-12-10 Completed Date: 1998-12-10 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: H1768-72 Citation Subset: IM |
Affiliation:
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Human Cardiovascular Research Laboratory, Center for Physical Activity, Disease Prevention, and Aging, Department of Kinesiology and Applied Physiology, University of Colorado at Boulder, Boulder, Colorado 80309, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Aged Aging / physiology* Arteries / innervation*, physiology* Baroreflex / physiology* Heart Rate / physiology Humans Male Middle Aged Sympathetic Nervous System / physiology* |
| Grant Support | |
ID/Acronym/Agency:
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AG-06537/AG/NIA NIH HHS; AG-13038/AG/NIA NIH HHS; HL-39966/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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